I am wanting to purchase the Da Yi 6x17 film back for 4x5 cameras. But I keep hearing mixed messages regarding usable focal lengths. Some from this very thread I think.

What I read is that the camera has mechanical vignetting at 180mm and beyond by a quarter inch at least. And you can go as wide as 75mm?

In contrast I have read from one vendor that apparantly the corners are slightly vignetted at 180mm.

And I have seen photographs from one using the back with a 180mm lens that showed no vignetting at all.

Problem being is that most user "reviews" are about 6 years old. Has the design changed which would explain the different results?

Has anyone here purchased a brand new one and used one in the last couple years? Can you share your experiences please?

Does anyone have a website for Da Yi? I can't find one to get my answers straight from them.