Canon EOS 5D Mark III Instruction Manual (en)

w: HDR (High Dynamic Range) ShootingN
Using a tripod is recommended. For handheld shooting, using a fast 
shutter speed is recommended.
HDR shooting of a moving subject is not recommended because the 
movement of the subject will appear as afterimages in the merged 
image. HDR shooting is suited for still subjects.
In HDR shooting, 3 images are captured with different shutter speeds set 
automatically. Therefore, even in s and a shooting modes, the 
shutter speed will be shifted based on the shutter speed you set.
To prevent camera shake, the ISO speed may be set higher than usual.
If [Auto Image Align] is set to [Enable] and the HDR picture is shot 
handheld, the edges of the photos will be cropped, lowering the 
resolution slightly. Also, if the images cannot be aligned properly due to 
camera shake, etc., auto image alignment may not take effect. Note that 
when shooting with excessively bright or dark exposure settings, auto 
image alignment may not work properly.
If you perform handheld HDR shooting while [Auto Image Align] is set 
to [Disable], the 3 images may not be properly aligned and the HDR 
effect may be minimal.
Auto image alignment may not work properly with repetitive patterns 
(lattice, stripes, etc.) or flat, single-tone images.
The color gradation of the sky or white walls may not be reproduced 
correctly. Irregular colors or noise may appear.
HDR shooting under fluorescent or LED lighting may result in unnatural 
color reproduction of the illuminated areas.
With HDR shooting, the three images will be merged after you take a 
picture. Therefore, it will take a longer time to record the HDR image to 
the card than with normal shooting. During the merging of the images, 
BUSY” will be displayed and you cannot take another picture until the 
merging is completed.
In HDR mode, the options dimmed in the camera menu cannot be set. 
When you set HDR mode, the Auto Lighting Optimizer will be set 
automatically to [Disable]. It will revert to the original setting when you 
cancel the HDR mode.
If the image-recording quality is set to RAW, the HDR image will be 
recorded in 73 quality. If the image-recording quality is set to 
RAW+JPEG, the HDR image will be recorded in the JPEG quality set.
You can also set HDR shooting with [z3: HDR Mode].