Nikon D3100 and Non-cpu lens?
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I've noticed that when I use non-cpu lens on my Nikon D3100, the exif data shows up as 0.0 mm".
I'm using a Promaster 80-200mm 4.5. I was wondering if there was anyway to display or change the exif data so that it displays the correct aperture and focal length?
Sorry if it's a noob question, still learning my camera!
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Nope, being non-CPU means that information is not collected.
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Without a CPU, the body just can't see the lens, this is also why your meter won't work.
The D7xxx series get around this, but the D3xxx and D5xxx can't.
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You can't take pic
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The CPU in the lens is what collects the information from the lens and sends it to your camera which is then written to your image file.
Some cameras have a "non-CPU" feature in the menu where you can enter the data of each non-CPU lens you use.
Look on pages 167 to 169 of your user manual for a list of compatible lenses for your D3100
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