Reversal Ring Metering Question

[richterjw]

<p>I just bought a generic reversal ring for my EOS bodies, primarily my EOS 3. I am aware that the coupling between body and lens for EOS is electronic rather than mechanical and that the camera will register the aperture as "00" without the lens properly attached. My question is: If I attach the lens correctly and meter the scene (with, for the sake of illustration, an EF 50mm f/1.8) with the lens wide open, then detach the lens and attach the reversal ring, and set the shutter speed to the "correct" speed, will the film now be correctly exposed?<br>

If there is a good/better way to do this, I'd really appreciate any information. Thanks for your help. JR</p>

[tommyinca]

<p>You need to consider two other things. One is effective aperture. When you increase magnification, amount of light are reduced from normal distant. With a 50 reversed, you are near 1:1. The other is bellow effect for reversed lens (the 50 doesn't have much of that).<br>

I would add about 2 stops (of light) with the meter you read. Best, borrow a digital body and mark it with the different extension ring/tubes you will be using. This avoid using complicated calculation and tables. But if you want to do that, buy a book or do a search, there are a lot of those arround from the film days still. </p>

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[tommyinca]

<p>I just look, the EF50/1.8 has some bellow effect when reversed. Use -2 1/3 to -2 1/2 stops of compensation when you meter.</p>

[richterjw]

<p>Thanks for the work on that, Tommy. JR</p>

[tommyinca]

<p>BTW: If you get one of those auto focus focus chip and attach it to your reverse ring, you can use the EOS bodies' TTL meter. You can use either A mode or M mode metering still. There will be a small amount of metering inaccuracy due to the aperture you set may not be what the AF chip tell the camera bodies' computer but it will be close. It is TTL after all. You need to learn the set-up and fine adjust accordingly. </p>