October 23, 2014, 01:13:46 AM

Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.


Messages - jrista

Pages: 1 2 [3] 4 5 ... 298
31
EOS Bodies / Re: Multilayer Sensors are Coming From Canon [CR2]
« on: October 15, 2014, 09:29:29 PM »
I've been curious for some time why Lightroom doesn't make extensive use of the capabilities of my video cards...if games can render vastly more complex scenes 60 to 120 times per second using a GPU, Lightroom should be able to do what it does on a 5-layer RAW quicker than it renders a bayer RAW now.

Agreed.  DxO Optics Pro used to be rather slow at displaying images at 100% on my Mac, and even filmstrip thumbnails weren't very fast.  A version back (IIRC), they added GPU acceleration and it sped the rendering up significantly.

The guy that writes the Camera Raw code says GPU acceleration would help very little with the Camera Raw pipeline.


I honestly have a very hard time believing that. There is no way the current code is as parallel as it could be when run on a GPU. CPU's simply cannot achieve that kind of parallelism. I wouldn't be surprised if they had to completely rewrite the ACR pipeline to properly take advantage of GPU power, but I think they should do that anyway, and build in support for pipeline-level plugins so third parties could add things people have been asking for since v2 was released...like debanding support, or AF point overlays, etc.

So, you know more than the guy that's writing the code?  Kind of arrogant, don't you think?


I write heavily parallelized and highly threaded code for a living. I have been for nearly two decades. I think I have the background knowledge to know.


Will you guys knock it off with this crap? I've had enough.

32
Animal Kingdom / Re: Show your Bird Portraits
« on: October 15, 2014, 09:28:13 PM »
Blue Jays and Peanuts - The Fall Fiesta


Every fall, the Blue Jays return. Noisy, obnoxious, and incredibly beautiful, these birds seem like they belong in the rainforests of Papua New Guinea with all their colorful friends. They are also incredibly intelligent birds, extremely clever in finding and rooting out food, and particularly sneaky bastards. ;) I've spent the last couple of years "training" the Blue Jays that frequent my yard. They come when I play back Blue Jay calls from my WP8 Sibley guide, come when I tap peanuts on my deck, and seem to enjoy the game of "Grab the peanut before a photograph is made!"


The Scrub Jays are a little easier to capture photos of, they are a little more aggressive with the Blue Jays, and tend to get all the peanuts. This year, I managed to lure in a couple Blues, and with some a clever setup, captured a number of wonderful shots. There is mere moments to frame, focus, and shoot before they are gone. The 5D III's slower frame rate makes getting the perfect moment a little more difficult, however it's larger frame makes for a much more pleasing background.


Canon EOS 5D Mark III
Canon EF 600mm f/4 L II
Gitzo GT3532LS w/ Jobu Pro 2 Gimbal











Here are some shots of the setup used to get these images:








While I was snapping shots of the setup, my quarry showed up again, and grabbed a little more bait. :D



33
EOS Bodies / Re: Multilayer Sensors are Coming From Canon [CR2]
« on: October 15, 2014, 08:03:40 PM »
I've been curious for some time why Lightroom doesn't make extensive use of the capabilities of my video cards...if games can render vastly more complex scenes 60 to 120 times per second using a GPU, Lightroom should be able to do what it does on a 5-layer RAW quicker than it renders a bayer RAW now.

Agreed.  DxO Optics Pro used to be rather slow at displaying images at 100% on my Mac, and even filmstrip thumbnails weren't very fast.  A version back (IIRC), they added GPU acceleration and it sped the rendering up significantly.

The guy that writes the Camera Raw code says GPU acceleration would help very little with the Camera Raw pipeline.


I honestly have a very hard time believing that. There is no way the current code is as parallel as it could be when run on a GPU. CPU's simply cannot achieve that kind of parallelism. I wouldn't be surprised if they had to completely rewrite the ACR pipeline to properly take advantage of GPU power, but I think they should do that anyway, and build in support for pipeline-level plugins so third parties could add things people have been asking for since v2 was released...like debanding support, or AF point overlays, etc.

34
EOS Bodies / Re: Multilayer Sensors are Coming From Canon [CR2]
« on: October 15, 2014, 07:11:06 PM »
Basically, if your computer is barely tolerable now, it might be intolerable with a multilayer sensor.  In practice, though, the apps will probably evolve to take better advantage of multiple cores, and this will probably make the difference moot.


They should really be evolving to take advantage of GPUs. GPUs were designed to do this kind of stuff, and do it wicked-fast. They also have gobs of their own memory, so you wouldn't necessarily have to waste as much system memory on image rendering. Just about every computer has a GPU of some kind these days...either integrated into the CPU, or as an add-on card. Even laptops have dedicated GPUs.


I've been curious for some time why Lightroom doesn't make extensive use of the capabilities of my video cards...if games can render vastly more complex scenes 60 to 120 times per second using a GPU, Lightroom should be able to do what it does on a 5-layer RAW quicker than it renders a bayer RAW now.

35
EOS Bodies / Re: Patent: Variable Diffusion Focusing Screen
« on: October 15, 2014, 05:14:08 PM »
Cool stuff! I wonder if this would work in conjunction with Canon's existing transmissive LCD and all the visual cues and feedback available in their current OVFs.

37
Animal Kingdom / Re: BIRD IN FLIGHT ONLY -- share your BIF photos here
« on: October 13, 2014, 03:11:23 PM »
American Golden-Plover - Martha's Vineyard

100-400mm at 400mm 1/1600th, ISO 160, f/7.1 , late afternoon.


Very nice!

38
Animal Kingdom / Re: Show your Bird Portraits
« on: October 13, 2014, 03:10:26 PM »
Canon 7D with Tamron 150-600; 1/1600th, f6.3, ISO 400


Very nice shot.

39
I also had one from the Iceland trip. In my view a very cool landscape, with a very prehistoric look.

5DIII, 1/1250s, f4.0, ISO100 (handheld)

That's an awesome landscape.

40
Lenses / Re: Canon 600mm f/4L IS II USM Purchase
« on: October 09, 2014, 06:06:58 PM »
CPW doesn't always have the best prices. When  I bought my 600/4 II last year, I eventually found a better price on Vistek, a Canadian store. I spent a mere $10,860 on mine, which was well below the lowest price CPW had. I like CPW, but they don't seem to include Vistek...and when it comes to getting the best deal on high end Canon lenses, even with currency conversion and/or import fees, they are usually WAY less.

I bought mine from Canada 2 years ago and saved a bunch. Looks like that is no longer possible with price changes. Canada prices are now higher. Could be due to currency valuation that gets factored in to prices Japan will charge when they periodically make changes.
http://www.photoprice.ca/product/03580/Canon-EF-600mm-f4L-IS-II-USM-price.html

Hmm, yeah, things are more expensive. The exchange rate right now is apparently 1.1183 CAD = 1 USD, which makes the $13199 CAD Camera Canada price $11,802 USD. That's still a decent deal, but with currency/import fees, it'll still top $12,000.

I explicitly timed my purchase to utilize an ideal peak in exchange rate. The price in Canadian was fixed, and I was watching the exchange rate day after day until it peaked, bought on that day, and the next day it dropped. That was part of the reason I got such a good deal. Only a few days before, the price in USD was around $11,100. :P Sometimes thats the way to do it, though.

41
Lenses / Re: Canon 600mm f/4L IS II USM Purchase
« on: October 09, 2014, 05:16:09 PM »
CPW doesn't always have the best prices. When  I bought my 600/4 II last year, I eventually found a better price on Vistek, a Canadian store. I spent a mere $10,860 on mine, which was well below the lowest price CPW had. I like CPW, but they don't seem to include Vistek...and when it comes to getting the best deal on high end Canon lenses, even with currency conversion and/or import fees, they are usually WAY less.

42
EOS Bodies / Re: Multilayer Sensors are Coming From Canon [CR2]
« on: October 09, 2014, 01:09:14 AM »
Think about it. If read noise is 35e-, and the maximum signal strength is 68,000e-. If your doing 16-bit conversion, then your gain is 1.0376e-/ADU . That's almost unity gain...at ISO 100! Unity gain is what you want. With 14-bit conversion, your gain is 4.15e-/ADU. So, with 14-bit, your read noise turns into 8-9 tonal levels. With 16-bit, your read noise turns into 33-34 tonal levels. That's the bottom of the signal, though. For 16-bit, you still have 65502 levels for all the signal detail above the noise floor. Any gradients in the image at tones 35 through 65535 are going to be smoother with 16-bit conversion than with 14-bit conversion.

The noise floor does not only 'exist' in the lower-end of the signal range, it exists through-out the range event to the clip point.

Let's do a math exercise:

Here's a stream of signal:
0  10  100  1000  10000  100000

If my sensor has noise floor of 3-bits (0~8), even if I sample it using full precision, I got this:
3  12  107  1004  10002  100005, my lowest 3 bits are drown in noise, even for the highlight.

If I sample it with 1/8 precision (chops off lower 3 bits), I get:
0  1   13   125   1250   12500

Then recreate the signal by multiplying the sample signal by 8 times:
0  8   104  1000  10000  100000

And mix it with random number generator for 3-bits:
5  10  109  1001  10007  100004

The results of high and low precision sampling only fluctuates within noise floor, so are essentially the same.

The conclusion? If you are sampling more precision than your SNR, you are just sampling noise more precisely, which is still noise, and is same as if you don't sample as precise, then add noise in post.

Apply this to your example, when you have 35e- noise floor, your tonal range is not 65535-35 = 65500, but rather 65535/35 = 1872 levels (~10.8 stops), because the bottom 5 (!) bits are unstable noise.

I don't disagree, however I would still take a finer sampling of noise over a coarser sampling of noise. I mean, if your sensor has an analog range up through 68,000e-, with 35e- noise, that's how much noise can fluctuate up to. You might have a bunch of pixels where the correct signal value is for a midtone gray at 34,000e-. With noise, you are going to randomly fluctuate up to 35e- around that value, so you might have:

34,004
34,035
34,009
34,014
34,010
34,020
34,012
34,000

If you sample these analog values at 14-bit, you get the following:

8193
8200
8194
8195
8194
8196
8194
8192

If you sample them at 16-bit, you get the following:

35283 
35315 
35288 
35293 
35289 
35299 
35291 
35279

If you multiply the 14-bit samples by four to put them into the same numeric range as the 16-bit sampling:

32772
32800
32776
32780
32776
32784
32776
32768

I'd rather take the finer and more random sampling that a 16-bit ADC allows, than the often repetitive sampling that 14-bit ADC does. It's that repetitive sampling with fewer bits that can lead to posterization in smooth gradients (like sky), lower SNR regions (shadows), etc. I'll take a finer, more random sampling of noise any day...despite the fact that it's still just sampling noise.

43
EOS Bodies / Re: Multilayer Sensors are Coming From Canon [CR2]
« on: October 08, 2014, 11:56:53 PM »
I'd say that most FF cameras could benefit from a 16-bit ADC. Even Canon cameras, which still have high read noise, can benefit.

You won't benefit anything by sampling the noise floor 4 times more precise. I could as well read the sensor at 12-bit and fill the lower 4-bits with random noise generator and get a "smoother tonal gradient".

Your only thinking about the bottom range of the signal. Once your above the read noise floor, it's clean signal limited only by photon shot noise. You very much do still benefit from higher bit depth in that (very vast) range of signal.

Think about it. If read noise is 35e-, and the maximum signal strength is 68,000e-. If your doing 16-bit conversion, then your gain is 1.0376e-/ADU . That's almost unity gain...at ISO 100! Unity gain is what you want. With 14-bit conversion, your gain is 4.15e-/ADU. So, with 14-bit, your read noise turns into 8-9 tonal levels. With 16-bit, your read noise turns into 33-34 tonal levels. That's the bottom of the signal, though. For 16-bit, you still have 65502 levels for all the signal detail above the noise floor. Any gradients in the image at tones 35 through 65535 are going to be smoother with 16-bit conversion than with 14-bit conversion.

You don't gain in editing latitude...you would still have the same amount of dynamic range...but you do gain in tonal fidelity.

44
EOS Bodies / Re: Multilayer Sensors are Coming From Canon [CR2]
« on: October 08, 2014, 11:28:54 PM »
Guys, is it possible to get 16-bit images with FF DSLRs in theory? Would it give any real life benefit vs. 14-bit?

You won't benefit from a higher bit depth if your full well capacity in electrons is less than the maximum digital unit supported by the bit depth. With 14 bits, you can represent digital units from 0 through 2^14, or 16,384. With 16 bits, you can represent digital units from 0 through 2^16, or 65,536.

Most APS-C sensors don't have enough full-well electron charge to really benefit from 16-bit ADCs. Canon sensors top out at around 26,000e-. That's more than the 16k supported by 14 bits of data, but not enough more to warrant 65k. It may even be beneficial to "oversample" electrons, at base ISO, relative to the output bit depth. If you had ~32ke- FWC, you would effectively convert every two electrons into one digital unit. That's good dynamic range (oh please, don't let that be misinterpreted! :P) A couple Nikon APS-C cameras have 30-40ke- FWC.

Full frame sensors, at least with current pixel sizes, gather a lot more charge per pixel than APS-C sensors. Most are over 55ke-, including Canon's older FF 1D series cameras. The 5D II had nearly 65ke- exactly, and even the old 5DC had over 55ke-. The 5D III, 6D, 1D X all have FWCs over 65ke-. The D800 (and A7r) have 45ke- FWC, which is on the lower side, but the D810 cranks it up to nearly 80ke- at ISO 64. The A7s has a whopping 155ke- FWC at ISO 100.

I'd say that most FF cameras could benefit from a 16-bit ADC. Even Canon cameras, which still have high read noise, can benefit. You won't see an editing latitude increase on a Canon camera (not with current read noise levels anyway), however overall, you should still see improved tonal grading. Convert 65, 80, 150 thousand electrons into 16k digital units, and your needlessly limiting your tonal range. Convert 65, 80, 150 thousand electrons into 65k digital units, and you greatly expand your tonal range...that should mean smoother gradients, softer shadow falloff (until you hit the read noise floor), etc.

So, assuming you have the electron charge capacity in each pixel to support it, you could benefit from 16-bit ADC. I don't think many APS-C sensors currently would really benefit. I think most FF sensors could benefit, especially those with really high FWC counts...the 1D X, the 6D, the A7s, the D810.

45
EOS Bodies / Re: Multilayer Sensors are Coming From Canon [CR2]
« on: October 08, 2014, 11:16:47 PM »
Here is one of the layered sensor patents from a few years ago (2011):

http://translate.google.com/translate?hl=en&sl=ja&u=http://egami.blog.so-net.ne.jp/2013-05-22&prev=/search%3Fq%3Dhttp://egami.blog.so-net.ne.jp/2013-05-22%26client%3Dfirefox-a%26hs%3DC0u%26rls%3Dorg.mozilla:en-US:official

This one seems to apply the nanocoating concept to the red layer. Nanocoating uses nanoscopic scale spikes of differing sizes on a reflective surface to produce a non-abrupt transition layer. Reflections occur at abrupt transistions in refractive index, so by creating a non-abrupt transition layer, you can nearly eliminate reflections entirely. This is different from standard multicoating, which still allows reflections to occur, it just cancels them out via wave interference.

Here is another patent from 2012:

http://translate.google.com/translate?hl=en&sl=ja&u=http://egami.blog.so-net.ne.jp/2013-05-22&prev=/search%3Fq%3Dhttp://egami.blog.so-net.ne.jp/2013-05-22%26client%3Dfirefox-a%26hs%3DC0u%26rls%3Dorg.mozilla:en-US:official

This is another sensitivity increasing patent. This apparently uses dielectric antireflective layers underneath the preceeding layer to reduce ghosting reflections. Not sure if this is intended to be used in conjunction with the nanocoating of the red layer or not...it seems to explicitly call out the blue and green layers (which are higher up than the red layer).

Canon also has their more recent patent for the five-layer sensor with UV and IR layers:

http://translate.google.com/translate?sl=auto&tl=en&u=http://egami.blog.so-net.ne.jp/2014-06-27

This patent is interesting, because it seems to depict a multi-layered BSI design, at least based on the diagram of the sensor (all the transistors are on the back side...that alone would be HUGE for layered sensor sensitivity...if you look at the ChipWorks electron micrographs of current Foveon designs, the transistors take up a huge amount of die space, as Foveon is still an FSI design...which is probably the biggest reason that sensor suffers so in low light.)

It was discovered some time ago that infrared light diffuses and reflects back subcutaneously in human skin. It can be used to greatly reduce the appearance of skin blemishes (I found a page a while back that shows that most skin features effectively disappear when you shoot full infrared). I'm not sure what UV light does for skin...apparently Canon found something useful with UV light.

Anyway, wtlloyd, there's some reference material. :) That's what Canon's got for multi-layered sensors.

Pages: 1 2 [3] 4 5 ... 298