View Full Version : Lupes for GG focusing
I have decided to get back into 4x5 and am noticing how difficult it is to focu on the GG and the eye strain involved. I know that a lnese focuses on only one, and only one plane, but under the GG, I don't get the feeling of sharpness or d epth of field that I did thru my 35mm and 6x7 viewfinder. I am using a cheap Pe ak 10X lupe and on a Zone VI (try not to laugh) field camera. A professional LF photographer told me I would have far less trouble with a 4 or 5x lupe and that it was worth getting a good one like a Schneider or Rodenstock.
Any thoughts on this from anybody.
I agree. I use a Schneider 4X.
I recently bought a Toyo 4X loupe as suggested by a friend, and I really like it. He noted correctly that the 4X is much easier to focus than the more powerful ones, since you're focusing on image rather than on every little grain of the GG. Check it out. It's got a good, workable length, and the rubberized ends make putting it to the GG guilt-free. Good luck!
You will get as many opinions on loupes as there are people. My favorite loupe I use for both viewing transparencies and the GG, and isn't specifically designed for LF. It's the Peak Anastigmatic 4x loupe. To me, it's sharp, has a very flat field and has good contrast. It's far from the most expensive one out there. It is a fairly big piece of glass. Pentax also has an interesting 5x-ish loupe which has very long eye relief, but isn't as distortion free in the edges and corners as the Peak. You basically want a loupe which can focus so it can be set to the image forming surface (other notes in the archieve have talked about how to do this in detail). What power loupe to use is somewhat a personal choice within certain bounds. The ~3.5x to 5.5x range is most common. Most people would find a 10x very difficult to use on a GG. For me, the power preference is somewhat a function of the type of GG in place. For a fresnel/gg combo, I like the 4x. When I'm using a camera with a Boss screen, I like to use a much more powerful loupe (~7x). If your anywhere close to NYC, B&H is a great place to check out loupes. They probably have >25 different loupes on display, and will get from inventory any other ones they sell.
The Horseman 6x lupe is long enough to be used into the focusing hood. A good po int to me.
This is not a joke! Buy some cheap eyeglasses with a power of +2 or more diopters (if you already wear glasses, add this) and use instead for the lupe. Youl'l have the ability to view the complete GG and have both hands free for adjustments. Focusing a 4x5 is not so critical (unless you use very short lenses) that a 6X lupe is needed. Maybe your fresnell glass is a bit coarse, it doesn't matter otherwise, than making focusing difficult with a 6-10X lupe. A focusing hood, if such one is available for Zone VI, will speed up the process and as packed, protect the GG.
I had taken the suggestion off this forum in the past to buy reading glasses of +3.0 or so. This works to keep hands free and provide about the right magnification. I have found it difficult to use with both eyes open as I had hoped for. With a 90mm lens using the reading glasses requires me to keep one eye closed. I assume this is because the angle of light coming to each eye is so different but haven't really thought it through. Anyway, try the reading glasses, $10 bucks at the drug store and you have both hands free to focus and tilt. If nothing else you'll need the reading glasses by the time you're 45.
I use a Silvestri x6 loupe, one big advantage is that the loupe comes supplied with a screw in tilting mechanism that enables you to check right into the corners of the screen. It comes with a neck cord and eyepiece cover, it cost #80 (sterling).It also has adjustable dioptre.
Michael S. Briggs
A lower power loupe or magnifier will work much better. At somewhere between 4X and 6X (typically) you will be seeing all the image detail allowed by the grain of the ground glass. Going to higher magnification won't give you any more information, but will make the image dimmer.
My preference is about 4X. Another good source for loupes and magnifiers is Edmund Scientific: http://www.edmundscientific.com
When using a short-focal length lens, using a magnifier or a loupe without its base can help. That way you can view the ground glass at an angle instead of straight on. In the corners the rays will arrive from the lens at an angle and most of the rays will continue on a similiar direction after scattering on the ground glass.
Hi,Todd: For years, I've been using a 16mm movie lens (objective). It is long enough, clearing very well the focusing hood. Wollensak Anastigmat, Raptar 3inch f2.5 Cine Telephoto.The best, is that I paid $5.00 at a local camera show since nobody loves them. Tito.
You might try the Peak 8x rectangular lupe (around $50). It is designed for viewing 35mm slides full frame, but it works very well for focusing my Toyo AX. The rectangular shape allows me to see right into the corners of the ground glass and it is fairly sharp edge to edge. The 8X magnification makes critical focusing easy.
I use +2 or +4 dioptre reading glasses for viewing the whole screen and rough tilt/swing/shift/focus. I don't find them good enough for pin-sharp focus, so I use a loupe for fine movements. My camera loupe is a very cheap 8x that I bought 20 years ago, and it suits me. You should probably visit a good camera shop, with your camera, and compare loupes until you find one you like.
I picked up an 80mm enlarging lens for $12 and it serves me very well. I can make out everything down to the grain of the glass. It is by far the best GG focusing gadget I've ever used and others in the field I've met have liked it too. It is also very light weight and fits in my front shirt pocket. James
Powered by vBulletin® Version 4.2.0 Copyright © 2013 vBulletin Solutions, Inc. All rights reserved.