I rented a Mamiya M7 not too long ago. And one of the things that I really liked was the 43mm lens's very nice brightline external viewfinder. For most of the w eekend I kept it close at hand, giving me a quick and inconspicous way to check out how a shot would look.
Now that I'm a LF convert. I've started thinking how nice it would be to have so mething along those lines for my 90 and 210 LF lenses. There are lots of old vie wfinders for screw-mount rangefinders. But of course, the 35mm frame isn't the s ame shape as 4x5. Granview makes some sort of finder for their handheld 4x5. I believe it uses a m ask system to fit to a large range of lenses. But I have no idea if it's any goo d.
Has anyone else researched this?