Achieving adequate DOF in 8x10

[Pere Casals]

If you use the same aperture diameter (d), DOF is the same on all formats.

This is only like this if you consider the same circle of confusion, but usually you can consider a circle of 0.2mm for 8x10 and a circle of 0.03mm for 35mm film. This ends in very different accepable DOF, depending on application.

For example f=360mm, f/16, Dist = 10m

DOF 0.2mm for 8x10 is 5m

DOF 0.03mm for 35mm is 0.71m

http://www.dofmaster.com/dofjs.html

So in this case 8x10 DOF is x7 larger than with 35mm


The 0.2mm circle of confusion for 8x10 would be acceptable for Karsh style portraits I guess, for a large landscape print one may consider a smaller circle that's close to lens performance for the scene microcontrast and print size, perhaps 0.1mm or even 0.05.

Of course if same framing was to be done for 35mm film then perhaps a 40mm focal would be used, instead 360mm, with large DOF.


What I mean is that in general for 8x10 larger circles of confusion are allowed to say something is in focus, because still it does not demote resolving power. This is because perhaps we enlarge less, or because sometimes less local optical performance (per mm) is obtained.

[Christopher Barrett]

I like this DoF calculator because it also gives you comparable DoF's for many other formats. I often set up my floral still lifes on 35mm digital and use the calculator to choose my LF lens and aperture when I switch to LF.

https://www.pointsinfocus.com/tools/...305&dst=3&u=us

[Nodda Duma]

I like this DoF calculator because it also gives you comparable DoF's for many other formats. I often set up my floral still lifes on 35mm digital and use the calculator to choose my LF lens and aperture when I switch to LF.

https://www.pointsinfocus.com/tools/...305&dst=3&u=us

Thanks for the link and tip. I was going to begin experimenting with dry plate still lifes and this is helpful.

[jesse1996]

I Totally understand, I honestly just uploaded some exposure test shots with the first two images. I find it very ugly myself honestly but figured it got the overall point across.

[jesse1996]

that photo right there destroys just about nay doubts i had about 8x10, crisp all the way through!

[MAubrey]

This is only like this if you consider the same circle of confusion, but usually you can consider a circle of 0.2mm for 8x10 and a circle of 0.03mm for 35mm film. This ends in very different accepable DOF, depending on application.

For example f=360mm, f/16, Dist = 10m

DOF 0.2mm for 8x10 is 5m

DOF 0.03mm for 35mm is 0.71m

http://www.dofmaster.com/dofjs.html

So in this case 8x10 DOF is x7 larger than with 35mm


The 0.2mm circle of confusion for 8x10 would be acceptable for Karsh style portraits I guess, for a large landscape print one may consider a smaller circle that's close to lens performance for the scene microcontrast and print size, perhaps 0.1mm or even 0.05.

Of course if same framing was to be done for 35mm film then perhaps a 40mm focal would be used, instead 360mm, with large DOF.


What I mean is that in general for 8x10 larger circles of confusion are allowed to say something is in focus, because still it does not demote resolving power. This is because perhaps we enlarge less, or because sometimes less local optical performance (per mm) is obtained.

Actually, since BetterSense is talking about physical aperture, rather than relative aperture, he's correct regardless of differing CoC's.

5mm aperture on a 300mm lens for 8x10 is ~f/64.
5mm aperture on a 43mm lens for 35mm is ~f/8.

Focused to 10ft, both will have a DOF of ~9.2ft.

From http://www.dofmaster.com/dofjs.html:

[Pere Casals]

Actually, since BetterSense is talking about physical aperture, rather than relative aperture, he's correct regardless of differing CoC's.

5mm aperture on a 300mm lens for 8x10 is ~f/64.
5mm aperture on a 43mm lens for 35mm is ~f/8.

Focused to 10ft, both will have a DOF of ~9.2ft.

From http://www.dofmaster.com/dofjs.html:

Sorry, I missed "aperture diameter". I was not used to the "aperture diameter" parameter, an interesting concept.

Just I'd like to add a side concern: a larger CoC may not demote sharpness of an small print, but most good LF lenses lose resolving power by /22 as difraction limited systems.

[Jac@stafford.net]

A rule of thumb: A frame including 6' to infinity @ F/22 with 6° to maximum of 12° top rear tilt does wonders for DOF.

[Pere Casals]

A rule of thumb: A frame including 6' to infinity @ F/22 with 6° to maximum of 12° top rear tilt does wonders for DOF.

I'll remember that rule

[MAubrey]

Sorry, I missed "aperture diameter". I was not used to the "aperture diameter" parameter, an interesting concept.

Agreed, "aperture diameter" was a bit of an unusual. It took me a couple reads before I realized it myself!