How to use a loupe with/without glasses

<p>I've read through dozens of forum threads on loupes and diopters but none seem to address my specific problem. I have just recently taken up Medium Format film photography. I use a Pentax 67, and I just shot my first roll of Velvia 120 slide transparencies. The lab technician and I reviewed them on a light board. She said they were all in focus. (Note: I am both farsighted and nearsighted, and I can't wear contacts.) When I looked at the slides using the same loupe the lab technician had used, I couldn't make them be in focus without lifting the loupe about 3/4" off the slides (ready for the weird part?!) WHETHER OR NOT I used my reading glasses.</p>

<p>It makes sense to me that I would need a loupe that had a built in diopter and (according to some info in various threads) that I might even have to have a diopter made by my optometrist if I wanted to use a loupe WITHOUT wearing my reading glasses, but what the heck does it mean when I have to raise the loupe 3/4" off the slides WITH glasses too?!!! How am I ever going to be able to determine whether a photo is in focus without either guessing how far to keep the loupe above the slide or even more embarrassing having to ask someone else to review the focus?</p>

<p>My thanks to any and all who think they know the answer.</p>

<p>The loupe has to be held at a distance where you see an in focus image of the slide. It doesn't matter where you have to hold it. Some loupes have an adjustable focus and that one may be set for someone to be able to see clearly without their glasses, forcing you to hold it off the light table.</p>

 

<p>Most loupes are adjustable, but have a fairly short eye relief so I can't use one while wearing glasses. Most high-quality loupes have adjustable focus. You should have no problem if your prescription is within +/- two diopters. If you have to raise the loupe 3/4", that might be a problem - the focusing helix would have to be at least that long.</p>

<p>A reasonable alternative would be a 7x (no higher) Hastings Triplet (the design) magnifier. They're very compact and have superb optical corrections, and a good one is half the price of a comparable loupe (q.v., Edmund Optics or Baush and Lombe). You hold it to your eye (sans glasses) and at a distance to render the subject in focus. There's no skirt, so they are tiring to use and don't block off extraneous light. Hastings magnifiers come in 7x, 10x and 20x powers, but anything higher than 7x is of little use for evaluating photos (and have very short working distances).</p>

<p>I use loupes all the time with my glasses. Both on a light table and for my view camera. A good loupe has an adjustment/focus ring. I have never seen one with this that can't be adjusted for someone with prescription glasses, but what is in focus for me is not going to be in focus for someone else. You have to adjust for your eyes, much like you would a telescope or binoculars--or even your diopter adjustment on your camera!</p>

<p>Some loupes have no focus ring and with those, it generally means picking them up off the table some distance--they are just magnifiers! (maybe even inverting them so you can get closer to the film)</p>

<p>Some time ago, I actually bought those jeweler magnifiers and find those work great. I have a swing down extra power magnifier for critical focus on the view camera, but I still use the loupe in some cases. I also found them useful for looking at film and Polaroids and for spotting prints.</p>

<p>Maybe it is because you are both near sighted and far sighted.. which actually makes no sense to me but what do I know. I have the same issues as far as sometimes wearing glasses with my loupe and sometimes not and it does make a difference how far I have to hold the loupe up or not up but one thing is that your eyes are adjusting all the time. Personally I have given up on using on the surface type loupes and I hold a lens in my hand that needs to be a few inches off the focus surface. It is not difficult to find focus and then recognize when the film or ground glass image is not in focus .. or is in focus. One of the things I hate worst about getting old.. aging eyes.</p>

<p>Thank you all for your responses!</p>

<p>I think in my inexperience and ignorance I am missing something fundamental. Please don't laugh (smiling is okay) at my next question.</p>

<p>If you are adjusting the loupe either by a focus ring, diopter or by changing the distance from the negative, how do you know if the image is in focus, and you are not simply making it in focus with your adjustment?</p>

<p>It is impossible to make an out of focus image become in focus by adjusting the loupe. Out of focus is out of focus and that is a sharp as it can be. You can however make a sharp image look out of focus by misfocusing your loupe. Perhaps it is just a matter of getting to know the loupe.. a learning curve. </p>

<p>D Purdy thank you for your reply.</p>

<p>In some ways it makes sense, but I still don't quite get it. The way it made sense is that everyone (tech, wife, etc.) said the slides were in focus regardless of their vision (.i.e, contacts, glasses, 20-20 vision.) What doesn't make sense is when you say, "You can however make a sharp image look out of focus by misfocusing your loupe." How do I know if I'm misfocusing my loupe and making the image out of focus or that the image really IS out of focus? The answer I guess has to be your last sentence.</p>

<p>I've been struggling trying to decide which loupe to buy for all the reasons above and because I'd like to find one that is large enough to cover the entire 6x7 slide, that has a variable diopter, and yet is not much more than $100 max. In other words, I want it all. In the mean time, I needed something to get by with so I purchased a Carson LL-55 5x from my camera shop.</p>

<p>Back to your last sentence. If I get what you're saying, I either need to buy another loupe or stick with the Carson and THEN use either loupe with a consistent method that matches other people's sense of being in focus. For example, create a 3/4" spacer for the Carson, and always use it when I review new negatives. Or to put it another way, Occam's Entropy Razor "The simplest solution that requires the most effort is almost always the right answer."</p>

<p>Once again, thank you D Purdy and all who contributed such fine advice!</p>

<p>" How do I know if I'm misfocusing my loupe..." that is easy, look at the edge of the film and/or the writing just inside, that will always be sharp if the loupe is in focus! Besides, you will know--at least I can tell when things "should" be in focus.</p>

<p>Seriously, the jeweler's magnifiers are really a great way to look at film. You will look funny if in public, but I have been using them for almost 30 years. I have had art directors make sketches of me in them while we worked on a shot. As I said, you can get them in one power and then add a flip down piece that increases the magnification. This is what I am talking about:</p>

<p>http://www.amazon.com/Donegan-OptiVisor-Headband-Magnifier-Magnification/dp/B0015IN8J6/ref=sr_1_1?ie=UTF8&s=home-garden&qid=1272594516&sr=8-1</p>

<p>I got them at a cutlery shop and there were several different magnifying powers available for the main lenses, then a single piece, looks like a standard magnifying glass, that screws onto one side or the other--I guess you could get two of them, but they are too strong to use both eyes at once.</p>

<p>Well duh! Someone hit me in the forehead please! Of course, the "FUJI RVP100" is always going to be in focus. Why didn't I think of that?!!! Thanks John. I assume the last remaining 1/4" of freeplay in focus range (i.e. moving the loupe closer or away) is either loupe/magnification dependent or eye correction dependent.</p>

<p>I looked at the headband magnifier (thanks for the link.) Let me say first, that if I was concerned about looking funny in public I'd never have gotten through high school much less made it to 55! They seem like a really good idea, but my eyes not only need distance glasses and reading glasses but they also require very different lenses between the left and right eyes. So is there any way to make jewelers magnifiers work with them?</p>

<p>I wear my glasses with these, so I assume it shouldn't be a problem--my eyes are the same as yours it sounds. I wear the graduated lenses (bifocals), so depending on what part of the lenses, my glasses, I look through determines how far from the ground glass or film I will be when in focus. </p>

<p>I just pulled my one set out, I have two, and I bought the number 5 lenses for the main magnifier and that gets me about 8 inches from the film. The little swing in one doesn't have a number on it, but if you can find cutlery shop that has these, I am sure you could test them (if there are choices). I end up about 2 inches from what I am focusing on with that swung down. That is powerful enough to critically focus my 4x5, but there are times I need the 7x loupe I carry as well.</p>

There are also some flip down magnafiers that clip to your glasses. Very slim, and fit in a pocket easier.

<p>As somebody mentioned, graduated lenses can throw in an additional wild card. They come in different shapes as regards the invisible focus zones, and your glasses must be perfectly fitted to your face for consistency. In addition you must train yourself as to how to use them by daily practice to know your focus spots. To this day, I can't read book titles on a library shelf when I turn my head vertical to read horizontal titles.<br />If you have graduated lenses, this will affect your loupe technique. You must experiment.</p>

<p>Hi John:</p>

<p>I don't have graduated lenses, but one thing I have certainly noticed is that with my prescription reading glasses I have to wear them and focus on something close for a minute or more before I can start to review the slides. I've set up spacers (actually two packs of playing cards) that I've adjusted to a known focus length that support the loupe above the slides. Then I wait until the "FUJI RVP100" is in focus before I examine the slides for sharpness.</p>

<p>Nevertheless, I think you're comment is an important one to have in this thread as I have many a friend who do wear graduated lenses (part of growing old I guess.)</p>

<p>Stuart</p>