Viewfinder Magnifier or Diopter or both?

[deliciouspizza]

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I have been using a Match Technical 1.25 magnifier for a while and it does make a small difference when focusing at 1.4 and below. But, it seems to lower the contrast of the viewfinder slightly which makes focusing a little trickier despite the zoom. Also, the limited FOV becomes a serious problem with any lens wider than a 50mm. At least for me, a glasses wearer.

 

It's hard to tell if it really actually helps though.

[thighslapper]

Japan Exposures Mags have built in variable dioptre correction.

 

The 1.35X is the best of the two available. Very bright and crisp.

 

I have one on all my cameras and only take it off using sub 28mm lenses ..... and as with an M I then use the EVF, it stays permanently on my M240....

[thighslapper]

That's what the viewfinder's -0.5 dpt preset is for. However there is no reason I'm aware of for some additional negative preset of the viewfinder magnifiers. It's very annoying to need two different diopter lenses, one for the bare eye-piece and another for the 1.4× magnifier.

 

Maybe it's not actually a negative diopter built into the magnifiers but just the effect of magnifying the viewfinder's own -0.5 dpt ... I don't know exactly how the viewfinder and the magnifier interact. Anyway, if that's the case then the magnifiers should include some positive compensation so the effective preset would remain constant.

 

I've always assumed it was something to do with giving the optimum usable range......

 

On my JE variable 1.4X dioptre mag there is a 1/4 turn between perfect focus at infinity and 1m. I have the postions drilled and marked. I too never got on with the excess minus on the Leica mags and the constant fiddling with dioptres.... which are impossible to remove from the finder if screwed tightly in .... and as you say don't work properly with the same value as the viewfinder alone.