Blackmagic Forum

1) How many stops in pro res?
2) Is the sensor size 21.12mm wide as per the technical specs page here
http://www.blackmagicdesign.com/nz/prod ... /techspecs
or 22.12mm as per the sensor size illustration here.
http://www.blackmagicdesign.com/nz/prod ... technology
3) How much noticeable difference do people think there will be between 12 and 13 stops.

Mark2929 wrote:3) How much noticeable difference do people think there will be between 12 and 13 stops.

I don't know what people think, yet i think the answer depends on how much grading you're going to do in postproduction. In a perfectly lit scene you probably won't notice any difference, but the more you tweak the footage, the more you'll miss that 13th stop. Still 12 stops is an excellent dynamic range, and combined with BMs great color science you'll capture beautifully stunning images.

Lots and lots of grading so - obviously stops are useful to me. So how much will I lose?

This is a 16 stop DR chart, with ISO scales..based off the Alexa.



To over-simplify a response...the DR difference from 13 to 12 stop would be one stop of available information, which when looking at a visual representation like this chart, should give you an idea of how "much" you're losing.

you're image quality is still going to largely depend on your exposure and the contrast level you light your scene with.

Mark2929 wrote:...
2) Is the sensor size 21.12mm wide as per the technical specs page here
http://www.blackmagicdesign.com/nz/prod ... /techspecs
or 22.12mm as per the sensor size illustration here.
http://www.blackmagicdesign.com/nz/prod ... technology
...

Nice catch. I hadn't noticed that typo before (I've always used the numbers on the Tech Specs page for reference). I don't know which one is correct, regrets.

I wonder if Blackmagic Design is aware of that error on their website?

P.S.: I've sent Kristian Lam a PM about this typo.

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Mark2929 wrote:1) How many stops in pro res? ...

BMD hasn't released that info about the BMPC-4K yet. In fact they haven't "officially" released similar info about the original BMCC, either.

However, John Brawley has posted that there is "a small difference" in the BMCC's dynamic range when recording ProRes compared to RAW, the latter being slightly better. I understood this to mean <1-stop less with ProRes.

I suspect results will be similar with the BMPC-4K, subject to end-user testing.

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sean mclennan wrote:you're image quality is still going to largely depend on your exposure and the contrast level you light your scene with.

Sean
Looking at that I would want to lose 2/3 of a stop from the shadows and a third from the highlights.

Pete
Cheers!!! Maybe the sensor is a little bigger.

Mark2929 wrote:...Is the sensor size 21.12mm wide as per the technical specs page...

Yes, anything else is a typo. Multiply 3840 by .0055 (the photosite size).

Rick Lang
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