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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

Megapixel of the sensor vs. actual output

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doondoon

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This is a subject that has always confused me a bit.

Is the sensor on RED / EPIC higher resolution than what it outputs (4K-6K) ? In other words how is the sensors resolution measured? Is it in Megapixels or in "K".

Maybe I'm getting "K" mixed up with "megapixels".

(megapixels is millions) and (K) is thousands correct ?

sorry, I know it's a totally goof question.
 
Just depends on what you choose as your final project size.

http://www.red.com/cameras/tech_specs/

The active sensor area is 4520 x 2540, which is 11.5MP. Let's say you are shooting in 4K 16x9 mode, which is 4096 x 2304 (9.4MP) -- the area outside of 4096 x 2304 on the sensor is just used for a look-around area on the viewfinder.

So you record 4096 x 2304 pixels (4K) in RAW Redcode and that has to be converted / debayered into RGB, either 4K or 2K, whatever you select. Technically if you convert 4K RAW into 4K RGB, the pixel size is the same for the frame but you've tripled the amount of data to handle because you've got separate 4K signals for red, green, and blue now.

Now there is a difference between the size of the files and the measurable resolution after debayering, which is usually less, like 75% of the original pixel resolution. So your 4K file may measure to 3K in terms of the amount of detail you have in the image. But lots of real world factors affect measurable resolution as well, a slightly soft-focused shot, a poor lens, etc. and you may only be able to measure 2K or less despite the size of the files being 4K.

"K" is thousands and 4K refers to horizontal resolution only, 4000 pixels across (though in industry terms, "4K" is usually 4096 pixels).

Megapixels refers to the total number of pixels, which you get by multiplying the number of horizontal and vertical pixels. "Mega" is millions.
 
doondoon said:
Maybe I'm getting "K" mixed up with "megapixels".
Click to expand...

"K" is the width of the image, in thousands (or more accurately, 1024's) of pixels. 4096 pixel wide image is called "4K", regardless of it's height.

"megapixels" is the total amount of pixels in the image in millions. 4096*2048 sized image has 8,388,608 pixels, or "8MP"

Red One has 4520*2540 pixels, so it's pixel resolution is "4.5K" or "12MP".

The actual amount of detail any camera can resolve is always less than it's pixel resolution, because of lenses, optical low pass filtering and possible bayer pattern sampling all eat away some of the theoretical resolution.

Edit: David was faster - and remembered to mention that Red One doesn't record all active pixels ;-)
 
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David Mullen ASC said:
Just depends on what you choose as your final project size.

http://www.red.com/cameras/tech_specs/

The active sensor area is 4520 x 2540, which is 11.5MP. Let's say you are shooting in 4K 16x9 mode, which is 4096 x 2304 (9.4MP) -- the area outside of 4096 x 2304 on the sensor is just used for a look-around area on the viewfinder.

So you record 4096 x 2304 pixels (4K) in RAW Redcode and that has to be converted / debayered into RGB, either 4K or 2K, whatever you select. Technically if you convert 4K RAW into 4K RGB, the pixel size is the same for the frame but you've tripled the amount of data to handle because you've got separate 4K signals for red, green, and blue now.


Now there is a difference between the size of the files and the measurable resolution after debayering, which is usually less, like 75% of the original pixel resolution. So your 4K file may measure to 3K in terms of the amount of detail you have in the image. But lots of real world factors affect measurable resolution as well, a slightly soft-focused shot, a poor lens, etc. and you may only be able to measure 2K or less despite the size of the files being 4K.

"K" is thousands and 4K refers to horizontal resolution only, 4000 pixels across (though in industry terms, "4K" is usually 4096 pixels).

Megapixels refers to the total number of pixels, which you get by multiplying the number of horizontal and vertical pixels. "Mega" is millions.
Click to expand...

So the sensor on the Canon 5D or Nikon D700 is roughly "4K" as well (their sensors are around 12 megapixels). That makes me wonder how a single frame from one of the above cameras holds up against a single frame of the RED camera.... it seems like the Nikon or Canon would be less compressed since they only have to take one picture at a time vs. 24 fps.

thanks for your explanation David. It puts things into perspective for me
 
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