OK... I know the camera will give a beep when it determines all is in focus, but I wear progressive lenses and sometimes I am so sure all is in focus... the camera affirmed my decision, yet it is off, way off! Sometimes it is because of movement.
I am mainly talking about macro, flora focusing. Do others have this problem?
Leave your glasses on or take them off? I do have one good eye It is strange how my eyes have changed as I have become a senior citizen.
Oh, yes, Barbara, I certainly share your difficulty with focussing!
Look through the upper part of the eyeglasses' progressive lens; that part is supposed to correct our vision for eye-is-focusing-on-infinity, and the viewfinder is designed to be looked at as if it were at 'infinity' distance. Now that you've made me think about it, it's quite possible that looking through the progressive lens too close to the upper edge will introduce inaccuracy because the progressive lens probably isn't ground accurately all the way to the top edge. (I know that my "computer glasses"--bifocals the upper part of which correct my vision for things about 30" away--have chromatic aberration: if I look straight at my monitor, lines near the side edges of the screen have a distinct purple fringe. I'm sure the retailer's answer would be "Well, you're not supposed to be looking out of the edges of your glasses!" It was disheartening to discover this real flaw in my eyeglasses.) So I guess we have to find out where the upper part of the progressive lens's prescription starts to drop off. If you have 20/20 vision in your good eye (I no longer have a good eye), that would be surer.
Fortunately, there are several NPN eye specialists who can set us straight on this.
Anticipating them, a related question:
We should be using our 'reading glasses' part of the progressive lens (or our reading glasses) when focussing in Live view, right?
Barbara, I've been there too! I became so frustrated with the issue that I went out and got contact lens specifically to wear when out shooting. They were great .... except for the fact I forgot that with lenses corrected for looking through the viewfinder I couldn't see the camera controls!
I won't bore you with how the whole story played out but for the time being I've returned to wearing my progressive bifocals when shooting ... the lesser of two evils as it were. I feel your pain.
Posted by Dan Baumbach on June 1, 2009 at 10:19 AM
I wear progressive eye glasses and I've never experienced this problem. I believe that I look through the top part of my glasses when I focus. I still have to use the built in diopter correction on my D100, but I can focus correctly and the camera confirms my manual focus. I can also focus my 4x5 with a loupe with no problems.
Corrective lenses cannot make the image on the ground glass of an SLR look sharp if it's not. Use the camera's diopter correction to make sure you can see the camera's in finder read outs sharp and clear. Then you should be able to see the ground glass the same way.
Barbara,
I have used tri-focals for the last 15 + years. I was an interior architect in a previous life and I found that progressive lenses didn't give me the clarity that I needed. I used on camera correction in 35mm days. And even if it wasn't the most convenient, I put a cord on my glasses and dropped them down around my neck before shooting an image. With Digital, I make the adjustment to the diopter correction eyepiece, remove my glasses and then shoot away. It seems to work perfectly for my macro photography.
Good Luck and keep us posted.
Dave
Barbara,
I've worked in ophthalmology for about a decade now - retina mostly, but also 2 1/2 years in general ophthalmology. Dan is right, progressive lenses (multifocal) can not make anything in your viewfinder (or Live View for that matter) appear sharp when the lens is not in focus. This is because the camera is set on a plane of focus and your glasses will not be able to overcome that set plane of focus - no matter what their strength. The problem that I see all the time with my patients is that they choose glasses & frames based on "style" rather than function. I can't say that I blame them. They often choose frames that hold lenses that are very narrow (the height), and they don't get much "room to work" with their progressive lenses. You may want to consider getting standard bifocals for your photography, the top lens would be strictly for walking around & viewfinder work, and the lower portion (the readers) would be for liveview/lcd/camera controls. With progressive lenses, it can be difficult to get things in sharp focus quickly because you are constantly adjusting your head angle to find the sweet spot.
Dave Bartlett is also correct with using his diopter correction - but it is possible, that if you are like me, you have some astigmatic correction in your glasses.
Here's a quick lesson in refraction, I have always found that an educated patient makes better decisions. There are 3 corrective properties to any lens in optometry. Sphere, cylinder, and axis. The amount of sphere someone has corrects for myopia or hyperopia. Myopia (near sighted) means that the light rays that are passing through your cornea, your pupil and then your crystalline lens (or IOL if you've had cataract surgery) are being focused in front of your retina (the film of your eye). The Sphere correction in your lenses is being used to "push" the focusing point further back and onto your retina. With hyperopia (farsighted), it is the opposite - the light rays are being pushed too far back and things appear blurry because you can't bring the focused rays forward enough onto your retina. When we are young, most of us can "accommodate" - meaning our crystalline lens (where cataracts form) can flex enough to focus the rays on our retina. As we age, we lose this accommodative ability - this is called presbyopia. If you look at your glasses rx, the first column will be Sphere and your correction will be written with either a + or - in front of it. + means that you are hyperopic (far sighted) - so it takes a thicker lens to pull the light forward onto your retina, and - means that you are myopic (near sighted) and that the glasses are pushing the light backward onto your retina. "Cylinder" correction in glasses is to counteract astigmatism. Astigmatism is usually caused by your cornea not being perfectly round - and it makes light rays passing through it focus on multiple depths in front of and behind your retina. It twists and corkscrews the light, if you will. The larger the Cylinder power, the more astigmatism you have. The final number is the Axis - this relates only with the Cylinder power - it is the Axis of your Astigmatism correction. It is written as a degree (from 1-180) and helps to readjust the twist and distortion that your cornea is doing to the light rays.
So Wayne is right about the contact lens issue. Contacts are made for focusing at one distance - USUALLY. Some people can adjust to what is called "mono vision" - one eye wearing a contact that corrects for distance and the other eye wearing a contact that corrects for near/reading. This can be problematic though - I suggest you talk to your optometrist about this if it sounds interesting. For photography (especially nature) I don't recommend contacts. We are typically walking through areas with trees, tall grasses, branches, etc. and contacts don't protect your eyes at all. Just to correct one thing though - there is no such thing as progressive bifocals or trifocals. There are 4 main different styles of glasses with many subsets. Single vision - one lens built to focus at a single distance (generally made for reading, computer, or distance), bifocal - two lenses in the same frame (one for near vision and one for distance), trifocal - 3 lenses in the same frame (one for near, one for middle ground like computer or dash board, and one for distance), and multifocal/progressive lenses - these are glasses that get thicker the lower you look through the frame. Multifocal lenses are the most "flexible" lenses out there (meaning they can help you focus at more distances) but are also more difficult to get used to, because you are always looking for that sweet spot.
It is too bad that we can't find an easy way of correcting for astigmatism in the viewfinder. You can buy corrective and prescription diopters for many of the major camera manufactures out there, but they only correct for the Sphere part of the equation and not for your astigmatism. In theory, you could have these made to include a Cylinder correction, but as soon as you turn the camera to a vertical position you would be shifting your astigmatism correction 90 degrees - can you say vomit?
Sorry about the novel - I hope this helps some and confuses less. Please let me know if you have any questions.
If the camera is focused on your subject, and you see it in focus in your viewfinder, thru whatever part of your glasses lens, then the image recorded should be sharp. Your camera's AF may beep green when focused otherwise than you wish however, and your vision of the image must be the ultimate confirmation of focus, not the AF algorithm used.
If the camera is not focused, the image will not be sharp... and no adjustment of your eyeglasses (or your viewing angle thru them) can make the image either appear sharp in the viewfinder, or be sharply recorded.
The focus of your camera lens and the focus of your eyeglasses lens are cumulative, but the sensor (or film) only sees the camera lens part. Your glasses cannot make an OOF image appear sharp in the viewfinder. The key is for you to see the viewfinder image sharply thru your glasses. This is the only way you can determine before releasing the shutter that the camera is focused as you wish. The diopter adjustment should allow this for most users, but your corrected vision must be able to focus at the very short distance between your eye and the viewfinder image plane. If it isn't able to, you simply can't know what your camera lens is seeing.
If you see the image as sharp in the view finder, it IS sharp, and will be recorded so if the camera is functioning properly... (unless the camera and/or subject move during the exposure of course).
I am going to Proclear Multifocal Toric (soft contacts) after 35+ years with RGP (hard contacts) for a number of reasons including being able to focus my D80 AND being able to read its controls. Would you be so kind to give your experience/thoughts on these lens?
Note to others: Proclear Multifocal Toric Contacts were recommended for me since I have Myopia (near sighted), presbyopia and Astigmatism. They claim these are the only contacts that address all 3 issues. However they cost $560/year after a 20% discount.
Posted by David Taylor on June 2, 2009 at 12:20 AM
Hey Charlie-
I wish I could offer some insight regarding contacts - but I have primarily specialized in retina, which is the "ER" of eye problems. Things like ARMD (Age Related Macular Degeneration) and diabetic retinopathy are our main thing. I worked in general ophthalmology for a couple of years - but we generally dealt with eye disease and less with corrective lenses (contacts & glasses). So I have to preface my "advice" with that. I do think that multifocal contacts may be your best bet - just beware what I said earlier, contact lenses do not protect your eyes like glasses do. But, with your experience with long term wear of RGP's you will probably do fine. You will probably find them to be very comfortable and hopefully they will allow you to see well at multiple distances. Certain types of people adjust better to multifocal (glasses or contacts) better than others. Typically women do better with progressive lenses & monovision options, but every person is different. 2 rules, make sure you trust your optometrist (and follow their recommendations & follow up plans) & do NOT overwear your contacts. I don't care how good the box says they are for long term wear. Take them out every night and clean/condition them to the correct specs. Don't sleep in your contacts. EVER. I've seen doctors come in with eye pain because they slept in their contacts. They got an ulcerated cornea, required a transplant and some ever became fully infected and they lost an eye. I don't mean that they lost vision. I mean that they had the eye enucleated. You can probably guess how good a cardio-thoracic surgeon is without depth perception. These warnings are more for younger & newer cl wearers, you've been doing this for some time so you probably have good habits. I hope that your new contacts work well for you. All the best & let us know how they work out!
I've tried progressive lenses and they are frustrating at best to determine proper focus. Single focal length lenses are the answer for distance viewing. I just look under them to use the camera functions. I'm near sighted so this works well.
Discussion
10 repliesI am mainly talking about macro, flora focusing. Do others have this problem?
Leave your glasses on or take them off? I do have one good eye
Look through the upper part of the eyeglasses' progressive lens; that part is supposed to correct our vision for eye-is-focusing-on-infinity, and the viewfinder is designed to be looked at as if it were at 'infinity' distance. Now that you've made me think about it, it's quite possible that looking through the progressive lens too close to the upper edge will introduce inaccuracy because the progressive lens probably isn't ground accurately all the way to the top edge. (I know that my "computer glasses"--bifocals the upper part of which correct my vision for things about 30" away--have chromatic aberration: if I look straight at my monitor, lines near the side edges of the screen have a distinct purple fringe. I'm sure the retailer's answer would be "Well, you're not supposed to be looking out of the edges of your glasses!" It was disheartening to discover this real flaw in my eyeglasses.) So I guess we have to find out where the upper part of the progressive lens's prescription starts to drop off. If you have 20/20 vision in your good eye (I no longer have a good eye), that would be surer.
Fortunately, there are several NPN eye specialists who can set us straight on this.
Anticipating them, a related question:
We should be using our 'reading glasses' part of the progressive lens (or our reading glasses) when focussing in Live view, right?
I won't bore you with how the whole story played out but for the time being I've returned to wearing my progressive bifocals when shooting ... the lesser of two evils as it were. I feel your pain.
Corrective lenses cannot make the image on the ground glass of an SLR look sharp if it's not. Use the camera's diopter correction to make sure you can see the camera's in finder read outs sharp and clear. Then you should be able to see the ground glass the same way.
- Dan.
I have used tri-focals for the last 15 + years. I was an interior architect in a previous life and I found that progressive lenses didn't give me the clarity that I needed. I used on camera correction in 35mm days. And even if it wasn't the most convenient, I put a cord on my glasses and dropped them down around my neck before shooting an image. With Digital, I make the adjustment to the diopter correction eyepiece, remove my glasses and then shoot away. It seems to work perfectly for my macro photography.
Good Luck and keep us posted.
Dave
I've worked in ophthalmology for about a decade now - retina mostly, but also 2 1/2 years in general ophthalmology. Dan is right, progressive lenses (multifocal) can not make anything in your viewfinder (or Live View for that matter) appear sharp when the lens is not in focus. This is because the camera is set on a plane of focus and your glasses will not be able to overcome that set plane of focus - no matter what their strength. The problem that I see all the time with my patients is that they choose glasses & frames based on "style" rather than function. I can't say that I blame them. They often choose frames that hold lenses that are very narrow (the height), and they don't get much "room to work" with their progressive lenses. You may want to consider getting standard bifocals for your photography, the top lens would be strictly for walking around & viewfinder work, and the lower portion (the readers) would be for liveview/lcd/camera controls. With progressive lenses, it can be difficult to get things in sharp focus quickly because you are constantly adjusting your head angle to find the sweet spot.
Dave Bartlett is also correct with using his diopter correction - but it is possible, that if you are like me, you have some astigmatic correction in your glasses.
Here's a quick lesson in refraction, I have always found that an educated patient makes better decisions. There are 3 corrective properties to any lens in optometry. Sphere, cylinder, and axis. The amount of sphere someone has corrects for myopia or hyperopia. Myopia (near sighted) means that the light rays that are passing through your cornea, your pupil and then your crystalline lens (or IOL if you've had cataract surgery) are being focused in front of your retina (the film of your eye). The Sphere correction in your lenses is being used to "push" the focusing point further back and onto your retina. With hyperopia (farsighted), it is the opposite - the light rays are being pushed too far back and things appear blurry because you can't bring the focused rays forward enough onto your retina. When we are young, most of us can "accommodate" - meaning our crystalline lens (where cataracts form) can flex enough to focus the rays on our retina. As we age, we lose this accommodative ability - this is called presbyopia. If you look at your glasses rx, the first column will be Sphere and your correction will be written with either a + or - in front of it. + means that you are hyperopic (far sighted) - so it takes a thicker lens to pull the light forward onto your retina, and - means that you are myopic (near sighted) and that the glasses are pushing the light backward onto your retina. "Cylinder" correction in glasses is to counteract astigmatism. Astigmatism is usually caused by your cornea not being perfectly round - and it makes light rays passing through it focus on multiple depths in front of and behind your retina. It twists and corkscrews the light, if you will. The larger the Cylinder power, the more astigmatism you have. The final number is the Axis - this relates only with the Cylinder power - it is the Axis of your Astigmatism correction. It is written as a degree (from 1-180) and helps to readjust the twist and distortion that your cornea is doing to the light rays.
So Wayne is right about the contact lens issue. Contacts are made for focusing at one distance - USUALLY. Some people can adjust to what is called "mono vision" - one eye wearing a contact that corrects for distance and the other eye wearing a contact that corrects for near/reading. This can be problematic though - I suggest you talk to your optometrist about this if it sounds interesting. For photography (especially nature) I don't recommend contacts. We are typically walking through areas with trees, tall grasses, branches, etc. and contacts don't protect your eyes at all. Just to correct one thing though - there is no such thing as progressive bifocals or trifocals. There are 4 main different styles of glasses with many subsets. Single vision - one lens built to focus at a single distance (generally made for reading, computer, or distance), bifocal - two lenses in the same frame (one for near vision and one for distance), trifocal - 3 lenses in the same frame (one for near, one for middle ground like computer or dash board, and one for distance), and multifocal/progressive lenses - these are glasses that get thicker the lower you look through the frame. Multifocal lenses are the most "flexible" lenses out there (meaning they can help you focus at more distances) but are also more difficult to get used to, because you are always looking for that sweet spot.
It is too bad that we can't find an easy way of correcting for astigmatism in the viewfinder. You can buy corrective and prescription diopters for many of the major camera manufactures out there, but they only correct for the Sphere part of the equation and not for your astigmatism. In theory, you could have these made to include a Cylinder correction, but as soon as you turn the camera to a vertical position you would be shifting your astigmatism correction 90 degrees - can you say vomit?
Sorry about the novel - I hope this helps some and confuses less. Please let me know if you have any questions.
If the camera is not focused, the image will not be sharp... and no adjustment of your eyeglasses (or your viewing angle thru them) can make the image either appear sharp in the viewfinder, or be sharply recorded.
The focus of your camera lens and the focus of your eyeglasses lens are cumulative, but the sensor (or film) only sees the camera lens part. Your glasses cannot make an OOF image appear sharp in the viewfinder. The key is for you to see the viewfinder image sharply thru your glasses. This is the only way you can determine before releasing the shutter that the camera is focused as you wish. The diopter adjustment should allow this for most users, but your corrected vision must be able to focus at the very short distance between your eye and the viewfinder image plane. If it isn't able to, you simply can't know what your camera lens is seeing.
If you see the image as sharp in the view finder, it IS sharp, and will be recorded so if the camera is functioning properly... (unless the camera and/or subject move during the exposure of course).
Hth,
Kenn
I am going to Proclear Multifocal Toric (soft contacts) after 35+ years with RGP (hard contacts) for a number of reasons including being able to focus my D80 AND being able to read its controls. Would you be so kind to give your experience/thoughts on these lens?
Note to others: Proclear Multifocal Toric Contacts were recommended for me since I have Myopia (near sighted), presbyopia and Astigmatism. They claim these are the only contacts that address all 3 issues. However they cost $560/year after a 20% discount.
I wish I could offer some insight regarding contacts - but I have primarily specialized in retina, which is the "ER" of eye problems. Things like ARMD (Age Related Macular Degeneration) and diabetic retinopathy are our main thing. I worked in general ophthalmology for a couple of years - but we generally dealt with eye disease and less with corrective lenses (contacts & glasses). So I have to preface my "advice" with that. I do think that multifocal contacts may be your best bet - just beware what I said earlier, contact lenses do not protect your eyes like glasses do. But, with your experience with long term wear of RGP's you will probably do fine. You will probably find them to be very comfortable and hopefully they will allow you to see well at multiple distances. Certain types of people adjust better to multifocal (glasses or contacts) better than others. Typically women do better with progressive lenses & monovision options, but every person is different. 2 rules, make sure you trust your optometrist (and follow their recommendations & follow up plans) & do NOT overwear your contacts. I don't care how good the box says they are for long term wear. Take them out every night and clean/condition them to the correct specs. Don't sleep in your contacts. EVER. I've seen doctors come in with eye pain because they slept in their contacts. They got an ulcerated cornea, required a transplant and some ever became fully infected and they lost an eye. I don't mean that they lost vision. I mean that they had the eye enucleated. You can probably guess how good a cardio-thoracic surgeon is without depth perception. These warnings are more for younger & newer cl wearers, you've been doing this for some time so you probably have good habits. I hope that your new contacts work well for you. All the best & let us know how they work out!
Thanks for your advice. Appreciate it!!
Charlie