vision and focus

[sleith]

The diopter isn't strong enough for me to judge focus in my Nikon D800. It is no fun trusting auto focus when things don't look sharp and wearing bifocals to look through the viewfinder is difficult. I may try contacts and I did purchase a stronger diopter (which I confess I can't figure out how to change!) -- anyone with vision problems figure this out? Any suggestions? -- bifocal contacts - new diopter (which of course means I still need glasses on to see camera functions and glasses off to look through viewfinder). A conundrum.
PS - I am new not only to this forum but all forums - yes a forum virgin -- so if I'm not doing this right please advise:) and thank you for any help.

[HenkB]

I did purchase a stronger diopter (which I confess I can't figure out how to change!) -- anyone with vision problems figure this out?

I live right at the edge of this problem but have not exceeded the viewfinder compensation... yet. The D800 has a screw mount on the viewfinder. You should be able to remove the rubber eyecup, remove the planar element and insert the corrective element in its place. Lesser cameras have a flange mount that allows you to remove eyecups, etc by sliding up and off. The two sorts of attachments are not directly compatible.
Welcome to CiC, than which there is no better. You chose well. If you fill in your name, we will be able to address you more personally than just "you".

[GrahamS]

There have been some amazing advances and innovations in the design of contact lenses recently. This is from a manufacturers website:

quote:
What do “Simultaneous Image Design” and “Alternating Image Design” mean?
These are two of the different types of concentric bifocal pattern
lenses for bifocal and multifocal lenses.
• Simultaneous Design:
Puts the near and far portions of the lens in front of the pupil at
the same time, which makes the brain have to determine which parts of
the lens to use to get the best image resolution.
• Alternating Image Design:
This is the most similar to the bifocal and multifocal glasses
currently available and uses the bottom portion of the lens for the
near vision and the top portion of the lens for the distance vision.
The two parts of the alternating lens is separated by an almost
invisible line that your eye care provider uses to determine if the
lens is fitting properly.

From <http://www.visiondirect.com/bifocal-...ocal/qxc150586>
end quote

[sleith]

thank you - I am able to remove the rubber eyecup but not sure how to change the glass - do you turn it, pull it or ???? and my name is sue - I'll be sure to add it to the profile.

[sleith]

Has anyone had experience with different (multi vision) contact lenses and use with cameras? My eye doctor is recommending a type that has near focus in the center and distance focus outside and all around - but the post I just read has top and bottom. So many choices - I sure miss all those years I didn't need glasses!

[HenkB]

Taught by bitter experience, once having removed the eyecup by unscrewing it, I would have expected the planar glass to simply fall away.

[sleith]

I was a little afraid of damaging the camera as nothing seemed obvious after removing the eyecup.

[GrahamS]

If I remember correctly, the eye-piece lens does not come away - the corrective diopter screws in as a supplementary lens. There is also a choice of different eye-cups.

[jcuknz]

If I had this problem I would fall back on my answer for numerous problems/needs and buy myself a pair of plastic hobby glasses and immediately would probably have enough extra dioptres to simply stick onto the existing 'dioptre' lens. Extra thickness of the viewfinder shouldn't be a problem if wearing glasses as it would bring the viewfinder closer to your glasses. the plastic is easilly cut and sanded to suit the need.

Since you have bought another lens why not just place it over the existing lens and see if you can organise a setting which enables you to see a sharp image before fixing it in place.

With dioptres adding a +1 to a +2 gives you a +3 lens etc.

[tao2]

apologies if yev tried this already...

Turn the existing dioptre piece all the way counterclockwise - minus 4/5 or whatever. Don't wear yer glasses! Turn the wheel one click at a time, half-pressing the shutter button tae achieve focus each time, until focus/vision is correct (or not).

If that doesn't work, add the additional dioptre piece (it'll either screw in or push on (see your instruction manual). It'll work one of three ways, either...

1) Turn the existing dioptre back tae zero on the scale, then add the new piece and adjust 'til it's correct or-

2) Turn the original dioptre back tae fully anti-clockwise(minus 4/5 etc.) then insert the new one and adjust.

3) Turn the existing dioptre fully clockwise (+ max) then add and adjust the new piece.

The 3 methods above are for very fine tuning, as ye may find that the "correct" setting needs tae go up or down , one or even two steps either way. If ye know the dioptre setting for your viewing eye, it's even easier. Turn the existing dioptre fully clockwise(say +1.5) then, adding the new piece, turn the stops 'til your dioptre no. is achieved . i.e. If yer eye setting is +2.5-3, then ye'd need an additional 2-3 clicks etc.(settings are usually, incrementally, one click= one half )

The additional dioptre in my Sony ( a push-on type, the original piece left in situ) is strong, as ah use my left eye and it's very weak. With the Sony, ye turn the adjuster fully clockwise then adjust 'til correct. Ah don't need my varifocals for focusing nor for reading the viewfinder info; though, of course, my glasses sit on the top of my head (where they should be) for viewing/ adjusting camera functions.

[DanK]

I looked I to this recently but gave up. If you are substantially astigmatic, dioptric adjustment won't be enough. I had read about custom-ground diopters that can adjust for astigmatism, but I could not locate any. Moreover, an adjustment for astigmatism would not work if you rotate the camera. So, I gave up and continue to use my glasses. The biggest disadvantage is not seeing the entire frame.

Re bifocals: I don't find that an issue. I use the distance portion of the lens.

[tao2]

I looked I to this recently but gave up. If you are substantially astigmatic, dioptric adjustment won't be enough. I had read about custom-ground diopters that can adjust for astigmatism, but I could not locate any. Moreover, an adjustment for astigmatism would not work if you rotate the camera. So, I gave up and continue to use my glasses. The biggest disadvantage is not seeing the entire frame.

Re bifocals: I don't find that an issue. I use the distance portion of the lens.

If you are substantially astigmatic, dioptric adjustment won't be enough.

Ah'd say this...[IMG][/IMG]
was "substantially" astigmatic. As said above dioptric adjustment works for me - horizontally and vertically.

[sleith]

I confirmed again that original diopter is just not strong enough, then spent another half hour trying to take the old diopter glass out so I could try the higher magnification - i twisted, turned, pushed etc and cannot figure out how to remove anything but the rubber eyecup.... and can't find anything in the manual that helps so I checked other people who changed diopters (at BH Photo) and read several who commented on the ease of it all -- sigh --- I think I may have to take it to my local camera repair before I really screw things up. I've already ripped the rubber eyepiece after my 3rd time removing that.

I really appreciate all the help and suggestions I received from this forum, wow - amazing how helpful this site is ---- but I don't seem to be able to figure it all despite your (generous) wisdom.

[shreds]

Sue,

My Nikon D3 has a locking button adjacent to the eyepiece which needs to be unlocked by flipping to the left, and then the eyepiece itself simply unscrews anti clockwise. It is well documented in the manual, although I found out first then read the manual afterwards, like most folk!

I am hoping that being relatively high end Nikons, the process might be similar?

Yup. Manual looks identical. P36.

http://www.nikonusa.com/pdf/manuals/dslr/D800_EN.pdf

[sleith]

OMG It worked and I can see in focus again! You absolutely made my day -- thank you thank you thank you!!!! (and yes I feel a bit stupid for not finding that in my thousand page manual but I'm so happy I don't care

[shreds]

Hey Sue,

None of us read the manuals, that was why I used to make good money running photo courses.

It was always the first question and nobody ever had read them. Far easier to talk to someone who knows and can explain it like a human being! So don't feel stupid, no question ever is, and more to the point you can focus properly now!