How do I calculate the circle of confusion for Mark II 5D 1080p?

[salils]

I'm a little confused, 35mm motion picture film (22mm x 12.375mm) is supposed to have a CoC of .025mm. I've been reading on wikipeida and various sites that the CoC of 35mm full frame film is 0.024mm or 0.029mm. I'm guessing this is for print work so I guess that screw things up. How can I can calculate the CoC of the Mark II 5D for 1080p video display?

 

[derekhillier]

Hi

Try this

http://www.dofmaster.com/digital_coc.html

 

[salils]

Doesn't the circle of confusion change depending on the resolution you're shooting at though?

 

[robotsound]

I believe the frame size is the same either way. It's just a question of how many lines it skips.

 

[morgan_moore]

Doesn't the circle of confusion change depending on the resolution you're shooting at though?

I think the correct phrase may be

Acceptable COC that is perceived as sharp depends on screen size, resolution and viewing distance

S

 

[derekhillier]

Try this

Try this

http://www.rags-int-inc.com/PhotoTechStuff/DoF_Calculator/DoF_Calculator.html

 

[Otis Grapsas]

Most of the stuff on COC on the net is devoted to ancient still image print viewing and applied to video with massive amounts of ignorance and lack of common sense. It make sense to set COC in video to the sharpness limit of the system chain in the delivery resolution. Everything beyond the limiting resolution in the imaging chain (sensor->format->outputscreen) will appear to be in focus. That's based on the very difinition of COC.

HD video mode = one pixel = the width of the sensor / resolution of width. 36000um/1920pixels=18.75um/pixel (COC=0.01875mm).

For a 2/3" 1080p = 9600/1920=5um=0.005mm.
For a 2/3" 720p = 9600/1280=7.5um=0.0075mm.

As you see, COC depends on resolution and only tells you where the image will be maximally sharp for your imaging chain. For the same camera, it's limited by device resolution AND format resolution AND output screen resolution. A 1080p format using 960x540 sensor demands the 540p COC. If you intend to output an online video at 360p it changes to 0.150mm, even if you capture at 1080p using a 1080p format.

If you care for DOF in terms of blur at given points, you can easily calculate that also. The DOF look, is not limited by resolution. What counts is how the blur diameter relates to to the screen dimensions. What % of the screen size blur is equal to. If you care about 10pixel diameter blur, set COC to 10xCOC as I calculated it above. Then you have the distances that will get that blur amount.

With this method you can compare DOF and any blur point in any digital system.