50mm x 50mm Kodak CCD Sensor Spotted on Internet

[shutay]

Looking around the Internet for interesting electronics projects, I came across this blog post, detailing a 6-inch Kodak wafer that the poster bought at a flea market (including photos of it), containing 3 Kodak KAF-4300 sensors as well as an assortment of other smaller CCD sensors back from I would guess, around 2001 or so. Interesting that the KAF-4300 sensor is 50mm x 50mm and 4-megapixels in resolution. It's really a pity that this sensor never made it into a product for professional photographers. I would even hazard a guess that it could sell well even today but only if the price were right - so many photographers seem to bemoan the usual upward megapixel creep, asking instead for closer to 6x6 or 6x.45 full frame.

http://www.evilmadscientist.com/article.php/wafer
(sorry for not posting the photo here, but I haven't got permission to do so, click on the link to go see it)

It also makes me wonder if Phase One couldn't also sell the P65+ sensors that have been rejected due to quality control as 15megapixel backs instead if they still pass the grade at that lower resolution - they could set it up so that if it doesn't pass quality control at 60megapixels, but does at 15megapixels (i.e., some bad photo sites), maybe it could be restricted to operate only at 15megapixels. They would junk fewer sensors, but maybe it would cost them more in marketing later on...

Anyway, I'm sure I will now get a lecture about how it wasn't really worthwhile making such large sensors in the beginning because edge/corner performance of existing medium format film lenses weren't up to scratch...

[yaya]

Dicomed Bigshot

[Dick Roadnight]

Anyway, I'm sure I will now get a lecture about how it wasn't really worthwhile making such large sensors in the beginning because edge/corner performance of existing medium format film lenses weren't up to scratch...

Large low res sensors are useful for use with large format film lenses, like the Schneider Fine Art Gold 1100. (No, I haven't got anything bigger that 900). If you conclude that ¿old? film lenses have half the res of digital lenses, you need four times the area to get the same res.

[christian_raae]

yaya, that was siiick! :-)

[BJL]

... the KAF-4300 sensor is 50mm x 50mm and 4-megapixels in resolution.

Do you really not understand why there is very little interest amongst photographers in a huge, expensive sensor .... giving only 4MP (2000x2000) images? MF lens resolution would certainly not be a problem with such a pathetically low resolution sensor!

Those big Kodak sensors are still around: they are for X-rays and such. I guess that they are made without stitching, using Canon's 50x50mm stepper: note the match in size!  That stepper has a very coarse resolution of 0.5 micron making it useless for most sensors, but that is small enough for those huge 24 micron pixels.

[shutay]

Dicomed Bigshot

Wow, that's amazing. Thanks for pointing that out, Yair.

Do you really not understand why there is very little interest amongst photographers in a huge, expensive sensor .... giving only 4MP (2000x2000) images? MF lens resolution would certainly not be a problem with such a pathetically low resolution sensor!

Those big Kodak sensors are still around: they are for X-rays and such. I guess that they are made without stitching, using Canon's 50x50mm stepper: note the match in size!  That stepper has a very coarse resolution of 0.5 micron making it useless for most sensors, but that is small enough for those huge 24 micron pixels.

I was referring to it within the context of the period in which it was introduced. The sensor size would have eliminated the crop factor, enabling photographers to maintain the "look" of their lenses, and if the sensor size had been developed into photographic products for the pro/studio market, I'm sure the resolution would have been increased over time, just like the MFDBs that did get made started off at 6mp and now are at 60mp. I was just saying that we are familliar with the options that have been available so far which have emerged for whatever technical and economic trade-offs that had to be made to bring them to market, but that there were or still are other sensor options that never made it. You could even have mentioned the move away from square sensors for the majority of photographers too as another reason...

Interestingly, I've read also about TFT display technology being used to make very large sensor arrays for X-rays - of the order of 8x10 inches and so on, don't know which is more common in X-ray digital machines though.

[BJL]

shutay,

I was referring to it within the context of the period in which it was introduced ... I'm sure the resolution would have been increased over time

I see two problems:

1. the extremely low resolution makes it useless for "medium format" standard of IQ (the Dicomed Big Shot was 16MP instead), so I doubt that many MF users would have been interested ... at least not interested enough to actually buy it, though maybe some would lust after its size in internet forums!
2. It would not and has not been scaled up to higher resolution, probably for a combination of reasons I hinted at in my previous post
a. its target market of X-ray machines probably does not need greatly increased levels of resolution
b. its cost effectiveness relies on using that huge 50x50mm Canon stepper so as to make it without stitching, and that stepper is limited to very low resolution sensors by its large 0.5 micron minimum feature size.

And for all I know, its price could be astronomical.


This seems to be another case of the mistake of putting excessive emphasis on one virtue (here sensor size, other times high ISO ability, DR, resolution, etc.) and ignoring sometimes painful or fatal trade-offs involved (here, very poor resolution and/or huge cost.)