neuroanatomist said:
gshocked said:
On the side I am saving up for a Canon 7D.
Why? Hopefully only as a backup to your 5DIII. The only reason I can see to choose a 7D over a 5DIII is if the latter is broken.
The other reason would be the obvious crop factor advantage. I mean, that is basically WHY people pick the 7D for pretty much anything...REACH! Although, I would personally wait for the 7D II than the 7D, as that should bring APS-C IQ up a notch...not as good as the 5D III, but certainly better than the 7D.
neuroanatomist said:
Maui5150 said:
Reach is another... So the 300 becomes a 480
I still like the 5DIII but some like the crop sensor for length
The 'reach benefit' is mostly an illusion. It's a 'crop factor' not a 'magnification factor'. A 300mm lens doesn't
become 480mm on APS-C, you're just cropping away the outer part of the frame.
A 'reach benefit' for a 7D over a 5DIII only exists if you need more than 8.6 MP for your desired output. If 8.6 MP is sufficient (up to 16x24" / A2 prints), then the 5DIII image cropped to the FoV of the APS-C sensor will give you equivalent IQ at up to around ISO 800 (on the 7D), and progressively better IQ as ISO increases from there (at some point, probably ISO 3200 but certainly ISO 6400, the 7D's noise is so bad that an up-res'd 5DIII image would be better even if you do need all 18 MP).
Some might also cite the 2 extra fps as an advantage, and it is one in theory…but in practice, I believe the superior AF performance of the 5DIII will yield a higher overall keeper rate despite the lower fps.
The reach advantage is a pixel size thing as much as it is a crop factor thing. If the 7D had the same pixel size as the 5D III, then you would be correct, "reach benefit" would be an illusion. But the 7D has pixels that are quite a bit smaller than the 5D III's. If we only factor in pixel size, the 7D has a 1.5x "reach benefit", so a 300mm lens is quite literally like a 450mm lens on FF. That is no myth, that is ACTUAL advantage thanks to the pixel size difference.
I think that pretty much everyone knows that you get 18mp rather than 8.6mp with the 7D. Even if they don't know the exact numbers, the difference between the 7D and 5D III in terms of relative crop area is quite large. And it isn't just about printing large, either. The 7D offers you EVEN MORE cropping ability...so if you need to crop the center 50% out of the 7D image, your talking about maybe having 10mp vs. 4mp, at which point the argument for the 5D III almost becomes irrelevant. Don't forget the downsampling advantage, either. For those who primarily publish on the web, downsampling the 7D to web size has the effect of GREATLY reducing noise levels. Since your downsampling more than twice the number of pixels as the 5D III's 8.6mp, noise levels normalize quite nicely...such that you generally cannot tell any difference between the two, with the exception that the 7D images are more detailed, sharper, and crisper.
The general advantage of the 5D III is that you can use longer lenses with narrower apertures and achieve similar IQ for identical framing. For example, one could use the 500mm f/4 on a 5D III at f/8 with ISO 6400 and get similar IQ as a 300mm f/4 on a 7D at f/4 with ISO 1600. But, that assumes you can afford the 500mm f/4 lens, and need to stop it down to f/8 to get the DOF you want. In all other circumstances, the 7D + 300mm f/4 is the better option, because it puts more pixels on subject than the 5D III + 300mm f/4.
I completely agree about the frame rate. The 7D has it's AF issues, and the intrinsic jitter basically negates abut 2fps. That still doesn't make the 7D "worthless" relative to the 5D III. If you have the funds to buy a great white lens, then indeed, the 7D could really only serve as a seldom-used backup body. But if all you have is the 300mm f/4 L, then the 7D, even though it only has an "effective frame rate" of about 5-6fps from a keeper-rate standpoint, it still most definitely offers the reach benefit over the 5D III.
While you and I may be able to enjoy the benefits that Canon Great White Mark II lenses have to offer, it is still a rather rare commodity we have. Having only owned the 600/4 II for about eight months, I still remember quite clearly why I picked the 7D originally, rather than waiting for the 5D III. You can't deny the reach benefit with shorter lenses...it's real, and it's meaningful.
Otherwise, if you are in a dome with limited overhead lighting, you may find you need to increase the ISO to freeze the action, and in that case you might find a lot of noise.
