Bellows Factor with Bacon, photography tips with J Brunner

J Brunner shows off a super friggin cool bellows factor compensator thingie.

Category:

Education

Tags:

• Brunner
• film
• large
• format
• photography
• bellows
• factor

[stevevox1]

Fantastic, does that work equally with different lenses ? or is there a different size photo of you for each lens. I used to have a compensation guide on my studio wall ( measure from lens to ground glass ) but dont have the studio now nor the guide and this idea seems brilliant

[alternativecamera]

Hi stevevox1, yes, because the calculation is based on the image size on the ground glass, it will work with any focal length lens.

[1omegaB22]

What exactly is bellows factor, and is it an important factor when using a press camera such as a Crown Graflex?

[alternativecamera]

Bellows factor is the exposure compensation needed for close up/ macro photography when the image ratio exceeds 1:1. This is because at magnifications greater than 1:1 the amount of light reaching the film decreases.

[Daravon]

It doesn't have anything to do with 1:1 actually. It's just that on view cameras, the F-stops that are marked on the lens are only accurate when you are focused 'far away'. When you focus close, the actual f-stop of the camera is different than what the numbers on the aperture scale will tell you, so you have to compensate by opening the aperture more or exposing for a longer time.

[alternativecamera]

The point at which the fstop numbers goes off is 1:1. The reason the stop falls off is because at 1:1 the scale on the lens isn't accurate because you are using less of the image circle than the f-numbers are calculated for. This is true of all cameras, not just view cameras, although it is more frequently encountered with view cameras because the bellows extension makes the ratios possible without extension tubes, etc.

[PatMo1888]

Looks eat enough to good. Erm ...

[1omegaB22]

Hey, thank you!

[PartTimePhotography]

Good stuff - I'll pass this along to all my newsletter subscribers.

[nmc379]

who've helped me so much 8-] thank you!