question about crop factors

[Sam Eilertsen]

So, I've heard a lot about the "crop factor" on lenses when shooting on cameras like the R1 or the 7D which do not have FF35 sensors. In particular, I've heard people describe a 30mm lens as the "equivalent" of a 50mm, the 50 as the equivalent of the 85, etc, when shooting with an APS-C sized camera.

This confuses me when talking about video. An APS-C camera may have a 1.5x crop relative to an FF35. However, motion picture film itself is not FF35 sized, the R1 is designed to be similar in coverage to Super35, and the 7D is only a little smaller.

So, my question is, am I right in my conclusion that if I use a 50mm on an APS-C camera, in terms of the effects of focal length (compression of space, bokeh, etc), it will be fairly similar to using a 50 on a 35mm film camera, whereas if I use it on say the 5D, it will actually look wider than it would on film?

Thanks!

 

[David Rasberry]

Short answer: Yes.

You can download my Excel spreadsheet that calculates horizontal angle of view and crop factors vs focal length for common film and digital formats here:

http://www.scarletuser.com/showthread.php?t=3958

 

[camred]

I have another question and maybe you can help me.

I have to track a few shots , this shots were recorded with the red one 4k ( 4096 x 2304 )

Then they , reduce the shot to 2048 x 878 size . 2,33 : 1 aspect ratio .

If they used for example a 40 mm lens . What is the focal lenght that i have to use to track this shot ?



Thank you and a greeting

 

[Erich Ocean]

I have to track a few shots , this shots were recorded with the red one 4k ( 4096 x 2304 )

Then they , reduce the shot to 2048 x 878 size . 2,33 : 1 aspect ratio .

If they used for example a 40 mm lens . What is the focal lenght that i have to use to track this shot ?

40mm

 

[Mitch Gross]

Perhaps you might find this useful.

http://www.abelcine.com/articles/in...al-sensor-comparison-chart&catid=24&Itemid=45

 

[Sam Eilertsen]

Thanks.

 

[David Wyatt]

I've found an iPhone app called "Match Lens" quite helpful for working out lens equivalents on different formats - it's got film formats, video formats & still formats.

 

[David Mullen ASC]

It all depends on what your frame of reference is. If you've been shooting on FF35 cameras your whole life, then that's your reference to what a 50mm does, a 28mm does, etc. If you've been mostly shooting on 3-perf and 4-perf 35mm movie cameras and APS-C still cameras, then that's your frame of reference.

 

[J Davis]

Does anyone know the height and width in pixels of a 1:2.39 crop on the scarlet 2/3 sensor?