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Old July 16th, 2008, 09:27 AM   #451
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Quote:
Originally Posted by Biel Bestue View Post
Daniel, how is the camera performing with low light levels? when does grain appear?
I am getting ready to do a new set of tests this weekend. Hopefully I will have time. This time I will attempt to get a better idea of the dynamic range and will take it through a variety of gain and light levels.

However, I don't believe that the full potential of this camera has been reached... So, i'm not so sure that any of it should really hold any weight. I am now considering shooting a film with it, so tests should give me an idea of how far I can push it in its current state.
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Old July 23rd, 2008, 10:57 AM   #452
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I got a C-Mount -> Canon FD SLR mount adapter for ~$30 and took a few min to try it out. I did not have any Canon lenses at home, only Minolta so I hot glued them onto the end.

http://www.dreamstonestudios.com/delete/boat1.jpg
http://www.dreamstonestudios.com/delete/boat2.jpg

50mm SLR f/1.7 Minolta set at f/4... 0 gain, 12bit, 24 fps, I think it was at 36mhz. Behaves more like an 80-100mm on this camera.

Looking at a chart here...

35mm -> 16mm
-------------------
14mm | 5.6mm
16mm | 6.4mm
20mm | 8mm
24mm | 9.7mm
28mm | 11.3mm
32mm | 13mm
40mm | 16mm
50mm | 20mm
85mm | 34mm
100mm | 40mm
135mm | 54mm


I took some Canon lenses home, a 50mm and a 28mm. I would like to find a manual Canon FD 24mm or even a 20mm.
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Old July 23rd, 2008, 12:37 PM   #453
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36mhz is the shutter? how was it lit? did you had any chance to test the latitude? when does grain start to appear?
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Old July 23rd, 2008, 01:28 PM   #454
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Originally Posted by Biel Bestue View Post
36mhz is the shutter? how was it lit? did you had any chance to test the latitude? when does grain start to appear?
No, had no time to do anything other than throw the SLR lens on and see what that looked like. We have some clients right now keeping us pretty busy. Should have more time after this week.

36mhz is the shutter. The image is a bit brighter with 36mhz but there is a little rolling shutter distortion. IMHO its in tolerance, others may say otherwise. It would depend a lot on the situation. What your shooting, how its moving, how the camera is moving, and what light you have to work with... But I would not go any lower.

It was lit with ambient sunlight coming through windows and a 1,000w softbox about ~5 feet away.
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Old July 23rd, 2008, 01:34 PM   #455
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36th of a second is 36mhz?
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Old July 24th, 2008, 11:04 AM   #456
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36Hz would be 1/36th sec... 36mhz is 1/36000000th sec :P . are you talking about shutter or the pixel clock? my guess would be that you mean you are running at 36mhz pixel clock, and altasens does 2 pixels per clock... so 72MPps which at 1080p and 8b works out to ~34fps? this would probably give you a default shutter of almost 1/34th of a second since machine vision type cameras tend to default to full open shutter for best exposure...

total shot in the dark, but is that what you mean? :)
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Old July 24th, 2008, 01:31 PM   #457
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Quote:
Originally Posted by Noah Yuan-Vogel View Post
36Hz would be 1/36th sec... 36mhz is 1/36000000th sec :P . are you talking about shutter or the pixel clock? my guess would be that you mean you are running at 36mhz pixel clock, and altasens does 2 pixels per clock... so 72MPps which at 1080p and 8b works out to ~34fps? this would probably give you a default shutter of almost 1/34th of a second since machine vision type cameras tend to default to full open shutter for best exposure...

total shot in the dark, but is that what you mean? :)
Yeah its the pixel clock frequency. ~34 fps sounds about right. You can program it to expose at 24 fps, which improves light sensitivity.

Light sensitivity at both 50mhz and 36mhz is the same as long as the framerate is the same.
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Old August 19th, 2008, 02:31 AM   #458
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Hello everyone,

I've been following this project for some time but never posted on this before. It seems this thread is quiet for now. Is Sumix still developing the software toward digital cinema uses? What's the status of the current version?
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Old August 19th, 2008, 03:55 AM   #459
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It isn't that Eric, it is just that Sumix, despite following the steps of SI, doesn't have a clue about how to put the minimum required features on the firmware/hardware for being able to develop a successful approach.
Maybe they are just gathering experience to move to a higher goal...
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Old August 20th, 2008, 04:20 AM   #460
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From what I've gathered the camera head is capable of dumping 12-bit RAW data, and recording to Cineform RAW format is already working using StreamPix. So I would imagine only a more photographer-friendly software/UI is needed to do some basic shooting. Or am I missing something?

I have some coding background but nothing related to machine vision cameras. If I were to do it I think the easiest way is to record uncompressed RAW. The data rate of uncompressed 1920x1080 24p 12-bit RAW is around 600Mb/s, about the capability of a 3-HDD RAID 0, not so unthinkable nowadays. Cineform is great but to me the added cost is considerably high.

Of course there are hundreds of other features need to be added, but if things are on the right track, I think those can all be done in time. The idea of a SI-2K mini for 1/5 the price is very tempting. I hope this project will go on. I'm seriously thinking buying one when my bank account allow.
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Old August 20th, 2008, 06:09 AM   #461
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what do you guys think of "Panchromatic" cells? couldn't this be applyed to the summix camera? Bayer filter - Wikipedia, the free encyclopedia

there is a reference to an early version: Image:RGBW Bayer.svg - Wikipedia, the free encyclopedia wich i think it's the best of those, because there is equality in all color photosites plus a white photosite

this doens't give 4:4:4 but still al colors have the same amount of photosites plus an added bonus of more light because of the white one, wouldn't this be easy to add to the camera?

this wouldnĄ't give you more resolution but more light sensitivity
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Old August 21st, 2008, 03:41 AM   #462
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Hello Daniel,

This may be a little too late, but I think the reason your Cineform RAW AVIs look different from SI-2K's ones is because SI applies a 12-bit linear to 10-bit log transfer before the encoding while yours are untouched. SI does it to preserve the most of the 12-bit linear data into 10-bit, and though the image may look right, it isn't. Not mathematically anyway. It just so happens that the linear2log curve is very similar to a gamma curve.

A true linear (gamma=1.0) image will look very dark on a standard gamma 2.2 display. Though it may appear featureless at the dark area, the detail is still there. All you have to do is apply a 2.2 gamma correction in post to get a normal view. Make sure you use 16-bit/channel project setting if you are using AE, for if you clip it to 8-bit/channel you may get color banding.

Here are some test images of your clips. No CC was applied other than the 2.2 gamma correction.
Attached Thumbnails
Sumix 2/3" 1920x1080 CMOS-1.jpg   Sumix 2/3" 1920x1080 CMOS-3.jpg  

Sumix 2/3" 1920x1080 CMOS-5.jpg   Sumix 2/3" 1920x1080 CMOS-6.jpg  

Sumix 2/3" 1920x1080 CMOS-smx12a2c.jpg   Sumix 2/3" 1920x1080 CMOS-underexposed.jpg  


Last edited by Eric Wu; August 21st, 2008 at 04:38 AM.
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Old August 22nd, 2008, 01:02 PM   #463
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Eric,

Yeah you are correct it is the gamma. There is a Gamma Correction option in the new software which appears to have the same result. The last few images I posted is with the option enabled.

Sumix is currently working on a software update with more features and better designed for our application.
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Old August 22nd, 2008, 01:38 PM   #464
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what is the strange colors in the sails (the ones that aren't in shadow) in that picture:
http://www.dreamstonestudios.com/delete/boat1.jpg
it is due to the debayering? or some effect of the softness of the lens? is it the loss of optical resolution due to the use of an adapter for lenses much greater that the ones needed?

asuming that the effect is due to the lens, if some lens can make those kinds of effects in hight frequency areas (because the background doesn't display such effects) how can on know what lenses don't make those effects?
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Old August 22nd, 2008, 03:16 PM   #465
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Well there are two things to keep in mind about the pictures...

First... I'm mixing daylight (~5600k) and tungsten (3200k) lighting. So colors are going to look a little funny. Especially when mixed in the (white) sails.

Second... The color filter in the camera is incorrect. It blocks some colors more than others and leaves a tinted and desaturated image.

I have been referred to the correct filter, but I'm going to wait for Sumix to provide the official hardware fix.
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