Question for R5/R6 users with Sigma lenses

[joshmacde85]

Sigma released a statement a while ago stating that "AF can be used within the area of approximately 80% of the height and 80% of the width of the sensor surface" on the R5 and R6. I'm interested in getting the Sigma 70-200 Sport because I'm not interested in RF glass price or buying a used 70-200 L II. What's the reason for this AF area restriction? Is it because of distortion? Has this been a noticeable problem for tracking?

[Waddizzle]

If that is a statement from Sigma about a Sigma lens, don't you think that it would be best to ask Sigma?  I think so.

[kvbarkley]

I don't know that there has been a definitive answer. Even some Canon lenses have restrictions, it might be due to falloff.

[Waddizzle]

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@kvbarkley wrote:

I don't know that there has been a definitive answer. Even some Canon lenses have restrictions, it might be due to falloff.

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If I had to venture a guess, it would be because of vignetting when [the] lens is wide open for focusing.

[shadowsports]

If anyone is interested, here is the announcement he is referring to:

Operating conditions of SIGMA’s lenses for Canon EF mount with the Canon EOS R5 | SIGMA America (sig...

I follow these types of announcements closely, and they are ultimately what influenced my decision to go with Sigma over Tamron after buying my 6D2 in 2017. 

I'm first to agree that using Canon with Canon is preferred, but when you don't, going with a manufacturer who continues to actively address functionality and compatibility between its products and new body's as they are released makes a huge difference in over all user experience and satisfaction. It also allows your investment to retain its value over the course of its life.

Sigma's track record for addressing any compatibility issues with newer body's is very high.      

[ebiggs1]

"...the area of approximately 80% of the height and 80% of the width of the sensor surface..."

Who focuses in the outer 20% of a frame anyway? I doubt you have ever done that.

[Waddizzle]

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@ebiggs1 wrote:

"...the area of approximately 80% of the height and 80% of the width of the sensor surface..."

Who focuses in the outer 20% of a frame anyway? I doubt you have ever done that.

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Unlike DSLRs mirrorless bodies can focus all the way to edge of the frame just about.  They have thousands of AF points.  The EOS R has more than 5000 AF points.

[ebiggs1]

"Unlike DSLRs mirrorless bodies can focus all the way to edge of the frame just about."

Not disputing that.  But who uses or does that?  I don't think I have ever, no I have never, needed the outer 20% of the frame to get critical focus.  But then again I never use the outer focus points of my 1DX.