TTL Flash with MF lenses

jtvang125

Diamond Member
Nov 10, 2004
5,399
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Would the flash work in TTL with a MF lens on a dumb adapter? I'm thinking no since no focal length and aperture info are being sent to the camera.
 

slashbinslashbash

Golden Member
Feb 29, 2004
1,945
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The way that TTL works in most cameras, I believe this should work. The focal length and aperture aren't taken into consideration in most TTL implementations. It simply measures how much light comes through the lens.

However, I could be wrong. Try it out and see how it goes!
 

Syborg1211

Diamond Member
Jul 29, 2000
3,297
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I want to agree with slash that as long as you can meter through the lens (camera tell you underexposed vs overexposed), TTL flash should work, but I've never tried.
 

turtile

Senior member
Aug 19, 2014
633
315
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It depends on the type of camera and lens you have. I know with Nikon, you'll need to enter distance information and the focal length on the flash if it doesn't have a chip (AI). Chipped manual focus lenses will share this information.
 

Bearmann

Member
Sep 14, 2008
167
2
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With Canon cameras, ETTL sends out a pre-flash millliseconds before the actual flash. The light going Through The Lens (TTL) is measured, and an appropriate flash output is sent out based on the measurement. It doesn't care about the aperture, focal length, whether you have a polarizer on the lens, etc. All of those things will change the measured preflash so they don't have to be taken account of. I assume the Nikon is somewhat similar, though I don't know exactly how it works.