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I created an HDR image, why can't I save it as JPEG? |
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An HDR image stores color information in 32-bit precision and as such can't be directly saved in a Low Dynamic Range format such as JPEG. |
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An HDR image in itself is not very interesting for photographers since it can't be correctly displayed on monitors and even less printed. This is why the HDR image you created from several exposures needs to be further processed for photographic use. It needs to be tone mapped so that the values of the image data fit into the limited range that your monitor can display. |
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Once you have applied the Tone Mapping tool to your HDR image, the details in highlight and shadows captured with your multiple exposures will then become visible on screen and you will be able to save the result as JPEG (or as 16-bit TIFF image if you choose this option). |
| ^ |
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My camera does not shoot RAWs. Can I still use your software with JPEG pictures? |
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Definitely. Photomatix does NOT require images in RAW format. Photomatix works with images taken under different exposure settings, and works great when those images are JPEGs as well. |
| |
Most results shown on our example page have been produced from differently exposed jpegs, by the way. |
| |
So, the important feature to look at in a camera is Auto Exposure Bracketing (AEB): the ability to automatically take three or more exposures, preferably in two EV steps as detailed here. The higher the number of auto-bracketed frames, EV step and frame rate speed, the better it is for HDR processing. |
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| › |
What is the maximum file size that I can work with? |
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The file size to consider for Photomatix is the size expressed in number of pixels, i.e. width X height. Since Photomatix has to decompress the images for processing, the compression factor of the input images does not make any difference in the ability to process large files. |
| |
The maximum file size (in number of pixels) that you can process with Photomatix depends on the following:
| · |
the RAM your computer has |
| · |
the pixel depth of your images |
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the number of differently exposed images you are combining |
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the number of other memory-hungry applications opened on your computer |
| · |
the free space available on your hard drive |
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the processing mode (i.e. whether you are running Photomatix in batch mode or from the interface) |
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Additionally, it is important to note that there is an upper limit to the amount of RAM that is made available to applications like Photomatix. On Windows XP this limit is as low as 2 GB, regardless of your RAM (i.e. it will still be 2 GB via virtual memory if you computer has less than 2 GB RAM, but it won't be more than 2 GB if your computer has 4 GB RAM). |
| |
Then, memory fragmentation further limits the memory available to Photomatix, by making it impossible to allocate a contiguous block of memory large enough to contain the whole images data. |
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When combining large source images, please use Batch Processing available from the Automate menu. |
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When you create a large HDR image file that you want to tone map in Photomatix, then you will have to save the HDR image in the Radiance format (.hdr extension) to avoid out-of-memory issues.
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For an idea of the memory necessary to process your images, the following formulae give a rough estimate of the amount of memory needed (in bytes) |
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For the method "Highlights & Shadows - Auto" with Batch Processing:
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width * height * 3 * (bit-depth/8) * (numberOfImages + 1) |
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For the method "Highlights & Shadows - Adjust" (in Photomatix Pro version 3.0) with Batch Processing:
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width * height * 3 * (bit-depth/8) * (numberOfImages + 1) |
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For Tone Mapping with Details Enhancer an HDR image file opened in preview mode or using Single File Conversion (option "360° image" unchecked):
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For three 8,000 x 4,000 images with 8 bits per color channel, this will give approximately:
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32,000,000 * 3 * (3 + 1) = 384 MB with "H&S - Adjust" |
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32,000,000 * 18 = 576 MB with Details Enhancer |
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For "Generate HDR", the amount of memory is roughly the same as for "H&S - Auto", which can be quite high when the source images are in 16 bits/channel mode and/or when there are many of them. |
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However, there is an option in Batch Processing that avoids memory limitation by creating the HDR image file one strip at a time, provided the source images are TIFF files. When this option is checked, Photomatix will only load, process and write a given number of rows from the source images instead of the entire images. This way, you can create an HDR image stored in Radiance (.hdr) format from any number of large source images, even on a computer with limited RAM.
|
| ^ |
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| › |
How does your software handle color profiles? |
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Photomatix processes the RGB values of your source images directly, without converting them to another color space. This means that the resulting images produced by Photomatix will be in the same color space as the one specified by the ICC color profile of your source images. |
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When a color profile for the source images is available, Photomatix embeds it into the resulting tone mapped or combined image. |
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Please note, though, that in the case of a tone mapped image, the color profile can only be passed through if the Generate HDR and Tone Mapping steps are done in the same session. If you have first saved the HDR image file, then the ICC profile information will be lost and the Tone Mapping step won't know the color profile anymore. This means that you will have to assign the color profile of the original source images to the tone mapped image yourself. |
| |
However, since version 3.0, Photomatix Pro saves the name of the color profile in the header of the HDR image file when this is saved as Radiance (.hdr extension). This means you will not have to re-assign the color profile, provided the HDR image file has been saved as Radiance and the color profile is either sRGB, Adobe RGB or ProPhoto RGB.
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Additionally, Photomatix Pro is color managed for the display as well. This means it will show the correct color values based on the ICC profile of the image and the color profile set as display profile for your monitor.
On Mac OS X, the display profile is set under System Preferences->Displays->Color.
On Windows, it is under Settings->Control Panel->Display->Settings->Advanced->Color Management.
|
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I can't get sharp results with your software! |
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Lack of sharpness on tone mapped HDR images is often due to the use of Shutter priority mode instead of the recommended Aperture priority mode when bracketing shots. |
| |
It it important to set your camera to Aperture priority when shooting with Automatic Exposure Bracketing. This way, only the shutter time will vary, and the Aperture will remain the same. If you set it to Shutter priority instead, the depth-of-field will change between the shots, and this will lead to inferior results on the combined image. Additionally, there may be vignetting issues too. |
| ^ |
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Are there ordering rules for loading the images? |
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No. You can load the images in any order, regardless of their Exposure Value. |
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Creating an HDR image requires to assign an exposure to each source image. Photomatix automatically retrieves the exposure information from EXIF data. When the images do not have EXIF data, Photomatix will let you enter the exposure values manually, or automatically estimate them when running in batch mode. |
| ^ |
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| › |
What are the differences between Exposure Blending and HDR/Tonemapping? |
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Both processes start from the same source files: differently exposed Low Dynamic Range (LDR) images. And both attempt to produce as final result an LDR image that shows tonal details of the entire dynamic range captured by the different exposures. |
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The differences are in the process itself. Exposure Blending consists in combining the differently exposed images in such a way that highlight details are taken from the underexposed photos and shadows details from the overexposed ones. Since the bit-depth does not change throughout this process, the basis of Exposure Blending algorithms is a type of weighted average of the source images. |
| |
One of the advantage or Exposure Blending is that it is easy to understand and you can see what you are doing. Also, it is rather familiar to photographers who are used to doing this process manually in image editing applications. Another advantage of Exposure Blending is that it reduces noise. |
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HDR Tone Mapping is composed of two steps. The first step creates an HDR image from differently exposed photos. This HDR image can not be displayed correctly on a Low Dynamic Range monitor, which is why a second step called Tone Mapping is necessary. Tone Mapping consists in scaling each pixel of the HDR image, so that details in highlights and shadows show correctly on monitors and prints (those details are available in the HDR image but not directly visible in both highlights and shadows because of the low dynamic range of the display). |
| |
Tone Mapping algorithms vary from a simple gamma curve (which is often what cameras are doing when converting 12-bit RAW data to 8-bit JPEGs) to more complex operators commonly divided into two categories:
| · |
Global operators: mapping depends on the pixels' intensity and global image characteristics, but not on spatial location |
| · |
Local operators: mapping takes into account the pixels' surroundings (in addition to intensity and image characteristics). |
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The main advantage of global operators is fast processing. Local operators require longer processing times but they are better at producing a "good-looking" photograph (the human eye adapts to contrast locally). In Photomatix Pro, the Tone Mapping method "Details Enhancer" belongs to the category of local operators and the method "Tone Compressor" to the category of global operators. |
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The pros and cons of Exposure Blending vs Tone Mapping in Photomatix Pro are detailed under the section below. |
| ^ |
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| › |
Does Photomatix make use of dual and quad processors? |
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The current version of Photomatix Pro does not offer multi-processsor support. This is because Photomatix is an intensive image processing application. For such application, the bottleneck regarding processing times comes from memory accesses and not from a high number of operations. This means that the processor has to stay idle for many cycles, waiting for data to be fetched in memory. Adding more processing power in this case will just waste even more cycles. |
| |
Multi-threading does nothing to alleviate the memory access bottleneck, and may even have a negative impact on processing times because of the overhead incurred. So, multi-processing support would barely make any difference in processing speed of the most time-intensive functions of Photomatix, especially tone mapping with the Details Enhancer method and the "H&S" exposure blending methods. The only thing that can effectively help reduce processing times for these methods is adding more RAM to the computer (because it increases caching capability).
|
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A future version of Photomatix will add multi-threading support for the processes that can take advantage of it: Generate HDR, Tone Mapping with Tone Compressor, and to some extent RAW conversion. In the meantime, you can take advantage of a dual processor by having Photomatix run on two separate processors simultaneously. For that, duplicate the application. Once you have one copy of Photomatix Pro running, then launch the other copy. The OS will most likely run the other one on the other processor in order to balance the processing load. This is handy, for instance, when you are running Batch Processing to combine multiple series of bracketed shots into HDR image files, and want at the same time to tone map the already created images using the Tone Mapping interface.
|
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Why do you recommend not calibrating digital cameras for HDRI? |
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The purpose of calibration is to recover the tonal response curve of a camera. Such a curve gives the relation between a pixel value outputted by the camera and the luminance (i.e. amount of light expressed in candelas/m^2) of this pixel. Since High Dynamic Range values represent the luminance of the scene, it is necessary to know the camera response curve in order to reconstruct an HDR image from photographs. |
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Films do have a response curve. Digital cameras, however, work differently. The response of digital cameras' sensors is mostly linear, which means the response curve of the sensors is simply a straight line and calibrating the cameras' sensors is not necessary. |
| |
Firmware of digital cameras pre-processes the raw output of those sensors with a non-linear conversion.
However, the tonal curve used for the in-camera raw conversion has little to do with fixed characteristics of the camera.
It is determined by software, not by hardware, and may even depend on the characteristics of the scene or
lighting conditions of the capture.
|
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This means there is no such thing as a specific response curve for a digital camera. Moreover, even for a given scene, there is no guarantee that the curve applied by the firmware to the sensor values will be the same for all exposures.
Another problem is that the camera firmware may decide to apply a varying multiplying factor to the sensor values of each image in an attempt to correct for under- or over-exposure. When this happens, the underlying assumptions of algorithms used to recover response curves are not valid anymore.
|
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This is why we recommend using the tone curve retrieved from the color profile of the source images instead of attempting to calculate a calibration curve. |
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If you need an accurate HDR image and are using a digital camera, then you should shoot in RAW mode. Then, either create the HDR image from your differently exposed RAWs directly, or convert the RAW files to TIFF or JPEG without tweaking the tone curve in the Raw converter. |
| ^ |
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| › |
How many images can I merge? |
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The blending method "Highlights & Shadows - 2 images" merges only two images. If you have loaded more than two images, Photomatix will let you select the images to process. | | |
For HDR generation and all other blending methods, you can merge as many images as you want. |
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When you have 3 or more bracketed shots and are using the "Exposure Blending" functions of Photomatix, we recommend that you also try to merge fewer images, eliminating for instance images that do not add much values (e.g. an underexposed image where even the highlights are too dark to provide interesting details). |
| ^ |
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| › |
Does Photomatix Pro work with Photoshop Elements? |
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Photomatix Pro is a stand-alone application, which means it does not need another imaging application to run. |
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Once you have tone mapped HDR images with Photomatix, the resulting images are compatible with any image editing software, i.e. you will be able to further process them in Photoshop Elements if you need to. |
| ^ |
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| › |
Do you plan to release a plug-in for Aperture? |
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We are considering developing a plug-in for Aperture, but have not yet decided when we will start working on it. |
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Our intention is to offer two types of Aperture plug-ins:
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An Export plug-in that enables to export from Aperture to Photomatix Pro. This plug-in will be free of charge. | |
| · |
An Edit plug-in that enables to generate an HDR image (but not save it as Aperture does not currently offer 32-bit support) and tone map it. This plug-in will be sold separately from Photomatix Pro. Our intention is to price it similarly to our current Photoshop plug-in, and offer it as a bundle with Photomatix Pro too. There will be an upgrade price to the bundle (probably around $20 for existing Photomatix Pro customers). | |
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Is there any chance you will release a Linux version of Photomatix? |
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We have no plans for releasing a Linux version of the software. |
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However, it is possible to run the Windows version of Photomatix Pro under Linux through Wine. |
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To run Photomatix Pro after version 3.0, you will need to install the .NET framework under Wine. The instructions to install Wine and the .NET framework under Fedora and Ubuntu are
detailed here. |
| ^ |
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Does Photomatix Pro work with XP 64-bit or Vista 64-bit? |
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Yes, Photomatix Pro works fine with the 64-bit edition of both Windows XP and Vista. However, the current version of Photomatix Pro does not yet take advantage of the 64-bit capability.
|
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Is Photomatix Pro compatible with Mac OS 10.5/Leopard? |
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Yes. |
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What are the system requirements? |
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On both platforms:
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250 MB of RAM (more recommended, the more the better) |
| · |
500 MB of available hard-disk space (more recommended) |
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1,024x768 or greater monitor resolution |
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Color monitor with 16-bit color or greater video card |
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Windows platform:
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Windows Vista, or Windows 98, ME, 2000 or XP with .NET 1.1 framework or higher (if the .NET framework is not installed, the installation wizard of Photomatix Pro will invite you to download it from Microsoft's website). |
| | |
Mac OS X platform:
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Mac OS 10.3.9 or higher |
| · |
G3, G4, G5 or Intel processor |
| | ^ |
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What are the file formats and RAW files supported? |
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Photomatix opens and saves images in the following formats:
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JPEG |
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TIFF (8-bit, 16-bit and Floating Point) |
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Radiance RGBE |
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OpenEXR |
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The following formats are supported in read mode only:
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PSD |
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PNG (Mac version only) |
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Photomatix also supports Raw files from Canon, Nikon, Fuji, Sony, Olympus, Minolta, Pentax, Panasonic, Sigma, Phase One and Leaf, as well as Digital Negative (DNG). If your camera model is recent, though, you may have to wait till the next version of Photomatix Pro before it gets supported. |
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A list of camera models for which the current version of Photomatix Pro supports RAW files is
available here. |
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Tips & Tricks |
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What camera do I need to get good results with your software? |
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Photomatix works with differently exposed photos. To get good results, it is important that each one of the source
photos are taken with a sufficiently different exposure in order to properly cover the dynamic range of the scene.
Taking three photos separated by two EVs (i.e. two full-stops), or five photos separated by one EV,
will be sufficient for most outdoors scenes. |
| |
Many digital cameras include an Auto Exposure Bracketing function that makes the process of taking several exposures
easier and faster. If you select Aperture Priority and then use Auto Exposure Bracketing, the camera will automatically
take 3 or more shots at different exposure times when you press the shutter release button. |
| |
A camera offering the Auto Exposure Bracketing option is therefore recommended for taking HDR pictures. However, this
option won't be useful if the maximum EV step possible with Auto Exposure Bracketing is less than one EV for your
camera. If your camera offers less than that (for instance 0.7 or 2/3 EV), then Auto Exposure Bracketing won't be useful and you will have to
change the exposure times manually. |
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A list of camera models with their AEB settings is
available here. |
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A two-EV spacing is best for capturing images intended for HDR. However, a one-EV spacing is still OK if the camera
can take 5 or more frames with Auto Exposure Bracketing.
|
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| › |
I have a RAW file. Can I make different exposures with it to use in your software? |
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Yes, you can still use Photomatix when you have shot only one exposure in RAW mode. The big advantage, of course, is that you just need one image, so there is no need to use a tripod or to remember to auto-bracket, and it will also work if the subject is moving. |
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However, the range of "workable" exposures you can get from a RAW file is limited. If you are shooting a high contrast scene, you are unlikely to match the results you would have with taking the scene under different exposures that can cover the whole dynamic range. |
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There are three techniques for using Photomatix with one single exposure taken in RAW mode:
| · |
Technique 1: Open your RAW file in Photomatix to convert it into a pseudo-HDR image, then tone map it. |
| · |
Technique 2: Convert your RAW file into a 16 bits/channel image in your favorite RAW converter, open it in Photomatix, and tone map it. |
| · |
Technique 3: Create two or three exposures in your RAW converter and combine them in Photomatix as it they were "real" bracketed shots |
|
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Technique # 3 gives generally the best results. |
| |
For good results with techniques 1 and 2 (and to a lesser extent with technique 3), it is important to ensure a low noise level. For this, expose for the shadows when taking the RAW image, i.e. overexpose your shot. Even though the histogram of your camera may indicate that highlights will be lost, you should still be able to recover them during RAW conversion (unless the dynamic range of the scene is too high, but then one RAW file won't be sufficient). There are two examples obtained this way here. |
| |
Deriving "fake" exposures from a single RAW file (technique 3 above) is theoretically an improper way of creating a 32-bit HDR image. If you intend to use the HDR image file for 3D rendering, then you should not use this technique, as you will not get accurate linear pixel values required for image based lighting. However, if you are only interested in the tone mapped result, then creating "fake" exposures is a valuable technique, as long as you get improved results over technique 1 or 2. |
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You can see some examples obtained with technique 3 in this user gallery for instance. Also, this tutorial on RAW HDR Processing details the technique. |
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On the other hand, some high end cameras have sensors with a depth of 14 bits, which means two f-stops more of dynamic range. It is definitely a good idea to try the Tone Mapping tool of Photomatix on the 16-bit TIFF file derived from the the RAW data of such cameras. Also, the dynamic range of the RAWs of the Fuji S3 and S5 Pro is higher than RAWs of other DSLRs. |
| ^ |
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| › |
Do I need to process bracketed RAW files to 16-bit format first? |
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When you want to use the Average or H&S Exposure Blending functions of Photomatix, it is recommended to first process your bracketed RAW files in your favorite RAW converter, and then blend the converted TIFF or JPEG files in Photomatix. |
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When you want instead to merge your bracketed images into an HDR image, then having Photomatix directly process your bracketed RAWs is theoretically better for the accuracy of the 32-bit HDR image produced. This is because the data in RAW files represent the linear luminance values captured by the camera sensors, which is exactly what is needed for an HDR image. Also, the calculation of HDR values can rely on the exposure information retrieved from EXIF data when RAW files are used. And no clipping has yet taken place, which is important to preserve dynamic range. |
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However, Photomatix does not correct for chromatic aberrations, vignetting or lens distortions when processing RAW files. It does not offer noise reduction either. So, when noise, purple fringing or related problems are an issue, it is recommended to process your bracketed RAW files in a RAW converter that handles those problems. Then, use the converted output as source images for generating the HDR image. |
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Note that when using a RAW converter with files intended for HDR merging, you will need to disable sharpening and uncheck all tonal and exposure-related automatic settings (especially the Exposure adjustment setting but also adjustments for contrast, shadow, etc.) which should be set to zero. |
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It should be noted, too, that the advantage that RAW files may bring over jpeg or tiffs in terms of dynamic range is not really relevant anymore when several exposures are used -- if your bracketed shots properly cover the scene's dynamic range, jpegs will work as well as RAWs for creating an HDR image.
|
| ^ |
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| › |
What is the ideal exposure range and exposure spacing? |
| |
The ideal exposure range is the one that covers the dynamic range of the scene you are shooting. So the exposure range depends on the scene.
|
| |
For many outdoors scenes, 3 exposures spaced one or two EVs apart may be sufficient. However, for an interior with an outside view on a sunny day, for instance, the dynamic range can be quite high. |
| |
An E.V. (Exposure Value) is also referred to as a stop (or full-stop when it is one E.V.). One E.V. increment corresponds to a doubling of the amount of light hitting the camera's sensors. This means that a range of 8 E.V. can be achieved with exposure times ranging from 1/250 to 1 sec. for instance, assuming a fixed aperture and ISO setting. If you set your camera to +/-1EV step increments, you will need 9 frames to achieve that range. If you set it to +/-2EV, you will need 5 frames. |
| |
Regarding the exposure spacing, an increment of 1.5 or 2 E.V. is generally recommended. The advantage compared to an exposure spacing of one-EV is that it will limit the number of shots required to span the dynamic range, and therefore reduce the risks of mis-registrations and ghosting. It will also reduce storage needs and make for faster processing in Photomatix. On the other hand, a one-EV spacing -or lower- does have one advantage, which is to better smooth out noise when merging to an HDR image.
|
| ^ |
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| › |
How do I select the exposures? |
| |
First you have to determine how many exposures are needed and this depends on the dynamic range you want to achieve. One way of doing it is as follows:
| · |
Set your camera in manual exposure mode and select an aperture that is the most appropriate for your scene (e.g. f/8 for a motionless scene) and the lowest ISO setting. |
| · |
Measure the light in the highlights you want to preserve (in Av mode to point only the highlights, otherwise with spot metering). Take a shot with this exposure - let's name it time T1 - and look at the histogram to check that no important area is burned out. |
| · |
Measure the light in the shadows by pointing (or spot metering) the darkest area where you want to see details - let's name it exposure time T2. |
| · |
The ratio log2(T2/T1) gives you the number of E.V. needed to capture the dynamic range. We recommend an EV spacing of two f-stops apart for Photomatix (see question above), so your lowest exposure will be exposure time T1, the next one will be two stops more (i.e. T1 multiplied by 4), and so on till you get at the longest exposure time T2. | |
| |
Also, you can use the histogram preview in playback mode to check that you have captured a good range of exposures. You should have at least one picture without a large peak at the left side of the histogram, and one picture without a large peak at the right side of the histogram. |
| |
If you can not achieve the number of shots and exposure settings with the Automatic Exposure Bracketing function of your camera, then you will have to bracket more than once or set each exposure individually. In any case, make sure to shoot on a tripod, even if you can auto bracket. |
| ^ |
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| › |
How can I get good results when shooting a room with a bright view in the window? |
| |
The dynamic range of the inside of a room with a view outside the window on a sunny day is particularly high, much higher than the dynamic range of a typical outdoor scene. |
| |
The key to getting a good result with such scenes is to take enough exposures to properly cover the dynamic range. In most cases, you will need at least five exposures spaced two EVs apart. If you take less, you may get washed-out highlights, or noisy shadows, or black artifacts due to "holes" in the coverage of the dynamic range. |
| |
The best way to make sure you have taken enough exposures is to measure the light as explained above. Also, set the EV steps to +/- 2 if your camera allows it, but no more than 2 in order to ensure a "smooth" coverage of the dynamic range. If your camera does not allow more than a +/- 1 EV increments, remember that you will need more exposures than with a two-EV spacing.
|
| |
Then, when it comes to processing the shots, we recommend trying both Exposure Blending with "H&S - Adjust", and "Generate HDR" followed by Tone Mapping with Details Enhancer. |
| ^ |
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| › |
How did you take the Grand Canal picture on your example page while the boats were moving? |
| |
Taking differently exposed shots for HDR only works well with stills. For a scene with motion, the resulting image will show "ghosting" artifacts.
|
| |
Most cameras have an automatic bracketing exposure function which lets them take three or more shots successively while automatically changing the exposure. This is still not fast enough in most cases of moving scenes, but in the case
of the Grand Canal photo shown on our example page it was, as the boats' movements are almost unnoticeable in the final tone mapped image. There were two reasons for that:
| 1. |
The boats were moving slowly. |
| 2. |
The three shots were taken with a camera offering a high burst rate (the 1D MKII which can take up to 8.5 frames per second). |
|
| |
Since version 2.4, Photomatix Pro includes an option that reduces ghosting artifacts. When this option does not work well with your images, you can also try the ghost repair technique detailed in this tutorial (note that when the tutorial mentions HDR image, it refers to the tone mapped image in fact).
|
| ^ |
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| › |
What is the best workflow: Exposure Blending or HDR Tone Mapping? |
| |
This depends on the dynamic range of the scene, the characteristics of the differently exposed images and the effect you want to achieve. Our recommendation is to systematically try both, using Batch Processing from the Automate menu. |
| |
What we usually do for any set of image, is to first run the batch with the three following methods:
| · |
Tone Mapping with Details Enhancer |
| · |
Tone Mapping with Tone Compressor |
| · |
Highlights & Shadows - Adjust | |
| |
The table below lists the main pros and cons of both processes. |
| |
Pros |
Cons |
| HDR Tone Mapping |
| · HDR image file can be saved, enabling to tone map the same image with other methods or other settings. |
| · Ability to preserve details in shadows and highlights even when the dynamic range is particularly high |
| · High degree of parametrization, i.e. tone mapping methods can offer many settings to adapt image to one's liking |
|
| · When source images are noisy, tone mapping may further increase noise. |
| · In spite of the avaibility of settings, controlling the tone mapping operation is not easy. |
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| Exposure Blending |
| · Blending the images has the effect of reducing noise |
| · Blended image is close to the source images giving it a "natural" look |
| · Easy-to-understand process, no or few parameter setting |
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| · Lack of local contrast when dynamic range is high, "flat-looking" results in some cases |
| · Memory required for Exposure Blending increases with the number of source images and bit-depth. |
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I am getting noisy tone mapping results. Is there a way to avoid this? |
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The Tone Mapping method "Details Enhancer" enhances local details a lot. If the local details of your HDR image are noisy
(you can easily see that in the HDR viewer), then the noise will be enhanced as well, unfortunately. |
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Applying a noise removal tool to the tone mapped image is often the best solution.
You may still avoid having to do that with the recommendations below: |
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Case 1: Motionless scene (i.e. without moving objects)
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In this case, it should be possible to avoid noise in the HDR image if the differently exposed photos cover
the whole dynamic range of the scene. That is, making sure that at least one photo correctly exposes the deepest shadows
and one photo correctly exposes the highlights (see above). It is particularly important that your bracketed shots include an image taken with a sufficiently long exposure time to make the darkest parts of the scene visible. |
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There are some situations (e.g. low-light outdoor scenes) where correctly exposing the darkest part might not be possible.
Make sure in this case to enable the noise reduction function of your camera if there is one. You may also try taking several images at long exposure times and stack them together in Photomatix using the "Average" combination. Then, generate the HDR image with the result of the stacking at each exposure. |
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Also, it may be a good idea to lower the exposure spacing, for instance to one-EV increments instead of two. This is especially recommended if you are using a compact camera.
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Case 2: Scene with motion
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If you have a high-quality camera able to keep very low levels of noise at high ISO settings, then you can limit the number of bracketed shots to just two, each taken at high ISO with very short exposure times. The tone mapping tool is really good at retrieving shadow details from underexposed shots, so you don't need to expose more if your camera has an outstanding signal-to-noise ratio.
In this case, you may also try with just one shot taken in RAW mode and convert it into a "pseudo" HDR image in Photomatix to tone map it.
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If you don't have such a camera, then you may still try with a limited number of images taken at high ISO settings, and then
apply a noise reduction tool to the tone mapped image. |
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If you are applying the Tone Mapping tool to a single RAW instead of differently exposed images, then the chance of getting noisy results is higher, unfortunately. In this case, we recommend exposing for the shadows by slightly overexposing your shot. |
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In any case, the problem of noise made more visible with Tone Mapping only applies to the Details Enhancer method. You can still avoid it by using the Tone Compressor method instead. |
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Also, Photomatix Pro offers several Exposure Blending methods. Combining your images with those methods is an effective way of reducing noise. The resulting combined image will show less noise that the individual source images taken under different exposures. We recommend in particular the new "H&S - Adjust" algorithm of Photomatix Pro version 3.0 currently in beta release (Windows - Mac).
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How do I reduce/eliminate "halo" effects with tone mapping? |
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There are several ways to achieve that. The simplest and most effective one is to use the Tone Compressor method for tone mapping your image, as this method is free from halo artifacts. |
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With the Details Enhancer method, the setting Highlights Smoothing (under the S/H tab) is useful for reducing halos around objects placed against bright backgrounds. The other adjustments that may help are lowering the Strength or increasing the value of the Light Smoothing setting.
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Can I use your product for combining multiple scans? |
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Yes, Photomatix can be used to combine two or more scans from the same film scanned under different exposure settings.
There is an example produced with 3 scans from a film's negative
here. You may also try with scanned slides,
but it is better to do it with negatives, as the dynamic range for film's negatives is higher than for slides.
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We would recommend combining the differently exposed 16-bit outputs from your
scanner with the Exposure Blending method named "H&S - Adjust" (in Photomatix Pro version 3.0). Since this blending
method is mostly automatic, it is recommended to use the Batch Processing function to
process the 16-bit scans to avoid out-of-memory issues.
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The scans will need to have the same size before processing them. Also, the option "Align images" will have to be checked in order to correct for possible mis-registration of the scans.
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Error messages and unexpected results |
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The Tone Mapping preview does not look the same as the final output image. |
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This should only happen if you use the Details Enhancer method to tone map the image. The preview is pre-computed by tone mapping a low resolution version of the original image. The low resolution version does not contain the same pixel values as the entire image. That is, the input is different, and this makes the Details Enhancer algorithm behave differently.
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The preview has for purpose to give you an indication of how the final tone mapped image will look like, and how changes in the settings influence it. It is not an exact representation of the final result, unless you use the Tone Compressor method to tone map the image. |
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When the final result is not like you wanted it, you can undo the Tone Mapping (from the HDR menu on Windows and the Edit menu on Mac) and try the Tone Mapping again using other settings.
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The differences should be less noticeable with a lower value for the Strength and Light Smoothing settings, and a value of 0 for the Black Point. Also, it is a good idea to select the higher preview size for the tone mapping window. |
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When the final result is very different from the preview and far darker, this is usually due to the fact that the input HDR image includes many irregular values due to noise. Those irregular values disturb the Details Enhancer process which then produces a dark output. The reason the dark output does not happen with the preview is that the absolute number of abnormally low values is then lower. |
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In this case, one workaround that sometimes helps is to slightly resize the HDR image file. This is because the interpolation done for resizing has the effect of smoothing out the noisy low pixel values. Another workaround is to apply a noise reduction tool to the source images before generating the HDR image. Also, in case the most underexposed source image of the bracketed set is too dark to be useful for the highlights of the scene, then removing this file from the HDR image creation may help too. |
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The workaround that will work in all cases is to tone map using the Tone Compressor method.
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When I try to run Photomatix, I get the message "Application has generated an exception that could not be handled" or "The application or DLL is not a valid Windows image", or "The application failed to initialize properly". |
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Such error messages are usually related to a corrupted installation of the .NET Framework. |
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You could try uninstalling and reinstalling the .NET Framework on your PC. An easier alternative is to download our special version of Photomatix Pro which embeds the .NET Framework, and thus should solve the issue. |
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You can download this special version directly from the link below. Please note that the download is substantially larger (23 MB) than the usual download of Photomatix Pro for Windows. |
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Download Photomatix Pro 3.0.3 with the .NET framework embedded (23 MB). |
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Using Photomatix for panoramas |
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I am stitching panoramas. How should I integrate Photomatix in my workflow? |
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As you know, getting a seamless panorama is best achieved by maintaining a constant exposure when shooting the panorama's views. The problem is that the right exposure is different for each view. Photomatix Pro can help solve this dilemma. |
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First of all, you will need to shoot each one of the panorama's angles of view at different exposures (for instance three exposures at 0, -2, +2 EV). Those exposures should remain the same for all of the angles of view of your panorama.
This is easy if your camera has an auto-bracketing function -- set the exposure to manual mode, then select auto-bracketing after having set the appropriate aperture (the bracketing function will change the shutter speed automatically). |
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If your panorama software supports 32-bit HDR stitching (e.g. Realviz Stitcher Unlimited 5.6 or higher), then you can use Photomatix to create the 32-bit HDR images in input of stitching, and later on to tone map the 32-bit HDR panorama once it has been stitched. In this case, integrating Photomatix in your workflow is not different than with standard images and you don't need to read the rest of this section. Please refer instead to the section on large files. |
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If your panorama software does not support 32-bit HDR stitching, there are two possibilities for integrating Photomatix in your panorama workflow:
| 1. |
Stitch-then-HDR: create multi exposed panoramas and process them in Photomatix |
| 2. |
HDR-then-Stitch: process your bracketed images in Photomatix and stitch the tone mapped or combined images |
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We are using the first workflow, i.e. Stitch-then-HDR. This means producing one panorama for each exposure level and then merging those panoramas in Photomatix. |
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However, the Stitch-then-HDR workflow assumes that the differently exposed panoramas are stitched the same way, i.e. using the same control points for each panorama. This can only work if your stitching software makes it possible to replicate the stitching parameters used for one panorama to another panorama, so that it can stitch your differently exposed panoramas exactly the same way. This is possible, for instance, with software based on Panotools (see below) and with Realviz Stitcher (see below). If this is not the case (e.g. with Panoweaver), you will have to use Photomatix prior to stitching, i.e. merging your bracketed shots for each one of the angle of views and then stitch together the resulting images. |
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The second type of workflow, HDR-then-Stitch, avoids multiple stitches per pano, which is an advantage if your pano is composed of a limited number of views. The drawback, however, is that this approach may not work well with the dynamic range increase techniques that take the most advantage of local contrast, especially the Tone Mapping tool. Because local contrast is specific to a given view, those techniques produce images with different tone levels, making them more difficult to stitch. |
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It does not necessarily mean, though, that you won't be able to stitch images obtained via HDR Tone Mapping. We have heard for instance that Realviz Stitcher does a good job at stitching tone mapped images produced by Photomatix Pro. If you have similar experiences with other stitching applications, please let us know. |
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In any case, we recommend using Photomatix in batch mode for processing panoramas. The Batch Processing of Photomatix Pro has been designed with the needs of panographers in mind. |
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Realviz Stitcher returns an error "Image size must be the same" when I load HDR images produced with Photomatix. |
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When the Align images option is selected and your bracketed images are slightly misaligned, Photomatix will by default crop the images after having corrected the alignment shifts. This means that the width and/or height of the resulting HDR image will slightly differ from the width and height of the source images, and also differ from the width and height of the other HDR images as the alignment correction is specific to a bracketed set. |
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To bypass the cropping of the resulting image after alignment, please check the option Don't crop located next to the Align images option on the Batch Processing window. When the Don't crop option is checked, Photomatix will not change the size of the images after alignment and Stitcher will not complain.
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My tone mapped panorama shows a straight vertical seam line. Is there a way to get rid of it? |
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Yes. To get rid of the seam when tone mapping an HDR panorama with the Details Enhancer method, you will have to check the option "360º image" before running the Tone Mapping. |
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Please note that checking this option increases the memory requirement for processing the image quite a lot.
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If you are tone mapping with the Tone Compressor method, then the option is not needed as you will never get a vertical seam line when using a global type of tone mapping operator such as Tone Compressor. |
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Could you detail how you stitched the panoramas shown on your samples page? |
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The panoramas shown on the examples page of this site have been stitched with Panorama Tools (also known as PanoTools). |
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In order to produce identically stitched panoramas per exposure, we did the following:
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Loaded the images shot at the middle exposure into PTGui |
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Set the control point and stitched a first panorama for the middle exposure |
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Saved the project file (.pts) |
| 4. |
Then for each one of the other exposure sets:
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Loaded the images belonging to the same exposure into PTGui. |
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Selected Apply Template and chose as template the project file created for the middle exposure. |
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This gave us one panorama at each exposure level. We then processed the differently exposed panoramas in Photomatix Pro. |
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Important note: the Align Images option should be unchecked when processing differently exposed panoramas in Photomatix. |
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For the two panoramas processed with the Tone Mapping tool, we also used Enblend, applying it to the differently exposed panoramas. Enblend was particularly useful in this case as it removed the stitching seams that the tone mapping tool would otherwise have enhanced as local details. |
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One note about using Enblend with Photomatix. The TIFF file produced by Enblend should be flattened before processing it in Photomatix. If you intend to use the tone mapping tool, then it is recommended to ensure that the transparent background becomes black (i.e. pixel values at 0) and not white when flattening the image, or even better to crop the panorama. |
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How do I produce identical panoramas for HDR with Realviz Stitcher? |
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If you want to create a panoramic HDR image from differently exposed panoramas following the after workflow described above, you will need to ensure that the panoramas at each exposures are stitched exactly the same way.
If you use the templates from Stitcher to get identical panoramas from bracketed images, you will experience spatial shifts and consequently multiple contours when composing the panoramas in Photomatix Pro. |
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So, you will have to do the following instead:
| 1. |
Create one folder per exposure, i.e. if you have for instance taken three bracketed shots per view, create 3 folders. |
| 2. |
Place under each folder the images of the panoramas taken at the same exposure. |
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Rename the images under each folder so that each folder has exactly the same filenames. For instance, if you r panorama is composed of five views, rename the files into something like view1, view2,..., view5. Then keep the same name to refer to the same view taken at another exposure and stored under another folder. |
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Stitch one of the panoramas (medium exposure value in most cases). Don't forget to align the horizon and save the project. |
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To stitch the next panorama, do one of the following:
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Either rename the folder for one of the other versions and fool Stitcher into "thinking" it's still working with the same images as before. |
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Or open the project file from Stitcher in any ASCII-editor with a search-and-replace function and change the name of the folder to the next version for all occurrences. Take care not to touch any other values, save it as plain ASCII again and open it in Stitcher by making it look at "all files" in the "open" dialog. |
Now you can stitch the next exposure, but take care not to touch the position of the panorama it ends up with -- no alignment, zoom or pan. |
| 6. |
Process all your exposures in the same way and name them accordingly. |
| 7. |
Put the differently exposed panoramas together in Photomatix. You'll have to supply the exposure values by hand since they get lost in the process, just take notes or check one of your original's EXIF data.
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Do you have any advice for shooting virtual tours? I'm a beginner and using a 360º one-shot lens. |
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Select a small aperture (e.g. f/8 or higher f-stop number if you camera supports it). This is important to ensure a sufficient depth of field with one-shot systems. |
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Select a low ISO setting (e.g. 100). |
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Set your camera in Aperture Priority mode, so that only the exposure times (i.e. shutter speed) vary when you are taking the bracketed shots. |
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Select Auto Exposure Bracketing (in continuous shooting mode). The camera will automatically vary the shutter speed and shoot the scene at different exposures. |
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Set the stop spacing for auto-bracketing at +/-2. If this is not possible with your camera, +/- 1.5 should be still OK. If the maximum stop-spacing on your camera is lower than that, you will have to vary the exposure times manually. |
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Make sure to take enough exposures to correctly cover the dynamic range of the room. If there is a bright window, you
will probably need 5 exposures spaced by two EVs or even more (which means you will have to bracket twice if your
camera can not take more than 3 autobracketed frames in 2 EV steps). |
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If there is a bright window, it is a good idea to switch on all available lighting in the room. |
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For a good quality panorama, we recommend stitching multiple views rather than using a one-shot system.
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Licensing, upgrades and download |
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I haven't yet received my serial code, when will I get it? |
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Our resellers Plimus, SWREG and share-it email your license information immediately after purchase
if you have ordered by credit card. If you did not receive this email, this is either due to a delay on the server of the reseller or because the email has been rejected by your spam filters.
Please contact us to request the resending of your
license information. |
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My hard drive crashed and I lost my license key. Can you send it to me again? |
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Yes. For that please email us mentionning the first and last name of the person who purchased the software. If possible, please include the addtional following information to help us locate your order:
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The approximate date of the order |
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The email address you used for the purchase |
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Whether you have ordered through SWREG, Plimus, Share-it or another type of reseller |
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My registration key won't work |
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If you have purchased a license for our software, then the registration
key emailed automatically to you must work. Please try not to type the registration information but instead
copy and paste the License Key (and the User ID if applicable) from the email.
This way you will avoid any typing error. Also, please note that the registration information is case sensitive.
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If the registration still fails with copying/pasting, this is probably because of an additional space or return character at the | |
