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diffraction limits: hopefully the MP race is over
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PostPosted: Thu Aug 20, 2009 5:14 am    Post subject: diffraction limits: hopefully the MP race is over Reply with quote
There is hope that the MP race is over, the key word is: 'diffraction limit'
see: http://www.luminous-landscape.com/essays/brick-wall.shtml

Not sure if that had been posted before, but I find it interesting. Hopefully in future the emphasis for new sensors will be on less noise at higher ISO and better DR instead of on more PM.


PostPosted: Thu Aug 20, 2009 5:53 am    Post subject: Reply with quote
I want a 6MP full frame CMOS sensor made by today's standards! Such a sensor would blow your socks off with regards to high ISO noise Very Happy


PostPosted: Thu Aug 20, 2009 7:28 am    Post subject: Reply with quote
just my thoughts Spotmatic!

according to the reasoning of the linked article more MP as reached now won't make any sense, so there is hope that future advancement of sensor technology may focus on IQ.

I have been very disappointed that every new dSLR offered more MP but often not better IQ, higher DR or less noise at high ISO. If somebody at least would have offered a choice, the same camera with 2 different sensors. That even could have been smart marketing as it might have made more prospective buyers aware that more MP isn't everything and many users might have jumped on that camera.

As it is I still don't find enough reasons to upgrade from my *istDs. For me it would not necessarily have to be FF, your K-7 with 8 MP ( I'd prefer over 6 Wink ) but less noise and higher dynamic range and I'd not hesitate.


PostPosted: Thu Aug 20, 2009 8:15 am    Post subject: Reply with quote
Of course, one can always downsize the pictures from today's sensors and the amount of noise will be similarly reduced. I'd expect, e.g. the Sony 24.6 mpix sensor in A900/D3x to have rather excellent noise performance downsized to 6 mpix.


PostPosted: Thu Aug 20, 2009 8:29 am    Post subject: Reply with quote
Arkku wrote:
Of course, one can always downsize the pictures from today's sensors and the amount of noise will be similarly reduced. I'd expect, e.g. the Sony 24.6 mpix sensor in A900/D3x to have rather excellent noise performance downsized to 6 mpix.


I am not sure about this. This is nothing but an interpolation in the opposite direction.
It is true, of course, if the camera offers a combination of pixels in order to reduce noise, but only very few can do that.


PostPosted: Thu Aug 20, 2009 2:59 pm    Post subject: Reply with quote
LucisPictor wrote:
I am not sure about this. This is nothing but an interpolation in the opposite direction.
It is true, of course, if the camera offers a combination of pixels in order to reduce noise, but only very few can do that.


I'm not sure I see what you mean; the basis for the conversation was the idea that some people would prefer sensors with a lower pixel count in order to trade resolution for lower noise, so we're speaking of noise per pixel. Since any reasonable downsampling algorithm (in camera or not) combines multiple pixels into one (instead of just picking one pixel per area), noise per pixel is obviously reduced along with the pixel count. (This is easily observable when viewing prints or web-size images next to 100% crops.)

One advantage of downsizing from a higher pixel count is that the resulting low-resolution image is much better than that of a camera with a CFA sensor having the same (lower) pixel count natively; demosaiciking artefacts are also hidden in the process. (Sigma cameras with the non-CFA sensors, i.e. Foveon, obviously don't have the problem with demosaiciking in the first place, but they can still benefit from digital filtering.)


In any case, the “less megapixels = less noise” thing is just based on pixel peeping the image at 100% instead of at equal size. The real way to less noise (total, not just per pixel) would be to increase the size of the sensor… Let's see when, if ever, digital medium format becomes affordable. =)


PostPosted: Thu Aug 20, 2009 4:58 pm    Post subject: Reply with quote
Spotmatic wrote:
I want a 6MP full frame CMOS sensor made by today's standards! Such a sensor would blow your socks off with regards to high ISO noise Very Happy


+1,000,000,000!

I want a full-wafer sensor with same pixel density of XT/350D, or even 300D. Considering 5DII FF sensor pixel density is 2x of the XT/350D, and given other improvements in manufacturing processes, full-wafer sensors at 1/2 pixel density should be possible with reject rates low enough to be relatively economical. Wafer sizes (according to Wikipedia: http://en.wikipedia.org/wiki/Wafer_(electronics) ) are 1", 2", 3", 4", 5", and 150mm, 200mm, 300mm, and by year 2012, 450mm. Imagine a (conservative) 3" sensor! What a camera that would make! SmileSmileSmile And a 450mm sensor?! 450mm is nearly 18"; a full-wafer 18" sensor?! WOW, WOW, WOW! Ultra-Large format digital!


PostPosted: Thu Aug 20, 2009 5:35 pm    Post subject: Reply with quote
I want money to afford 4x5 large format or 6x9 at least and really don't care digital at all.


PostPosted: Thu Aug 20, 2009 6:40 pm    Post subject: Reply with quote
Attila wrote:
I want money to afford 4x5 large format or 6x9 at least and really don't care digital at all.


I hear you Attila.. I have a long way to go, and what a great journey it will be Wink


PostPosted: Thu Aug 20, 2009 7:15 pm    Post subject: Reply with quote
kuuan wrote:
Attila wrote:
I want money to afford 4x5 large format or 6x9 at least and really don't care digital at all.


I hear you Attila.. I have a long way to go, and what a great journey it will be Wink


Yes it is if anybody hold a 6x9 slide in own hands after all I don't think so want any digital anymore. I can just imagine same with 5x4 Shocked


PostPosted: Thu Aug 20, 2009 8:02 pm    Post subject: Reply with quote
Ha Ha! Smile My imagination goes too crazy sometimes. I have 14-inch process lens that covers 16x20-inch (wide angle). I like to hold Provia slide of that! Also make nice contact prints of landscapes. Actually I have necessary woodworking skills (small racing sailboats) and may someday build the camera!


PostPosted: Thu Aug 20, 2009 8:16 pm    Post subject: Reply with quote
siriusdogstar wrote:
Ha Ha! Smile My imagination goes too crazy sometimes. I have 14-inch process lens that covers 16x20-inch (wide angle). I like to hold Provia slide of that! Also make nice contact prints of landscapes. Actually I have necessary woodworking skills (small racing sailboats) and may someday build the camera!

Laughing


PostPosted: Thu Aug 20, 2009 10:43 pm    Post subject: Reply with quote
Attila wrote:

Yes it is if anybody hold a 6x9 slide in own hands after all I don't think so want any digital anymore. I can just imagine same with 5x4 Shocked


That just moves the digitization step from image capture to post processing. And post processing now includes some destructive, non reversible chemical steps.


PostPosted: Mon Aug 31, 2009 7:37 pm    Post subject: Reply with quote
Arkku wrote:
Of course, one can always downsize the pictures from today's sensors and the amount of noise will be similarly reduced. I'd expect, e.g. the Sony 24.6 mpix sensor in A900/D3x to have rather excellent noise performance downsized to 6 mpix.


That is not exactly true. The problem is the native pixel density has not decreased. At capture time, the noise is recorded along with the image. When reducing the size, you will be keeping relatively the same amount of noise as the resize software does not know noise from detail. Resizing will make the noise smaller along with the detail, though, so less noticeable at 100% pixel peeping view. Using a lower resolution sensor will - in theory - capture less noise natively.

Look at what Canon has done with the 1dsmk3 and 5Dmk2. 21MP and less noise than the 5D. Now imaging what they could do with a low-res sensor that starts with less noise to begin with. I think 6MP is pushing it though, I would probably vote for 10MP. Smile


PostPosted: Mon Aug 31, 2009 7:50 pm    Post subject: Reply with quote
ChrisLilley wrote:
Attila wrote:

Yes it is if anybody hold a 6x9 slide in own hands after all I don't think so want any digital anymore. I can just imagine same with 5x4 Shocked


That just moves the digitization step from image capture to post processing. And post processing now includes some destructive, non reversible chemical steps.



And keep alive obsolete technology.+ few years later I can get even more higher resolution scan due I believe scanning technology will be also improved. I love digital cameras too, but I would like to have film for long time too. They need to live together not against to each other. I like to shoot on film mostly landscapes, because I believe they are better everything else just fine on digital and most of the cases better too.


PostPosted: Mon Aug 31, 2009 9:41 pm    Post subject: Reply with quote
I hope a Full Frame war is next.
Sony made a step in right direction with A850, but I am waiting FF camera from Pentax.


PostPosted: Mon Aug 31, 2009 10:09 pm    Post subject: Reply with quote
tkbslc wrote:
The problem is the native pixel density has not decreased. At capture time, the noise is recorded along with the image. When reducing the size, you will be keeping relatively the same amount of noise as the resize software does not know noise from detail. Resizing will make the noise smaller along with the detail, though, so less noticeable at 100% pixel peeping view. Using a lower resolution sensor will - in theory - capture less noise natively.


The whole point is that 100% pixel peeping view is not they way to compare noise, and where many online comparisons (e.g. dpreview's side-by-side noise samples) go wrong. For the comparison to be fair, one would either need to enlarge the low-resolution image (thus enlarging the noise along with the image, including CFA demosaicking artefacts, etc), or to downsample the high-resolution image (thus making the noise smaller as well, along with other faults). Of course high resolution is not a guarantee of a better image, e.g. if the sensor resolution was not the limit or if the sensor itself is inherently more noisy, but neither is low resolution any guarantee of less noise and lower resolution imposes more of a limit for large output sizes (100% crop being the ultimate, and indeed absurdly large, size).

So, for a given output size the higher resolution image is not necessarily at any disadvantage despite higher initial noise per pixel, because the noise averages* out and just like other pixel-level defects (because indeed, as you said, the resizing algorithm can't, in the general case, tell noise apart from the other data).


* As a hypothetical example, consider an image of a grey card that should ideally be completely mid-grey, but has random noise. Now, downsize that to exactly one pixel by taking the average of all pixels in the image—the more pixels you have, the closer to perfect mid-grey you will almost certainly get in that one-pixel image. (The resizing doesn't even need to be with a computer: one could just print the image and observe less apparent noise the farther away one goes to view this print.)


PostPosted: Mon Aug 31, 2009 10:11 pm    Post subject: Reply with quote
Attila wrote:

And keep alive obsolete technology.+ few years later I can get even more higher resolution scan due I believe scanning technology will be also improved.


Aren't current scanners good enough to hit the limit of the film's resolution (or at least that of the lens or diffraction)? Or are you referring to scanners at a given price point? =)


PostPosted: Tue Sep 01, 2009 3:03 pm    Post subject: Reply with quote
Arkku wrote:
Attila wrote:

And keep alive obsolete technology.+ few years later I can get even more higher resolution scan due I believe scanning technology will be also improved.


Aren't current scanners good enough to hit the limit of the film's resolution (or at least that of the lens or diffraction)? Or are you referring to scanners at a given price point? =)


I looked into film scanners recently, as I often see Nikon film SLRs going for inexpensive prices and it would be nice to shoot a bit of (full frame) film and to use a body that actually meters with my lenses (!).

Film purchase and developing costs are a drawback, of course. But the biggest drawback is the scanner. A good Nikon scanner is more expensive than a good full frame Nikon DSLR like the D700. A mid range, but still high quality, scanner plus associated software is still over 1000 euro. Its too much.


A good midrange to high-end consumer film scanner will provide 3500 to 4000 dpi actual resolution; 3500 dpi /25.4 * 36 is 4960 pixels on the long side of the frame. My 12 Mpx D90 gives 4288 pixels on the longs side of the (DX) frame. An oil immersion wet drum scanner may give higher resolution, but that's well outside an amateur budget.
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