Slide loupe as focusing loupe?
I've been reading a few posts here about which focusing loupe to buy and I got confused.
I learned that horseman, toyo and wista are some of the best focusing aids around, but I also found some people saying that regular negative loupes work good as a focusing aid. Is that so? I had the impression that a focusing loupe had an offset for the focus point in order to account for the glass thickness.
I know you get what you pay for, but I guess my question is if using a cheap (around $20 bucks) loupe is better than no loupe at all?
Re: Slide loupe as focusing loupe?
Some may argue, in part due to the size/dimensions, but I have found the square based Horizon 4X Loupe (allows viewing GG corners) to make a very fine GG Loupe and have compared it against other Loupes over at APUG. Do a search at APUG for the testing. Use the Black Skirt instead of the clear for the GG. The optics are very good, though it is about $43 from B&H Photo:
http://www.bhphotovideo.com/bnh/cont...ughType=search
Re: Slide loupe as focusing loupe?
Richard,
This looks like a good device - is there enough adjustment to get it to focus on the image behind the gg and still have a little room to adjust for old tired eyes?
Re: Slide loupe as focusing loupe?
Re: Slide loupe as focusing loupe?
My kids lost my loupe. My four year old daughter likes to wear it as a necklace. Until I find, or replace, it, I'm using an inverted 55/1.8 Super Tak to check focus. YMMV, FWIW, yada yada. :p
Re: Slide loupe as focusing loupe?
Hi Ed and Padu,
There is plenty of adjustment on the Horizon to adjust for +/- focus and your eyes at the film plane on a lightbox or the GG. Bogen Imaging used to distribute the Horizon Loupes. My friends there indicated that the Loupe which is made in Russia is supposed to be made from optics made by Zeiss Jena. Based on sharpness and performance of my Loupe I would not doubt it. I found that the Loupe on the GG because of its field of View and Sharpness appeared to be better and performed better than my older Rodenstock 4X Loupe and my Fuji Professional 4X Loupe. It seemed to be very close to the performance of my very expensive 5X Leica Loupe.
I suspect that the optics and performance of the Horizon will be far better than the 8X Loupe that you have referenced. That particular Loupe from my understanding is not that sharp.
I also found that as much as 6X or 7X was about the maximum comfortable limit of magnification that I found with my Linhof Technikardan 45S with the original GG or the Satin Snow replacement with or without the Linhof Fresnel (beyond picks up too much GG grain) with a variety of lenses including my Rodenstock f6.8 90mm Grandagon N MC, Rodenstock f5.6 Apo Sironar S, my Rodenstock f9.0 Apo Ronar 240mm MC, and my Rodenstock f9.0 Apo Ronar 300mm MC.
The 4X Horizon Loupe appears to be a very very good comprimise for magnification, light transmission, field of view, and extreme sharpness across the GG.
Rich
Re: Slide loupe as focusing loupe?
I use a finger print loupe that I bought at a police garage sale, good glass, highly corrected and I paid $10 bucks for it, they no longer required it because they had changed to a digital finger printing system, was made by Rodenstock and it about the best I have ever looked through.
Dave
Re: Slide loupe as focusing loupe?
I don't think you need anything special in a loupe that's used only for fine focusing on a ground glass. Some people use 50mm lenses from their 35mm cameras as loupes, some use reading glasses bought at a drugstore, some use a plain magnifying glass, others use all sorts of different things. The expensive loupes (e.g. $50 and up) are loupes mostly designed for viewing slides on a light box. Since color accuracy, among other things, is important for that use those loupes tend to be expensive. But I think that when using a loupe on the viewing screen of a LF camera all you're doing is magnifying what you see without a loupe. You shouldn't need a finely made optical instrument to do that.
I like the square loupes just because they make it easy to use along the edges of the screen and in the corners (if you don't have cut-out corners). I don't exactly understand what you mean by "I had the impression that a focusing loupe had an offset for the focus point in order to account for the glass thickness." I think that all the loupe does is magnify that which you can already see on the screen, so I don't know offhand why the loupe would need to offset anything to account for the glass thickness. But then I'm far from being a loupe expert.
Re: Slide loupe as focusing loupe?
The image is formed on the ground side of the screen, thickness of glass makes no difference at all in fine focus, if you have 1 inch thick piece of glass, as long as the ground side of the glass in in the right position, you should be able to fine focus with just about any magnifying glass, as long as the ground glass you are using, at least transmits a clear image to focus on.
Dave
Re: Slide loupe as focusing loupe?
Quote:
Originally Posted by
Padu Merloti
I use the 4x versjon, works great.