EOS 5D Mark III vs. EOS 1D X - Differences?

[HDNitehawk]

Rick, my only comment here would be to ask why someone might have bought these super-tele's in the first place. The 5DIII is going to have ever-so-slightly smaller pixels and will therefore be able to resolve fine features a wee bit better (all other things being equal). Since super telephoto lenses tend to be tack sharp everywhere they'll have the resolving power to dig the extra detail out of the "grain." Therefore, if someone is hell-bent on shooting birds with a FF camera the 5DIII may be the better choice. That said, the 1D4 or even the 7D might make more sense for the same arguments. Just a matter of whether the FF sensor is important or not.

I brought it up because; specific to John asking the question "thoughts and advice from the forum", he has mentioned that he would like to have a 500mm F4L.

The 5D III will probably not be the better choice for shooting birds. The frame rate, spot metering, burst rate, and possibly the expanded AF options will make the 1D X a better birding camera than the 5D III. All of those items will trump any slight IQ and resolution power you may get out of the 5D III. The 1D X ability to handle the higher ISO’s will be a big benefit as well, with wildlife much of the time you are limited to available light. It is always a fight to keep enough speed for moving wildlife and still have a reasonable ISO to get a decent picture.