October 01, 2014, 08:30:58 PM

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 - sarangiman

Pages: [1] 2 3 ... 24
1
EOS Bodies / Re: Just for Jrista: 2014 Market Data
« on: September 27, 2014, 04:26:41 AM »
With exmor sensors you don't even have to bother thinking about getting the optimal exposure, you can focus on the other stuff and just shoot.

Yeah, I totally agree. I always have to get just the right amount of ETTR with the 5D III, so I'll usually (with landscapes, I work it a bit different with birds and wildlife) take a couple test shots to make sure I have the exposure right. With the A7r, it just isn't an issue...get the exposure generally right, take the shot. If your off by a third of a stop, either over or under exposed, it doesn't matter. You can usually recover it either way.

Now this is just crazy talk. Stop making excuses for being lazy and sloppy. You should learn to focus on everything all at once. You should even manually focus, like the pros did decades ago. And make sure you don't leave any more than 0.5 EV highlight headroom and then try to show there's noise in the shadows - you'll be lambasted.

Ok, on a more serious note: isn't that what I've been trying to say all along? That equipment getting out of the way opens up creative potential?

Anyway, make sure you don't take 'don't have to bother thinking about getting the optimal exposure' too far... actually depriving the sensor of light (via faster shutter speed or smaller aperture) does cost you image quality, no matter what sensor.

But, yes, it's a very 'free-ing' thing to not have to worry about excessive read noise - generally the only cost you'll pay by underexposing with Exmor is image detail that just looks like it was shot at a higher ISO. And that's usually not exactly devastating, given the ISOs people willingly accept shooting at these days.

2
EOS Bodies / Re: Just for Jrista: 2014 Market Data
« on: September 26, 2014, 11:51:15 PM »
I for one would be interested in seeing comparisons of pics taken in real situations that photographers face.
The shooter draws a conclusion, provides the RAW files and anyone can see if they draw the same conclusion.

This would be much better than the pointless technical banter that never proves anything or goes anywhere.

This is a very fair, valid request. A little difficult to do, but very worthwhile. What makes it hard is that it's actually very difficult to find sunsets/sunrises that do bottom out a, say D810. So it's hard to show the real difference, i.e. 'what's possible'. And if you do find the right high dynamic range scene, you're probably a landscape photographer who woke up at 2:30 am to shoot a sunrise at a beautiful location, not do a head-to-head test which is fairly challenging to do with the quickly changing light of a good sunrise/sunset. You also have to bracket both cameras all over the place so that you can go back home and then find the one where the highlights are just short of clipping, or where ACR can recover detail/color to taste.

I'm not saying it's impossible, it's usually just hard to do well. Hopefully someone will do it (well). I'll try at some point, maybe, before I sell off my 5D3.

...so here I am. Trying to be a man of my word.

I respect that. Good luck!

3
EOS Bodies / Re: Just for Jrista: 2014 Market Data
« on: September 26, 2014, 08:23:29 PM »
So it seems the reason I've been seeing posterization issues and Sarangiman hasn't when doing the emulated high ISO trick is due to Sony's compression algorithm.  Good to know I'm not the only person seeing this.

To be fair, I rarely see it with my A7R, so I think some of it may be due to your use of the A7 (IIRC)?

But, yes, Sony's compression is very, very annoying under certain circumstances. And that's a great reference/study you linked to, by the way.

4
EOS Bodies / Re: Just for Jrista: 2014 Market Data
« on: September 26, 2014, 06:23:49 PM »
I don't need a novel, I need a cohesive thought that can be backed up with supporting information. You think you know but you don't, you think you can explain but you can't, very convincing........

What don't you understand about RGB values in the low single digit percentages being shadow detail?

Why are you still talking about percentages on a histogram that represents the Raw values converted to ProPhoto RGB internal space and then converted to sRGB output and then converted to a percentage?

I analyze *actual* Raw numbers using RawDigger. Quit convoluting this analysis. I don't even know what your point is anymore.

My point is that you can't just do +3 or +4 EV pushes for these sorts of comparisons on brighter tones to demonstrate the differences. If you don't see a difference, you're not pushing deep enough shadows. If you don't have deep enough shadows while you're exposing for highlights, then your scene doesn't have enough DR for it to matter whether or not you're shooting Exmor or Canon.

I never said it's just about how many stops you can push. It's about what tones you're pushing. You seem to be stuck on this 'but XYZ percentage *is* a shadow'... what? First of all, what's a shadow depends on your exposure, and second, my signal of 7 out of 16,000 on a linear scale would be 0.04%. So, no, single digit percentages don't impress me.

I think I know? Not even going to respond to such a patronizing comment considering I do full SNR analyses of sensors...

5
EOS Bodies / Re: Just for Jrista: 2014 Market Data
« on: September 26, 2014, 05:13:09 PM »
No it wouldn't, a +100 shadow lift is a +100 shadow lift, it doesn't matter where the highlights are, or even if there are any. The entire image is as irrelevant as it was in sarangiman's crop which all the DR'ers thought was "amazing", see what you are doing here? Trying to make what you want/expect to see fit into what you actually do see.

This is completely misleading. A +100 shadow lift is not just a +100 shadow lift as you're implying. Whether or not you see banding/noise depends on where the tones you're pushing initially resided in the 16-bit Raw file.

It's pointless to have any other discussions until you at least appreciate that.

Unless you can explain better why that is misleading, after all the RGB values increase exactly the same numbers as an exposure slider lift does, then I agree, you and I have nothing to discuss.

What, specifically, is misleading?

It's not just about the amount of the push. It's (the signal of) what you're pushing.

And, no, I'm sorry, I don't have time to write a novel on this right now. Honestly, I'm not being snarky. Perhaps someone else can explain.

6
EOS Bodies / Re: Just for Jrista: 2014 Market Data
« on: September 26, 2014, 04:36:43 PM »
Seems you're more reasonable now, in most regards? :)

Isn't it amazing how people are reasonable when they agree with you?   ::)

Yes, that's it. I'm happy he's agreeing with me. Not happy that he's:

  • No longer making claims about a camera he hadn't owned or even touched (5D3)
  • Making claims about highlight headroom without doing a controlled comparison between Nikon and Canon cameras
  • Irrelevantly claiming that my D800/5D3 results were wrong b/c I didn't give both cameras ~0.5EV more exposure to totally get near clipped highlights in the sky. Yes, b/c that would've changed the end result.

It couldn't be that I'm actually happy b/c he's no longer making those illogical statements, right?

Must be some psychological comfort in finding someone who's agreed with me. Yes, that must be it.

7
EOS Bodies / Re: Just for Jrista: 2014 Market Data
« on: September 26, 2014, 04:33:29 PM »
No it wouldn't, a +100 shadow lift is a +100 shadow lift, it doesn't matter where the highlights are, or even if there are any. The entire image is as irrelevant as it was in sarangiman's crop which all the DR'ers thought was "amazing", see what you are doing here? Trying to make what you want/expect to see fit into what you actually do see.

This is completely misleading. A +100 shadow lift is not just a +100 shadow lift as you're implying. Whether or not you see banding/noise depends on where the tones you're pushing initially resided in the 16-bit Raw file.

It's pointless to have any other discussions until you at least appreciate that.

8
EOS Bodies / Re: Just for Jrista: 2014 Market Data
« on: September 26, 2014, 07:30:23 AM »
I used to think that cameras handled highlights differently. I actually still think that to a small degree, they do, and in some ways I think Canon cameras do handle highlights better. I definitely no longer think that there is nearly as much headroom in the highlights as reported by the camera itself as I used to think, though.

When I say the 5D III burns highlights, I mean that highlights go from "good", with nicely separated tones, to "poor", where things are all just blended together mush, and often a near-blown-white creamy color...VERY FAST. There isn't any room up there...you go from good clean highlights that are eminently recoverable, to not fully blown, but not really usable either, in a heartbeat. There are only a few levels at the upper end of the linear range where your highlights aren't blown, but where they seem to bleed into each other across color channels. When I first got my 5D III, I ETTRed with it the same way I did with the 7D, and it simply did not handle that the same way.

That's different from the 7D. The 7D seems to have a lot of highlight headroom. I've overexposed shots with the 7D by a couple of stops, and was able to recover quite nicely in the end, without any actually blown highlights. I could ETTR quite far with my 7D, and sometimes I'd clip highlights, but it wasn't that often that they became an unusable creamy-white blur before that point.

Now, this is based off of what the camera reports. I've long been an ETTR fiend...it's kind of the only way to use Canon cameras. If you don't push the exposures in-camera, your losing a lot of usable DR, because the read noise is higher than with Exmor sensors. The way the 7D reports the highlight clipping point, you can still expose for about a stop or so before you actually clip the highlights in RAW. I guess it's just a difference in how Canon generates the JPEGS, but I find that I barely have the ability to expose a third to two-thirds of a stop with the 5D III before the highlights get to the point of unusability, and usually at that point they clip as well. Same meter, in both cameras...so it has to be a difference in how the JPEGs are generated.

Anyway, even when shooting in manual mode, you ultimately determine your exposures based on the in-camera histograms (generated from JPEG), in-camera highlight warning (generated from JPEG), and in-viewfinder metered/exposure compensation scale. The scale seems to be based directly off the meter, however you never quite know how the tones will distribute in the image until it's taken. So in the end, you base the "properness" of your exposure off the in-camera histogram. That histogram, at least base off of my own experience with my own 5D III, is unforgiving of highlight overexposure. When you do ETTR...the 5D III tends to "burn" the highlights...since there really isn't much room there.

I suspect the 5D III was updated to simply be more accurate. That's a good thing, but when you have spent years with a particular camera that behaved a particular way, you tend to base your experiences off of the thing you have the most experience with. My 7D, being quite forgiving with highlights, is my reference point.

My limited experience with the D800 seems to indicate much the same. It seems their highlights just kind of ride up to the top, then suddenly they clip. There isn't the same kind of headroom as the 7D. Again, that's probably just the camera being more accurate, when it tells you the highlights are clipped, it usually really means it. The difference with the D800 is...you simply don't NEED to ETTR. Not nearly like you do with Canon cameras. You still can, but it's just not a necessity. Two years ago, I'd never done more than hold a D800 for a few minutes in a store, so, I did not have any real depth of understanding about how it's data is really distributed. I also had delusions about how good the 5D III was...truly, delusions. :P It's really NOT as good as thought it was back then, not from a low ISO DR standpoint anyway.

I base the 'properness' by taking a lot of shots at different exposures and then choosing the one just short of clipping in important channels such that even recovery won't help. But for actual DR tests, I also bracket and choose the file that's is just short of clipping (a certain threshold number of) green channels. Then work backward to where SNR hits a threshold.

Anyway, what it *seems* you're saying from all this is that back then you had a whole bunch of delusions, limited experience with the other system (D800), and so therefore took all of this to somehow mean you could call my entire controlled comparison, using matched shutter speed and aperture, between the 5D3 and the D800, and I quote: 'ABSOLUTE BULL PPL!'.

Yes, that particular scene didn't have enough DR to demonstrate the difference artistically, but it didn't take anything away from the point (well, besides a little beauty). And anyone who is capable of understanding the interplay of read and shot noise in determining SNR of tones really shouldn't have gone off on that rant. So honestly at that point I was just confused.

Which is why I left, especially after more guys joined (or used) your bandwagon - guys I thought we'd come to have an understanding with. Lot of the same forum behaviors still exist, years later. Seems you're more reasonable now, in most regards? :)

9
EOS Bodies / Re: Just for Jrista: 2014 Market Data
« on: September 26, 2014, 03:28:25 AM »
MIDTONE banding with gray fog and blue skies are where i first noticed problems with Canon images when I had my 5d2, ages ago.
Shadow pushing landscapes with every Digic 4 body showed me the FPN issues in shadows.
Quick testing of my 5d2 showed me that FPN was readily visible in smooth shades only 2 or 3 EV below metered middle if pushed only +1 stop.
I still maintain it was the most disappointing body I ever had, and possibly a lemon but... there were more of them out there like that.


I'm feeling somewhat vindicated by so many more of you, some who've previously argued against these very observations, corroborating this problem.
My only question is, WTH took so long for some users of same equipment to notice this?!?  ???

Well, I'd noticed the banding with the 7D a long time ago. I also acknowledged it a long time ago, in many posts. The 7D banding is easier to clean up, since it is so extremely regular (they span eight pixels, the stride of the ADC channels). The 5D III banding is different. It's not as pronounced, per-se, but it is still there...and it does NOT clean up well with Topaz DeNoise 5. I only got the 5D III maybe four or five months ago? So, it's been only relatively recently that I got enough personal, first-hand time with the 5D III to fully realize how frustrating its banding issues are. That may account for why it "took me so long", as you put it. ;P

I am happy with the 5D III at higher ISO, however it has been rather disappointing for me at lower ISOs. I thought it would be better...and it simply isn't. ISO 400 with BIF against a blue sky can sometimes be really ugly at times. I don't feel that it has much in the way of shadow pushing at all. If your very careful, use heavy GND to compress contrast on-scene, ETTR like mad (which is also another weak spot of the 5D III...it burns highlights), then you might not actually have to lift a stop. The shadow falloff still isn;t good, though....you can see the poor quality of the shadows even without pushing. The only real remedy there is to crush the blacks a bit...but I've never been a big fan of stark contrast in landscapes...

So yeah. I really do notice the issue now...it's depressing.

Well, I'm sure many have noticed it, and just worked around it.

I myself noticed it years and years back, actually when the 5D Mark II was first released. But I usually got eaten alive when I mentioned it (not just here, in fact). Even by people like jrista some 2+ years ago, sadly! Ironically, jrista, one of your counter-arguments back then was something about more highlight headroom with Canon files. Which just isn't the case - most of these sensors map the data off the sensor in a linear fashion, so there should be no difference between brands, cameras, etc. Save for maybe the D810 at ISO 64, where DxO full SNR curves suggest non-linearity - which'd essentially mean that highlights that 'look' clipped in fact aren't b/c they've been rolled off. Honestly, I'm suspicious about that... actual non-linearity at the sensor level is kind of a holy grail, so I'd expect Sony or Nikon or DxO or someone to be ranting mad about that if they'd actually achieved it.

But anyway your comment years ago about highlight headroom and my D800/5D3 comparison being bull is particularly ironic now in light of you mentioning the highlights burn easily ;) Which, btw, I'm not so sure is entirely, quantitatively, accurate... again, since these systems map the data linearly. Unless there's some difference in (non-)linearity of charge build-up in the photodiodes, but unless you've really done some thorough side-by-sides, I wouldn't go around claiming one system has more highlight headroom than another.

10
EOS Bodies / Re: Just for Jrista: 2014 Market Data
« on: September 26, 2014, 03:19:48 AM »
EDIT:  To answer PBD, you probably could push the 70D files by 3 stops and not be bothered by FPN but you'd still have plenty of shot nose to get rid of and that will eat some of the detail in NR software.  the 7d2 might perform similarly.  the 6D would get away with it in some shots, as will the 60D as I've done it for some shots with acceptable results. Other digic 4 bodies, not likely as capable.  older digic 2 and 3 bodies would behave a bit like the 70D and allow a good push in many cases but would have even greater overall noise levels to deal with.

Did you mean 'read noise' instead of 'shot noise'? Even an ideal camera will be shot-noise limited ;)

11
EOS Bodies / Re: Just for Jrista: 2014 Market Data
« on: September 26, 2014, 03:18:15 AM »
Not in Lightrooms percentage scale it isn't. If I take an RGB value of 32 30 27 and lift it three stops I get 86 85 81, if I take an RGB value of 66 70 79 and lift it three stops I get 98 98 99 (no 99.9's ether), if I take 26 20 14 I get 81 72 60, all for an average of less than triple the value and that doesn't include the obviously nearly blown set.

I'm just saying that a stop is a doubling of light. 2^3 = 8.

So when you literally said 'triple those numbers'... that's incorrect. The percentages, I assume, are percentages of the 8-bit 'Melissa RGB' values. Don't quote me on that though.

Melissa isn't an 8 bit colour space. The LR "editing space" is a minimum of 16 bit and can work automatically in 32 bit too.

Right but I believe the histogram is based off of a mapping to sRGB output from the internal ProPhoto RGB (16-bit IIRC) space. So I'm not sure the percentages work out entirely predictably every time.

My point was that you're not literally 'tripling' the raw signals when you do +3 EV. You're multiplying them by 8.

This isn't very productive. If you do find out exactly what the percentages mean, though, please let us know.

12
EOS Bodies / Re: Just for Jrista: 2014 Market Data
« on: September 26, 2014, 02:50:41 AM »
Not in Lightrooms percentage scale it isn't. If I take an RGB value of 32 30 27 and lift it three stops I get 86 85 81, if I take an RGB value of 66 70 79 and lift it three stops I get 98 98 99 (no 99.9's ether), if I take 26 20 14 I get 81 72 60, all for an average of less than triple the value and that doesn't include the obviously nearly blown set.

I'm just saying that a stop is a doubling of light. 2^3 = 8.

So when you literally said 'triple those numbers'... that's incorrect. The percentages, I assume, are percentages of the 8-bit 'Melissa RGB' values. Don't quote me on that though.

13
EOS Bodies / Re: Just for Jrista: 2014 Market Data
« on: September 26, 2014, 02:04:43 AM »
We are talking about shadows, so sub 10% RGB values in Lightroom, your belief is that you cannot triple those numbers in a Canon file without seeing excessive noise and banding with current generation Canon sensors?

3-stop push is not 'tripling'. It's multiplying by 8. And a 6-stop push is multiplying by 64.

And, yes, since vignetting correction for 24/1.4 is 3 EV, and since I'm - on a number of occasions - noted visible noise/banding from just vignetting correction, yes, I do believe you can't push 3 EV without a noise cost for many lower tones.


My standards are high, though. It's all about the quality of the falloff into the shadows for me. I've seen far too many of my images that show banding right up into the midtones without any exposure pushing at all, let alone a three stop push. To me, I find that 100% completely unacceptable. I've even had that problem with some of my bird photography when shooting at ISO 400 or lower (not all that common, but sometimes the light is ridiculously good.) At the very least, even though it's usually correctable, correcting it affects detail. Reducing the random noise affects detail more. Reducing the color and gaussian components of read noise affects detail even more. It's just one layer on top of another with Canon files. Every layer nuking a little bit of detail. If you really try to clean up the shadows, they just end up mush, and no amount of fiddling seems to bring in that incredible soft tonal falloff that you get with a D800 or D810.

Oh yeah, thanks for reminding me of this. I'd forgotten that I've even seen banding in blue skies in some shots, possibly b/c the other channels were underexposed? Then when I averaged shots to get rid of some of the noise and get a cleaner image, the banding became even more apparent.

14
EOS Bodies / Re: Just for Jrista: 2014 Market Data
« on: September 26, 2014, 01:37:06 AM »
Do you honestly believe you can't push Canon files three stops?

Not without a noise cost. Unless you're talking about ISOs 3200 and above, where now even the lowest signal is amplified to be at or above the noise floor of Canon electronics.

And my initial post about noise after just correcting vignetting - that was a 3 stop push (Canon 5D3 | 24/1.4). So, I believe that answers your question. How much was your push in your example?

I don't follow, either you can lift three stops or you can't, where the highlights are is not in question, ETTR is not in question; were the lifted portions of the image, specifically shadows, lifted three stops and maintained any kind of image quality, that is the question.

Do you believe a Canon sensor, from the current generation, can be lifted three stops and still maintain good quality shadow detail, lack of noise and banding?

No, it's not that simple. It depends on the tone you're pushing. Actually, it depends on the exact signal you're pushing, and where it is in relation to the noise floor. Which is high for Canon.

What's impressive is that is a SIX STOP push. That's the noise levels SIX STOPS deep in the exposure. Imagine what that means for shadows only two or three stops deep. It means they are PHENOMENAL.

What it means, which you can quantitatively show, is that there's (almost) no noise cost in doing that push vs just shooting the correspondingly higher ISO.

And that's an incredibly cool concept. It opens doors.

In another context, it's no wonder people call black-point hacked D800's "CCD-like" in the astro world. The quality of noise in Sarangiman's deep push examples are very much CCD-like in quality...very clean, very random. Run an FFT on a dark frame from that camera, and I bet the resulting image would exhibit nearly perfect Gaussian traits. Personally, I think that's amazing. I've run FFT's on Canon darks...they are nothing close to resembling a perfect Gaussian noise FFT image.

I wonder if that's at least partly b/c Nikon finally decided to add a black offset. A great (albeit not new) idea in my book.

15
EOS Bodies / Re: Just for Jrista: 2014 Market Data
« on: September 26, 2014, 01:29:00 AM »
Impressive? If you CR members can make money off photo's like this congratulations and I admit I'm an idiot and should take up another hobby (maybe lawn bowling/or maybe BINGO) else they are crap.

Hey, you said it buddy, if you think I took that photo for any reason other than a test to prove a point.

Pages: [1] 2 3 ... 24