Canon vs Sigma MFA

[YuengLinger]

Two questions, really.

First, how does the Canon method of microfocus adjustment differ from Sigma? I know Sigma has a USB dock and an app, and that Canon does MFA right from the back-of-camera menu system.

What I'd like to understand is whether Canon is also adjusting the lens itself, as in the Sigma method, or is making some adjustment in the body?

My other question is specific: Will a 5D Mk III be able to apply MFA to the latest Sigma 150mm 2.8 Macro? I find clear info about the Sigma 35mm 1.4, but little (and confusing) info about the macro.

Thanks!

 

[Loswr]

The Canon adjustment is to the body only. Newer bodies keep track of the lens serial number, which is important since the adjustment is specific to a given combination of body and lens (the particular copy, not model).

The Sigma adjustment is to the lens only, which makes sense since Sigma cannot control the camera body. The upside to that is the adjustments are much more comprehensive. For example, different AMFA values can be applied at different subject distances for a Sigma lens via the dock. The downside is the corollary to the above statement – the appropriate adjustment is specific to a particular body and lens combination. If you shoot with only one body, that's not a problem. However if you shoot with more than one body, you might be in trouble – I've had AFMA values vary by over 10 units from one body to another for the same copy of a given lens.

The Canon AFMA should work with any lens, including the Sigma macro. Newer bodies will not recognize the serial number of a Sigma lens, of course.