Quote Originally Posted by Markus Albertz
Dear all,

At some point in the future, I will take the plunge to 11x14 / 12x20 ULF. I already have a Nikon M 450 f9 but am looking for a triple convertible lens with enough coverage for ample movements; something equivalent to my Wollensak 13-20-25" that I am using on my 8x10 at the moment. I presume the desired focal lengths would be in the range of ca. 18-23-30" (?). I would appreciate any helpful suggestions, offers, etc. I am not in a big rush (this is a long-term plan) but want to keep my eyes open.

Thanks & best wishes,

I have tried a bunch of triple convertibles (B&L, Wollensak, Zeiss) on both 7X17 and 12X20. My experience is that the performance is not worth the trouble with the single elements. Performance on the corners is dismal, even with single elements in the 20-28" range. Same is true of the big modern convertible Symmars, say the 360mm. Great lens with both elements but indivudlaly the elements won't cover even 7X17.

In my opinion you would get vastly superior performance with apo lenses in the 20" to 35" category.