Shen Hao Fresnel?

[Josh Z.]

I have a Shen Hao 4x5 (HZX-45IIA) with a Satin Snow ground glass. I have a 90mm f/8 that I use a lot on the camera and have always had trouble composing with it due to it being very dim. Some time ago I cut up a page reading fresnel from Walgreens and fitted it to the back, which helped a lot, but is just barely satisfactory. Recently I tried my 90mm lens on an Arca and Horseman, both with built-in fresnels and was really impressed.

I'm wondering what I can do that will get me the most bang for my buck to brighten up the screen with the 90mm. Will the Shen Hao fresnel on Badgers site do it? Or should I really be thinking about spending $200+ on a Maxwell or similar?

I also have a 210mm f/5.6 that I use all the time without problem. So I don't think I need much improvement, but then if the $80 Shen Hao fresnel isn't going to be much better than my DIY plastic fresnel, maybe I should bite the bullet? Thoughts?

Thanks.

[Bjorn Nilsson]

I don't know about the Shen Hao fresnel, but its focal length etc. should be similar to the Arca, Horseman, Sinar (the one I use) etc. and should give you a similar screen as the above mentioned... I would buy the dedicated ShenHao fresnel.
This light falloff effect is due to the short focal length and the angle at which the light rays falls on the ground glass. As you've noticed the illumination is nice and even with your 210 lens. Even if you set it to f/16 it's easier to focus and compose than your 90mm at f/8. (Just make a drawing of how the light hits the ground glass and it's easier to understand. From the 90mm it's close to 45deg at the corners. From the 210 it's say 15-20 deg.)

//Björn

[Brian Ellis]

I've used many viewing screens on the market - BosScreen, Maxwell, Beattie, OE screens from Linhof, Ebony, Tachihara, Deardorff, and probably some I've forgotten. Maxwell was the best, BosScreen was next, the rest weren't worth talking about in terms of ease of focus with a variety of lenses ranging from 80mm to 300mm compared to Maxwell and BosScreen. With the Maxwell I could see a difference in brightness between the edges and the center with an 80mm lens only by looking very hard and of course longer lenses were no problem at all. BosScreens cost about $100 less than Maxwell and do a good job though there are some issues with them in extreme heat and cold (so I'm told, I never had a problem in Florida heat and never used it in cold). They also aren't technically "bright screens" though they give a similar effect by spreading the light evenly across the entire screen. If you search here for "Maxwell," "BosScreen," and maybe something like "viewing screen" you'll find more information than you wanted to know.

[jetcode]

My Shen-Hao GG is brighter by at least a stop than the SS glass but is not evenly illuminated like the SS.

[Scott Davis]

I put a Canham 4x5 GG/Fresnel on my Shen-Hao and it works great. I think it costs about $50 or so from The View Camera Store.

[BarryS]

Even with a fresnel on my 4x5 Chamonix, using my Nikkor 90mm f/8 is a real pain. I don't think there's any magic solution, but give Bill Maxwell a call--at the very least, it's entertaining talking to the guy. Fresnels are optimized for a particular focal length, so I'd specifically look for something appropriate for 90mm. The Chamonix has a Graflok back, so I've considered having a special groundglass/fresnel in a frame just for the 90mm--it would weigh much less than a whole back (and probably less than a faster 90mm). I've put off buying anything wider than the 90 until I figure this one out.

[timbo10ca]

Try 3Dlens.com- cheap, and pretty good quality. I got a 210mm focal length lens for about $30 delivered- see my post:

http://www.largeformatphotography.in...096#post367096

Tim