Viewfinder flare, effect of recessed windows ?

[Laforet]

According to Dan Chang and his excellent service guide, the flare problem is when strong light light hit the verticle diffuser on the frameline illmination window (no, nothing to do with the RF patch)post-M3 models which causes excessive light to hit the RF patch and causes it to white out. So any post-M3 Leica is able to flare😛

The problem is made worse when Leica removed one condenser lens from the RF assembly. The condenser lens itself serves to brighten the 90mm frame and does not contribute to the flare; however some other parts had to be adjusted to compensate for its absence, and this is known to have caused subsequent cameras especially vulnerable to this problem.

One ingenious solution is to cover the illuminator window with a few layers of frosty tape, or with black tape if you can live without the framelines. SHADE from leicagoodies serves on a silimar principle using a slightly different material, I have not seen or used one so I cannot comment on that.

 

[Krosya]

I had my M6 CLA'd by DAG and while there he fixed the flare issue. Now it's perfect and it's a lot cheaper than going with a different camera, like M7, MP, etc. Plus I have a Hexar that doesn't flare either.

 

[JNewell]

Laforet is right - there is no "flare free" finder for the M2 and following cameras, though it is referred to that way. If the lawyers were writing the ad copy, they'd insist on referring to it as the "reduced flare" fix.

 

[Lance]

So why is the illumination window that vertical design when a frosty one like the M3 supposedly work better? Is it just to bug us?

And what exactly are the changes when upgrading to the MP finder?

Wow, is that new guy irritating or what?

 

[Laforet]

Erwin Puts has a good entry on this topic:

http://www.imx.nl/photo/leica/rangefinder_engineering_fro.html

As it has shown, M2-type finder must have some light deflected at an angle to project the framelines. This is a compromise to allow a smaller magnification and equally bright and clearly defined framelinesas the M3 has....