2x3 "credit card" fresnel lens for placing against ground glass

[loccdor]

Has anyone tried these cheap wallet-sized fresnel lenses and placed them against a ground glass to see if they get a brighter image that helps with focusing a lens with a dark maximum aperture?

The groove pitch of the fresnel is 0.2mm. They come in packs for $5.

 

[ic-racer]

I, non-destructively, placed a larger and thicker one on the back of my view camera in 2012 to see if it made any difference. It is still on there, I think it helps composing. . It also serves as a ground glass protector,

 

[blee1996]

I tried one of those 8x10 fresnel for book reading, and find the pattern a bit distracting. It does even out the brightness. So it is a tradeoff.

In the end, I still prefer plain good ground glass with dark cloth and loupe.

 

[loccdor]

Thanks for the opinions. They are cheap so I guess I will try it.

 

[abruzzi]

I haven't found any issues with slow lenses, i.e. ƒ9, ƒ11, but rather wide lenses. On my first 8x10 the seller provided a 8x10 book-reading fresnel that he had cut down to fit over the entire ground glass. It didn't help for focusing at all, in fact it actually made it harder because the fresnel lines were very visibly, and with the fresnel between the GG and the loupe, it threw the loupe a little out of focus. My loupe is fixed focus so it actually put the fresnel lines in sharp focus.

It helped for composition when using a 120mm or 165mm lens. I find that with wide lenses to see the entire ground glass lit, I needed to be a certain distance from the ground glass. For a very wide on 8x10 that was like 4 feet which was too far for me to manipulate the controls of the camera or tripod. The fresnel allowed me to get closer and still the image edge to edge. This is less of an issue on 4x5because the distance needed to see the whole screen lit is closer. If I stuck a ƒ11 490mm apo-Ronar on the 8x10 camera the fresnel was completely unnecessary.