90mm 2.8 Tele-Elmarit M ('FAT') on mirrorless

[Shiftworker]

Wanted to add a 90mm to my Rokkor-M 28 and 40 for a 'micro' lens set for my Sony A7rIV and Lumix S5. Tried the obvious 90mm F4 but it was a mediocre performer away from the center unless well stopped down. Thought I had bagged a good deal on the Elmarit but again it's pretty horrible at the edges unless stopped well down. I know this 'should' be a better performer but looking at the design the rear element is very large and very close to the sensor so maybe it's just not working well with the mirrorless filter stack. Anyone with any similar experiences and M-mount 90 that works on mirrorless? Thinking of the Hexar 90mm 2.8 or Voigtlander 3.5 if I can find one. Have the C/Y 85mm 2.8 which is superb but with adapter it's no longer 'micro' even if it's small in itself.

[Shiftworker]

Just got hold of the 'thin' version of this lens which has a much smaller rear lens element further away from the lens flange. Not saying this is the reason as the 'fat' one could be just a bad sample ( if this is even possible with Leica lenses) but the image resolution at the edges wide open is much better.

[mcbroomf]

I have a text only pdf by Putts that describes the Leica stable.  Unfortunately no lens numbers or diagrams.  However he says this for a later version of the Elmarit M (not Tele Elmar which come earlier).  Not sure when "today" was mind you ...

"Elmarit-M, 1990 & 2.8/90, Elmarit-R, 1980

In 1980 the Wetzlar designers recomputed the 2.8/90 for the R again and created the
best 2.8/90mm ever in the Leica history (R and M). The first series of the R-version
have been built in Portugal. The M-version arrived on the market in 1990, and is,
even today, one of the best lenses in the Leica M stable. We seem to have reached a
temporary platform here and while the new Apo-Summicron-M Asph indicates the
future direction as far as design methodology is concerned, an upgrade would not be
very cheap."

[Shiftworker]

Mine's from 1973.

[mshea]

After reading your post I figured I'd do a brick wall test with my 1988 lens on my A7RIII. For some stupid reason, I bought a Techart ages ago and never bothered to use it. That's the only adaptor I have and it may be contributing decentering issues. Given that caveat, I'd say my experience is the same as yours. Corners are fuzzy at wider apertures and they become acceptable at around f/11. Lovely rendering in the center of course!

Merrill