Aperture to depth of field normalisation across various formats

[Ricgal]

I am setting a very precise portrait brief for 5x4 and would like to open it up to other formats whilst retaining the same dof.
Is there a chart or formula somewhere to calculat what aperture would correlate 150mm and f16 on 5x4 with 50mm on 35mm format? I am guessing f8 ish.
I would need to do the same with MF and dx/apsc formats-- 10x8 too come to think of it
Thank you for your help
regards
Ric

[Bob Salomon]

The Rodenstock DOF/Scheimpflug pocket calculator calculates both for all forats from 35mm to 8x10. It will also indicate exposure corrections, if needed.

[SergeiR]

I am setting a very precise portrait brief for 5x4 and would like to open it up to other formats whilst retaining the same dof.
Is there a chart or formula somewhere to calculat what aperture would correlate 150mm and f16 on 5x4 with 50mm on 35mm format? I am guessing f8 ish.
I would need to do the same with MF and dx/apsc formats-- 10x8 too come to think of it
Thank you for your help
regards
Ric

https://www.google.com/search?q=dof+...ient=firefox-a

[cosmicexplosion]

https://www.google.com/search?q=dof+...ient=firefox-a

Hey thanks for awesome link sergei

[dave_whatever]

Doesn't equivalent dof for equivalent angles of view just factor in the ratio of the film diagonal? That is to say, if you had a short framed with a 90mm lens on 6x7 shot at f/11 then to get roughly the same dof with a 150mm lens on 4x5 you'd shoot at f/22 (double the diagonal, so 11x2 = 22). Not sure I've explained that right but thats the rule of thumb I tend to use.

[Helen Bach]

Doesn't equivalent dof for equivalent angles of view just factor in the ratio of the film diagonal? That is to say, if you had a short framed with a 90mm lens on 6x7 shot at f/11 then to get roughly the same dof with a 150mm lens on 4x5 you'd shoot at f/22 (double the diagonal, so 11x2 = 22). Not sure I've explained that right but thats the rule of thumb I tend to use.

It is that easy. You can apply the much maligned 'crop factor' to both the focal length and the f-number.

[Ricgal]

Dear all- thank you all for your well informed and balanced posts. Being less than a* at maths I will probably check out the DOF calc for iPhone on the site suggested.
All the best
R

[dave_whatever]

Of course in that example the ratio is actually about 1.7 not 2, so more like f/18 if were being picky,but you get my drift.

[Jim Jones]

Ric, f/4 on 35mm format has about the same DOF as f/16 on 4x5 where the angle of view is about the same and the print size, viewing distance, and acceptable Circle of Confusion are the same.

When images captured on different formats are viewed at the same size and distance, the DOF is dependent only on acceptable CoF, subject distance, and entrance pupil diameter. This reduces the calculations to math we can manage in the field. It also makes DOF scales on view cameras work with any focal length lens for a standard print size and CoF. My math skills have deteriorated in the 60+ years since high school, so I'll leave it to one of you youngsters to present this subject in a more digestible form.

[drew.saunders]

This site has many versions of their calculator, an explanation of the CoC chosen for each format, and you can pick your own CoC for the charts if you don't like the default for your format.

http://www.dofmaster.com/