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05-11-2015, 05:19 PM   #1
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Focal length info on playback accuracy

I'm interested in some new lenses so I'm playing around with my 18-135mm, taking shots at different focal lengths to see if I like the working distance, FOV, etc. However, I'm noticing that using the distance scales on the lens doesn't necessarily translate to the focal length reported by the info on the playback screen. Seems like it's rounding off to certain values.

For instance, I'm trying to shoot at 77mm. There is a 70mm marking so I go a little beyond that. I take a picture and check the info, it states 78mm. So I make a minute adjustment and shoot again. Upon review, it's still 78mm. I keep going further and it still reports 78mm until I go so far that it has to jump to another number (60-something, IIRC). But anywhere around the 70mm area, it reports 78mm.

Is there a reason for this? I haven't offloaded those images and checked the exif data on the computer. But I would like to know why the on-camera info doesn't correspond with the focal length markings on the lens.


Last edited by Zerv; 05-11-2015 at 10:33 PM. Reason: bad speeling :)
05-11-2015, 05:29 PM   #2
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QuoteOriginally posted by Zerv Quote
I'm interesting in some new lenses so I'm playing around with my 18-135mm, taking shots at different focal lengths to see if I like the working distance, FOV, etc. However, I'm noticing that using the distance scales on the lens doesn't necessarily translate to the focal length reported by the info on the playback screen. Seems like it's rounding off to certain values.

For instance, I'm trying to shoot at 77mm. There is a 70mm marking so I go a little beyond that. I take a picture and check the info, it states 78mm. So I make a minute adjustment and shoot again. Upon review, it's still 78mm. I keep going further and it still reports 78mm until I go so far that it has to jump to another number (60-something, IIRC). But anywhere around the 70mm area, it reports 78mm.

Is there a reason for this? I haven't offloaded those images and checked the exif data on the computer. But I would like to know why the on-camera info doesn't correspond with the focal length markings on the lens.
There are breakpoints on the data that the lens reports back to the camera. Whatever you see in playback mode is what the camera was told by the lens, and there is certainly some wiggle room.

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05-11-2015, 10:11 PM   #3
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Live with it DA55-300 behaves similar (at least at the long end).
QuoteOriginally posted by Zerv Quote
I haven't offloaded those images and checked the exif data on the computer.
That will not make a difference; the info in the review/playback is extracted from the EXIF.
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