Super 8 depth of field verses 16mm

[Henderson]

I know that depth of field tables are different between 35mm and 16mm but what about between 16mm and Super 8. The reason I ask is because I downloaded a DOF calculater and all the calculations are the same for 16 and 8 but not 35.

[MovieStuff]

Actually, for all practical purposes, the depth of field per focal length is identical regardless of what camera you put the lens on. For instance, if you put a 12mm lens on a Nikon, it will look like a fisheye lens with lots of distortion and depth of field out the ass. In fact, you won't really even need to focus. If you put that same lens on a Super 8 camera, it will look "normal" with no distortion because the 8mm format only uses the very middle of the image where distortion is non-existant or minimized. However, your depth of field will still be out the same as it was on the Nikon. Depth of field accompanies the lens and exists, even if no camera is attached!

Roger

[mattias]

the only format dependant parameter in the dof formula is the size of the circle of confusion, which is the diameter of the smallest detail the film/ccd/whatever can register. how you calculate this depends on the emulsion used, how you want to view the results and almost even the phase of the moon. the most important part of the formula is the focal length of the lens though, so you can really use any chart for any format. since super8 is less sharp than other formats the circle of confusion is bigger and the dof thus larger, so you'll always be on the safe side.

/matt

[Henderson]

Actually, for all practical purposes, the depth of field per focal length is identical regardless of what camera you put the lens on. For instance, if you put a 12mm lens on a Nikon, it will look like a fisheye lens with lots of distortion and depth of field out the ass. In fact, you won't really even need to focus. If you put that same lens on a Super 8 camera, it will look "normal" with no distortion because the 8mm format only uses the very middle of the image where distortion is non-existant or minimized. However, your depth of field will still be out the same as it was on the Nikon. Depth of field accompanies the lens and exists, even if no camera is attached!

Roger, back to my original question. Would the tables be different between 8 and 16 because according to the ACS manual a 35mm LENS on a 35mm camera will render a DOF at 25ft of 15'4"near and 67'1"far and on a 16mm camera it will render a DOF at 25ft of 19'0"near and 36'5"far. So what would it be on a Super 8 camera?
Henderson

[crimsonson]

Like they said, technically the DoF is exactly the same for the same lens in any camera. But the overall result is dependent on the Circle of Confusion and for simplicity's sake we will use the size of the imaging plane instead.
So for S8, it is compareable to 1/2" CCD.

[Lucas Lightfeat]

Mattias

If the only format relevant parameter is the circle of confusion, but it's not that important really, why does the ACS manual say what Henderson says, if you can rely on any chart for any format?

Anyway, there is a specific super8 DoF chart in the archives here:

http://www.8mm.filmshooting.com/communi ... es/dof.php

Lucas

[mattias]

because the circle of confusion is different for different formats. the numbers henderson posted don't sound right though. the difference isn't that big and since 16mm is a smaller format it should actually have a slightly deeper dof, not shallower. the reason why the circle of confusion (cof) is important is that slightly out of focus objects won't look as out of focus on a smaller format or one with a lower resolving power, since they're not as sharp. this means you don't have to be as dead on with those formats, which is wexactly what the cof is about...

[tim]

Depth of field does not depend on either format or film. It is simply a calculated value of the ability of an ideal lens to produce an image of a given degree of sharpness over a spread of range. Camera lenses which actually permit the theoretical limit of resolution to be obtained tend to be rare anyway.

Depth of field is only format dependent if a lens is not corrected to adequately cover the film frame. Then, the image sharpness in the corners of the frame deteriorates so that depth of field becomes irrelevant.

In practice, the resolution of lenses is only about twice as good as film, even at large apertures. Thus, perceived depth of field is only affected by film if a very fast (large grain) film is used with a fairly small aperture lens.

[mattias]

Depth of field does not depend on either format or film. It is simply a calculated value of the ability of an ideal lens to produce an image of a given degree of sharpness over a spread of range.

yes, but this "given degree of sharpness" depends on the film stock.

however, now that i think about it, the format itself probably acts the other way from what i previously wrote. the smaller the format the larger the magnification during projection, so a smaller format actually has a slightly smaller coc (and thus shallower dof), am i right? i still think the lens sharpness and emulsion resolving power matters the most and i've never had any trouble using 16mm charts for super-8, but still?

/matt

[Lucas Lightfeat]

however, now that i think about it, the format itself probably acts the other way from what i previously wrote. the smaller the format the larger the magnification during projection, so a smaller format actually has a slightly smaller cof (and thus shallower dof), am i right?

Mattias, I'm amazed that you're asking a question about this, as you are normaly such an authority on cinematographic related details, but I can assure you that 35mm has a much shallower dof than 8mm. I forget about the circle of confusion, but the rules are as follows:

Greater Depth of Field

Wide lens
High f stop number (small apperture)
Subject far from camera
Smaller format (eg. Super8)

Lesser Depth of Field

Telephoto lens
Low f stop number (wide apperture)
Subject near camera
Large format (eg. Super35)

So the variable introduced with the circle of confusion is something we cannot easily account for because it is film stock and format dependant, so quite a complex issue, but it is not really important (unless you are fascinated intelectually, of course) as Awand, our thoughtful moderator, has posted a chart which stretches into the Super8 range of focal lengths.

Happy focussing

Lucas

[Lucas Lightfeat]

however, now that i think about it, the format itself probably acts the other way from what i previously wrote. the smaller the format the larger the magnification during projection, so a smaller format actually has a slightly smaller cof (and thus shallower dof), am i right?

Mattias, I'm amazed that you're asking a question about this, as you are normaly such an authority on cinematographic related details, but I can assure you that 35mm has a much shallower dof than 8mm. I forget about the circle of confusion, but the rules are as follows:

Greater Depth of Field

Wide lens
High f stop number (small apperture)
Subject far from camera
Smaller format (eg. Super8)

Lesser Depth of Field

Telephoto lens
Low f stop number (wide apperture)
Subject near camera
Large format (eg. Super35)

So the variable introduced with the circle of confusion is something we cannot easily account for because it is film stock and format dependant, so quite a complex issue, but it is not really important (unless you are fascinated intelectually, of course) as Awand, our thoughtful moderator, has posted a chart which stretches into the Super8 range of focal lengths.

Happy focussing

Lucas

[Guest]

I can assure you that 35mm has a much shallower dof than 8mm.

In practical terms, that is true. The "normal" lens for 35mm film has less depth of field than the "normal" lens for 8mm.]

-HOWEVER-

When COC mechanics are taken into account, there is a feeling held by some that depth of field is also related to the size of the final image. In other words, depth of field can theoretically change depending on whether the image is viewed large or small. For instance, a shot made with a telephoto lens (where the subject is isolated with the background in soft focus) may lose some or its "isolation" if the image is printed at 4x6 inches as opposed to 4x6 feet. The idea is that the COC is reduced in the 4x6 print and, therefore, areas of the print that were originally out of focus will appear in focus.

I tend to see this more as an illusion and not so much a result of changes in actual depth of field since the differences in visual acuity of each person, as well as viewing distance, play as much a part as anything. One could stand far enough away from a 4x6 foot photo that it ends up being as small as a 4x6 inch photo to the unaided eye. Does the person standing 5 feet from the photo see different depth of field than someone standing 30 feet from the photo? Theoretically, yes. But in a practical sense the difference has to be so exaggerated as to not be an applicable technique.

Also, if one puts a 50mm lens on an 8mm camera and backs away enough so that the subject is the same size in the frame as it is when the 50mm lens is used on a Nikon, then depth of field considerations are somewhat different. Therefore, depth of field or, rather, "perceived" depth of field can depend on a variety of factors other than just what focal length or f stop is being used. In general, though, I tend to take the simpler view that smaller formats have more depth of field than larger formats, even though there are other factors that can equalize the playing field a bit.

Roger

[S8 Booster]

Do not know if this is of any use but here is the DOF chart for the Schneider 6-70mm lens.



R

[Guest]

Do not know if this is of any use but here is the DOF chart for the Schneider 6-70mm lens.



R

Yeah, I just read that although DOF is pretty much the same across each individual format (e.g., Super 8, 16, and 35), each particular lens has its own tables with more precise readings because the construction of each lens is unique. Circle of confusion for 35mm is 1/500, 16mm is 1/1000 and Super 8 is even smaller although closest to 16mm. Thus, if need be, a 16mm table will work as a "ball park figure" of Super 8 Depth of Field.

Lucas, if you find a DOF table for your 6080 let me know. That's what I'm hunting for. I'll hook you up if I find it.
Henderson

[jessh]

It's nice to see so much conflicting information stated as fact ;-)

here is a link that I believe explains the whole DOF matter rather well: http://luminous-landscape.com/tutorials ... /dof.shtml

it isn't specifically in relation to super8, but it should help you figure out what to believe :-)
It helps to get rid of some common misconceptions as well, "Most people also believe that wide angle lenses have more depth of field than telephoto lenses (false)." read the whole article and look at their examples to find out what they mean by that.

Basically Depth Of Field like almost anything else is a very relative term, there is no absolute depth of field for any given setup, it depends on the circle of confusion used. And unfortunatly there is no absolute circle of confusion for any given format. Acording to The Filmmaker's Handbook[/u[ 'Traditionally 1/500" circle of confusion was used for 35mm filming, and 1/1000" was used for 16mm'(Appendix B)

The reason that a smaller circle of confusion is used with 16mm than 35mm is that ther 16mm frame has to be magnified more in order to cover the same space. If you were planning on projecting your super8 frame to the same size screen as commonly used for 16mm and 35mm films I would use a 1/2000" circle of confusion. Since most super8 ends up on a much smaller screen you can probably get away with a larger circle of confusion, so you could use 16mm tables. I personally use a program on my palm pilot to do the calculations.

While 35mm is said to have a much shallower depth of field than super8, at the same focal length it will actually be the exact same if you are using the same circle of confusion, and if you use a smaller circle of confusion 35mm will actually have more depth of field at the same focal length. But since with super8 you use much smaller focal length lenses, you end up getting much more depth of field for the same amount of coverage.

could someone please post what the ACS manual says about the subject, specifically whether it includes a circle of confusion that should be used with super8. I really need to buy myself a copy, but they are so damn expensive.

~Jess