Mix-n-Match elements

[Gary Smith]

Hi,

Posted this on APUG as well, thought somebody here might have some additional input. In the process of getting a new Fuji 90mm, I actually won two 90mm SWD f5.6 lenses. Both lenses are nearly identical, the serial numbers are less than 250 units apart. One of them has has a slightly nicer front element and the other has a slightly nicer rear element. I was wondering if there were any problems taking the nicer elements and putting them together. They are the same exact lens with produced roughly at the same time, so I cant imagine any great differences between them. .

My initial tests show no noticable difference on the ground glass through a range of movements, in any of the combinations of elements; both in original form and the mixing of elements. I took a few test shots, but have not developed them.

Any thoughts would be greatly appreciated. Any specific problems or unexpected things that could arise from doing this?

Thanx!

Gary

[Glenn Thoreson]

If it works, it works, but it's not something I would advise doing. For one thing, a 90mm lens is not necessarily 90mm. It could, and probably does vary by a mm or even more. The elements are matched at the factory to accomodate this. The only way you're going to find out is try it. If the results satisfy you, you're in business. I can just about guarantee they won't be as good as the should be, however. Back in the days of the Speed Graphic, there was a whole gamut of focus scales for any given lens because of the variation. That's how critical the design is.