#%$& Glasses

[Sal Santamaura]

..I also insisted on distance glasses whose optimum focus is at INFINITY! Not just the few feet to their chart on the wall. I like this much better for landscape photography and for driving. Again, some optometrists didn't even know what I was talking about. (It's amazing.) The one I like actually takes me outside his office with some of his lenses, and we look for the combination that allows me to see trees best off in the distance...

Actually, it's not just a "few feet" to those charts on the wall, it's 20 feet. That's where the denominator comes from in 20/20 -- 20-point type at 20 feet.

Our eyes have a focal length (in air) of 17mm and an aperture range of f/2.1 to f/8.3. Using the formula Struan Gray posted elsewhere

Infinity = 0.75 * (focal length/f-number)^2 where infinity is measured in meters and the focal length in millimeters

leads to a figure of 49 meters for optical infinity when our pupils are fully open and 3.1 meters with pupils maximally contracted. So, if your favored optometrist takes his equipment outside on a bright day, your resulting prescription shouldn't be different from one obtained when performing the refraction in his office. If it's dark enough outside so your pupils open larger than f/6.0, the results should be slightly different.

This is an interesting comment. I always assumed that glasses were optimized to focus at a hyperfocal distance and then worked OK from there to infinity...

They are -- that 20-foot distance to the chart -- and they do for most purposes under most conditions.

For me, there's a difference. Of course, one can make things out in the distance, but it's not in sharp focus.

But, one sacrifices being able to see things sharp at intermediate ranges. I didn't think to mention this in my original post. For example, things on the dash of a car won't look as sharp, or some things in a room. But, my eyesight is good enough at those intermediate distances that I don't wear glasses in the house. Only for driving, walking, when I'm outside. For me, it's worth the trade off. I dislike photographing and having that loss of sharp focus in the distance.

In addition to being 55 and suffering from the presbyopia that this thread is about, I've also worn eyeglasses to correct myopia since the age of 8. While it varies a bit from year to year, my distance correction is usually in the -6 diopter range. I've never had a refraction performed outdoors; it's always done using the standard 20-foot chart. Unlike you, I do wear glasses in the house. In fact, they are placed on the nightstand when I retire and back on my face first thing in the morning. I'd run into walls without them.

I think your approach to refractions has resulted in "overcorrecting" your myopia. The "hyper sharp" distant vision you describe sounds like what I experience when using an old set of eyeglasses with lens strengths 0.25 - 0.50 diopter stronger than my current prescription. It feels very unnatural.

My optometrist (of thirty years) works with me to achieve 20/15 acuity. I've never lacked extremely sharp distant vision when driving or photographing. Unless your presbyopia is far advanced, you should be able to accommodate intermediate distances in a room. Things on a car dash are somewhat closer, and might need additional correction. You are probably a candidate for progressive lenses. Since settling on those, I've happily regained the full range of focus distances. Some will say that the inability of progressives to provide sharp vision in all directions is unacceptable. My response is that substituting still-functioning neck muscles for atrophied eye muscles and hardened lenses is the least-bad tradeoff.

[David Beal]

Ben, one thing you may notice is how yellow the world is. I had my cataracts done a month apart and was amazed that looking through the unoperated eye was like looking through a filter. The opthamologist said that's what happens to our lenses as we get older and (he said) if you look at original oil paintings of artists who painted into old age, you can see an increase in the use of yellow as they aged (because they didn't perceive that the yellow they saw was "yellow" enough).

I got monovision 5 years ago after retinal detachment surgery. It's true that you can drive and read without glasses, but in abundance of caution I got glasses to drive, and in an abundance of cheapness got a bunch of $2 readers and knocked out the right lens.

But like most everybody else I'd be lost without a loupe.

And I'm only a youngster of 63!

[Jim Graves]

58 same problem. I use 3.0 reading glasses but I have a 3x pair of filp downs I got a Cabelas. They let me get with in 4 inches of the GG for fine focusing. Cost about 10 bucks.

Thanks, Alan ... after reading your post, I ordered a pair ... I just got my 4.0 flip-downs today ... put them on my 3.5 reading glasses ... PERFECT!!!!!! No more backing up and pulling the dark cloth off the camera! Can't beat the price and they are very sturdy and very clear.

[Ben Hopson]

David, I had not heard about cataracts affecting the way we see yellow. I have heard that colors will be much brighter after the surgery. It will be interesting to see how the world looks after having the surgery. I don't think I would mind things seeming yellow for a while as long as they are bright and not fuzzy.

I am another who has always used a loupe to focus. I cannot remember ever making a large format exposure without the aid of the loupe. That will most likely not change.

Ben

Ben, one thing you may notice is how yellow the world is. I had my cataracts done a month apart and was amazed that looking through the unoperated eye was like looking through a filter. The opthamologist said that's what happens to our lenses as we get older and (he said) if you look at original oil paintings of artists who painted into old age, you can see an increase in the use of yellow as they aged (because they didn't perceive that the yellow they saw was "yellow" enough).

I got monovision 5 years ago after retinal detachment surgery. It's true that you can drive and read without glasses, but in abundance of caution I got glasses to drive, and in an abundance of cheapness got a bunch of $2 readers and knocked out the right lens.

But like most everybody else I'd be lost without a loupe.

And I'm only a youngster of 63!

[D. Bryant]

Frank,

What strategies work best for those of you who have decent far vision but need reading glasses for camera operation? What's the smoothest working method -- any tips?

I went to my regular eye doctor and requested that his optician have a pair of +4 diopter power glasses made. Once I explained why I had the new pair in about a week. I choose a cheap metal frame and the set cost about $40. Which I could apply to my flexible spending account. About the strongest you can find in the drug store is around +2.5. They have worked great. I'd rather spend my money locally than purchasing over the internet.

I use these for looking at the ground glass of my view camera, or when setting the aperture and/or shutter speed of a lens. It's also very useful for chimping an LCD display for digital cameras.

Hope this helps,

Don Bryant

[rvhalejr]

.,. This getting old crap blows .,.

I think "Old Age and Treachery" means that I know more tricks, if not ways to cheat.

There is a 2X magnifier for the DSLRs viewfinder (my spot meter) and some MF cameras have a flip up magnifier that levels the playing field.

For the other MFs and 4x5(s) I use a 30-40x loupe (pocket microscope). AA apparently used this trick by drilling holes in the gg and using a hair (mine is .002" measured with digital calipers) to locate the emulsion plane.

We went round-and-round about the pros and cons of this technique in another thread (its on hold for now), but I think we old people should not share this trick with the 30 somethings as to keep a level playing field (seniors need some advantages).

My trick modification was to replace the GG with clear glass, replace hair (or wire) with developed film grain and tinker focus with the "senior's" loupe across the entire frame. I'm slower than most but when it comes to tinkering and clever tricks, well, you be the judge.

Anyway, I've had a lot of fun with it and use the computer to zoom in on the end product. It's a lot more photographically correct to use a computer to see detail than using a loupe (or magnifying glass) to look at a print (or image).

Use a focusing aid in a gallery or a museum is just not acceptable behavior. However, I recently saw some gigapixal images of well known "masters" work in europe. To my great surprise and pleasure were the ***PERFECT*** tear drops rendered among the cracks in the paint.

I usually take a mono-pod or a fancy walking stick with me, and as it turns out the "seniors loupes" double as Monoculars with a near focusing distance of about 10ft. Using the Mono-pod (or walking stick) to steady the monocular affords one the same FOV one would have being only 1-2 feet from the piece, which in the case of priceless works would be impossible to do.

Pehaps these are a few of the silver lining secrets that await those traveling toward the sunset .,.

R.

[aduncanson]

Quote:
Originally Posted by Alan Rabe
I use 3.0 reading glasses but I have a 3x pair of filp downs I got a Cabelas. They let me get with in 4 inches of the GG for fine focusing. Cost about 10 bucks.

Thanks, Alan ... after reading your post, I ordered a pair ... I just got my 4.0 flip-downs today ... put them on my 3.5 reading glasses ... PERFECT!!!!!! No more backing up and pulling the dark cloth off the camera! Can't beat the price and they are very sturdy and very clear.

I just did the same thing, adding the 4x "Flip'N Focus" from Cabellas to the readers that I had earlier chosen for viewing the entire grounds glass. My initial impression is that it is a great solution. I feel that I can fous with confidence.

- Alan

[Bill_1856]

Amazing how few of the posters use contact lenses.

[Turner Reich]

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Amazing how few of the posters use contact lenses.

Can't, astigmatisms.

[Alan Rabe]

Whoa, 4x, that is new. I only have a three. I just orderd a 4. Price wnet up a bit but nothing new these days. You're right though. It is a great solution and is I feel much easier to deal with than loupes.