5.0 High Dynamic Range Imaging
HDRI
High dynamic range photography is used for the mirror ball to capture the radiance or light information from the scene. Light from the scene falls onto the sphere and is reflected back. Photos are taken of the mirror ball at normal exposure, several stops above, and several stops below to capture the highlight and shadow details that are usually clipped in non-HDR images.
This is a High Dynamic Range Image – well, sort of. What you see to the left is a compressed version of the final HDRI product, created from the pictures taken below at different F-stops.
The process is fairly simple:
Set Normal exposure
Take a photo +/- 1 stops above/below normal
Take a photo +/- 2 stops above/below normal
Take a photo +/- 3 stops above/below normal
Take a photo +/- 4 stops above/below normal
To set your normal exposure, choose an F-stop in the middle of your lens/camera's range.* Compensate for the lighting situation by adjusting the ISO and shutter speed/angle. When the image looks good, only change the F-stop to capture different exposures!
20151020 Apartment Test. Canon HDR photo set for my thesis.
A chrome ball is not necessary for taking HDR photos, but it helps demonstrate how details in the highlights and shadows appear as the exposure changes. Since this was a test for the process, it was shot with a Canon DSLR. Later, you'll see that I captured HDRI from the cameras I used for my final shot, the Arri D21.
What you don't see in this post or the photos is my extreme thorough testing of the process for shooting the HDRI test set. I was familiar with the process from my courses at RIT, but I wanted to explore how different features would impact the result. I created a spreadsheet of all the possible variations I could shoot and spent several hours shooting this scene to test Every. Single. Option.
I progressed through every single F-stop, with a locked ISO and shutter speed. Then I locked down each F-stop and progressed through the ISO options, and did the same with shutter speed. So. Many. Photos.
To summarize: the only adjustment to make when shooting different exposures is to change the F-stop.
You captured your first set of HDR photos, now what?
Photoshop:
File > Automate > Merge to HDR Pro
Browse and select photos
Click ‘OK’ and wait for the next window to pop up
Manually select your ‘normal’ exposure OR
Select the photo to set as the normal exposure with the arrows
HDR Pro
Change to 32-bit
Click ‘Tone in ACR’ (Adobe Camera Raw)
Make any adjustments as needed
Save as
Uncompressed
.tiff or .psd
Web
.jpg or .png
Post Production
.exr, .hdri, .hdr or, .rad (radiance) file
Photo Sets
This next section contains several photo sets from the HDR photos I took for my thesis project. Due to file size limitations, what you see on your browser may not be how the file actually looks. These are compressed.
Also due to file size, these files are listed as Free Products.
20150509 Day Shoot. Arri D-21 HDR photo set. Chrome ball in Skybridge
Free .hdr file download.
20150509 Day Shoot. Arri D-21 HDR photo set. Chrome ball in Skybridge
Set of 8 photos to download for free.
20150509 Day Shoot. Arri D-21 HDR photo set. Chrome ball in Skybridge
20151216 Night Shoot. Arri D-21 HDR photo set. Chrome ball in Skybridge
Set of 8 photos to download for free.
20151216 Night Shoot. Arri D-21 HDR photo set. Chrome ball in Skybridge
Free .exr file download.
20151216 Night Shoot. Arri D-21 HDR photo set. Chrome ball in Skybridge
20151125 Skybridge. Nikon HDR photo set. Chrome ball in Skybridge
Free .hdr file download.
20151125 Skybridge. Nikon HDR photo set. Chrome ball in Skybridge
Set of 16 Photos to download for free.
20151125 Skybridge. Nikon HDR photo set. Chrome ball in Skybridge
Notes:
Finding the “Normal Exposure” for a camera can be difficult at times. This can often be found in the manual somewhere, and will be different for all camera models.
I did shoot a panosphere in HDR using this process, however, that file is more than 10GB and takes a really long time to open.
These photos have been color corrected
