Timeline for Why can't digital camera sensors expose each photosite individually?
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Aug 12, 2013 at 10:02 | comment | added | fortran | @StanRogers what you are talking about is the older "Super CCD", the newer EXR processor can do different exposure times for half of the sensor to increase the DR, but all pixels are equally sized (although with a quite exotic diagonal layout and a colour mosaic different than the traditional Bayer array). | |
Jan 4, 2012 at 14:43 | vote | accept | CommunityBot | ||
Jan 4, 2012 at 14:43 | comment | added | user7264 | Thank you for the in-depth answer. It's quite interesting that I see everything that I overlooked when I suggested this idea, glad that you pointed it out. Selective area mapping would be the best approach but you are right, who would make the decisions? Surely if the camera did them itself, it would obviously be intended for the masses but having to map the scene on your own would be useless since it is obviously easier to do it with a professional software on the big screen and not with the camera (with some quality loss, that would, I believe, be insignificant). Cheers! | |
Jan 3, 2012 at 23:24 | comment | added | whuber | It's an interesting discussion, Stan, and I agree with you, too, but it looks we have strayed from the question. From your comments it seems we have established the practicability--perhaps even the existence--of a camera that comes close to that posited in the question and (to paraphrase the famous (apocryphal?) Churchill quotation) what we're discussing at this point is the price :-). | |
Jan 3, 2012 at 22:10 | comment | added | user2719 | ... And both of them still get blown highlights. You need to extend substantially further to avoid the issue altogether, and at some point the practicality breaks down, at least at the mass-market level. Studio shooters don't need it; most consumers don't need it. I do mostly environmental portraiture, and I can't think of too many times I needed it (overexposure has made many of my images). The overhead just wouldn't be worth it to most people, so that's going to create an expensive niche product. | |
Jan 3, 2012 at 22:00 | comment | added | user2719 | Again, straight processing will give a crappy image if the source is HDR. The limitation is not in the capture, but in the processing—how many haloed images do you need to see before you come to the conclusion that HDR processing isn't simple? Well-meaning people screw it up royally, and they know what they want the image to "say". Then the storage and write speed problems are still there, too, and there's another use compromise. A camera can be all things to all people, but at what cost in both price and ergonomics? 14-bit capture and DR compression are here now; 16-bit won't be far behind. | |
Jan 3, 2012 at 21:42 | comment | added | whuber | Thanks for the EXR reference. It shows my suggestion is not just plausible, but real. Now hasn't HDR software addressed the processing problem? If you have managed to capture a wide dynamic range with an integrated sensor, then in effect you already have a perfectly registered HDR stack. The limitations of this technology will be the limitations of HDR, to be sure. | |
Jan 3, 2012 at 20:54 | comment | added | user2719 | A better simple approach already exists in Fuji's EXR sensor. It has different-sized sensels; a small sensel and a large one are paired at each source pixel site on the sensor. While that can provide for a wider capture range, it's still limited in what it can do -- you can still blow out the highlights if you want to get all of the shadows. (And Fuji's current implementation uses too many pixels on too small a sensor.) Assume a perfect implementation with multiple sensor sizes -- that still leaves the processing problem—and that, not the capture, is the real issue. | |
Jan 3, 2012 at 20:44 | comment | added | whuber | This is a great analysis (and I'm voting it up as such). But in the end I find the conclusions unconvincing. After all, it wouldn't be hard to create a "dumb" matrix of sensels, some of which are masked by, say, a six-stop ND filter. (Use one of the G's in the Bayer filter for this, for instance.) No significant change in electronics would be needed; nothing about the cameras, lenses, etc., would change; but in return for a tiny loss in sensitivity you would obtain the ability to distinguish (coarse) gradations within blown-out pixels. That's close to what the OP asks for. | |
Jan 3, 2012 at 18:51 | history | answered | user2719 | CC BY-SA 3.0 |