privatebydesign said:
jrista said:
I'm not sure where print came into play. I think, when evaluating sharpness, the only thing that really matters is actual image dimensions. The 7D's physical APS-C frame is indeed smaller than the 5D III's by the ratio you mention, but the output image is MUCH closer to the 5D III's output image dimensions.
The 5D III full RAW image size is 5760x3840. The 7D full RAW image size is 5184x3456. In relative terms, the image sizes are red and blue below, where as your skewed sizing, based on physical sensor dimensions, greatly puts the 7D at an undue and unrealistic disadvantage (green):
I know you dislike the 7D, but I think you are making a very unfair comparison that isn't benefiting the underlying point at all. The 7D it IS capable of being razor sharp, even with the 100-400...and with that particular lens, the 7D is not capable of really reaching its full potential.
I don't think chasinglight's problem is that he is using a 7D. Far more likely than that, I think there is probably some lens/body tuning that could be done, and after that, it is largely a matter of technique. If you use a tool properly, you can maximize it's potential, and the 7D has a LOT of potential. That doesn't mean it will produce better results if you have the ability to fill the frame with both the 7D and the 5D III...the simple fact that the 5D III has more total pixels means it will produce a better image. All it means is that chasinglight can work on a few things that cost him nothing, yet allow him to produce better results.
I don't quite know where to start addressing this post.
I think the best thing would be for you to go and reread the thread.
I'm not debating the entire thread...only "Reply #38",
It does amuse me, however, that you claim to limit your involvement now to a specific post in this thread yet are obviously carrying baggage from other threads that have no relevance to this one. where I believe you to make an incorrect comparison between a 7D image and a 5D III image by scaling the 7D incorrectly, which results in a significant and further reduction in detail of the 7D image relative to the 5D III image.
Err, that would be completely contrary to the effects of enlargement, enlarging more makes things less sharp, my comparison is set up to be fair and favours the 7D, When it comes to what was actually resolved, magnification relative to the final output is not the sole factor.
Output is the sole factor that needs or should be considered, be that an 8"x10" print, a 20"x30" print, a 30"hi res monitor or an iPad, you can only make a fair comparison if both outputs are the same size, theory and speculation is not worth anything, output is king. What is the point of comparing different sized outputs? None, it is an exercise in futility.
privatebydesign said:
I am the one who has constantly said the 7D is a more than capable camera, how you have managed to infer from that "I know you dislike the 7D" , I just don't fathom and am in complete disbelief at.
You've come off at me fairly strong in a number of threads over the last couple of months where you seem to put the 7D in exceptionally bad light relative to other cameras.
No, you have taken umbrage at my position, supported with my own images and hands on experience that I don't believe that it has a "tele advantage" in real world shooting over a cropped same generation ff sensor, I have never berated the 7D and always qualified that opinion that there are still very good reasons to buy one, just not because it gives you a "free" TC. You have repeatedly made a point of calling out how the 7D's resolution advantage is effectively meaningless.
From my personal hands on real world testing that was the case. Given the repetition, I can only conclude you dislike the 7D.
I'd suggest you reread the actual comments I made, they were always restricted to the output resolution and peoples false opinions of it based on theory, never the cameras capabilities. I also still believe you are comparing things incorrectly.
That is your perogative, but just as your objections to my posts in the DOF/compression thread, you are wrong, you just don't see it yet, and putting the 7D in unfair light.
If you understood what I was doing you would realise that reducing the size of the 7D output, to compare like with like, actually helps the 7D. Making things smaller makes them sharper. Even detailed articles about the 7D's resolution advantage from a well respected Ph.D., Roger Clark, seem insufficient to get you to even meet at some middle ground.
What middle ground is there to meet? This isn't a negotiation! I have used and tested both formats against each other, I set up specific tests to determine the actual realisable resolution differences, I have posted my results of a test set up to maximise the advantage the 7D has and even in perfect test bench situations the differences are small, in real world shooting AF makes more difference. You have displayed no experience with the ff cameras, have run no tests, have posted no comparisons and yet continue to argue your theoretical opinion, based on... theory. Photography is a visual medium, theory is all well and good, but show me the photographs. I tested them, I made them, I printed them, my experience is not based on theory,it is based on images.
Sorry if I've misread you, but I've been going by both the intensity of your responses to me when I debate the issue with you, and the frequency at which you bring up how nearly worthless the 7D's resolution advantage supposedly is.
In my experience it is, but that is a far cry and very different from calling the 7D worthless. Just because I don't respect your theory, when I have prints that prove it incorrect, doesn't mean I don't like the camera, I was debating your opinion, not the cameras worth. As for the frequency, well the more often I see incorrect theory the more often I will try to educate, DOF and equivelance, and perspective are more of my pets, I have been linking to the Equivelance page for 18 months now and there is a definite turn of common knowledge that now gets the concept, I don't claim many converts, but a few.
privatebydesign said:
Further "The 7D it IS capable of being razor sharp, even with the 100-400.." I KNOW, and I posted 11 links of razor sharp images shot with a 7D and 100-400, of birds, at 400, and some wide open!!!!! DID YOU NOT SEE THEM?
No, I came in on page three,
Well there's the thing, take something out of context and you don't know what people are talking about. I guess...saw a post by you that put the 7D in unfairly poor light, and responded. Again, I wasn't responding to the entire thread, and having read through the rest, I'm a bit confused by what seems to be conflicting information in different posts.
I suspect that is your preconceived discrimination of what you expected my opinion to be, not any inconsistencies in my posting.
privatebydesign said:
Or this "I don't think chasinglight's problem is that he is using a 7D" I have repeatedly said his main problem is subject distance (magnification) NOT THE 7D. Funnily enough that is why I used MAGNIFICATION as the comparison between his and Alan's images.
Using magnification alone, and ignoring pixel sizes completely, is the issue I was debating. I think that is oversimplifying the issue. There are effectively an unlimited number of potential output sizes,
Yes, and the only fair comparison is to equalise them, if I want an 8" x12" I want an 8" x12", I don't want an 8" x 12" from the 5D MkIII and a 12" x 18" from the 7D, which is what you are saying is a fair comparison. both smaller and larger than the native image size for each camera.
Digital cameras don't have a native image size! They have a native number of pixels, but that is very different. I think it is only fair to compare them at their native sizes.
If you were to standardise ppi as a comparison you would be going against any common sense idea of fair, or comparison, you would also put the 7D at considerable disadvantage as you would be enlargeing it around 50% more. Assuming the same bird is photographed at the same distance with both cameras, there is both a magnification difference
Not in focal length limited situations, like this one, the magnification onto the sensor is the same. as well as a pixels on subject difference. Since the issue is sharpness, pixels on subject matter. This is effectively a pixel peeping situation, so considerably reducing the size of the 7D's native output is skewing the basis for comparison.
No it isn't, it is favouring it, I don't understand why you struggle with this concept. More pixels equals sharper, less enlargement equals sharper, my fair comparison uses more pixels from the 7D and enlarges it less than yours, that puts it at an ADVANTAGE.
I get the feeling we are just going to agree to disagree on this point...so I'm happy to end the debate here.
And yet you didn't.......
privatebydesign said:
Alan suggested an $8,000 investment, I said no, GET CLOSER. I know in focal length limited situations the 7D will outperform (by a very small margin) the cropped 21MP 5D MkII/1Ds MkIII, and while I have not tested it against the 5D MkIII I would expect the results to be similar. To summarize that last sentence, I know in focal length limited situations the 7D will perform better than a cropped FF image, though not by much and certainly not as many as the pixel numbers would have you believe. I also KNOW, ALL PIXELS ARE NOT EQUAL, to compare one 7D pixel to one 5D MkIII pixel is moronic, it just doesn't work like that.
I agree, one needs to get closer. But in practice, there are limitations in doing that. Birds infrequently just sit still and let you get as close as you want. There IS an argument for buying better gear. It may not be the best advice for someone in chasinglights position, but it is not an invalid argument either. There are also consequences of getting closer. There is a zone within which one is closer to the bird, but also affecting it's behavior. If all you have is a 400mm lens, then either you deal with the behavioral changes, wait long enough for those behavioral changes to subside (which may never occur), slap the lens on a sensor with denser pixels
there you go again with your theory, or get a longer lens.
Again, if you had taken a few moments to acquaint yourself with the thread you would have realised we were talking about a very specific situation here. Alan has a FF body and a 300 lens with a 2XTC, chasinglight has a 1.6 crop body with a 100-400 lens, they are both focal length limited, they both need to get closer, but obviously, not to the detriment of the bird or the image. Having said that chasinglights setup actually gives him a narrower fov than Alan (though less magnification), hence my (everybody's) consistent suggestion that that was where the main improvement would come.
We disagree about the "by a very small margin" part.
That is fine, when I see your comparison images I might respect your opinion more, having said that I am not the only person who has come to the conclusion I have, several other prominent posters, have said exactly the same thing, but then they actually had experience with the cameras, they were not relying on theory. All sensor pixels may not be equal, but that doesn't really matter.
In my fair comparison, not it doesn't matter, in your ridiculous and contrived comparison it is supremely important, in fact that is all you are comparing. One only has to look at the two photos at full size to compare sharpness.
No, one has to look at two photos THE SAME SIZE to compare sharpness. I fear you are so anti me you will refuse to see that, just like the "compression" you were convinced was true, it wasn't, and your comparison isn't If one reduces the resolution of one image from its original size, THAT makes for an unfair comparison.
You don't sound like you print much, though you claim you do, there is no reduction in resolution, there is an increase in resolution for the denser sensor and an increase in ppi figures to take that difference into account, simple really, nothing is lost. And, again, the denser sensor is at an advantage. You are converting your bias against the 7D,
I don't have one, I have an opinion backed up with images and hands on experience that is agreed with by other owners of the two that contradicts common wisdom, your theory, that the much higher pixel density of the 7D gives it a meaningful resolution advantage in real world shooting over a same generation ff sensor cropped to the same sensor area. the notion that its pixels only give it a "very small margin" benefit, directly into actual image comparisons. If you are going to scale for comparison, scale them both to the same size
YES, THAT IS THE POINT, THEY MUST BE SCALED TO THE SAME SIZE, not the same %, don't scale one and leave the other unscaled.
privatebydesign said:
In focal length limited situations, as this one is, per pixel comparisons are worse than useless, subject magnification is THE ONLY FAIR comparison, it is the only relevant metric for comparison of output. It maintains equivalency, you are comparing like with like. How do you adjust for different DOF figures if you compare on a per pixel basis? How do you adjust a sharpness figure when you magnify one image more than the other? You can't! Compare same magnification and you get a true comparison, you know what will look better in print, on a screen, or any other end use output.
Again, I disagree. As a matter of detail resolved, for example feather barbs, pixel peeping WILL show a meaningful difference. That difference may or may not matter for the artists final choice of presentation. If the image is shrunk and uploaded online, and that is the only thing ever done with it, then sure...per-pixel comparisons are effectively meaningless. On the other hand, if you scale up a heavily cropped 5D III image against a lightly cropped 7D image, and print at 16x24, then the 7D's resolution benefit IS meaningful.
Oh, you almost got it then! A tightly cropped 5D MkIII image and a lightly cropped 7D image WILL REPRESENT THE SAME SENSOR AREA! We strongly disagree on how meaningful the denser pixel advantage is, but then my opinion is based on actual hands on experience and I draw my own conclusions from my own tests, but you nearly stumbled into the whole point there without looking. Per-pixel comparisons...or rather more realistically comparing both cropped images at full size, is an entirely valid way to evaluate IQ.
But then you lost it again :-( comparing smaller to bigger is not a fair comparison.
I am not even considering anything like a scientific test here, either...it doesn't take much to see improved sharpness with a little bit of eyeballing. I'm not talking noise here, either...just sharpness. The 7D image may indeed be considerably noisier in smooth OOF backgrounds, however even a noisy 7D image can still be razor sharp in the detail areas where it matters. Noise is also considerably harder to see in a print, so the greater resolving power of the 7D will have a meaningful impact on the sharpness of the final print. The 5D III noise would likely clean up considerably better, but the improvement is going to be less visible in a print than the sharpness factor.
All theory and conjecture, so irrelevant. However you have posted images before that show heavy noise reduction in oof areas, but none in detailed areas, you seems to think noisy detailed areas are sharper because they have noise, they are not, they just appear sharper, put some noise in a very slightly soft image and it appears sharper too.
As for DOF, from a technical standpoint, you are correct. From a practical standpoint, it usually doesn't matter.
No, it doesn't matter in same magnification enlargements, but look at stuff 50% more enlarged, or at the pixel level, and your CoC figures go out the window. Unless you have a DOF issue such that a critical part of your subject is affected...for example the end of a birds bill ends up out of focus...that matters. If the important parts of your subject are in focus,
At what magnification? My same sized magnification, or your 50% more for the 7D? DoF and sharpness changes dramatically with enlargement, my comparison equalises that, yours does not. at least in bird photography, DOF usually isn't a make or break issue. More of the butt end of a bird might be more blurry with one camera over the other,
No, in focal length limited situations, like this one, the DoF is the same for both cameras IF you use the same output magnification (if the birds in print are the same size), again, my comparison allows for this, yours does not. but if the eyes, bill, and a sufficient part of the birds head or body are sharp and clear...that's what really matters.
Anyway, I don't want to antagonize you further. You and I will likely never see eye to eye on the 7D/resolution issue (or, for that matter, the pixel density/resolution issue for any set of cameras, now or in the future). We disagree. I guess we just agree to disagree.
No antagonism, seriously, just disbelief in how incorrectly you took the meaning of my post. I am sure we will disagree, until, like AlanF, you actually own/use/test your theory and find it to be as false as your compression theory.
http://www.canonrumors.com/forum/index.php?topic=12718.msg228755#msg228755
http://www.canonrumors.com/forum/index.php?topic=10289.msg186746#msg186746
http://www.canonrumors.com/forum/index.php?topic=12730.msg227863#msg227863
http://www.canonrumors.com/forum/index.php?topic=12767.msg228235#msg228235
But then you have already had that conversation. Both before, and after his 5D MkIII purchase........
http://www.canonrumors.com/forum/index.php?topic=12718.msg228755#msg228755