Fresnel for 6x17

[Travis]

Hi everyone.

I have just received my new ShenHao 4x5 field camera and 6x17 roll back with special GG viewer attachement. I ordered the items directly from ShenHao in China as I live in Australia. I'm very happy with the quality of the items and believe they are great value for money.

I have taken the camera out, and as expected, the image on the GG is very dark at the edges (I'm using a SA 90mm/f8). I have looked through many posts on this site relating to fresnel lenses and screen brightners, but I'm still unsure which solution is going to be best for my situation. I would prefer not to have to try and remove or replace the GG in the special viewer if possible. I think I remember reading a while back on this site that there is a product available that you can cut to size and simply attach to your GG. Is this right?? If so, where is it available? Remember, I live in Australia, so telling me to go down to a particular shop in the U.S isn't much good.

Thanks!

[Frank Petronio]

I don't see why you couldn't cut a 6 x 17cm chunk out of the center of an 8x10 fresnel, other than the fresnel costing more than the Shen Hao back...

[Brian Vuillemenot]

...or just cut a 5X7 Fresnel in half. You can also get cheap fresnel lenses sometimes at book or department stores. They are sold as 8.5X11 inch magnifiers for whole book pages, but I've heard that they work equally well as Fresnel lenses for large format cameras.

[jose angel]

Yes, I am using my 8x10" with one of this cheap plastic magnifier and it works (at least with 300-450 lenses). The image is not great at all, but good enough to me to compose; then, I retire the plastic sheet and focus on the GG.

Mine came for a 3M DIN A4 retroprojector replacement, is very cheaply made; IMO, it is worth to try it if you don´t want to spend money or if you like to preserve your GG. Good luck,

[Brian Ellis]

Edmund Scientific, if they're still around, used to sell very inexpensive sheets of Fresnel lenses. Another possibility if you are willing to spend some money (probably more than your back cost) would be to ask someone like Bill Maxwell to cut one for you, he could probably also help with the correct focal length. You might have to make a long distance telephone call and with Bill "long" means really long (as in "long time") but who said large format was going to be cheap?

[paul owen]

Hi Travis Did you have any luck finding a suitable fresnel screen for the viewer? Same thought has crossed my mind (using a book magnifier) but wondered what luck you had? Regards Paul