Bellows factor

[Christie Photo]

geezzzz.... it's been a while since I had to think of this.

Isn't it the bellows [draw] X [apertue] ÷ [focal lenght] = effective aperture?

So for example: shooting with an 8 1/4 inch lens with a 10 inch draw at f 11 gives you an effective aperture of f 13.3

 

[christopher walrath]

It is not so complicated for LF work, once you extend the belows past the focal length of your lens you will need to make some adjustment. In the field, typically 1 to 2 stops additional exposure is all that is needed. No need to break out the commodor64.

Dude! I gotta VIC20.

 

[Helen B]

Isn't it the bellows [draw] X [apertue] ÷ [focal lenght] = effective aperture?

Yes it is, for lenses that are neither telephoto nor retrofocus. It's the same formula that Herz and I have given, arranged in a slightly different way. It's all very simple really.

Best,
Helen

 

[JC1220]

Dude! I gotta VIC20.

:hail: