[14Goudvink]

I just received a second hand Vortex Viper non-HD and noticed a few things. With the diopter set at zero and after finding the sharpest view with the focus wheel the left hand barrel was in sharp focus but the right hand barrel was fuzzy. So I adjusted the diopter (on the right barrel) and found a sharp focus with the right side as well. To get this sharp focus I had to turn the dioper quite a bit from the zero position.

I use glasses and with other bins I set the diopter at zero and that's it. Somebody know why the zero diopter setting doesn't work for me with these bins? Could there be something wrong with them?

Thanks,


George

[FrankD]

I have run into this many times before. It is usually the result of the diopter not set correctly at the factory. As long as it doesn't continually change position you should be fine.

[14Goudvink]

Thanks, Frank, that is reassuring, much appreciated.

[Cluster]

Several of my past bins are like this, odd and sometimes apparently large differences in dioptre adjustment.
For fun, you could try to focus on something with your left eye in the left eyepiece and then look through the right eyepiece with your left eye and adjust the focus using the dioptre (for bins with a RH dioptre). The result "should" give neutral focus on both the right and the left and so the dioptre should be at Zero. Few of my cheaper bins do, so they were out when they were new.....

Dave

[Pileatus]

The easiest way to set a diopter is to start at 0 and see how things look. Then, after a short period of use, add (+) a bit of diopter and see what it does to the overall view. Obviously, if the view worsens you should return to 0 and start over. Add some minus (-) and see if the overall view improves. You can add/subtract as much diopter as you need...but do it incrementally.

The trick is to use BOTH eyes in a completely natural manner and give your eyes enough time to relax between trials. Closing one eye causes eyestrain and trying to set the diopter as you look through both eyepieces may not be very relaxing. I could set the diopter with both eyes open on my Leica Ultravid but, due to the inevitable lag in my accommodation, it just never came out right. My trial and error method solved the problem.

I can sense a change in sharpness with the smallest change in diopter. It's worsened as my eyes age but, thankfully, there are bins with extremely sharp images. I think deteriorating eye accommodation is a major reason why alpha bins sell so well to older birders. In my opinion, it's just easier to maintain eye comfort with a bin that starts out deadly sharp. I call it the OW (Optical Workload) factor and I want it as low as possible.

FWIW...
My current SE is generally set at 0. If I use my wife's SE I add a bit.
My Leica required about half a diopter and my SV requires a bit more.
Interestingly, new (and darn near perfect) eyeglasses required me to add diopter to both the Leica and the SV. My SE remained about the same. I guess the point is forget about ZERO diopters and set each bin accordingly.

PS
How many binocular reviews are corrupted by improperly set diopters? My guess is more than a few.

[brocknroller]

I, too, have noticed that the bins I've owned or tried varied in where I needed to set the diopter. Most work for me at either 0 or +1. One bin had to be set at +2, another needed to go the opposite direction to -1.

One of the two Obie 15x70s I had wouldn't come to focus even at +4, so I turned it a bit farther since there was a bit more travel and the rubber eyecup and housing came apart in my hands (the housing wasn't made of metal, but of cardboard! Crap!). Sent it back for a refund.

As long as you have enough diopter travel to accommodate your eyes and others who use the bin, it should be fine. But if the diopter starts to "creep" and you find that you need to change the setting farther out than you had before, it needs repairs, because it's just going to get worse until the diopter setting is above/below the range of your eyes and you won't be able to focus that barrel. That already happened to me on one bin.

<B>

[brentwood]

You often find this on used & nowadays on new ones as well. If it bothers you, it can easily be fixed . The barrel that is imprinted with the diopter is normally attached with just 2-3 screws tightened to the inner barrel. Often these screws are hidden beneath a screw off finish ring or a rubber eye guard. Loosen, don't remove, these screws. The outer barrel can now be easily rotated to the zero mark & then retightened. You cannot wreck anything, unless you drop & lose one of the screws!

[Simon S]

Focus on a star with the side without the dioptre then with the same eye and 0 set on the other side see if the focus remains sharp.

[14Goudvink]

Thanks for all the insights, I never thought there was so much to know about a dioptre setting :-)

Simon
I just did your test, not with a star (haven't seen a star for days) but with bricks on a building at a distance of about 450 meters. Looking with my left eye (my best, but non-dominant one) the focus remained sharp. The previous test I did in the classic way:
> cover right hand objective (the dioptre ring is on the right hand ocular);
> focus;
> cover left hand objective and achieve perfect focus with the dioptre ring.

Other bins I have used or still use are perfect at dioptre 0: Leica Trinovid and Ultravid, Swaro 8x32 SV, Nikon 10x42 SE.

What does this tell me about the Vipers? Or about my eyes (or brain)?

George

[ceasar]

My diopter setting is minus 1 or close to that. Sometimes it will change subtly which is why I prefer a right eye diopter over the new modern diopter integrated into the focus wheel.

Once in a while I get a binocular that requires a different setting. My 10 x 32 LX L is one of them. My diopter setting on that particular binocular is slightly less than plus 1. It never bothered me and I used that particular binocular hard for several years. I upgraded it to a new Nikon 10 x 32 EDG and my diopter correction on that one went back to minus 1 where it has stayed for 2 years now.

Bob

[LPT]

"To get this sharp focus I had to turn the dioper quite a bit from the zero position."
If you have to turn the diopter adjustment so far from the 0 setting that it can't be turned practically any farther, there may be a problem with focal lengths. The view may be okay but the objective lens or oculars are not not spaced correctly and should be adjusted if possible. However, if the the diopter can still be turned quite a bit in either direction and if, after adjustment the right and left eyecups are reasonably level with each other, there is no problem and no reason for concern.

[Simon S]

As LPT says, the binoculars are faulty. The dioptre should be at "0" when they are at the same focal length.

[14Goudvink]

I'm a bit confused. Doing the test Simon suggested the focus remained sharp (see post number 9). This would suggest the bins are good???

It is only when I adjust the diopter in the 'normal' manner (see post number 9 for a description) that I have to set the diopter away from zero to get the sharpest view. With other bins 0 is my best setting. This would suggest the bins are faulty???

As to LPT's post: I do have to set the diopter quite a bit from 0 to get the best view, but the diopter can still be turned farther. The best setting for me is about halfway between 0 en the fartherst setting possible. This would suggest the bins are good???

I'm a bit lost...

[LPT]

Originally Posted by 14Goudvink

I'm a bit confused. Doing the test Simon suggested the focus remained sharp (see post number 9). This would suggest the bins are good???

It is only when I adjust the diopter in the 'normal' manner (see post number 9 for a description) that I have to set the diopter away from zero to get the sharpest view. With other bins 0 is my best setting. This would suggest the bins are faulty???

As to LPT's post: I do have to set the diopter quite a bit from 0 to get the best view, but the diopter can still be turned farther. The best setting for me is about halfway between 0 en the fartherst setting possible. This would suggest the bins are good???

I'm a bit lost...

If after setting the diopter it can still be turned a reasonable bit in both directions then it sounds like the bins are good with no focal length problems. As I think somebody mentioned before the scale could be loosened and reset so that its center mark is closer to zero but this is not really very important more cosmetic than anything else. Sounds like the binoculars work ok and there's nothing to worry about.

[14Goudvink]

Thanks, I rest reassured :-)