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Messages - jrista

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1621
Found  interesting info on  Sony 7R image quality vs. 5Dm3, Nikon D800E and Pentax 645D with 100% comparison crops at different ISOs at imagine -resource:
http://www.imaging-resource.com/camera-reviews/sony/a7r
 Very interesting to see comparison of Canon 5D M3 with Sony a7R  at ISO 3200  both  low contrast high details shorts and for high contrast ones.


What surprises me is how much sharper the A7r is compared to the D800E. Both have no low-pass filter, but the A7r has noticeably more detail before sharpening. I wonder if that is due to literally not having a low pass filter at all, where as the D800E is actually blurring (separating) light in one direction, then "unblurring" (converging) it. Guess that, despite its special filter stack, it still isn't quite as good as not having a filter at all...


How does a FF mirror less with shallow 'flange" distance cope with the angle of light striking the extremities of the sensor at a more acute angle than on a camera with same sensor size but longer 'flange' distance ? I thought the angle of light hitting the pixel 'buckets' was a potential problem on FF due to a shadowing effect. I presume that on the Sony  it's either not a real problem anyway, the pixels are shallower, or the signal is being amplified at the extremities.


Sony developed a way to create microlenses that deal with increasing angle of incidence as you approach the corner of the sensor. Instead of a uniform microlens layer, the layer changes as you reach the edges. I am not even sure Sony was the first to develop the approach...I thought I read a paper about Panasonic or one of the other companies developing such a technique a year or so ago. Anyway, the microlenses are designed to guide light at a high angle of incidence into the pixel well in the edges of the frame.

1622
EOS Bodies / Re: New high resolution camera
« on: November 20, 2013, 08:46:55 PM »

Partisans on both sides will argue their case. I really don't care. I think there is room for both and it depends more on the photographer, on his or her particular needs, on his or her post-processing skills and on the ultimate use of the photograph.

I have always maintained exactly the same point of view, there are very good reasons for preferring either system on an individuals basis based on their needs and output criteria. What bugs me, seriously bugs me, is when people who haven't compared  images they actually shot themselves make endless theoretical arguments in support of a case that is easily settled by looking at a couple of images. Sure the theory side s a nice distraction, but photography is a visual medium that fully supports an empirical standard.

I have posted these images many times before. I post them again because it seems some posters have a genuine interest in the empirical results.

The test; I was interested in a 7D to compliment my 1Ds MkIII for focal length limited situations, internet wisdom was that with my 300 f2.8 I would achieve an effective 40% "reach advantage" using a much higher density crop camera than cropping my lower density ff camera. Both sensors were of a similar generation, actually the 7D (the wildly well received sports and BIF crop camera) is newer so has a slight technological advantage. I made a setup to show the biggest differences you could ever attain, solid tripod with the lens mounted on it, all I dd was swap bodies, Live View manual focus, cable release, remote flash for good contrast, 300 f2.8, optimum aperture, optimum iso (200 which favours the 7D slightly too) etc etc, things I could never use in the circumstances I wanted the 7D for but I wanted to see this 40% more reach.

Image on the left is the ff image, the red rectangle is the full image from the 7D. I then noticed a human hair next to the ruler. The 7D image is reproduced at over 100%, the 1Ds MkIII image was interpolated in PS to give the same pixel numbers as the 7D crop and is well over 200%.


My conclusions have always been that whilst in this perfect situation the 7D does have a slight resolution advantage it is very slight, and, given the extreme conditions I had to go to to see even that small difference I realised the differences in AF, iso, contrast etc would affect real world images to a greater degree than the mythical 40% more reach. I didn't get a 7D because I felt the cropped 1Ds MkIII images were close enough in ideal situations and any differences disappeared in real world shooting situations.


Now I invite you to draw your own conclusions.

Personally, and I stress that as I have 20/10 vision, and I don't necessarily want to make conclusions for anyone else...but personally, the 7D image is definitely sharper. Is there more visible detail? A bit. Not by a "vast" margin...but the scratches have more definition. The key thing, though, is that everything is sharper. The hair is razor sharp, the highlights are better defined. The grooves of the scratches on the ruler appear to actually be grooves with the 7D, where as for the most part they just appear to be white smudges with the 1Ds III. The threads of the green spool behind the ruler are better defined, particularly the dark threads...crisper, sharper. The topmost dark thread is kind of "dotted", and that fact is much more apparent in the 7D shot than the 1Ds III shot.

Additionally, and this ultimately boils down to personal preference, but I like the colors of the 7D better...just a bit richer, slightly more color contrast. I'll happily admit that may just be how the RAW was converted, and I know that for the most part the 1D series tends to have better out of camera color.

Again, this is what I personally observe. It is a lot easier to see these differences if you place both images directly on top of each other and swap back and forth, but it certainly isn't necessary to pick out the differences. Is it a massive difference? In the specific case of the 1Ds III and 7D, no. However these are just two random cameras chosen for comparison. One could also choose the 1D X and say the D7100 24mp sensor, and the difference would be more pronounced. Hell, the difference between a 1D X and D600 or D800 should be quite clear, and all three are FF sensors. As I said before, which camera's you compare, whether the sensors are crop or FF, doesn't matter to me. Fundamentally, my argument is that smaller pixels lead to better results (all else being equal.)

The 1Ds III and 7D is a close race, but that doesn't change the fact that the 7D wins. If we had our hypothetical 7Dx with half the pixel pitch (71.6mp), the difference would indeed be "vast", and the hypothetical 7Dx would win hands down, no contest.

As for reach, reach is primarily a factor of framing. Fundamentally, I think when most photographers talk about reach, they are referring to the sensor ratio, in which case the 7D would have a 40% advantage. In terms of pure pixel pitch reach advantage, there is no way to define that as a single ratio...it would entirely depend on the pixel pitch of the sensors you are comparing, which makes it a rather non-viable way to define reach advantage. There are dozens of different pixel pitches used in hundreds of different sensors. It would take a rather complex graph to define the pixel pitch centric reach advantage for every one.

1623
Found  interesting info on  Sony 7R image quality vs. 5Dm3, Nikon D800E and Pentax 645D with 100% comparison crops at different ISOs at imagine -resource:
http://www.imaging-resource.com/camera-reviews/sony/a7r
 Very interesting to see comparison of Canon 5D M3 with Sony a7R  at ISO 3200  both  low contrast high details shorts and for high contrast ones.


What surprises me is how much sharper the A7r is compared to the D800E. Both have no low-pass filter, but the A7r has noticeably more detail before sharpening. I wonder if that is due to literally not having a low pass filter at all, where as the D800E is actually blurring (separating) light in one direction, then "unblurring" (converging) it. Guess that, despite its special filter stack, it still isn't quite as good as not having a filter at all...

1624
Third Party Manufacturers / Re: Zeiss Otus Initial Impressions
« on: November 19, 2013, 11:40:32 PM »
Quite the impressive lens. Boke is beautiful, and it is razor sharp. Seems sharp is really "in" these days. It used to be in portraiture that a little softness was desirable, but it seems people want to extract every amount of detail they possibly can these days, right down to the pores in their skin.

1625
EOS Bodies / Re: New high resolution camera
« on: November 19, 2013, 09:40:50 PM »
I don't agree with this.

I know you don't, and you argue my examples when I show them, that is fine, you make your cjhoices for yourself and I'll make mine for me.

But I never questioned system resolution as a concept, I know full well the interplay of the elements within that system. We just come to different conclusions when looking at the images they produce, I don't care a fig for technical theories, just understanding why I see what I see.

Well, the example I've usually seen from you is the 7D vs. the 1D III, and I think your argument usually boils down to the fact that the AA filter on the 7D is fairly strong, thus diminishing the value of the 7D. I won't deny that a strong AA filter throws another factor into the mix, and it is a factor to take into account when actually measuring different devices. Even so, the use, or not, of an AA filter isn't a reason to stop pushing megapixel count/spatial resolution. My theory always assumes "all else being equal"...in which case the AA filter would be tuned to provide similar results around nyquist for any given sensor resolution.

I don't deny that it is important to use empirical data as well, however empirical data can and is often interpreted differently. It's a subjective measure, and how the data is interpreted, according to what criteria, and by whom, are all important factors in normalizing empirical results. Personally, I see a meaningful, if not "ideal", improvement in resolution with the 7D over the 1D III in your past visual examples, you do not... That is an important discrepancy, and just because the data is yours does not inherently invalidate the observations of others. I have very good 20/10 vision with my corrective lenses, and perhaps that plays a role. If the 7D had a weaker AA filter, the difference would likely be even more pronounced. One could also perform a test with the AA filter removed from both cameras (thus eliminating the additional factor), and I think the difference in spatial resolution would be quite clear in that case.

Your argument is usually perceptual (subjective), where as I try to make mine objective. Perceptual/subjective arguments, while not invalid, are hard to use as a viable basis for comparison because of the very fact that they can be interpreted differently in the absence of normalization. You see the 7D as having no visual benefit over the 1D III...I see the 7D as indeed having a visible benefit over the 1D III, if not quite as much as theory would have predicted...all using the exact same source images that you yourself produce. That is a war neither of us will win, and one which doesn't help anyone else understand the fundamental value of having a higher resolution sensor.

A 24mp APS-C sensor would arguably demonstrate an even greater lead over the 1D III...I'd be very curious to see you perform a visual comparison of say a D7100 vs. the 1D III, or even the 5D III that was identical to your test of the 7D and 1D III. I'd wager the D7100 clearly outperforms either Canon camera in the realm of final resolving power (spatial resolution).

I'm sorry if my replies frustrate you, but you often seem to be making the (subjectively based) argument that there is no value whatsoever to increasing megapixel count beyond the point where Canon currently is (~20mp APS-C, ~24mp FF). From an objective standpoint, there most definitely is, and I think it is important that people understand that. All else being equal, you don't lose anything by moving to a higher resolution sensor, and in fact you almost always gain something.

Subjectively, images from the D800 (at least at lower ISO/in good light) are superior, often vastly superior, to anything that you can get out of any Canon camera on the market right now. As a Canon fan, I don't really like to give a bone to the competition, but in this case, both subjectively and objectively, a higher resolution sensor most definitely has something to offer...and in a clearly visible, empirical way.

No as always you completely misrepresent me, invent what you think my assertions are, even though I never actually mention them (AA filters would be a fine example) and you, yet again, refuse to even recognise the cameras I used to make my tests, there is quite a difference between a 1D MkIII and a 1Ds MkIII. But you, with your 7D and 20:30 sight have drawn your own conclusions, and bearing in mind the amount of difference between what I write and you either misrepresent, or make up, it is clear what they are.

Sorry, I know it is the 21.1mp FF 1DsIII you used...I just miss typing the s for some reason. I never intend to misrepresent the cameras you have used.

I am a photographer, that is nothing special though other than the fact that I leave and breath by images (which have never been world beaters), I don't care for theory other than an interesting diversion when I am at the computer, in my world empirical rules, I don't care for yours and AlanF's theories on why my 300 f2.8 should give me 40% more reach on a 7D as opposed to a 1Ds MkIII, I just know it doesn't, because I actually did it. And that seems to be where we differ.

AlanF used to make this wonderful theoretical argument about how the 7D vastly outperforms the FF cameras for reach, a direct test of pixel density, until he got a 5D MKIII, guess what he shoots his focal length limited birds with now?

I would use the 5D III for birds as well, but not because of pixel pitch. I'd use it because of its AF system, which is without issue vastly superior to the 7D AF system. I don't argue these points because I am a die-hard 7D fan. I'm the first to admit the 7D definitely has it's flaws, and one of the biggest is the AF system. It's better than Canon's 9-pt systems, but it has plenty of issues of it's own that reduce the keeper rate. It is easy to argue the AA filter is too strong as well, and that is often a matter of opinion...really depends on how often you shoot subjects that might produce aliasing. If I had the money to buy a 5D III right now, and use it for my bird photography I would. It's a better camera overall.

That said, I wouldn't have any illusions that, assuming I could shoot the same bird with the same lens on both the 5D III and 7D, assuming both locked focus ideally, that the 7D would resolve more detail from the same distance. That isn't too much of a problem with the 5D III, though...I can always close the gap by throwing a 2x TC on my lens and using f/8 AF, and any edge the 7D may have had disappears at that point. But that isn't the point I usually debate. I am not sure about AlanF's arguments that the 7D "vastly" outperforms the 1Ds III/5D II. I would agree that, with it's archaic AF system, the 5D II was at a pretty healthy disadvantage to the 7D. The 1Ds III? Not so much. I DO indeed believe that in your prior visual comparisons of the 1Ds III vs. 7D resolving power, the 7D detail, while not "vastly" superior (and probably not 40% superior) was better by enough of a margin to clearly see it. Maybe 25%-30% better...but as far as technology goes, a 25% improvement anywhere is usually a damn good one.

(To contrast, performance improvements in successive generations of CPUs are often only in the 10-15% range, if that. Extensive overclocking of a CPU might buy you an additional 20%, and if you are really freaking good, use expensive liquid cooling technology, etc. you might be able to extract 40% in a good overclock. If your a total wackjob with tons of disposable income, you might use liquid nitrogen and an elaborate cooling setup to double your CPU performance.)

Now, we regularly butt heads on the 1Ds III vs. 7D thing. Let's assume the 7D had pixels twice as small (i.e. you could fit 4 7Dx pixels into one 7D pixel.) Do you believe the resolution advantage of the 7Dx would be moot in comparison to the 1Ds III? The margine isn't massive between the 1Ds III and 7D. But it would be quite considerable between the 1Ds III and our hypothetical 7Dx. I may simply be misunderstanding you, but by your arguments, it always sounds to me like your trying to make the point that a camera like our hypothetical 7Dx is unnecessary, and therefor should never be made in the first place. If I'm wrong about that, please let me know. As far as I am concerned, which cameras are actually compared don't really matter...1Ds III vs. 7D, 1D X vs. 7D II, 5D III vs. 1D X...the actual cameras and their sensor's don't really matter to me. My point is that there is value to increasing sensor spatial resolution, and there will continue to be value for quite some time.

P.S. I have never said nobody would ever benefit from a high mp camera, but the number of people who are committed to Live View manual focus, tripods, and top quality lenses are few and far between, play that off against the number of times they will reproduce that image where the extra resolution would make a difference and you start to understand why the downside of high mp cameras becomes obvious, faster processors and programs and storage are not as cheap as is often put forward.

The question becomes how many is enough? For some whatever the number becomes it will never be enough, for many people crop cameras and current mp are more than capable, for most FF is overkill, truthfully overkill, I believe the ever steepening slope of diminishing returns begins in the mid 20 for ff sensors; for AF users, for hand held users, or iso's over a few hundred, for people without the very best glass even now it is moot, they are already far below their cameras potential.

Comparing photos from the D800 with photos from the 5D III, while the 5D III still tends to lock focus faster and better, when both focus properly, the D800 still has more detail. A lot more detail. So...is 23mp really enough? Is 36mp really enough? I've seen photos from some smaller form factor mirrorless and compact cameras that have even smaller pixels, and the detail levels, assuming a roughly equivalent focal length, are even higher. With some of the latest models of these cameras, which use very advanced sensor fabrication technology, not only are the detail levels high, but noise levels are still acceptable.

Assuming we don't simply divide pixels size, and also assume that pixel quality increases at a similar rate...then I think enough is a long ways away. I think we can push the envelope 3x, maybe 4x farther than were Canon is now (i.e. approaching 100mp FF), before we actually reach a point where we truly have more than enough. Why? Because then we have sufficient raw pixel information to support full 2x2 pixel downsampling to 25mp, which would greatly reduce noise, improve dynamic range, and still support printing at very large sizes. Or, it would allow cropping the middle 25% of the frame, and still having quality similar to the current 5D III. Whichever you do most often, more pixels would never be a bad thing, and quite probably a good thing, even a better thing.

Is such a capability overkill? Well, depends on who your referring to. For most entry-level DSLR users, certainly. For a range of professional, or avid enthusiast/hobbyist photographers, probably not. There is never anything wrong with better quality. Getting better quality is the reason we are all here on CR, bickering about these kinds of things. We all want, hell we all THRIVE, on better quality. If it wasn't for such a strong desire to extract ever more quality from our photos, we wouldn't have any need to upgrade our cameras at all, or spend so many hours of our lives debating the issue in forums like this. It is ok if you are personally happy with 21.1 to 22.3mp, but that does not mean continuing to push the resolution envelope offers no value to everyone else. Just because 50mp or 100mp is overkill for the average casual photographer does not mean it will never have any use or value to someone far more serious about their work. As someone who has a very good optical prescription for my eyes, I can attest to the fact that with 20/10 vision, what I get now from the 7D is not enough. The 5D III, assuming identical framing, is an improvement...but I've also seen better. Therefor, I want better. And even better. As far as I am concerned, keep improving everything, on all fronts, until you reach some unbreakable physical limitation or exponentially accelerating costs that would obliterate any value in the technological gain (and I don't think we are even remotely close to either yet.)

I'd point out that, beyond just the theoretical, I'm not arguing that every random joe with a $500 DSLR or mirrorless needs more megapixels. I'm arguing that more resolution cannot ever be a bad thing, and if it cannot ever be a bad thing, why stop improving it? Even if we don't use every single original pixel in our final output, the more pixels you start with only ever means better results in the end (especially if you downsample the result), assuming you otherwise use the device effectively.

1626
EOS Bodies / Re: Canon EOS 7D Mark II in 2014 [CR2]
« on: November 19, 2013, 08:57:56 PM »
I'm going to go with "not cheap" as a baseline. If they only lose 50% of their chips per wafer that's $50-$500 per sensor in raw materials. I guess that's a big spread, but the possibilities are kind of scary to think about.

If I understand pp11 correctly at 0% loss worst case a raw ff sensor would be $250 ($5000/20) - strangely the article gives such a large price span for a dslr-sensor quality wafer, so I guess the cost would be much lower than this to prevent doing the exact calculation we're trying to do.

The big question is how much yield they get, maybe not as much as in computer processors as these are designed to work around defective circuits while on a dslr sensor a big flaw cannot be covered up.

Btw the paper is from 2006 and the aps-h advantage seems to have gone by now - maybe a lot of other things have also changed since then.

Since 2006, at the very least, 12" (300mm) wafers have become far more common. I doubt the costs of an 8" wafer still top out at $5000, I think they are quite a bit cheaper. I don't know if Canon has yet moved from 8" wafers to 12" wafers for their APS-C and FF fabrication, but even if they have not, it is highly doubtful their 8" wafer cost is $5000 (if it was, they would have a SEVERE handicap relative to the likes of Aptina and Sony, both of whom use 12" wafer fabs to produce CMOS Image Sensors (CIS).

I think Canon is currently using more advanced 12" wafer production for small form factor sensors, and I believe those fabs can produce 180nm transistors with Cu metal interlinks, lightpipe tech, etc. It is my sincere hope that they are using these fabs to produce the new 7D II and future BigMP sensors...but who knows for sure. There really isn't much good, solid information about this stuff.

1627
Lenses / Re: Lots of New Lenses Coming in 2014 [CR2]
« on: November 18, 2013, 09:48:52 PM »
105 2.8 TS Macro (replacing 90 & old 100 macro)


How large do you expect the front element of this Tilt-shift to be?


Agreed. Aren't most of the current TS lenses f/3.5 max aperture?


Sorry, I don't get the point.  How big do you think it would need to be?  The 45mm and 90mm are f/2.8. The TS-E 90mm takes 58mm filters, and the front element is recessed and noticeably smaller than the filter threads.  There's clearly room to add 10-15mm to the focal length, increase the image circle to match the 17/24, and still have a pretty small front element.




Hmm. I thought that most of the lenses had an f/3.5 aperture. If the current 45 and 90 have an f/2.8 aperture, then my post was indeed pointless.

1628
EOS Bodies / Re: New high resolution camera
« on: November 18, 2013, 09:48:02 PM »
(I've cut a bit of the nested quotes for ease of reading, don't think it changes what I'm about to say in any way)

outputBlur = sqrt(lensBlur^2 + sensorBlur^2)
outputBlur^2 = lensBlur^2 + sensorBlur^2
outputBlur^2 - sensorBlur^2 = lensBlur^2
lensBlur = sqrt(outputBlur^2 - sensorBlur^2)

Now I don't know of any way to convert DXO's P-mpix measure into simple lp/mm or blur circle size, as they take into account a number of perceptual factors like acutance, and use the lens' best performing aperture. Regardless, P-mpix is taking into account the convolution of the final image. You will never see any lens produce as many P-mpix as the sensors the lens was tested with...the P-mix value will always be lower, because you can never achieve the maximum potential of either lens or sensor.

The main problem with DxO PMPix is just that - it has no definition. It is an undefined quantity of measurement, where we only know the rudimentary basics of the general procedure, and almost nothing about the weighing factors. It's - in a sort of ways - closely related to the older commonly used SQF metric, but with changes to both cutoff in spatial frequencies and way to arrive at the final metric score.

Well, I was going to respond with a link to a page that described (at least largely, although it didn't specify the exact math) how P-mpix worked...however the page appears to have disappeared from the entirety of the net. (Which, ironically, speaks entirely to your point...that DXO is keeping it too secretive.) As such, I completely agree. P-mpix is a useless factor, telling you jibber jabber about thingamamonkey...which really isn't surprising, given that the lens scores and camera scores from DXO are also useless factors.

I don't really give DXO the time of day anymore. There are far more useful benchmarks for camera equipment out there that provide more useful insight. DPR, PhotoZone, TDP, etc. are vastly superior resources.

1629
Well, not much of a shower this year. I think I spotted two meteors total with my eyes. Between the bright moon, and eventual cloud cover, nothing really interesting.

Did some research, and it seems the Leonids won't be exhibiting much more than their "base" ZHR of 10-15 for decades. It won't be until 2094 before another thousands-per-hour Leonid meteor storm occurs (the last ones were in 2000 and 2001, which ZHR's of over 6000 and over 4000, respectively.) Kinda sad.

In 1833, the Leonids gained their fame with reported hourly rates well over 200,000 per hour...the entire sky from the Rockies to the Appalachians was lit up a continual shower of meteors...too bad they didn't have DSLR cameras back then...I'd have loved to see what that looked like :P

1630
Lenses / Re: Lots of New Lenses Coming in 2014 [CR2]
« on: November 17, 2013, 08:21:30 PM »
105 2.8 TS Macro (replacing 90 & old 100 macro)

How large do you expect the front element of this Tilt-shift to be?

Agreed. Aren't most of the current TS lenses f/3.5 max aperture?

1631
EOS Bodies / Re: New high resolution camera
« on: November 17, 2013, 08:19:45 PM »
How exactly do DxO mark arrive at that headline lens "score"? an average of lens performance across focal lengths/apertures? wide open? stopped down?
As JRista explained, DxOmark appears to have a Nikon bias on lens tests - BUT, that's because, for whatever their reasoning, part of their lens test also included a measurement that takes into account the signal to noise ratio of the camera body it's being tested on.  Possibly for consideration of final noise quality in printing.
The innately lower noise Nikon bodies thus boost Nikon lens scores..

I can see the logic for testing lens/sensor combinations even it won't give you a measure of lens performance relative to each other across different systems.

What I can't understand is giving one headline score or indeed exactly how this P-Mpix number was arrived at. At least with DxO's sensor marks its clear what the headline scores represent a certain level of performance at a certain setting or settings(even if you disagree with weighing performance in that fashion) and you have the ability to view other settings numbers. Here you just have one number then just an "P-Mpix map" that leaves you guessing based on colour and seems to max out at 12 P-Mpix.

Personally if anything I'm seeing more Canon bias here than I am with the DR figures. I'm no expert at the methodology of these tests but I can see nikon's clear advantage in DR when it comes to real samples. On the other hand I'm not seeing the "equalising factor of superior canon glass" nearly as much, D800 shots clearly look like they capture more detail than 5D3 shots to me.

With your last paragraph there, you are hypergeneralizing. I posted a very explicit example of two directly comparable lenses. DXO Mark's tests demonstrate that in every respect except T-stop, the Nikon lens performs worse than the Canon lens (for the 600mm f/4 in this case). The D800 has a great sensor with great DR...but the lens tests (which have nothing to do with DR) demonstrate that even the 36mp sensor cannot help Nikon's current 600 f/4 lens design keep up with the Canon lens design.

The PROBLEM, here, is that Nikon's lens was "scored" the same as Canon's lens. Given the raw data, the Canon lens should have scored better, without question. That begs the question...why? The only edge the Nikon 600mm had was 0.1 T-stops better transmission. So, DXO is really telling us that the end-all be-all of optical quality is having a tenth of a stop better transmission? Seriously?

There is clearly something wrong with DXO's scoring. Their lens tests are unabashedly biased, which makes you question every single one of their scores, and to some degree their approach. That's all I am saying. I'm not making any comparison of the general accuracy of DXO vs. DPR or anything like that...just saying that DXO has a severe and blatant bias, and people who use their information need to be aware of that.

Good morning
I do not agree with the statements above, let us all se how a high resolution camera would behave together with  Canons 600mm lens.
Due the magazine  Photo here is Sweden and MTF test of the "super tele lenses" there ar no difference between Canon or Nikon in terms of contrast and resolution .MTF test conducted by Hasselblad here in Gothenburg  and done so for 20 years  and today  with the latest white light D50 MTF equipments which not even Zeiss in Gemany have.
If we look at other good lenses for example  from Zeiss  they  doesn't scores high together with 36Mp in DXO tests but highly in Lenstip, Photozone, Hasselblads real MTF lab.
To believe that canon lenses would generally get higher marks than Nikon, Zeiss and others is in my opinion an over-reliance on Canon lenses . 
Janne

I'm not really sure where you are going with this. If the Canon 600mm f/4 II could be adapted to the D800 body, I have no question it would perform considerably better than the Nikon 600mm f/4. I'd bet a score in the high 20p-mpix range, maybe even 30p-mpix, is probably possible with the D800+EF 600/4 II. If/when a high-mpix Canon body comes along, I have no doubt the 600/4 II lens will score very high on it. Which was the entire point of Canon replacing their lens lineup in the first place...to make sure they had lenses that could take full advantage of higher resolution sensors when they finally arrived on the market. Canon is just taking the inverse approach that Nikon is...lenses first, then sensors. Nikon seems to be taking the opposite approach, sensors first, then lenses. Nikon's new 800mm f/5.6 lens is extremely high quality, is designed just like a modern Canon lens, and would probably score more like Canon's Mark II L-series superteles than one of Nikon's older designs (sadly, neither the Canon nor Nokin 800mm lenses have been tested...however, given DXO's bias, they did add the Nikon 800/5.6 to their database, while they are STILL ignoring the years-old Canon 800/5.6.)

1632
EOS Bodies / Re: New high resolution camera
« on: November 17, 2013, 08:09:45 PM »
Quote
The PROBLEM, here, is that Nikon's lens was "scored" the same as Canon's lens. Given the raw data, the Canon lens should have scored better, without question. That begs the question...why? The only edge the Nikon 600mm had was 0.1 T-stops better transmission. So, DXO is really telling us that the end-all be-all of optical quality is having a tenth of a stop better transmission? Seriously?

Again I can see the worth of measuring the whole package although it obviously means comparing lenses will be harder.

The "whole package" has nothing to do with it. The sole area where the 600/4+D800 performed better than the 600/4+5DIII was in the T-stop category. It performed better by a "whopping" whole 0.1 stops (a TENTH of a stop). Somehow, that one tenth of a stop in better transmission was enough, by DXO's standards, to overcome lower resolving power, worse vignetting, and worse CA? The issue isn't the whole package. The issue is the bias. There is no way that a tenth of a stop of additional transmission is worth that. That is immeasurable, given that camera metering can vary by that much or more for the same scene if several shots are taken in succession.

There is no whole package issue here...there is a blatant bias issue. The two lenses should not score the same, even WITH the D800's sensor being factored into the mix. The sensor is plain and simply not even close to enough to make the Nikon 600mm f/4 lens compare to the new Canon 600mm f/4 L II.

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There is clearly something wrong with DXO's scoring. Their lens tests are unabashedly biased, which makes you question every single one of their scores, and to some degree their approach. That's all I am saying. I'm not making any comparison of the general accuracy of DXO vs. DPR or anything like that...just saying that DXO has a severe and blatant bias, and people who use their information need to be aware of that.

Not sure where I stand on the "bias" but to me DxO's "pro Canon" P-Mpix score seems much much dodgier than there "anti Canon" DR scores. The methodology of it is only vaguely hinted at and all we get is a headline score that doesn't even state how its achieved(one focal length? an average?). The results disagree with my own viewing of sample images as well, the D800 has a much larger advantage in resolution than these numbers hint at. I see no such discrepancy with the DR figures where the Nikon cameras clearly do outperform the Canon's in recovering shadows at low ISO.

There isn't anything dodgy about the P-mpix score. It tells you how much of your base sensor resolution is perceptually "lost" due to sensor and lens manufacturing defects. In the case of the 5D III + 600/4, you lose 2.3 megapixels...indicating both the sensor and the camera are excellent in combination. In the case of the D800 + 600/4, you lose 18.3 megapixels. In terms of relative loss, you lose 10% resolution with the 5D III+600/4, and 50% resolution with the D800+600/4. The P-mpix score uses the lenses ideal aperture, where vignetting and CA are at their lowest without losing too much to diffraction. In the case of the Nikon 600mm f/4, based on the 18 P-mpix score, you clearly have to stop down a fair bit in order to reduce CA to the 9µm that DXO measured...CA would otherwise be higher at wider apertures, which would have indeed detracted from the final "score".

Remember that output resolution is a convolution of the resolutions of the components involved. The Canon lens has extremely high resolving power, which when combined with the 22.3mp sensor, results in a high quality result. The simple formula sqrt(lensBlur^2 + sensorBlur^2) closely approximates output blur circle for a DSLR, assuming you know the other two factors. Blur circle size can easily be converted into spatial resolution. We know the 5D III has a 6.25µm pixel pitch. If we also knew the outputBlur size, we could solve for the lens as so:

outputBlur = sqrt(lensBlur^2 + sensorBlur^2)
outputBlur^2 = lensBlur^2 + sensorBlur^2
outputBlur^2 - sensorBlur^2 = lensBlur^2
lensBlur = sqrt(outputBlur^2 - sensorBlur^2)

Now I don't know of any way to convert DXO's P-mpix measure into simple lp/mm or blur circle size, as they take into account a number of perceptual factors like acutance, and use the lens' best performing aperture. Regardless, P-mpix is taking into account the convolution of the final image. You will never see any lens produce as many P-mpix as the sensors the lens was tested with...the P-mix value will always be lower, because you can never achieve the maximum potential of either lens or sensor.

1633
EOS Bodies / Re: New high resolution camera
« on: November 16, 2013, 09:12:33 PM »
How exactly do DxO mark arrive at that headline lens "score"? an average of lens performance across focal lengths/apertures? wide open? stopped down?
As JRista explained, DxOmark appears to have a Nikon bias on lens tests - BUT, that's because, for whatever their reasoning, part of their lens test also included a measurement that takes into account the signal to noise ratio of the camera body it's being tested on.  Possibly for consideration of final noise quality in printing.
The innately lower noise Nikon bodies thus boost Nikon lens scores..

I can see the logic for testing lens/sensor combinations even it won't give you a measure of lens performance relative to each other across different systems.

What I can't understand is giving one headline score or indeed exactly how this P-Mpix number was arrived at. At least with DxO's sensor marks its clear what the headline scores represent a certain level of performance at a certain setting or settings(even if you disagree with weighing performance in that fashion) and you have the ability to view other settings numbers. Here you just have one number then just an "P-Mpix map" that leaves you guessing based on colour and seems to max out at 12 P-Mpix.

Personally if anything I'm seeing more Canon bias here than I am with the DR figures. I'm no expert at the methodology of these tests but I can see nikon's clear advantage in DR when it comes to real samples. On the other hand I'm not seeing the "equalising factor of superior canon glass" nearly as much, D800 shots clearly look like they capture more detail than 5D3 shots to me.

With your last paragraph there, you are hypergeneralizing. I posted a very explicit example of two directly comparable lenses. DXO Mark's tests demonstrate that in every respect except T-stop, the Nikon lens performs worse than the Canon lens (for the 600mm f/4 in this case). The D800 has a great sensor with great DR...but the lens tests (which have nothing to do with DR) demonstrate that even the 36mp sensor cannot help Nikon's current 600 f/4 lens design keep up with the Canon lens design.

The PROBLEM, here, is that Nikon's lens was "scored" the same as Canon's lens. Given the raw data, the Canon lens should have scored better, without question. That begs the question...why? The only edge the Nikon 600mm had was 0.1 T-stops better transmission. So, DXO is really telling us that the end-all be-all of optical quality is having a tenth of a stop better transmission? Seriously?

There is clearly something wrong with DXO's scoring. Their lens tests are unabashedly biased, which makes you question every single one of their scores, and to some degree their approach. That's all I am saying. I'm not making any comparison of the general accuracy of DXO vs. DPR or anything like that...just saying that DXO has a severe and blatant bias, and people who use their information need to be aware of that.

1634
EOS Bodies / Re: Canon EOS SL1 in White Coming Soon
« on: November 16, 2013, 01:19:22 AM »
The Nikon Df is controversial (I like personally).. and this is even less exciting..

Nikon's volume is much lower than Canon's, so being controversial is kind of an essential way for them to get more visibility and maybe scoop up some more market share.

Sadly, Canon's massive volume and market share are kind of their problem...even with competition from the SoNikon alliance and a variety of other camera and sensor manufacturers...they apparently don't feel enough pressure to push the IQ envelope much.

Personally, I hope the Nikon Df takes off. Might spur Canon into a more innovatively competitive mode. ;)

1635
EOS Bodies / Re: Canon EOS Rebel SL1/Kiss X7 in White
« on: November 16, 2013, 01:16:43 AM »
Isn’t she pretty?

Hmm...nope. Looks like an eye-sore to me. But, to each his own...

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