Messages

I've seen a test that indicates it does not matter if you denoise before or after color work.. but I'm sure there are situations which could give other results.

To me it makes sense to use video denoising and not doing it on the separate stills. It should be easier for the software to see the difference between detail vs noise using several frames on a static background. I used Magic Bullet first but lately Neat Video which gives better results on half the time (at least when I did the comaprisons a year or two back).

I still see ugly pattern and color noise on 5Dmk3 raw video.

Will we ever have noise without pattern and down on pixel level?

I installed LR5 and Resolve lite this weekend and will try to get the hang of them to see what it gives. Also have raw2dng and Rawmagic installed.

So far my 5d3 raw video looks like crap but I guess it's the Pilot to blame.. :-)

Can anyone explain why the raw2dng app generates a mov. file  after i drag my Raw file to the app? Is that mov. file a raw video file or it is the normal video file?

You can chose to output DNG and if you wish even a Prores file. The .mov is Prores.

Strange thing for me is my first try resulted in playable Prores with a thumbnail and after that I get a .mov file without thumbnail and not playable.

Hard to say, only did a quick test.

I use a Sandisk Extreme Pro CF 16GB specified to 90MB/s. I can record 1920x1080 25fps. Only tried up to 15 seconds or so but no dropped frames afaik.

I also managed to record 1s to a SD card, Sandisk Extreme Pro 45MB/s. I assume the buffer fills up and then it's stop while pictures are shipped to the card.

No every photosite generates one pixel. This is true for all digital imaging sensors.
So 5D3 has 22M photosites = 22M pixels = 11M green pixels + 5.5M red pixels + 5.5M blue pixels
Before demosaicing the pixels have only a 14bit brightness value, the demosaicing will reconstruct the full rgb color for every pixel by interpolation.

Thanks that explains a lot to me. I thought bayer type camera sensors typically had like four photosites for one pixel... just like an LCD display have three (one R, one G, one B) photo diods for each pixel.

I guess that also explains why a certain signal can be smaller in data size when in "non debayered"/raw form as compared to a YUV or RGB signal where new information actually have been added (interpolated).

As hinted earlier but not understod by me, my calculation was three times to big. Dividing my number by 3 actually results in a data rate very close to the actual ML 14bit raw output.

Thanks!

Hi!

I found a cheap DNG converter. Free 30 day trial, then something like 20-30USD with 30 day money back if not happy.

Convert DNG to TIFF, JPG and more.

http://www.contenta-converter.com/download.php?language=en&keywords=converter%20file%20dng&gclid=COWArbWAiLgCFfR6cAodbSoALQ

There. I corrected that for you. 

The Bayer color filter array will filter one color per photosite: either red, green or blue. As a result, for every 4 pixels there is 1 red, 2 green and 1 blue. There are more greens because humans are more sensitive to it. That's what makes bayer "compression". To get true rgb color you will need a debayering (demosaicing) algorithm. It will interpolate for every pixel the missing 2 colors from the neighboring pixels. Typically this is done by photo editing software. By the way: this is where moiré is generated.

Ok, I think we are close now.. So a 22 Megapixel sensor like in 5D3 means 22 million photosites, not 22 million groups of four (two green, one blue, one red) photosites or actuall photo sensing elements?

The reason why cameras use either a bayer filter (or prism in 3CCD/3xCMOS) is simply because in the end all sensors are grayscale, so we need to filter each color and feed it separately to the sensor. Either on photosite level (bayer) or else on sensor level (3ccd).

This I understand.

About 5D3: I'm not sure ML devs know the exact technique it uses to downscale to Full HD.
Here is what I know:
- The output is 14bit bayer, same format as the sensor but 1/3th of the resolution in both dimensions, so exactly 1/9th the information
- 5D3 probably uses all pixel information in its downscaling (unlike line skipping which typically uses one pixel out of nine)
- Its downscaling is better than line skipping: less moiré and aliasing artifacts

But in such case wouldn't the info actually be "de-bayered"?
Anyway I'm looking forward to finding out how this is managed in 5D3.

Thanks!

Maybe other kinds of compression are better, but bayer is what comes off the sensor, that's why it's referred to as raw (raw meaning unmodified*). And you won't get more information by recompressing it, I'm sure you understand that.
You could however influence quality when choosing the debayering method.

With you all the way.

You really need to learn what a bayer pattern is.

Know what it is.

But even if you don't, you should know that one of the reasons all color cameras (except for 3CCD ones) get their color from an optical bayer filter is because it's a very efficient way of compressing the data.

Or a 3CMOS such as EX1R which has no Bayer pattern or filter.

There I said it. A bayer filter is like an optical compressor applied before capturing.

Don't get that.

*) You can do some transformation on raw that results in raw. An example is line skipping: by repetitively skipping a multiple of 2 H/V lines every n lines, you will result in another true bayer pattern. This is what happens to all ML raw videos that use full sensor width, except on the 5D3

So if ML raw video on 5D3 use all the photosites of the sensor, how can the signal be raw? It must bake together groups of photo sensors/photo sites and somehow the 14bit information of something that will end up as 1080p (approx. 2MP) MUST be a higher bitrate signal than 10bit 422 1080p.

Either I have more to learn than I realize or I suck at getting my message out of my brain. :-)

Thanks!

I will do more homework but I don't see how 14bit RAW (without any kind of subsampling) can be more efficient in storing (more) info than 10bit YUV 4:2:2 uncompressed. It just doesn't make sense.

Hi, my first post here!

This I don't get.. Uncompressed 10bit video with YCC 4:2:2 subsampling is approx. 120MB/s.

How on earth can 14bit raw be less?

Going from 10bit to 14bit means an increase of 40% in data and using full color sampling (equivalent to 4:4:4) should increase bitrate further.

Also since the "raw" file we record to CF is something like 1080P obviously the sensor output must have been manipulated from "all pixels" to pixelbinning 9>1 or line skipping hence the term raw could hardly apply. Debayering must have taken place in the Digic processor already.

14bit color depth x three primary colors x 1920x1080 pixels x 24fps = 2090Mbit/s

2090Mbit/s equals approx. 261MB/s.

I use Sandisk Extreme Pro CF with max 90MB/s.

Someone please enlighten me.