Fresnel on the cheap...

[scott]

Hi all -

I'm sure this is well known, but it's news to me, and I finally got around to trying it and am impressed with the results.

My vision is getting worse over time, as would be expected. But focusing on a dark, albeit fine, ground glass has gotten harder in the last few years. I read a thread on a FB large format group about Fresnel lenses for ground glass screens and one of the posts (several actually) suggested that a cheap-o plastic magnifier sheet off of eBay or Amazon would work fine, as they're Fresnel lenses anyway. I looked into it, found a 4-pack of roughly 8-1/2 x 11 sheets for about six bucks shipped, and bought them.



They've been sitting in the basement for quite a while. Tried one on the 8x10, but haven't really tested it out yet. Yesterday I had a minute, and interest as I want to start shooting the 4x5 in the wild more, so I kind of eyeballed it and cut one down to size. Installed under the ground glass clips today and set up outside to see if there was a noticeable difference.



(I didn't shoot a before shot, sorry). Day and night. Can see the whole screen at once, and the rings are less obtrusive than on my Yashica-Mat or Bronica. With a reversed 50 mm lens I can fine focus easily. I can't wait to take this out and try it in real life - planning a test trip to the rec area forest Monday.

So, there you go. Brightscreen on the cheap.

Scott

[PFMcFarland]

Nice result there, Scott. I might do that myself if I ever get the old rig out again.

PF

[GrahamS]

I love it when a plan comes together....

[melek]

That really brightens the screen. Are these made from flexible or stiff plastic? And did you simply place them on top of the existing ground glass?

[Brazile]

The plastic is a little flexible but not much. My understanding is that they can be placed on either side of the glass, but if you put it on the inside, it messes with the focus point a bit so you have to take that into account. Some people cut down the 8x10 sized ones to fit smaller formats, so I know it's possible to do so.

Robert

[scott]

This is one of the flexible plastic Fresnel screens. Was easy to cut with a scissors. I looked up where I got them recently, though I don't remember right now, but I think on Amazon, and they were cheap (I'll try to confirm that today). It's mounted on the viewing side of the ground glass, which is where most of the aftermarket screens are mounted these days. A lot of people recommend figuring out the focal length of the Fresnel and matching it to the focal length of the lens being used (as closely as possible); I think this is only necessary if the Fresnel is on the lens side of the ground glass. I think it doesn't really matter the way I have it mounted. My Yashica-mat and Bronica both have plastic Fresnel viewing screens - this cheap-o plastic one is finer that either of those.

[scott]

Just for the sake of completeness, here's the view on the 8x10:



Works a treat. 10/10, would buy again.