DOF with different formats/same/different lens/2K windowed

[MarkusKloiber]

There's been a lot of postings regarding DOF.
what i tested some years ago and found out with different still photography formats is:

1.For an equivalent field of view, the small-sensor camera has at least x-times MORE depth of field than a full-frame camera would have - when the focus distance is significantly less then the hyperfocal distance.

2.Using the same lens on a small-sensor camera and a full-frame camera, the small-sensor image has x-times LESS depth of field than the full-frame image would have (but they would be different images since the field of view would be different)

3.If you use the same lens on a small-sensor camera and a full-frame camera and crop the full-frame image to give the same view as the digital image, the depth of field is IDENTICAL.

4.If you use the same lens on a small-sensor camera and a full-frame camera, then shoot from different distances so that the view is the same, the small-sensor image will have X-times MORE DOF than the film image.
Close to the hyperfocal distance, the small-sensor camera has a much more than x-times the DOF of a full-frame camera. The hyperfocal distance of the small-sensor camera is x-times less than that of a full-frame camera.


add2) I printed both, the small format and larger format to 8"x12".
since i had to enlarge a 35mm neg. 8.46x times and the 6x9 3,38x times, the larger format yielded in (0.4X) MORE DOF.

[Nick Gardner]

I think a simpler way to say what you just did, is that a 50mm lens focused at 6' at an f-4 will have the same depth of field on any format. Only the angle of view changes. Incidentaly, depth of field is only affected by f-stop and image magnification, focal length is irelevent. For example if you shoot a wide shot on an 18mm lens at a 5.6, practically the whole world is in focus. Now do the same shot on a 300mm. By the time you back the 300mm up far enough to get the same frame as the 18mm, you have the same depth of field. By the same token if you shoot an ecu on the 18mm, the actor is so close to the camera that the depth of feild is the same as if you backed the camera up and used an 85mm.

Nick "math is cool when it comes to focus" Gardner

[MarkusKloiber]

I think a simpler way to say what you just did, is that a 50mm lens focused at 6' at an f-4 will have the same depth of field on any format. Only the angle of view changes.

Nick "math is cool when it comes to focus" Gardner

Nope. I tried to explain it in "2."
a 50mm lens on 35 will have more DOF than a 50mm lens on 16mm (different FOV of course), since you're calculating with different circles of confusion.
check your kelly guild.

EOS 40D/EOS 5D
capture at the same distance,same F/stop, same Focal length. enlarge (but don't crop the full frame image!) to the same print size image.
voilà.

[Stephen Williams]

Nope. I tried to explain it in "2."
a 50mm lens on 35 will have more DOF than a 50mm lens on 16mm (different FOV of course), since you're calculating with different circles of confusion.
check your kelly guild.

EOS 40D/EOS 5D
capture at the same distance,same F/stop, same Focal length. enlarge (but don't crop the full frame image!) to the same print size image.
voilà.

Hi,

The DOF is identical as Nick previously explained. If you cut out a 16mm frame out of 35mm frame the DOF does not change.

Stephen

[MarkusKloiber]

Hi,

The DOF is identical as Nick previously explained. If you cut out a 16mm frame out of 35mm frame the DOF does not change.

Stephen

Hi Stephen,
I remember one of my old photographer Buddys saying: "DOF relates to a print or other reproduction of an image."
I think this question is an old chestnut.

[Stephen Williams]

Hi Stephen,
I remember one of my old photographer Buddys saying: "DOF relates to a print or other reproduction of an image."
I think this question is an old chestnut.

Hi Markus,

By adjusting the CoC you are assuming a different size of viewing I think, 35mm film has a greater DOF on a SD television than on a large screen.

Stephen

[MarkusKloiber]

Hi Markus,

By adjusting the CoC you are assuming a different size of viewing I think

Stephen

Grützi Stephen,
That is exactly what i mean.
You cannot really compare the 2 DOF. (50mm/16mm format and 50mm/35format) but somehow you can.
you "use" a CoC of 1/1000 for 16mm work (since the image needs to be blown up much larger to fill the same screen/whatever)
...since a CoC of 1/700 for 35mm is vital, you'll see that if you projected both prints on a screen of let's say 5x9 meters, the 35mm would have more DOF (on the screen).

[Stephen Williams]

Grützi Stephen,
That is exactly what i mean.
You cannot really compare the 2 DOF. (50mm/16mm format and 50mm/35format) but somehow you can.
you "use" a CoC of 1/1000 for 16mm work (since the image needs to be blown up much larger to fill the same screen/whatever)
...since a CoC of 1/700 for 35mm is vital, you'll see that if you projected both prints on a screen of let's say 5x9 meters, the 35mm would have more DOF (on the screen).

Hi Markus,

I generally use CoC 1/2000 for S16 blow up, with sharp modern lenses & 1/700 for 35mm on TV.

Stephen