The age of long-sightedness

[helged]

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Dear all, I have - inevitably - entered the age of gradually more long-sightedness (+2 or thereabout at present). The glasses I have compensate for the long-sightedness, which is good. There is, however, a (minor) problem.

 

When looking at my high-res monitor, I see blue/yellow color casts around high-contrast objects/lines when the eyes are oriented away from the eyes center line. This means I have to move my head all the time when examining the screen to check blue/green color casts in the photo. Likewise, I see false color casts all the time.

 

Since camera lenses are delivered with quite some difference wrt optical properties, I would guess that also glasses can be more or less optically perfect. Any suggestions/experiences with respect to minimizing the color casts seen through glasses? Any manufacturers/brands/types of glasses that are optically preferable?

 

Thanks!

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[jaapv]

That does sound like you have ultra-thin high refractive glass. Ask your optician for a pair of old- fashioned thick glass spectacles

[tobey bilek]

They are all single element lenses. Hence they split the spectrum. This is the main reason camera lenses have multiple elements.

 

I really don`t see the effort of turning your head 5 deg to see the edges. The center should be ok. If not, then I would take the suggestion of old fashioned lenses. I have learned from others, the thin lenses have a narrow field of sharpness unlike the old ones.

 

There is another issue in that lenses could be ordered in various curvature of field with the same correction thus keeping the lens the same distance from your eye. Cost reduction won. Now one size fits all or not. So if your eyes are deep set or not recessed much, you are going to have a problem. You would think when you pay something >$500 for glasses, they would be perfect for you.

 

You should also notice the distortion towards the edges, my minus lenses do a nice barrel if I notice a door frame 40 deg off axis while still looking straight and they have less than 1 diopter correction.

 

Think about some computer glasses. Mine are set for arm length on top and a bifocal for 12/14 ". They are superb for computer, worthless for anything else.

[helged]

Jaap and Tobey - much appreciated feedback. I will contact some of the local stores to see what they can offer.

[Alberti]

I have two pairs of true bifocals, one for the computer and hobbying (40-50/80-100 cm), the other standard (distance) and reading (30cm). Both are Hoya Executive Bifocals. I could not live with varifocals.

 

There are also glasses with two elements so correction is done better.

Glass quality differs a lot, various options available.

Don't count on the web presence of this Hoya company. Couldn't be worse.

 

hope this helps albert

[lars_bergquist]

Strange. I wear varifocals – same pair for everything, including Leica photography – and I have never been troubled by this phenomenon. In fact, I cannot see it even when I try!

 

The old man who skipped the bifocals

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I've worn glasses for more than forty years and I've had exactly one pair which made colored edges. Orange and violet. I learned to live with it. the next pair didn't do that, anymore.

[esophoria]

This is an interesting thread for me.

 

I am an optometrist, who has spent much of his career not doing patient care but rather designing ophthalmic instrumentation including retinal digital cameras. Some comments:

 

The actual term for long-sightedness is presbyopia (old eye.) The crystalline lens within our own eyes hardens through out life and turns yellow...thereby absorbing much of the natural blue part of the spectrum in everyday life and additionally losing its ability to focus on closer objects.

 

The color fringing mentioned in previous posts are due to that person having/using polycarbonite lenses. One of the safest (no breaking of lenses) lenses known..they do suffer from moderate to severe chromatic aberration. A better choice would be "high-index" lenses with an anti-reflective coating. Bottom line: very little color distortion or dispersion of light almost equally as safe.

 

Some people adapt very well to PALs (progressive addition lenses) sometimes call variable lenses...not really an accurate term. Those who adapt started wearing them at an earlier age than those who migrated from wearing traditional bifocals or trifocals. The field of view is significantly larger and there is little if any prismatic jump...all negatives of bifocals or trifocals.

 

For my Leica M9, I sometimes use their magnifying lenses (which are really telescopes) to help me with accurately focusing the lens.

[Alberti]

Hmmm .. that is a good idea:

use viewfinder magnifying lenses (which are really telescopes) to help me with accurately focusing the lens.

I had no trouble with my M2, M6 was a disaster relatively, M8 a gift again. A magnifier will help me for sure.

I agree the high refractive (thin) lenses can be good, I have them, they can give a very wide angle of view without artifacts.

 

(Instead of a magnifier I could go custom design and order a an M2-type viewer without the 28 mm, why not?

Would give a better end result I think . . . , less glass, less layers etc., even easier focus)

albert

[jaapv]

Well, an M2 type viewfinder is not on offer for the M9, so ordering it won't get you very far. Quite apart from the fact that is a technical impossibility.