Ole said:
Some Ektars are Tessar-type, some are not. If the 101mm covers 4x5, I'll assume that it's a different design
Ole, the 101/4.5 Ektar is a tessar type. I have two, have counted reflections.
Don't forget that what people mean by "covers" is pretty elastic. Every individual seems to have his own definition, not always applied consistently.
For example, I have a 3"/4.5 Velostigmat Ser. II. I've shot it on 2x3 to see what it would do. At f/22 the image it produces is as about sharp in the corners as in the center, i.e., not at all sharp. Some might say covers 2 1/4 x 3 1/4, but I don't use it.
I also have a 1.75"/2 Elcan. The Vade Mecum says correctly that it doesn't cover 6x9 -- there's mechanical vignetting -- and incorrectly that it covers 6x7. Yes, it illuminates a 90 mm circle. But at f/8 and f/11 the outer couple or three mm the image is quite soft. I rate it as not quite covering 6x7. Usable, if one can accept fuzzy corners, but I stick with my 47/5.6 SA even though the Elcan is a little wider.
There were recently discussions of 180/6.8 Dagors, lousiness of, and 150/9 GRIIs, utility of, on Q. T. Luong's LF forum. In both, users exposed, um, optimistic coverage claims made by an eBay seller. What's interesting about the Dagor thread is that the person who initiated it by reporting that his lens didn't, after all, cover 8x10, had recently sold one and had asserted in the listing that it covered 8x10 with room for movements.
Cheers,
Dan