Sumix 2/3" 1920x1080 CMOS

[Jose A. Garcia]

I'm not so crazy...

Sometimes I like to think I can do things like creating a fullHD camera from scratch just by myself, but those thoughts don't last.

What I'm actually considering is to buy the camera again once I have a little money to spare. My production team is keeping the HV20 and I'm always looking for things to do on my free time. I still think we can develop a great low cost digital cinema cam.

[Gottfried Hofmann]

Originally Posted by Farhad Towfiq

.
I suggest if you decide to continue with this project to keep it as simple as possible. Mechanical integration, lenses, computers, display, power supply, programming, third party software, and endless testing is just too much for a single person.

Well, I just want to attach a lens, plug the cam into a notebook and start recording. So no mechanical integration, display, power supply. Just software (maybe programming) and endless testing ;)

[Jason Rodriguez]

Hi Daniel,

I'm looking at all your RAW files, and it appears as though the physical column arrangement of the sensor is reversed when it's being recorded.

So for example, your column alignment rather than being column:

1, 2, 3, 4, 5, 6 . . .

is more like 3, 1, 2, 6, 5, 4 . . .

This is causing some significant aliasing artifacts that shouldn't be there. This alignment would cause the RAW encoder to think the bayer pattern phase is still the same, but the row mis-aignment will cause some serious issues.

Also it could simply be a simple column mis-match (rather than three-way column out-of-order like above), meaning instead of column:

1, 2, 3, 4, 5, 6 . . .

it's

2, 1, 4, 3, 6, 5 . . .

This would cause a bayer phase reversal, and would also cause bad aliasing to occur as well. If the bayer phase was guessed correctly, then you would be getting the correct color, but the aliasing would not be removed.

Point is your images are demonstrating aliasing that shouldn't be there. Your images should be much smoother.

Thanks,

Jason

[Daniel Lipats]

Jason,

Thank you for your analysis. This is something we have been working on. The videos are indeed showing aliasing:
http://dreamstonestudios.com/persona...s/aliasing.jpg

The aliasing is most prominent when CineForm is set on "playback - Quality" setting.
When using "playback - Fast", the aliasing is gone.

Hopefully this is something that will be fixed soon.

Thanks a lot.

[Jason Rodriguez]

The reason you don't see it as much on "Fast", is because that algorithm is a simple bilinear demosaic . . . still though, even with bilinear, I'm seeing it on my machine here, and the resolution loss is very evident.

Thanks,

Jason

[Farhad Towfiq]

Daniel, Does the codec software confuse the order of the colors? We do not see this problem in our Bayar data and deBayer images. Perhaps the codec is assuming a different order of GRGB than the sensor is putting out.

[Daniel Lipats]

Farhad,

When selecting the CineForm RGB Codec, you have to specify the pixel order. I have tried all 4 pixel order settings, this one is the only one that works at all. Its also the same pixel order as in the documentation.

I don't think there is a problem in the Sumix Bayer data. The videos the Sumix software outputs seem to display correctly.

I am working with NorPix to resolve this issue.

[Daniel Lipats]

Here is a bit of an update...

First of all, the bug with cineform has been fixed. New versions of cineform should work fine now. I have not had a chance to test it yet.

I did have a chance to test some new software from Sumix for the camera tonight. Its getting better, has more features and becoming easier to use. Has a new RAW capture mode, along with the old AVI. I was very happy to see zoom options, so now the video can be scaled down to fit on lower resolution monitors without cropping.

However, it still lacks a few basic features which are very important to our needs. Here they are summarized:

1) Preview
When recording, the video preview shuts down. No way to watch what your capturing.

2) Recording
You still have to specify how many frames you will record ahead of time, for example the default is 100. Once you hit record, the software captures 100 frames and when complete it dumps that to the hard drive. I can see the need for this because a single hard drive is simply too slow. A raid setup would be required for real time capture to disk.

Right now the Sumix software supports an uncompressed AVI format. If a 3 second uncompressed AVI video is ~600mb, then 60 min of video is about ~720gb.

I think we have to consider some form of compression.

[Biel Bestue]

but still we should have the possibility to shot uncompressed, an option to choose is always wellcome

[Peter Moretti]

Originally Posted by Paul Curtis

Can you apply different LUTS at different exposures (a 3D LUT?)

The CCD vs CMOS thing is an observation. Every 'raw' image out from cmos i've personally seen looks desaturated and the colour red is usually off (even the red camera images seen very flat). CCD on the other hand seems more faithful to the scene. Now whether this is an issue of pixel size (perhaps), because the CMOS has onboard electronics in each pixel reducing the size compared to a similar CCD. Or whether it's fundementally because of the difference in materials i don't know. If anyone can agree or refute my observations i'd like to hear more and understand why.

cheers
paul

Paul, I would imagine this has to do with the fact that most of the CMOS camers are single sensor design. So they use a Bayer sensor pattern that over-represents the greens at the expense of red and blue. Hence raw images will look greenish and desaturated.

On the other hand, most of the CCD cameras are three sensor design, so you are getting the full amount of color raw.

This may be the explanation for what you are seeing.

[Jason Rodriguez]

Not quite true . . . just look at the Viper, a 3CCD camera that still has green as the most sensitive color. Also the Andromeda modification for the DVX100 showed magenta highlights where you find that the green has clipped before the red and blue channels.

The "green" can be very simply removed by white-balancing though. So when you see a "green-ish" RAW image, it simply means there is no white-balance applied.

Thanks,

Jason

[Daniel Lipats]

I have been playing with different settings and im starting to finally get some good, clean images from the sumix camera. Its giving my Panasonic DV camera a run for its money in terms of dynamic range and sensitivity.

Here are some tests I shot this morning. Set at 12bit, 24fps, 0 gain. Unfortunately I forgot to white balance! So they all have a bit of a green tint to them. I tried to remove with some post work.
http://dreamstonestudios.com/delete/frame63_zeiss.jpg
http://dreamstonestudios.com/delete/frame_lens2.jpg

Here is a still from the same setup taken with a Panasonic 3CCD DV camera:
http://dreamstonestudios.com/delete/IMGA0245.JPG
http://dreamstonestudios.com/delete/IMGA0241.JPG

I think my next move should be getting my hands on a real HD c-mount lens. The images are a bit soft, and I think they can be improved on a lot.

I'm starting to like the results.

[Noah Yuan-Vogel]

Good to see you are still working on this. The images look nice but i cant tell if the edge blurring is from poor lenses or odd bokeh, and is it just me or does it look like there is still some infrared light being picked up? i remember finding that without correct IR filtration on my old sumix camera images had a similar reddish tint and a some diffusion from the IR light not focusing correctly. it doesnt look that bad on yours compared to my old camera but it does still appear to be there at least to my eyes. im not even sure how you can compare to your panasonic (gs series?) dv camera... :P

[Daniel Lipats]

Noah,

I think its just poor lenses. Something odd about this Zeiss one especially. The picture with lens2 prefix is sharper. I'm looking to spend $300-$500 on a decent c-mount prime but I can't find anything I like. I don't want to make another uneducated purchase, I have spent over a grand on poor lenses already.

The reddish tint is actually my rushed color correction attempt. It hurt the color quality a bit but does look better, it was pretty green. I will be shooting more tests and will make sure to white balance.

Yeah, I think its a GS150. I wanted to show what the scene looks like through a CCD camera and its the only one I have here at home. I hope to put it head to head with prosumer HD cameras soon, but first need better optics and a faster network card.

[Biel Bestue]

Daniel, how is the camera performing with low light levels? when does grain appear?