Canon 5D Mark II always records 40mm in EXIF with EF 17-40mm f/4L
Asked 2/22/2017
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2 answers
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I’m using a Canon 5D Mark II with an EF 17-40mm f/4L. The camera and lens otherwise seem to work normally, but every image records 40mm as the focal length in EXIF, even when I know the shot was taken at 17mm or another zoom setting. Other metadata like ISO and shutter speed appears correct.
Can incorrect focal length in EXIF affect the actual image in any way, or is it only a metadata/reporting problem? Is there anything I can try before sending the lens or camera in for warranty service?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
9y ago
2 Answers
0
Generated from our catalog & community — verify before relying on it.
Incorrect EXIF focal length should not affect the actual photo. EXIF is metadata written by the camera’s electronics; it reports information about the shot, but it does not determine the recorded pixel data.
So if your images look normal, this issue is most likely limited to reporting/logging problems—such as Lightroom showing the wrong focal length.
Because ISO, shutter speed, and other EXIF fields are correct, the problem is likely specific to how focal length is being communicated/recorded between the lens and camera body. The provided answers don’t give a confirmed fix, but checking the camera and lens manuals/specs is a reasonable first step to see whether there’s any relevant behavior or limitation documented.
If the lens is still under warranty and the EXIF is consistently wrong with this lens, service may be the practical solution if you need accurate metadata.
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UniqueBot
AI9y ago
0
EXIF is just text produced by the camera's computer. It doesn't control the contents of the pixel values.
As to why it always reports the focal length as 40 mm: you may want to study the user's manual and spec sheet for both the camera and lens carefully, tho' a quick skim doesn't appear to provide that level of detail.
For general info, I found a complete list of the EXIF data this camera body records. While that's not particularly helpful for the posted question, I noticed this comment at that page:
the one piece of basic information I really wanted to know, was I set to manual focus or auto focus, is missing*.
*Note: I later realized that this information is included but because I dedicated auto focus to to a button on the back of my camera I can make manual adjustments while in AF mode and my 5D is none the wiser… stupid 5D
So it is possible, I guess, that some particular programmed configuration causes the camera body not to "keep track" of the current zoom setting.
Originally by user25396. Source · Licensed CC BY-SA 4.0
user25396
9y ago
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