35mm lenses on a 16mm camera

[Steven]

Dear colleagues and cinematographers,

 

I am a focus puller and have a question concerning the depth of field I get,when I use 35mm lenses on a 16mm camera.

First of all,the movie will be screened on t.v. so the circle of diffusion for t.v.should occur.

Due to the prospect of having a more different focal lenght range,for my next project we will have Zeiss T2.1 35mm lenses on our 16mm Arri SRIII camera.

 

Now I compared the ratio and it showed,that for a 24mm(35mm T 2.1) i get roughly the image, a 16mm (16mm T1.3) lense would give me; or for example a 32mm(35mm T 2.1) gives me the same ratio as a 20mm (on a 16mm Zoom Lense) i would get....

 

Now my question,how deep is my depth of field,for example on the 24mm(35mm T2.1) do I have the depth of field of the 35mm depth of field chart ,or is the depth of a corresponding 16mm lense in this case 16mm T.1.3 my valid reference...

 

Can I use my kelly wheel,or do I need a samuelson hard plastic depth of field calculator,since I am able to change the circle of diffusion for 35mm lenses to the 16mm t.v. value.

 

Thank you very much for any assistance.

 

stefan

[Patrick Neary]

Hi-

 

A 24mm lens has the depth of field of a 24mm lens, regardless of what format camera it's mounted on.

[Steven]

Hello Patrick,

 

but this means,that if you compare an image created with a 16mm lense with an image of the same ratio/angle of an 35mm lense you get quite different depth of field...sounds a bit odd to me,will try to get some more informations about this topic.

 

Thanks a lot anyway.

[Wendell_Greene]

Steven, please check out the information on this subject from a past thread:

 

http://www.cinematography.com/forum2004/in...owtopic=559&hl=

[Mitch Gross]

A given lens at a given aperture does indeed yield the same depth of field no matter what the shooting format. Field of view has nothing to do with depth of field. The only issue is in the measurement is the circle of confusion, which is format-irrelevant. You mentioned the Samcine wheel, which I consider a very useful tool. You'll notice when using this wheel that there is no marking for 35mm v. 16mm or any other format. The only consideration in the scaling of depth of field is what circle of confusion tollerance you choose to use. I personally always go with the tightest tollerance, although in theory the lower resolution of SD video broadcast means that you could use a larger c.o.c.

[Steven]

Thank you Wendell,thank you Mitch,

 

I read the discussions from the link you gave me and now the subject is much more clear to me.

 

Greetings from Bavaria.

 

stefan

[Laurent Andrieux]

One thing you have to consider, too, is that for getting the same frame, you'll need a wider lens in 16, so you'll get more depth of field than in 35.