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Messages - torger

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31
EOS Bodies / Re: DR and RAW bit depth on Canon's forthcoming...
« on: February 28, 2012, 02:09:57 AM »
How do all the high end medium format digital backs get such good DR? do they read at a higher true bit rate though sampling before the AD converter?

The good DR of medium format is a bit of a myth. They do have 16 bit ADC, but that's meaningless since the noise levels are too high, 14 bit would yield the same result. I've also heard the exposure metering is different from DSLRs, underexposing more so you get more highlight headroom so you can push more in Lightroom which some mistakingly think means that there is more dynamic range.

And then there is what you compare with. If you compare with Canon 5D mark II, yes, there is better dynamic range, because the MF sensors are usually very nice random noise, not patterned noise like on the 5D. But compare with a Sony Exmor sensor and the MF sensor has a little bit less DR. All MF vs DSLR tests I've seen has been with Canon cameras, and they always lose. But they would lose against a Nikon or a Sony with a Sony Exmor sensor too.

Then there is the larger sensor area, there is some DR gain from that since you can gather more photons (less shot noise), but that gain is not very large.

Throughout the years many DSLRs have been released with less than perfect DR, while MF sensors has at least since 2003 had good DR. But that's only on base ISO of course, those CCDs are not good at high ISO. DSLRs have always aimed for more all-around performance including high ISO. Anyway for several years if you have got MF you know that base ISO performance will be great, which has helped established the belief that MF is generally superior, although some DSLRs today mave even have greater DR.

32
EOS Bodies / Re: DR and RAW bit depth on Canon's forthcoming...
« on: February 26, 2012, 03:50:08 PM »
the comparisons are between different sensor generations, with 2+ years difference in release. A more relevant comparison would be between the 5d MkII and D700 or the 7D and D300s. Even the 1D MkIV is now over two years old.

The new G1X sensor which is fairly large, does not look very promising in that regard, but perhaps they've made it deliberatly worse than the 7D sensor to not compete within their own lines.

There's also the thing that Canon simply don't have the Sony Exmor technology. The big difference is that the ADC is on chip. Canon does not have that. Sony Exmor is a minor revolution (for low ISO). What you can expect from Canon is a gradual evolution. You'll certainly see "good enough" performance, but I'll (almost) eat my shorts if it will be world-leading.

33
EOS Bodies / Re: DR and RAW bit depth on Canon's forthcoming...
« on: February 26, 2012, 03:39:28 PM »
I won't start an argument over Nikon vs. Canon, but since you say you know about these things: From what I see, a Canon raw image with "highlight tone priority" is not linear - or am I mistaken?

The raw file content is always linear, since the sensor is linear. How Canon DPP interprets a RAW file with highlight tone priority may be a different story. You need a "dumb" raw processor like dcraw or similar to actually be sure that there's no non-linear trickery added to the RAW data in the conversion.

34
EOS Bodies / Re: DR and RAW bit depth on Canon's forthcoming...
« on: February 26, 2012, 03:31:18 PM »
I think the videos speak for themselves...modern sensors, including canons, offer far more DYNAMIC range than 7-8 stops.

May be true, I haven't actually done any subjective tests of how many stops the files actually contains, I have just compared different cameras to eachother and see I sometimes get problems when I push shadows etc. The actual number is not too important, the relative differences are though. What the camera can record in a scene which then can be compressed into a print without visible noise.

The raw files are 14 bit, meaning that 14 stops down the signal is either 0 or 1. At 13 stops down, the range is 0 - 4. Quite coarse quantization. I would be suprised if those last stops are usuable.

The videos are interesting, but I would certainly not use lightroom as some base to check how many stops (the actual number) there are in there, since you can't really trust that program's linearity, so I'd take the "13 or 14 stops of useful dynamic range" with a grain of salt. How much visible noise and dead colors you accept is also subjective, and it also dependent on the picture what works.

35
EOS Bodies / Re: DR and RAW bit depth on Canon's forthcoming...
« on: February 26, 2012, 03:12:33 PM »
A problem with DxoMark dynamic range measurements is that they do not show "usable DR". 14 stops measured DR just means that 14 stops down signal is equal to noise, that is how "engineering DR" is measured. But in a real photograph, such noisy information must be black, it is unusable. In fact, those parts of the image that are bright enough to show detail must have pretty good signal-to-noise ratio to look good. So perhaps only 7-8 out of those 14 is usable.

Another problem is that Dxomark does not measure pattern noise, random noise is much more acceptable to the eye than if you see patterns. And this is a weak spot with Canon. So a sensor with random noise with the same DR measurement as say Canon 5D mark II which have some pattern noise will have more dynamic range in practice.

One may argue that Canon sensors are already good enough and that DR problems never occur in normal images. Many photographers have that experience. But that the sensors are actually worse than the competition is easy to prove, just open a raw file from a Canon 7D and from a Nikon D7000 shot at base ISO and push both files 3-4 stops, and watch the noise in the dark parts.

Oh, remember that color negative film, if scanned with HDR on a high quality drum scanner (practically non-existent these days unfortunately), can deliver about 18 stops of dynamic range. There's still improvements to make in digital sensors... People *think* film has poor dynamic range, because they scan it with lousy flatbed scanners, or are used to old analog print workflows when you couldn't really expand the film S-curve. Also slide film while less DR than color negative do have quite good DR, assuming high end scanning equipment.

36
EOS Bodies / Re: Leaked photo of 5DIII/X to be 38MP ?
« on: February 17, 2012, 08:52:09 AM »
That calculation does not work, the navigation window is not scale-correct, at least not if I compare my 7D and 5Dmk2.

37
EOS Bodies / Re: 5D Mark III/X Information [CR1]
« on: February 16, 2012, 03:28:14 AM »
the dynamic range on the nikons isnt so much the sensor, but more their active-d lighting. Canon has their HTP, which isn't as good IMo, but if you shoot RAW....

That and since Nikon are using Sony sensors =P

that said, it might seem that Canon are lagging behind slightly - but the product is still brilliant - and if you were to threaten to jump ship because of that you're failing to see the big picture, or have too much cash.  If Nikon *did* somehow win this round - and they haven't because Canon hasn't even revealed their cards yet - theres still no reason to jump ship, Canon will come right back, because thats the way it is.

Yes on-chip ADC of Sony sensors seems to be key for DR. I hope they don't have a patent for it :-). I only consider RAW, so I'd say the practical DR is due to the Sony Exmor and the fact that they don't have as much pattern noise which subjectively kills some of Canon's usable DR.

Since I'm in the low ISO high resolution niche I'm a bit worried though, Canon seems to be that kind of player that care more about maximizing profit than to than to care for for all their users, including the less profitable niche users. But as you say, Canon hasn't revealed their cards yet. We'll see.

I would not "jump ship" though before we start to see what Canon will and can deliver. The latest three lenses suggest an interest for video (IS on wide angles) but also for high resolution (the 24-70 without IS but great MTF).

38
EOS Bodies / Re: 5D Mark III/X Information [CR1]
« on: February 16, 2012, 02:53:05 AM »
When I see Canon products coming out today I get the impression that pretty much everything except the sensors are great. I'm very impressed with the lenses coming out for example. However, to some of us the sensor is quite an important part of a camera. When it was D700 vs 5Dmk2 it was not a hard choice, about the same performance plus a lot more resolution.

Then Nikon started to impress with sensors, D3s, D3x, D7000 and now D800. This is really tough competition concerning dynamic range, low light capability and now resolution. Canon is now lagging behind. Will 1DX or 5Dmk3 change that? I doubt it, but we'll see once the products are out and properly tested.

39
EOS Bodies / Re: 5D Mark III/X Information [CR1]
« on: February 14, 2012, 11:46:09 AM »
No, I'm not saying anything about 5D3. I'm just thowing out a question of what Canon may have to do to make 5D3 competive if anything in the rumored specification is true. By the few specification points on paper it seems to have nothing compared to D800 so 0.5 stop better in high ISO performace could have been something to compete with.

As I said earlier I don't think that the masses care about detail differences in image quality. Less than 1 stop in ISO performance is details to the general user, they just conclude "it's about the same, as it has always been".

Having a lower MP number regardless of actual performance will be competitive towards a large group of users. I think many are turned off by having to deal with 36 megapixel files. In other words, lower MP can be a feature in itself, especially since D800 lacks sRAW and mRAW modes.

40
Canon General / Re: More Lens Suggestions [CR1]
« on: February 14, 2012, 11:28:00 AM »
Where's all the new TS-Es?  ;)

I'd love to see a TS-E 45mm upgrade (to improve optical performance), and after that a TS-E 90mm (to improve movement capability, optically it is already good).

41
EOS Bodies / Re: 5D Mark III/X Information [CR1]
« on: February 14, 2012, 10:51:01 AM »
And better color production.  I still feel like the XTi did better with flesh tones than the 5DII.

I hope you mean skin tones ;-)

42
EOS Bodies / Re: 5D Mark III/X Information [CR1]
« on: February 14, 2012, 10:41:52 AM »
I agree with you that comparisons are the only exact proof, but I don't believe Canon could allow itself to only use "mere ISO values in a marketing brouchure" and then not deliver in such high-end pro bodies, they would be the laughing stock then...I hope we will get blown away  :-*

I think the 1Dmk4 (ISO102400) proves that Canon indeed can put in high ISO numbers in the camera just to make them show in the brochure, not caring about how it actually performs. Thus, I will remain skeptical until real RAW samples and tests appear.

43
EOS Bodies / Re: 5D Mark III/X Information [CR1]
« on: February 14, 2012, 10:23:21 AM »
Well, define compete. IMO competitive doesn't need to mean undisputed best at everything. There is no such thing from any manufacturer, and if so, it never lasts long. I think even if they don't beat the D4 in high ISO, half a stop is barrely the difference between competing and not competing.

I agree. Half stop up or down is what fanboys can argue about, but won't make a difference on the whole. I don't think Canon will come out on top concerning sensor image quality this time around either, but it will not matter. Even if the sensor performs worse in terms of ISO than the 36 megapixel Nikon many users will just be happy with the fact that they don't need to deal with 36 megapixel files. Just as high megapixels attract some users (resolution for landscape/studio), a low number attract others (faster workflow, lower storage requirements). Finding out exact ISO performance is more complicated so I think most don't do that at all.

The high megapixel count may cause the D800 to look as a highly specialized camera, regardless if it performs really well at high ISOs. A more moderate count like 22 megapixels may attract more users just because it seems more all-around and sane, regardless of its actual performance.

44
EOS Bodies / Re: 5D Mark III/X Information [CR1]
« on: February 14, 2012, 09:54:12 AM »
Those that expect large ISO improvements in RAW files are in for disappointment. From market reasons it must be less good than 1Dx, and the 18 megapixel 1Dx may be as good as the 12 megapixel D3s in RAW performance. The D3s is about 1 stop better than 5Dmk2 (plus it can do very high ISOs which 5Dmk2 can't).

I'd say that a realistic expectation is that a 22 megapixel 5Dmk3 sensor is about 0,5 stop better than 5Dmk2 up to ISO6400, plus that the ultra high ISOs (ISO12800+) is more useful than on 5Dmk2.

45
EOS Bodies / Re: 5D Mark III/X Information [CR1]
« on: February 14, 2012, 08:55:29 AM »
The true genius of the D800 was the D800E. I would gladly take an 22Mpx 5dmkIII. But I want to be able to have no anti alias filter. It makes a world of difference for sharpness, and it wouldn't hurt the sort of photography that the 5D shooters usually do. In any case, you could always buy it with the AA filter.

I don't really understand not wanting megapixels because resolution is not important, but want to skip AA filter because, ehh, resolution is important? As I see it, it is only a good idea to drop the AA filter when the resolution of the sensor is high (like on the D800), meaning that diffraction will typically kill moire/aliasing problem and thus further blurring would be unnecessary.

No AA filter is better suited for those that has slow workflows with lots of PP, such as studio/landscape, that is for a megapixel monster, not for an all-around camera.

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