Do Glasses/Contact Lens Affect Focusing?

[wiltw]

wiltw,

Your error is likely due to just missing focus. Focusing by eye has an inherent margin of error that gets larger with low light, bad vision, etc. I'm just referring to the image as projected on the ground glass/viewing screen. Your vision (or lack thereof) won't affect the sharpest focus there since it is being projected onto a receiving surface that is not going to be affected by your vision. Getting things as sharp as possible, however, requires good vision and proper magnification. Even then, there is error. That's why auto-focus is better than focusing by eye; it is inherently more accurate.

What is not going to happen is finding two different places for sharp focus, one without glasses and one with.

Best,

Doremus

Not disagreeing with your commentary...my 6' missed focus' was certainly not due to a different assessment of 'sharp focus', but a wider range of 'slop' in subjective assessment of the blurry image my eye was seeing. Once, I stopped focus at about 6.5' and the second time I stopped at 6', although 'best' focus was at the 7' actual target distance as detected by my 'near' eye.

 

[Alan Edward Klein]

Alan,

I bought a pair of flip-down magnifiers (4x) that attach to the nosepiece of my glasses. I use just glasses for viewing the scene, glasses with flip-down magnifier for general viewing of the ground glass and, for fine focusing, glasses plus flip-down magnifier plus a 5-6x loupe. Never had a problem finding sharp focus.

Maybe a pair of flip-down magnifiers would work for you. Another alternative I use a lot is to keep my progressive glasses on a cord around my neck and a pair of 3-4 diopter reading glasses in a handy pocket. When I need to view the ground glass, the progressives come off and the readers go on.

FWIW, the reading glasses/flip-down magnifiers also help reading the mm scale on my cameras' beds and when setting shutter speed and aperture.

Best,

Doremus

You just reminded me I bought flip-down magnifiers for that purpose. I just haven't tried it but once or twice. Thanks for reminding me.

 

[dave olson]

I used to wear glasses, far sighted plus astigmatism. I was constantly rubbing the eyepiece of either 35 or 120 cameras against the lens. Well I've aged a lot and with that comes cataracts. Had the surgery and opted for far sighted (distance) corrected lens inserted. All I can say it is a pleasure to be able to hold any camera to my eye, and not hit the glasses lens. My distant vision is better than 20-20.

 

[wiltw]

Flip-down readers are also available. I dislike bifocal lenses, particularly when descending stairs, so I clip on readers onto my distance-corrected single vision eyeglassess, that I wear when not wearing monovision (one eye near, other eye far) contacts.

 

[guangong]

Contact lenses are the way to go. As for myself, I wear two lenses on each eye: one eliminates severe distortion of cornea, and one to correct vision. Result…perfect vision, no need for eyeglasses. Best solution for focusing lens.
However, I do protect eyes from the elements, especially windy days, not so much from the wind itself as from grit, etc blowing in the air and causing irritation. by wearing sunglasses (different shades depending upon season…thus further protecting eyes).

 

[eli griggs]

I'm riding back from the Charlotte V.A. at this moment, after an eye exam and it looks like I'll be getting cataract surgery very soon.

I chose distance vision and will still need readers, but I'm hopeful I will now be able to use diopters, the doc said my current vision would call for about a -11 lens, as is, so I'm looking forward to some reduction of that condition.

 

[Alan Edward Klein]

Contact lenses are the way to go. As for myself, I wear two lenses on each eye: one eliminates severe distortion of cornea, and one to correct vision. Result…perfect vision, no need for eyeglasses. Best solution for focusing lens.
However, I do protect eyes from the elements, especially windy days, not so much from the wind itself as from grit, etc blowing in the air and causing irritation. by wearing sunglasses (different shades depending upon season…thus further protecting eyes).

How do two lenses in each eye work?

 

[Alan Edward Klein]

I'm riding back from the Charlotte V.A. at this moment, after an eye exam and it looks like I'll be getting cataract surgery very soon.

I chose distance vision and will still need readers, but I'm hopeful I will now be able to use diopters, the doc said my current vision would call for about a -11 lens, as is, so I'm looking forward to some reduction of that condition.

Good luck with your operation.

 

[eli griggs]

Good luck with your operation.

Cheers!

 

[guangong]

How do two lenses in each eye work?

A soft lens is inserted, and over that a hard lens. My optometrist lives and breathes optometry and is one of the very best in NYC. I found Him 40 yrs ago when ophthomologests failed to discover reason for my deteriorating vision (their concern is the medical health of the eye, not quality of vision), and other optometrists equally unsuccessful.

 

[Sirius Glass]

A soft lens is inserted, and over that a hard lens. My optometrist lives and breathes optometry and is one of the very best in NYC. I found Him 40 yrs ago when ophthalmologists failed to discover reason for my deteriorating vision (their concern is the medical health of the eye, not quality of vision), and other optometrists equally unsuccessful.

Soft lenses correct focus but not astigmatism. Hard lenses can correct astigmatism which is you your ophthalmologist has achieved that success for you. Enjoy that success.

 

[guangong]

Soft lenses correct focus but not astigmatism. Hard lenses can correct astigmatism which is you your ophthalmologist has achieved that success for you. Enjoy that success.

Ophthomologist discovered nothing and achieved nothing. I don’t have astigmatism, but rather an uneven thickness of cornea which results in a distorted curvature of cornea. Interesting that ophthalmologists could only see this when pointed out to them by my optometrist. The soft lens smooths out the cornea’s surface. If not smoothed out, a hard lens would abrade cornea at bulges, leading to more sight damage.
My optometrist is, if not the best, one of the very best in NYC. (He lo longer accepts new patients). For health and medical treatment I always seek out the best. So that still fit. Alas, not being a Rupert Murdoch the twenty something girls are out of my reach, but those ladies younger than my age, say 65 to 85 are usually afflicted with too many medical preconditions.

 

[lxdude]

When one eye was done, the other eye's cataract was so immature that the doctor called it "juvenile".

It kept playing pranks, so they said to it, "Later, when you've grown up more."