RF series microlenses....

Feb 27, 2019
Excuse me for asking. But I can't seem to shake the idea of the EOS R/RP cameras, using the sensors of the 5DmkIV and 6DmkII, with "microlens adjustment" to compensate for the shorter back focal distance, are less than optimal with lenses of a longer back focal distance.

Here I am shooting with 16-35/2.8 ii and iii, 14/2.8ii, 16-35/4IS ... and I can't help but think they're not going to perform as well on the mirrorless bodies as on my 5DmkIV's and 5DmkIII because of the sensor microlens optimization.

Yah... I pulled the trigger on an RP, then an R just to say I did, but the question remains (for a week or so at least).

Any thoughts?
Reactions: Pape


Dec 31, 2018
there could be some kind of dicital reverting for them on body but i dont have any idea about this matter

Del Paso

M3 Singlestroke
Aug 9, 2018
The first camera with microlenses was, if I'm not mistaken, the Leica M 240, which I do own.
Quite often, I use it with adapted tele lenses from the Leica R, up to 560mm teles, and NEVER had an issue. So, no need to worry, since the EOS R has been designed with the use of tele lenses in mind, right from the start!
And , by the way, asking is absolutely legitimate, that's what fori are meant for!:)


Apr 25, 2011
I think there can be a slight measurable negative effect (slightly higher vignetting in particular) of microlenses not being optimized for longer flange distance while used with longer flange distance lenses. I doubt this effect will be visible.

Del Paso

M3 Singlestroke
Aug 9, 2018
Additional info: NON-retrofocus lenses (older Leica M types) show an ugly color shift on the wide side in mirrorless cameras without microlenses , Sony's A 7, for instance.


Mar 4, 2014
I am not an expert on microlens design, and I have been wondering about this as well. However, I think the change in design must be made to accommodate light beams that arrive at the microlens surface at a more oblique angle. This should not have an effect on lenses with longer back focal length. Maybe the microlenses are more convex or have a larger refractive index. (If they are thicker they could induce blur and vignetting, though, as they could block or capture too early some rays from the new lenses with shorter back focus.)
Feb 27, 2019
My own thought is that the longer focal lengths will not be "corrected/manipulated" as much as the shorter ones. Reason being that the angle of the rays will be much more "parallel" than those for the short focal lengths.

"....... This should not have an effect on lenses with longer back focal length. ....."

That, dear Sir, is the $64,000 question. The issue is always with short focal lengths, not long. The angles are much more critical with short focal lengths, more parallel with the longer focal lengths. I don't foresee an issue with the 300/4.0, just the wides.

I think... hope... that the RP and R will both arrive on Friday. Hopefully testing can follow.


Dec 25, 2012
As the EF lenses are already designed for a longer flange distance I doubt that adapted to the R they will suffer.
I have an R and use the 11-24, 17TS-E and 16-35 and have seen no issues at all.

The original concern was the adapting of M series Leica lenses optimized for film. Their very short film plane to rear element distance did, in fact, create issues for digital sensors that could not utilize light at acute angles and thus showed issues of vignetting and image smearing.

Mt Spokane Photography

I post too Much on Here!!
Mar 25, 2011
We saw a Canon patent for a new micro lens design for mirrorless cameras some time ago. The outer rows of the micro lenses were designed to pick up light more efficiently when it came at a shallow angle. A EF lens should work even better with less light fall off.
Reactions: Pape


I'm New Here
Dec 31, 2016
I actually have similar question, back in the days 4/3 system claims they decide with the form factor because they can make light hit the sensor at right angle, so the shorter flange distance for mirrorless in theory would degrade the peripheral IQ.

Micro lens modification might help improve that but I bet it comes at a cost for other focal length other than the ones they optimise for, maybe software fixable though