presbyopia and focusing the view cameragreenspun.com : LUSENET : Large format photography : One Thread
In using my 4 X 5, I find I have trouble accurately focusing. At age 36, I have slight prebyopia and I find I have to move my head away from the ground glass more than I'd like to be able to see it clearly. But when I do that, it's hard to see the fine detail, and the darkcloth sags.
I assume some kind of reading glasses are in order, but which are best? I recall hearing something about a jeweler's eyeglass and of course there are also plain reading glasses. Do either of these improve the situation significantly?
-- Lloyd Chambers (email@example.com), July 12, 2001
I'm sure reading glasses might be in order for everyday stuff. But using a loupe on the ground glass of your 4x5 might be more practical. Hint: I found that my Nikon 50mm lens (off my 35mm kit) works great as a loupe.
-- Dominique Labrosse (firstname.lastname@example.org), July 12, 2001.
Lloyd: I'm a little older than you and have fairly substantial presbyopia. I wear good quality "reading glasses" all the time at work, but I find they don't work well with groundglass focusing. Reading glasses are optimized for, you know, a foot and a half or whatever. So, anyhow, I just wear a loupe around my neck and pop it in my right (strong) eye when I'm ready for fine focusing. I use my reading glasses up to that point. It's all a bit awkward, but as you suggest large format photography isn't "opimized" for people with eyesight problems. -jb
-- Jeff Buckels (email@example.com), July 12, 2001.
I had my optometrist write me a prescription for special reading glasses (for my presbyopia and astigmatism) for 6-inch viewing. He was a little incredulous until I carefully explained how they were to be used. He told me to make sure the optician accounted for some parallax adjustment, since at 6 inches your eyes are not pointed "in parallel". The glasses stay in my camera case and work well. They are "half-glasses" so I can put them down low on my nose to look over the top of them. You might give this a try.
-- Steve Baggett (firstname.lastname@example.org), July 12, 2001.
Presbyopia? Does this afflict other denominations? Or does it mainly afflict elected executive officers?
-- Sean Yates (email@example.com), July 12, 2001.
I posted this in a loupe thread, but it bears repeating here. Those special prescription glasses are a stock item for surgeons who need a mild degree of magnification when working on something close. If you do a search on "surgical loupes" you'll get lots of hits.
-- Struan Gray (firstname.lastname@example.org), July 13, 2001.
The solution to Presbyopia ("old eye vision") is reading glasses. So called "Plus Spectacles" are, in my opinion one of the greatest technical inventions of all time. They are so simple as to make explanation difficult. Plainly put, the more the plus the closer you can get to the thing you are seeing and be in focus. When looking at a ground glass you are looking at the glass itself, not the object in the picture. So the problem is exactly the same as in viewing fine print.
You can experiment with drug store spectacles available in up to plus 4 strengths. You can also add spectacles together (wear two at the same time). If nothing else, this can help you let your optician know what prescription you need for your use.
There is no "wrong prescription" in reading glasses. The only variable is the focusing distance from the object viewed. Reading glasses will not "hurt your eyes"
The special viewing devices used by surgeons are actually spectacle mounted telescopes which are different from reading glasses (plus spectacles) in that they magnify objects at a distance (in this case about three or four feet) rather than allow you to get close to the object viewed (and still be in focus) as with reading glasses or ordinary jewellers loupes.
-- Steve Grimes (email@example.com), July 13, 2001.
Another possibility, alluded to in the initial question, is a clip-on jeweler's loupe. These can be attached to the wearer's eyeglass frame, and flipped down in front of one eye for magnification. This alternative gives the advantage of a longer viewing distance for general composition and a reduced viewing distance for critical focus. Two disadvantages of a jeweler's loupe are: 1. Lesser optical quality - they are typically not aspheric design. 2. As compared to a typical photographic loupe, there is no stand to block non-image light or provide optimal focal distance. One must move the head toward and away from the groundglass until image focus is found.
If you are so inclined, a jeweler's loupe should be relatively easily available from a quality optician, hobby or low-vision supply house. Look for a model with a sturdy mount, it will be bumped frequently by your darkcloth.
By the way, I am an optometrist, and disagree with the previous contributor's suggestion that the power of the reading glasses is unimportant. The wrong Rx may accelerate the development of focusing problems, and/or exacerbate underlying eye teaming problems. See your eye doctor for a prescription optimized for your needs and visual status.
-- Henry Friedman (firstname.lastname@example.org), July 13, 2001.
"Fortunate" that I am to be very myopic, there's one small compensation as presbyopia develops. I only need slide regular distance spectacles down my nose and look over them. Built-in 3.5X magnifiers!
-- Sal Santamaura (email@example.com), July 13, 2001.
Steve, one pair of surgeon's loupes I have fits your description, but the other is more like a ordinary pair of glasses. The lenses combine a diopter for magnification and a shallow angle prism to let you look about six inches in front of the tip of your nose without crosseye strain. Unlike reading glasses they don't occupy your whole field of view, so you can look past them to see the whole composition.
They're the best thing I have ever used for looking at a ground glass. I recently inherited a large collection of mapmaker's loupes, jeweller's loupes, geologist's loupes and much else besdes, and of all of them the wacky specs are the nicest to use. My only worry is that they're a bit delicate for heavy field use.
-- Struan Gray (firstname.lastname@example.org), July 13, 2001.
Wow lots of answers, but here is my input.
I am a sugeon and use surgical loupes. I would not suggest them because their field of view is so small and they are desined for looking down so that you would have to tilt your head back to see the ground glass unless you had the telescope part mounted straight ahead. Designs for Vision is the company that makes these and they are Extremely expensive (~1000.00). They are also designed for focal distances longer than you want.
If you don't need glasses for any other reason besides close up work (that is you are not far-sighted or near-sighted or have astigmatism)then yes, you can go to the pharmacy with your camera and dark cloth and set up. Then you can try out all the different diopter choices until you get a strength that works for you at the distance that you like to hold your head. Remember that the stronger the power you get, the smaller the depth of field you get so that holding your head at the right distance will become more critical.
If you do have a need for prescription other than just close up work and therefore normally wear glasses, then this option will not work because you will have to wear the reading glasses OVER your normal glasses which is a big hassel and does not fit well. There are clip on jeweller's loupes to the side of the glasses, but these will not allow seeing the whole ground glass at once. The is the "Optivisor" head band type magnifier (flips up and down) which jewellers, hobbiests and mineral people use, but the band is stiff and hot and tends to give a headache and the view is not full.
This puts you in the realm of prescription lenses.Bifocals are awful for this because you have to tilt your head back to see the whole image. I do know some people who compromise by simply taking their hand and lifting up their glasses to see just through the reading protion of the lens. Problem with this is that unless you use pretty strong bifocals (and at your age you probably do not) then the reading protion of the bifocal will probably not be strong enough anyway.
This brings you to the option of dedicated closeup glasses in their own frames. You can go to your opthamologist (MD) or optomotrist (non-MD) and have them mock up for you in their adjustable glasses any amount of personal prescription plus any amount of close up correstion in jumps of 0.25 diopters. You again bring your tripod, camera, and dark cloth and set up so you can look out a window and test all the options. They love this when you do it because it is so interesting to them to deal with this problem for photographers.
This leaves two options for frames. If you do not have any prescription needs other than just needing close up correction, then simply get a single vision close up lens in a frame, hang it around your neck with an eye glass lanyard, and take it on and off when needed. IF HOWEVER you normally need glasses for non close up living (ie far sighted, near sighted, astigmatism) then you are going to have two pairs of glasses hanging around your neck or going bak and forth into pockets. So here is a solution that I use.
You may remember from the 60's that it was very common for baseball players in the outfield to wear flip up and down sunglasses to keep from being blinded by the sun. These type of frames are still sold. You have to ask your optician to check through their catalogs for "baseball" frames. The stationary frame holds your normal persription and the flip up and down part hold your close up correction. Flip up, and you can look all over the world with your regular prescription. Flip down, and you have instant custom-chosen, close-up, full-view vision for under the dark cloth. They are quick, easy, and need no cord around your neck, or pockets to store them in. The only draw back that I can even find is that they are moderately heavy since they have four lenses and my nose gets tired if I try to wear them constantly. So I only put them on when I am actively making a shot and switch back to my untra light weights when I am walking around. Email me if you have any questions!
-- Scott Jones (email@example.com), July 13, 2001.
As a Dentist I used Design for Vision glasses -they were wonderful but as noted they aim down too much and they cost $$$-$750 20 yrs ago. I use 4X reading 1/2 glasses that get my eyes about 6-7" away- perfect for a 6x7. Then loupes for fine focus. George
-- George Nedleman (firstname.lastname@example.org), July 13, 2001.
Thanks everyone for your input.
I purchased a pair of 2 diopter reading glasses ($10, cheap to try) which seems to help me focus more easily close up. I will try those and see how they work.
-- lloyd chambers (email@example.com), July 13, 2001.
I think Sean Yates (answer #4) is way off the mark. Presbyopia is actually an intense fear of Presbyterians and the blurrier the better. You can't fear what you can't se
-- Wayne Campbell (firstname.lastname@example.org), July 15, 2001.