I haven't tried a Maxwell screen or the far cheaper alternative from Rick Oleson so I can't really comment, but I can't help wondering whether some people exagerate the benefits to justify their expenditure. After all, they are just simple fresnel lenses aren't they, or is there some magic technology involved which I don't know about?
As with most things, what seems simple in concept can be executed in various ways. A Yashica Electro GSN and a Leica M3 are both coupled rangefinder cameras, yes?
With Maxwell, you are paying a premium price. The design and the machining of the molds are top-notch. Quality control is top-notch. It is simply one of the best screens available. As to whether that is worth the cost to you or anyone else is your call.
The Oleson screens are good. The fresnel grooving is wider. The 'ground glass' look is grainer. The light spread is not as even as on a Maxwell. The chance of their being small defects is more. I think Rick Oleson would agree with all of my comments here.
So it isn't magic at work. It is execution. Bill Maxwell is working a small market. He seems to be trying to deliver the best product that can be achieved. I don't know optics and imaging so I can't say if his screens match what, say, the Air Force or NASA would be able to do. Most manufactured items work along a 'diminishing return' curve. After a certain point, producing a slightly better product takes a significant increase in costs. Cameras, optics, automobiles, watches, clothes....
When I bought a Rolleiflex, it had a Maxwell screen installed. Without that, I doubt I would have spent the money to install one. Having used one, though, it's hard to see most other screens as anything more than temporary until I can afford a Maxwell.
