Haven’t done a “techie” post in a while so here we go.
Recently, I had a chance to use a Canon 1D-X body for a couple of days and was really impressed. I work with Canon 5D Mark III (5D3) bodies for my professional work and was curious what kind of increase in quality another $3,400 dollars would buy me (5D3 sells for $3,400, 1D-X sells for $6,800 at B&H Photo).
First, let me say that the overwhelming criterium in my choice of camera bodies is low-light performance. There are many other legitimate ways to evaluate and critique a camera body, depending on the kind of photography you do most often. Low-light performance just happens to be mine.
Okay, back to it.
So, what do I mean by low-light performance? I’m looking at how well the camera can focus in low-light and the noise structure of the digital file at high-ISO settings.
In my (admittedly non-scientific) comparison, I found the two bodies were impressive and basically equal in their low-light auto-focusing capabilities. In terms of noise structure, the 1D-X had advantages in high-ISO performance on two fronts. First, the 1D-X gives equivalent hi-ISO noise performance at 2/3 to 1-stop higher ISO settings. Second, the 1D-X allows you to make "usable" pictures (for me) up to 102,400, and good-enough-for-most-situations images up to 25,600. Granted, it’s pretty noisy at 102,400, and you'd only go there if absolutely necessary...but, with some post-processing work on a file with a good exposure, you could definitely create a usable image at 102,400 (which is insane!). What’s equally amazing is the minimal amount of banding (which appear as noticeable “lines” across the image) at super-high ISO settings, especially realizing the highest settings are digital extrapolations beyond the sensor's actual light sensitivity limit.
So, on the three practical low-light, high-ISO criteria (i.e., autofocus, noise, banding), the 1D-X has about a one-stop advantage.
Of course there are tons of other factors upon which these two cameras can be compared, the two most practical of which would be weight and the number of frames that can be recorded per second. The 1D-X is at least 2-3 times as fast in continuous, high-speed capture (motor drive) versus the 5D3. For sports shooters, there’d be no question the 1D-X is a better choice. If you don’t need that one feature though, it'd be hard (for me) to justify investing in a 1D-X when I could buy two 5D3 bodies for the same price -- especially given the fact the 1DX is nearly twice as heavy as the 5D3 (3.4 lbs vs. 1.89 lbs). Depending on what you're doing and how you carry your cameras, that extra pound and a half can be a significant (and uncomfortable) difference.
To be clear, though, I’d LOVE to own a 1D-X. It’s an incredible camera and was a complete joy to work with. But, for my purposes - and in my pre-millionaire financial status - I’m going to give the 5D3 might vote for being a better value for the money. If money is no object, though, go for the 1D-X. Better still, if money is no object, buy ME a 1D-X!