Does any one know if you crop a 5D mark II 21.1mp file to an APS-C sensor size, would the image be equivalent to what's captured on a 30D since they have the same pixel density?
no... If anything, the equivalent APS-C cam is the 40d, 21.1MP/1.96~10MP
The 5d mk II, when released, should have excellent high ISO and dynamic range, much better than any of the XXD cameras, and hopefully better than the 5d classic. We're also dealing with an improved image processor as well. Don't forget about the depth of field advantage too for full frame.
I think orangefish has it wrong and the OP has it right. If one were to crop a 5D MKII file to the same size (i.e., number of pixels) then you would have a very similar image to a 30D in terms of pixels and field of view. Of course the reason you want full-frame is because you want to use all those pixels, but you always could crop in this way for the extra reach. The 5D MKII is also likely to have a better high ISO performance.
Yes the image will be similar: 21.1 Mp / (1.6 * 1.6) => 8.2 Mp
As far as depth of field issues, it will actually be the same. The only reason the FF cameras have different DoF is because we don't have to enlarge the image as much for a given print size. The 30D is taking the same image from the same lens, and just doing the crop before recording the image vs. doing it later in-computer. The optics are the same!
So if you're always going to crop your FF images down to 1.6x, you may as well have something like a 30D. Except that as Steve says, the pixel quality of the 5DII is likely to be better than that of the 30D. And you get the flexibility of not always having the cropping done for you...
mtnguyen wrote:
Does any one know if you crop a 5D mark II 21.1mp file to an APS-C sensor size, would the image be equivalent to what's captured on a 30D since they have the same pixel density?
Yes, exactly. Assuming your lens is focused exactly the same way, same camera-subject distance, etc. The only difference is that the 5D II sensor will likely have better noise characteristics and possibly better dynamic range. But you are correct about the similar pixel densities and all that implies, including equivalent output magnifications and the numbers of megapixels for equivalent crops.
Thanks everyone for your responses. My plan is to keep the 30D as backup once I purchase the 5D II. It's useful to know that (for example) my 24-105L lens will be cropped equivalently optically as well as pixel count, ignoring the differences between the 2 bodies such as AF sensor or pixel quality in high ISO.
Another way to look at it is what I don't see in my 30D view finder and image files are the missing ~13mp around my cropped image I would see in the 5D II view finder and image files.
