exposure compensation for bellows extension--small/medium format lenses

[lensmagic]

When exposing film using a view camera one needs to give additional exposure for close ups in order to compensate for bellows extension. Does the same apply to 35 mm and medium format cameras??? The front and rear elements of the small format cameras don't appear to move as focus is changed.

 

[Nick Zentena]

Yes but usually 35mm cameras have TTL meters so the camera handles things itself.

You'll notice with tubes they often give compensation numbers. Or for that matter cameras like the Mamiya RB/RZ have compensation numbers on the side of the body.

 

[Ian Grant]

A better answer is only when you start to use extension tubes & bellows, regardless whether you have TTL metering or not.

Ian

 

[CBG]

A better answer is only when you start to use extension tubes & bellows, regardless whether you have TTL metering or not.
Ian

True, but TTL changes what the user does or does not have to do about the lens extension light loss ...

When you have TTL metering, the camera "sees" the lowered light intensity, and tells you to adjust your settings if your camera is not automatic, or changes the exposure if you have automatic exposure.

If you use a hand held meter, or some sort of meter that doesn't see through the lens, then you will have to make appropriate corrections when your lens is extended, regardless of what format you use. Whether you use a minox or a 20x24" camera, if you shoot a (for example) life size image upon the film, you will have to somehow, add two stops, 4x, the exposure.

Best,

C

 

[nworth]

Bellows exposure compensation applies to small and medium focus cameras in the same way it applies to large format cameras. For normal picture taking, down to a couple of feet, the lens extension with these cameras is usually so small that no compensation is needed. But with longer lenses and short distances and with macro (especially using bellows or extension tubes) you need to pay attention to it. If the camera has an internal meter, it will probably do all the work necessary for you. In any case, unless you have a lot of recent experience, it is wise to bracket a bit under these circumstances since lighting and measurements can be tricky.

 

[DWThomas]

Having just gotten back a half dozen shots taken with a newly acquired Bronica Zenzanon PS 110 mm macro lens on my SQ-A, I can confirm exposure adjustment is necessary for MF. I did make adjustments, several were excellent, but the results suggest I could be more rigorous the next time.

DaveT

 

[David A. Goldfarb]

Yes, with any format, when you get to a magnification of 1:10 (subject on film:subject's actual size), then you need to think about exposure factor. Of course the larger the format, the sooner you'll be in that territory. With 35mm, it's pretty much just closeup work where you'll have to think about exposure factor, if you are using non-TTL metering or non-TTL auto flash. Even with TTL metering, meters can get pretty non-linear in low light, and you often have very low light with macrophotography. With medium format, you're in exposure factor territory with a tight portrait--maybe just 1/3 or 1/2 stop, but if you correct for it, you'll get better results.

I like to figure exposure factor as a function of magnification, because it works the same way with any camera, any format. Here's an explanation and a little table for converting magnification factor to exposure factor that you can tape to the back of your camera or wherever it's handy--

(there was a url link here which no longer exists)