Do Glasses/Contact Lens Affect Focusing?

Naples · Nov 30, 2023

Hello,

I am near-sighted and wear contacts lens to see distance. I have always worn contact lens when taking photos. Would I be able to accurately focus manually if I shoot without contact lens?

Thanks.

Andrew O'Neill · Nov 30, 2023

You shouldn't have any issues, as you are focussing the image on the ground glass. Are you using an SLR?

Naples · Nov 30, 2023

Andrew O'Neill said:
You shouldn't have any issues, as you are focussing the image on the ground glass. Are you using an SLR?

Yes a Nikon FE2 which is manual focus only.

grahamp · Nov 30, 2023

You have to be able to focus your chosen focus aid (ground glass, rangefinder spot, split-image, microprism, etc.).
This may mean custom prescription glasses, special diopters in the camera focus, etc. If you can do that without contacts, fine. Though I can't imagine you want to swap contacts out very often, so presumably you would use glasses.

Where things get difficult is if your eyesight needs significant correction for astigmatism or another issue that a simple diopter will not manage. I have to use some form of prescription glasses for close work, so I use flip up magnifiers with large format cameras.

I find SLRs next to impossible without using my 'computer' prescription which lets me focus around 3 feet. My regular and reading prescriptions are too far off.

You might fine gentle reading glasses in front of your contacts work if you just need to get a little closer. using a 35mm SLR with glasses can be awkward because you cannot get your eye as close to the eyepiece, but it is doable.

Brad Deputy · Nov 30, 2023

As long as the image is as sharp as you can see it, the lines converge, however your focusing screen works etc, this is sufficient.

Your own eyes are not focusing the image, you are simply verifying the lens focus.

Od course, with better vision you will have an easier time doing it.

Brad Deputy · Nov 30, 2023

grahamp said:
Using a 35mm SLR with glasses can be awkward because you cannot get your eye as close to the eyepiece, but it is doable.

I have a fairly strong prescription with astigmatism in both eyes, yet I have no difficulty with my Olympus SLRs. I do need to "peer" around the entire frame especially to see the exposure meter on my OM4 but I'm used to it.

Pieter12 · Nov 30, 2023

I am left-eye dominant and have a mono vision prescription, with the left eye corrected for distance. I use my left eye to focus through the viewfinder of SLRs and rangefinders and never have had any problem at all. I open both eyes with a view camera, so I don't know which is giving me the dominant, sharper image. The left (distance) eye seems best with a loupe and a grain focuser, too.

Naples · Nov 30, 2023

Thanks all. I think I'm going to shoot a practice roll, half with contacts and half without, and see if there is a difference.

With my contact lens in - which allow me to see distance - I cannot see well up close, such as reading a book. Wouldn't that problem also exist with seeing the image on the glass so close to my eye?

Chuck1 · Nov 30, 2023

I need to wear my glasses for distance (and when looking through an slr) to focus.
To read I lift my glasses up out of the way(to set the shutter speed and aperture)
But for focusing on a ground glass with a loupe no glasses.

Ian C · Nov 30, 2023

Whether you use a corrective lens or not, the point of best focus won’t change on a camera or on an enlarger. The corrective lens will make it easiest for you to see the image, and that makes the job of focusing faster and easier. That’s the purpose of eyeglasses or a diopter correction lens eyepiece on a camera.

Nicholas Lindan · Nov 30, 2023

Nikons, as they come from the factory, locate the focusing screen an apparent optical distance 1 meter away. If your eyes can focus clearly at 1m then you will be OK. If not, then you will need a diopter lens to bring the apparent focusing screen distance closer.

Pieter12 · Nov 30, 2023

Naples said:
Thanks all. I think I'm going to shoot a practice roll, half with contacts and half without, and see if there is a difference.

With my contact lens in - which allow me to see distance - I cannot see well up close, such as reading a book. Wouldn't that problem also exist with seeing the image on the glass so close to my eye?

You should be able to tell if the image is in focus without having to shoot any film. Is it in focus in the viewfinder? If not, it won't be in focus on the film, so no need to waste any film. If you cannot see anything in focus in the viewfinder, then you need to add a diopter adjustment to it or wear glasses or contacts (not reading glasses!). A waist-level ground glass or a view camera is a different story. You seem to be asking all these questions without having actually tried anything.

Truzi · Nov 30, 2023

You should be fine depending on how near-sighted you are. I wear contacts and am so near-sighted that I'd have problems doing everything else without them in.

As people have stated, the image from an SLR is on a screen, so it will be like looking at an image/photo/page of text.
You're not compensating for your own vision like you would looking through a telescope.

Pieter12 · Nov 30, 2023

Truzi said:
the image from an SLR is on a screen, so it will be like looking at an image/photo/page of text.

No! the image seen through a prism is at a virtual distance that is greater than normal reading distance. The image on a TLR ground glass is at whatever distance you're holding it from your eye.

Chuck1 · Nov 30, 2023

The prism is the issue?

Pieter12 · Nov 30, 2023

Chuck1 said:
The prism is the issue?

It’s not an issue. It’s just different, the light travels differently.

IMoL · Dec 1, 2023

I wear contacts for distance (mainly astigmatism, but not a particularly strong prescription) - in fact the reason I wear contacts rather than glasses is so I can use eye-level veiwfinders and see the whole screen. I can still use my cameras without my contacts in - things are not as clear but it doesn't affect focusing, just the ease of confirming the focus. It makes me a bit slower, but I don't think it affects my hit-rate much, if at all. With other camera types (mainly TLRs in my case) I always use the pop-up magnifier to confirm focus, with or without contacts in.

I need reading glasses for close up work and I have a harder time confirming camera settings than I do focusing.

Agulliver · Dec 1, 2023

I'm left eye dominant with quite significant astigmatism in that eye. Lately I've been prescribed glasses for this, which do make a significant difference but I still use cameras without them. Nearly always manual focus SLR and rangefindinder models. I have tried with the glasses and it's not any more difficult, I'm just still not used to wearing them and much of the time I don't bother.

Alan Edward Klein · Dec 1, 2023

When I focus I always go pass the focus point so it starts blurring a little than back again the other way. A couple of iterations allows me to find the optimum focus point even if its a little blurry due to my eye. The camera has found the actual focal point.

pentaxuser · Dec 1, 2023

With my contact lens in - which allow me to see distance - I cannot see well up close, such as reading a book. Wouldn't that problem also exist with seeing the image on the glass so close to my eye?

I think the OP's worry may be that he believes he is actually required to focus on the viewfinder which is very close to his eye and his contact lenses are for distance vision preventing him from focusing closely

pentaxuser

Pieter12 · Dec 1, 2023

So many are asking whether their distance vision correction is affecting how they are able to focus a camera. Well, I assume you all have cameras. Forget theoretical discussions. Can you focus them or not?

wiltw · Dec 1, 2023

First, understand that if your vision is blurry, then your ability to assess 'best focus' is diminished. Period. I will provide proof of that point in a bit.
Next, understand that most camera viewfinders have a virtual distance (depending upon brand) of about 30" to 1m.
Some cameras rely upon supplemental diopter lens to correct for eyes that have inability to focus close (most of us over about 45); some other cameras have dial-in diopter correction.
For example, if you can go into the drugstore and use off-the-shelf readers that are +1.25 to permit your distance vision eyes to read something held at arm's length clearly, you could buy a supplemental diopter or dial in +1.25 on your camera.

Real Test of Focus...

I just pulled out my Olympus OM-4, and set the dial-in correction to work best with my left eye, which is corrected by my optometrist to give me good reading ('monovision' correction) at computer screeen distances while my right eye is corrected for far distance...
If I focus using my left (near) eye, I can clearly see the split-screen alignment of things that I focus on (like a tree trunk) and I can see the microprism becoming 'factured' if focus is off...but if I switch to my right (distant) eye to focus, using the exact same focus distance as used with the left I, I cannot see split-screen alignment or microprism fracture. If I put focus at Infinity, the entire viewfinder is blurry thru my right eye, while it is sharp with my left eye. IOW, my right eye CANNOT perceive 'best focus' while I can perceive it with my left eye; by adjusting the dial-in diopter,
I can see the viewfinder clearly with my right (distant) eye via use of a diopter correction, perceiving split-screen alignment when in focusand microprism fracture when out of focus, because the range of diopter it can dial in is sufficient to correct my right (distant) eye. Even though the viewfinder diopter has been adjusted to my distant eye, I still can focus using my left eye!

Sirius Glass · Dec 1, 2023

I have used glasses for decades. Then I moved to contact lenses, first hard lenses and then soft lenses. I have always used glasses or contact lenses for range finder, slr and ground glass systems, and I have always found that any of the available eye correction systems will greatly improve the use and enjoyment of photography. I cannot imaging using any camera without some type of eye correction system. Your optometrist can help you find the best vision system to use for photography and your overall enjoyment.

Doremus Scudder · Dec 1, 2023

Using a diopter adjustment on your viewfinder is no different than using glasses on a viewfinder with no diopter adjustment. If you can see the viewing screen clearly with whatever glasses/contacts/magnifiers you choose to wear, then you should be able to focus correctly. The image is projected on the screen; you're just correcting so you can see the screen clearly. Do whatever is needed and go out and make some photographs.

Best,

Doremus

Pieter12 · Dec 1, 2023

As a side note there is a very expensive astigmatism-correcting auxiliary eyepiece available for Leica RFs. And Televue makes astigmatism correction eyepieces for telescopes that can be adapted for some MF SLR prism finders.

Do Glasses/Contact Lens Affect Focusing?

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