"Bright" Screens and Shen Hao

[Paul Frank]

Forgive me if this is a stupid question, I've read the archives and still am uns ure.

I have the Shen-Hao 4x5 field camera. Do I need a "bright" screen specifically built for my camera, or only built for a graflok back? Do the fresnel lenses or "bright" screens make a real difference? I shoot with just a cloth using 47/5. 6, 90/6.8, and 150/5.6 lenses. The wideangles are particularly troublesome, esp ecially in low light. Is there a ~$100 solution? Thanks in advance.

[Jason Greenberg Motamedi]

Paul,

It depends upon which 'bright screen' you want. You will have to have a custom made Bosscreen. Most fresnels should just drop in. I seem to recall that Badger had something specifically for the Shen-Hao. In any case, measure your back carefully (buy or borrow a calipers) and call around. Note that the 'grafloc' back ground glass size is not standard, so you can't just buy a screen made for one. You must measure, or call Jeff at badger.

I much prefer a bright screen over ground glass, but this is a matter of personal preference. I can't say if you will like it.

jason

[Eugene]

Paul, before you invest in a Bosscreen, try placing a dab of Vaseline on the frosted side of the groundglass, then wipe the Vaseline in a circular motion with Kleenex until it appears to be completely wiped away. You will find that this seems to give a brighter, finer grain effect to the groundglass. It's the same effect as the Bossscreen. A Fresnel focusing screen, placed on the smooth side of the groundglass is the best brightener for use with wide angle lenses. Look for a plastic one, there should be one available to fit the Shen Hao. It will fit on the groundglass, not on the graphlock back. Wisner sold one for under $100 for his 4x5 cameras.

[Eugene]

Paul, a P.S. to my post: I just accessed the Wisner website (Wisner.com). looking under accessories, he lists his snap-in plastic Fresnel screen at $80. I have been looking for the type of plastic sheet that you place on a printed page. It enlarges the printing, for people who have difficulty with their eyesite. I think that this type of material can be cut to fit the groundglass on my Shen hao. I have checked with Barnes and Noble and Office Depot. So far, no luck.

[David Willis]

Eugene, you can get a fresnel page magnifier at Edmund Scientifics. The web site is

www.scientificsonline.com

The part number for an 11" square fresnel is CR30708-77 and the cost is $4.95.

You can get a 7x10" 0.6 mm thick acrylic fresnel for $4.95 too. The part is CR30384-54.

If you want more expensive, optical quality fresnels, go to www.edmundoptics.com and search for fresnel. Be warned, they can be pretty expensive.

DW

[Paul Frank]

does adding a fresnel in front of the GG cause any focus shift?