Sensor+ vs. legacy fat pixel backs

[ErikKaffehr]

Ray,

Thanks a lot, I see your point. The high MTF per pixel helps with crispness on screen, but that would be limited to pixel peeping on screen, wouldn't it?

Lets say we shoot an image with 9 my sensor say 49x37 mm, that would yield 22 MP. Would we shoot the same subject with a theoretical sensor having 4.5 my pixels (that is 89 MP) and print both images 23x30", would the smaller sensor image be more crisp? I don't think so. On screen at actual pixels large pixel image may look more crisp, but that would not transfer to print.

I am a bit confused about high signal/high noise characteristics, tough. The way I see it noise in mid tones will be dominated by shot noise and readout noise would only affect the darks. Shot noise SNR would be proportional to square root of signal and still be good. Does PRNU come into play?

Best regards
Erik

Hi Erik,

Well when people talk about textural things, such as "film-like grain", then yes, I put that down to the noise characteristics.

Of course there are other typical "fat pixel" characteristics as well - the pleasing colour from Kodak's and Dalsa's choice of CFA bandpasses, the lack of an AA filter, the high lens MTF per pixel...these are all elements in "the fat pixel look".
I'd sum it up as The Four C's: Crisp, Colourful, Contrasty, and Crunchy noise. 

Ray

[Theodoros]

Ray,

Thanks a lot, I see your point. The high MTF per pixel helps with crispness on screen, but that would be limited to pixel peeping on screen, wouldn't it?

Lets say we shoot an image with 9 my sensor say 49x37 mm, that would yield 22 MP. Would we shoot the same subject with a theoretical sensor having 4.5 my pixels (that is 89 MP) and print both images 23x30", would the smaller sensor image be more crisp? I don't think so. On screen at actual pixels large pixel image may look more crisp, but that would not transfer to print.

I am a bit confused about high signal/high noise characteristics, tough. The way I see it noise in mid tones will be dominated by shot noise and readout noise would only affect the darks. Shot noise SNR would be proportional to square root of signal and still be good. Does PRNU come into play?

Best regards
Erik

Eric, I don't believe that Ray uses "crisp" to describe detail... I believe he means "punch" of the image (what I sometimes call "pixel definition")... After all, for many photographers more "detail" (after having "enough") is rather a disadvantage than an advantage for a good print. The Kodak 9mμ MFDBs seem to have more contrasty mids than the other backs, while they hold colour in the deeper dark areas surprising well and DR seems to be as extended as with any modern high resolution back around (at least on print)... The higher resolution Kodak sensors and all Dalsa sensors seem to be "duller" (less contrasty) in the mids which leads in a different (more "digital") look when it comes to print. In my view, the Kodak 9mμ backs can provide a print which is nearer to prints made out of negative film ....only with more extended DR than film. That's what I feel most people call "the fat pixel magic"... In other words, it's a matter of having the most pleasing and expressive print... the most communicative one... not the most "accurate" or detailed one.

[eronald]

Eric, I don't believe that Ray uses "crisp" to describe detail... I believe he means "punch" of the image (what I sometimes call "pixel definition")... After all, for many photographers more "detail" (after having "enough") is rather a disadvantage than an advantage for a good print. The Kodak 9mμ MFDBs seem to have more contrasty mids than the other backs, while they hold colour in the deeper dark areas surprising well and DR seems to be as extended as with any modern high resolution back around (at least on print)... The higher resolution Kodak sensors and all Dalsa sensors seem to be "duller" (less contrasty) in the mids which leads in a different (more "digital") look when it comes to print. In my view, the Kodak 9mμ backs can provide a print which is nearer to prints made out of negative film ....only with more extended DR than film. That's what I feel most people call "the fat pixel magic"... In other words, it's a matter of having the most pleasing and expressive print... the most communicative one... not the most "accurate" or detailed one.

Ah yes - print. Our children will speak of print, like today they speak about Vinyl. For scratching

Anyway, I don't know exactly how much "DR" one really needs to photograph a girl standing on a white cloth in front of a white wall with a megajoule of flash blasting her, but I suspect that yes, one can make the back expose to the right @ ISO 100 in most well equipped studios, and therefore one can live with "crunchy noise" even in the highlights.

Maybe some of that "fat pixel" look comes partly from the strong light which people use to make those images ...

I live in Paris, and the light here these days is so bad that just now, in the middle of an august afternoon I would be around 1/20 @ f4 for ISO 100 outdoors. I know this for a FACT because I just pointed my SLR out the window to check. It is now 5PM DST, and somewhere between 3 and 4 PM  solar time.

Quite obviously, people haven't being taking a lot of these fat pixel images with their digital backs outdoors in daylight around here ...and studio lighting brings a dynamic of its own to images, with a different DR requirement, different white balances etc from natural light. I think we should take this into account when talking about "fat pixel magic". Also, whether shades of greenery or autumn leaves are being discriminated, or skin color and texture; or sky and clouds. I'm not sure that a "people back" is a good "landscape back", or even that a good "architecture back" is a good "landscape back".

And by the way, mono CCDs (no CFA) from Dalsa and Kodak had very different spectral sensitivity curves. Don't ask me why.

Edmund

[bcooter]

What would you keep if you had time, and just wanted a good file?

Today?

I change my mind per week,  depending on what I'm shooting . . . but today




Not that either one shoots the "ultimate image quality" file, though for such a small sensor both are very good, withstand post production, small, use the same lens mount and a natural for a modern, spontaneous style of creative brief.

Not that either one are without their quirks, as both burn through batteries, though they really do surprise you with their build and file quality.

BC

[gerald.d]

...

Maybe some of that "fat pixel" look comes partly from the strong light which people use to make those images ...

I live in Paris, and the light here these days is so bad that just now, in the middle of an august afternoon I would be around 1/20 @ f4 for ISO 100 outdoors. I know this for a FACT because I just pointed my SLR out the window to check. It is now 5PM DST, and somewhere between 3 and 4 PM  solar time.

...

Edmund

Just crunching those numbers in my head, that's around the EV8 mark? Are you sure you'd taken off the lens cap?

[eronald]

Just crunching those numbers in my head, that's around the EV8 mark? Are you sure you'd taken off the lens cap?

Unfortunately, yes. There seems to be this thing called global warming, and here it translates into a summer of intermittent clouds and showers; a permanent network of contrail-clouds and pollution seem to haze up the remaining clear days. Really constant strong sumer light is something I do see regularly ... when I travel out of the city. The clear blue-sky winter days which I remember from when I was a young man are also gone. Add to this that I live in a built-up street, and unfortunately you get the perfectly accurate measurement I posted.

Edmund

[Theodoros]

Just crunching those numbers in my head, that's around the EV8 mark? Are you sure you'd taken off the lens cap?

Ed has a tendency to add a pin hole camera in series to his normal one... He drills holes on his caps!    Strange thing is my sister lives in sector "E" for 27 years now... obviously my sensor has different sensitivity to Ed's... 

[eronald]

Ed has a tendency to add a pin hole camera in series to his normal one... He drills holes on his caps!   Strange thing is my sister lives in sector "E" for 27 years now... obviously my sensor has different sensitivity to Ed's...  

Ok, this ain't proof of a weather trend but it sure looks kinda weird for a week in August ...I don't know when summer is coming.

I think this pic says we've had one dry three-hour spell today, and this week the temperature *high* is something like 73 degrees F, with most day highs well below that. I wore a sweater most of today.

When I moved to France, July and August were hot ...

Edmund

[EricWHiss]

Cheer up Edmund, you could live in San Francisco - here we are lucky to have a handful of days over 25C during the entire year. Mostly those days are in odd times like November or March, never in August.