I have noticed very, very minute bubbles or marks on the coating on the rear element of my 35'cron ASPH. Is this normal? and anything to worry about. Because its right on the edge of the back element will this effect the optical performance. The central area of the back element looks fine. Help!

-- sparkie (sparkie@mailcity.com), January 21, 2002

Answers

sparkie,

If its on the extreme edge then don't worry about it. If it is "off" the edge then your wide aperture images might look a little "soft". In practice you won't be able to discern the difference. If you bought it paying the full US retail price (a la Passport warranty)... take it back and demand another one. Teach those Leica QC slackers a lesson!!!!

;-)

-- John (ouroboros_2001@yahoo.com), January 21, 2002.

It used to be that bubbles were touted as proof of high quality optical glass. I haven't seen this claim in years. There was a time, though, when Leitz acknowledged "tiny bubbles" (we ought to have an FAQ by that title) and said they were harmless.

-- Bob Fleischman (RFXMAIL@prodigy.net), January 21, 2002.

Sparkie:

I think those bubbles on the very outer edge (present on my 35 asph 'Cron as well) is actually element cement to hold that element in place during assembly.

:) Cheers,

-- Jack Flesher (jbflesher@msn.com), January 21, 2002.