Grain Focusersgreenspun.com : LUSENET : B&W Photo - Printing & Finishing : One Thread
With age, I find it more difficult to focus on the aerial image of my inexpensive enlarger focuser. Also had some doubts after reading about error sources in such. For fun, I made a ground glass for it that can be interchanged with the "hair". I have ways to calibrate it, so that's not an issue. It's harder to see the grain, but there's no question about where the correct focus plane is. Not sure I'm happy with either design, and the quality of the magnifying lens leaves something to be desired. Question- what kinds of focusers do you use and what do you think of them?
-- Conrad Hoffman (firstname.lastname@example.org), February 25, 2002
The advice I was given about focusers which I am happy that I followed: All are about the same except the Peak #1, which is clearly better.
You can check focus almost anywhere on the paper and the Peak #1 is clear/bright enough to compare resolution at different f-stops. I'm now confidently printing about a stop more open and the results are visibly improved.
I haven't tried ground glass. I imagine this would be useful but less precise (and certainly not useful for guaging resolution). I use reading glasses with the focuser, which may be useful to you as well even if you don't think you need them for reading books (though you probably would benefit from them with books as well).
-- Eric Pederson (email@example.com), February 25, 2002.
I would like to second Eric recommendation of the Peak #1. I didn't start using a grain focuser until I was in my mid-thirties, but find it invaluable now.
-- Ed Farmer (firstname.lastname@example.org), February 25, 2002.
Try a Scoponet, Conrad. Somehow, they're much brighter than cheaper grain magnifiers. I think the mirror size has a lot to do with it.
I used to think that there couldn't be much difference between expensive and cheap magnifiers, having used LPL, Patersons and other makes quite satisfactorily. Then I came across a 2nd hand Scoponet at an irresistible price. Wow! What a difference. It was like opening the enlarger lens up another two stops.
The target in the Scoponet is a GG with a clear circle in the centre, giving two options for focusing - aerial or real image.
-- Pete Andrews (email@example.com), February 26, 2002.
I've heard many good things about the Peak, but unless I find a used one, it's a bit out of my price range. The Scoponet sounds interesting, but they don't seem to be widely available here- a Google search turned up dozens of links, but mostly across the big pond. Sounds interesting though, as I considered making a target consisting of both ground and ruled areas. My problem is holding visual focus on the crosshair while looking at the image- a larger ruled or ground area would make that much easier. Thanks!
-- Conrad Hoffman (firstname.lastname@example.org), February 27, 2002.
I've been going to photo swap meets for the past 5-6 years. I've noticed more and more and more late model darkroom stuff (enlargers, lenses, focussers, etc.). At the last one I picked up an Omega critical focusser (the same as the Peak #1 I think) that was still in the box for well under $100. Just 2 years ago a ratty one was going for over $100 so I think demand is softening for these things.
About the focusser itself, I find that it's lower height does help with checking in the corners although it's harder for me to peer at the same time as I reach up to adjust the head. I'm 42 and don't need glasses yet although the fine print is getting hard to make out. I didn't have trouble with an LPL unit I had before even focussing at f/8 or f/11 but the newer one is a bit brighter and has better eye relief.
-- Duane K (email@example.com), February 27, 2002.
Conrad, I purchased a used Scoponet & I find it works well;much better than the old LPL one I had or the Paterson Major I tried. It has one flaw;which is that it is a tall instrument.For 8X10 & larger;no problem but for 5X7 it is too close to the lens on my enlarger. I too looked for a Peak #1 & found them too expensive. Maybe one of the cheaper Peaks are O.K? maybe someone can let us know?
-- Melvin (firstname.lastname@example.org), February 28, 2002.
The Peak #1 is excellent for tired, 40+ year old eyes printing at 2 am.
-- Arnie Milowsky (email@example.com), March 01, 2002.
Did a few experiments and concluded a couple things. First, the quality of the magnifier is critical. A nice achromat or triplet is way better than any of the cheap single element jobs. I want a flat field and no color fringing. My unit had a single crosshair, and that's what I had trouble keeping my focus on. Replacing the crosshair with a ronchi grating, or even a piece of window screen (!) allows my eye to hold a stable focus. With those changes, my confidence in the result is far higher. Also good things to look for when buying a commercial unit.
-- Conrad Hoffman (firstname.lastname@example.org), March 01, 2002.