I got a question please guys.
Most photographers I know don't put much stock into the number of megapixels, often citing printing size as the sole benefit.
Is this true? Is there really nothing else to megapixels other than printing size?
The ability to crop is (or can be) a biggie. When I am shooting fast moving sports I often give myself a little extra margin in camera knowing that I can crop it later.
Indeed! And with wildlife, small birds, particularly, cropping gets the shot if you don't have a long enough lens.
This is often said, but rarely backup with proof, mainly because it isn't actually true.
Here is a same generation crop sensor at 100% and a cropped ff sensor upscaled to the same pixel number. Whilst there is a fraction more detail in the 7D image this was a bench test under ideal conditions; using AF, hand holding, higher iso etc, would all level the field. The 7D crop has over twice the pixels the 1Ds MkIII crop has!
Is there a good reason to own a crop camera? Sure, it might have better AF, it is easier to frame as the subject is magnified more in the viewfinder, the image you see is closer to the image you will get etc etc, but there is a mere fraction of difference in actual image resolution and even that small difference isn't realisable in real world shooting.
This argument is flawed on two fronts. First, the same things you claim detract from any benefit the 7D has also apply to the 1D IV. Camera shake, for example can diminish IQ well below the potential for either camera.
Second, and more important...final image resolution is the result a blend of each factor that detracts from initial resolution. Since final image resolution is a convolution of camera shake, AF missfocus, lens aberrations and diffraction AND sensor resolution...the 7D would still come out on top even WITH all of those things affecting IQ. Assuming the same amount of camera shake, AF missfocus, and lens resolution...the only difference between the two then is sensor resolution...and the 7D wins.
First, I am not presenting an argument, I am presenting empirical results of a test.
You were, intentionally or not. When you claimed that the previous statements were untrue, you started a debate, and proceeded to present your "argument" for your opinion...Second, I used a FF 1Ds MkIII not an APS-H 1D MkIV.
Ok, not that it really matters to the point being debated any. The point of yours that I am arguing against is the notion that all or nearly all of the benefit of the 7D's higher resolution as offered by higher pixel density is mitigated by "real world factors". And I quote:but there is a mere fraction of difference in actual image resolution and even that small difference isn't realisable in real world shooting.
This is the specific point of yours that I am debating. I think you are FUNDAMENTALLY WRONG...there ABSOLUTELY IS a difference that CAN be FULLY REALIZED in the real world. It would take some very significant camera shake or a severely missfocussed lens to diminish the resolution benefit the 7D has over the 1D III. Someone with particularly unsteady hands and a non-IS lens is probably at a much higher risk of "not being able to realize the 7D's resolution edge", but in general I think the edge is entirely realizable. I realize it every day, in both tripod-based and hand-held photography. It is the reason the 7D has been my body of choice for the last couple of years, and why I am holding out against buying a 5D III until the 7D II has been released and its upgrades evaluated.
I'll HAPPILY take an even HIGHER resolution sensor than the 7D has...because I know first hand that the extra resolution can be utilized even in a hand held scenario (or a missfocus scenario...a problem with the 7D that I believe is far more severe than its supposedly overdone sensor resolution).Third, I agree the 7D "wins", though I don't agree with the oversimplified knee jerk rhetoric.
First..."knee jerk"?? LOL...not sure where that came from
Second..."rhetoric"?? I know I can be wordy...I often use a lot of words just to be clear in getting my point across. Ironic, as I though my last reply to you was rather concise and clear, and explicit in its form as a STATEMENT, not a question...rhetorical or otherwise. (Unless, I guess, you think the use of the word "convolution" is rhetoric...)I even pointed out in my initial post that the 7D does have more resolution, just nowhere near as much as anybody would guess or expect, most people are pretty emphatic that the far denser sensor of the 7D would trounce the less than half the pixel numbers of the FF, but it just is not so. The 18MP of the 7D equate well to the 36MP of the D800, we all know, as a system, the 5D MkIII at 24MP and the 24-70 f2.8 MkII resolves more, as bench tested, than the D800 and Nikon 24-70 f2.8, 18MP to 15MP.
I'd be careful not to conflate spatial resolution with pixels on subject. Assuming one could frame identically, the simple fact of the matter is that the 5D II, 5D III, D800, or any other full-frame sensor with more than 18mp will produce a more detailed result. But I think that notion is counter to the prior discussion about why one would want an 18mp APS-C (not FF) sensor: crop factor. Identically framed, hands down, the full frame sensor with more pixels is going to produce a better result...not only because it puts more pixels on the subject, but because it puts more BETTER pixels on the subject.
Your very own argument, which equated a cropped 1D III to a 7D, implicitly assumes a focal-length limited scenario where one literally cannot frame the same. That falls in line with the prior discussion, and I have no question that if actual samples of photos taken hand-held with the 7D and 1D III in a variety of scenarios at ISO settings up to 1600...the 7D would trounce the 1D III. No contest. I might even buy a 5D III just to prove the point!I know and understand image resolution is a result of system resolution, I just pointed out, with images, the system resolution of an 18MP crop camera is not very much different from a crop from a 21MP FF camera. Again, that is not an argument, it is an empirical observation.
If you are claiming an "empirical" observation, sample data would be a necessity to back up your claim.
I can make the same argument, that I have made empirical observations that the 7D produces very different results (and superior, in terms of resolution usefully resolved) than something like the 5D II. As a matter of fact, a well respected scientist did just that very comparison (7D, 1D IV, 5D II), and his results are pretty definitively in favor of the 7D:
In the context of this discussion, I think the following statement from that article is key:QuoteThe sensor sizes are irrelevant in these examples. All three cameras could well have been full frame sensors. It is purely a test of pixel size and the trade of detail versus noise.
Additionally, the results of the test, as evaluated by Roger Clark:QuoteHere is my assessment:
In all the images, the 5DII images fail to show the subtle color differences that the 7D and 1D4 show. The color in the 1D4 and 7D are very close (until noise hides it).
ISO 100: 7D noise is small and detail is well above other images. 7D=top, 2nd=1D4
ISO 800: 7D noise is showing, but the detail is still well above the other cameras. 7D=top, 2nd=1D4
ISO1600: 7D noise is becoming prominent, but image detail is still very good. 7D=top, 2nd=1D4, but the difference is narrowing.
ISO3200: 7D noise is becoming objectionable and color is getting lost, in particular in Mare Serenatatis (the large circular dark area in the upper center). top=1D4, 2nd 7D. A good down sampling algorithm (like 2x2 pixel average) could improve the the image.
ISO6400: Noise is too apparent in 7D, and 5DII (which is slightly older technology than the 7D or 1D4). Top=1D4, 2nd=5DII. In my numerous sensor evaluations, I consistently see the 1D series sensors have fewer hot/bad pixels and the images here show that too: the 7D and 5DII images have a lot of "spiky" noise not seen in the 1D4 image.
The visual examples, which I cannot post here, CLEARLY demonstrate the benefit of having a sensor with denser pixels. The 7D images, while at times noisier than the 1D IV, have a more than measurable increase in overall detail...a very meaningful difference between the two cameras.
You might be well advised to go back and actually read my first post, it contains the images you ask for, the one on the left is a FF image (FROM A 1DS MkIII !) with an overlayed full image from a 7D, the red rectangle. They were shot from the same place with the same lens, a 300 mm f2.8 IS @ f5.6. This is a 100% demonstration of a focal length limited situation.
Now as I have repeatedly said, the 7D does have a fraction more resolution but it is not in the order most expect it to be. I did do further real world testing, though unfortunately don't have those images with me and they are not bench tested direct comparisons anyway (so would only lead to all sorts of not fair comparison claims), but after using both cameras side by side I concluded that the 7D gave me no more realisable resolution, I was surprised, but rather than throw down $1,500 because everybody said it would, I got a loaner and tested it for myself.
Other tests, by other people for their uses might show different results, I was surprised by my results but entirely happy they were accurate and got a second 1Ds MkIII. Again, there are many good reasons to own/buy a 7D/crop camera, but thinking you are getting a "free" TC is not the most sensible, or accurate, one.