Diopter problem (1 Viewer)

Hi all,

I purchased a Nikon M7 8x30 4 months ago, and I think I might have a problem with the diopter setting. I sometimes spend time to do fine adjustment, let's say I set it to +1, and a few hours later, I have to change it to -1.

What do you think about it ? Is it a mechanical problem ? Or could it be related to my bad eyes (I'm a myope, and I wear contacts) ?

If I use a Bushnell 8x42, the diopter is set to 0 all the time... The 0 setting has never worked for me with the Nikon.

Does anybody have experienced this kind of problem ?

Sygus said:

Hi all,

I purchased a Nikon M7 8x30 4 months ago, and I think I might have a problem with the diopter setting. I sometimes spend time to do fine adjustment, let's say I set it to +1, and a few hours later, I have to change it to -1.

What do you think about it ? Is it a mechanical problem ? Or could it be related to my bad eyes (I'm a myope, and I wear contacts) ?

If I use a Bushnell 8x42, the diopter is set to 0 all the time... The 0 setting has never worked for me with the Nikon.

Does anybody have experienced this kind of problem ?

Click to expand...

Hello Sygus

It is best to not take the Zero and +1 or -1 etc markings too seriously. They are there for guidance rather than strict accuracy. So on my 8 pairs of binoculars, none of the dioptre settings are exactly the same although some are very close.

You should always set the dioptre by focusing on an object at roughly the same distance every time. If you set it by looking at something at 15m and then later check it at 1,000m then it would not be surprising if you need to change it. You know already that your eyes perform differently at different distances. It is best to set the dioptre at a distance that is +/- the average distance at which you observe. So 200m might be a good average between rather close and rather distant.

In your example where you set it to +1 and later have to change it to -1, what happens if you check it later or the next day? Do you have to change it back to +1 or do you have to go to -2 and later -3 and so on?

Lee

Hello Troubador,

Thanks for the response. Actually, I've find out that only 2 settings work for me with the Nikon : 1 setting on the + side, and 1 setting on the - side (there's no real +1 or +2 marks on the diopter ring, but I know where "my" settings are). The "0" is never ok and I never have to set further than my "+ setting" or my "- setting".

With a fine adjustment, I don't see differences related to distance. If the "+ setting" is the right one in a certain moment, it works for something at 15m and for something at 300m.

Also, when I check the adjustment when I'm home, I always spot on the same tree, through a window. In a certain moment, the "+ setting" is the right one, and a few hours later or the day after, I have to set to the - one. And I set it back to the + one later...

Sygus said:

Hello Troubador,

Thanks for the response. Actually, I've find out that only 2 settings work for me with the Nikon : 1 setting on the + side, and 1 setting on the - side (there's no real +1 or +2 marks on the diopter ring, but I know where "my" settings are). The "0" is never ok and I never have to set further than my "+ setting" or my "- setting".

With a fine adjustment, I don't see differences related to distance. If the "+ setting" is the right one in a certain moment, it works for something at 15m and for something at 300m.

Also, when I check the adjustment when I'm home, I always spot on the same tree, through a window. In a certain moment, the "+ setting" is the right one, and a few hours later or the day after, I have to set to the - one. And I set it back to the + one later...

Click to expand...

Sygus

OK. It definitely sounds like viewing at different distances is not the answer.

One way to determine if it is your eyes or the binoculars that are 'changing' would be to set your dioptre in the usual way and then put the bins down and don't use them for a few hours and then do the dioptre check again. If you need to change the dioptre again then it would sound as though your eyes are changing.

One thing is not clear: does it always happen that you set the dioptre to (for example) +1 and then later you need -1 and then the next time +1 and then the next time after this it is -1. Do you see what I mean? If you are always moving with every check of the dioptre from one setting and then to the other and then the next time you go back, this would be very strange indeed.

Lee

Thanks again for your help Lee.

Troubador said:

One thing is not clear: does it always happen that you set the dioptre to (for example) +1 and then later you need -1 and then the next time +1 and then the next time after this it is -1. Do you see what I mean? If you are always moving with every check of the dioptre from one setting and then to the other and then the next time you go back, this would be very strange indeed.

Click to expand...

I alternate between these two settings only (+1/-1), but I can't see a pattern. Sometimes I stick to +1 for the whole day, some other day I alternate 3 or 4 times.

Troubador said:

One way to determine if it is your eyes or the binoculars that are 'changing' would be to set your dioptre in the usual way and then put the bins down and don't use them for a few hours and then do the dioptre check again. If you need to change the dioptre again then it would sound as though your eyes are changing.

Click to expand...

Ok, I'll try that for a few days. I'll let you know.

Sygus said:

Hello Troubador,

Also, when I check the adjustment when I'm home, I always spot on the same tree, through a window.

Click to expand...

I have noticed that when my eyes are tired I try to accommodate by adjusting the diopter. Overall I have found the correct position on all my bins and it doesn't change. Looking at a pattern on a tree could trick the eyes as there is not much contrast. IMO it would be better to use a resolution chart like this one http://www.gpsinformation.org/jack/photo-test/pics/AF-TT-4x6.jpg

I normally use an old license plate propped up on my fence to adjust the diopter. It has letterings of different sizes with some color pattern and works well for me.

Thanks Subzero ! For the test that Lee suggested, I look at a street light. This is better for seeing contrast indeed.

I only used my bins to look at this light, for a week now, and I never had to change the diopter setting. That would suggest it's a mechanical problem...

Sygus - [QUOTE I only used my bins to look at this light, for a week now, and I never had to change the diopter setting. That would suggest it's a mechanical problem...[/QUOTE]

Not necessarily as those lighting conditions don't change, whereas when viewing in daylight there are changes happening all the time.

Over a number of years my eyes have developed the same problem. In my case probably due to age. At one time my general setting for the dioptre was 0 on the majority of binoculars, but now it can move up to 1.5 dioptre in either direction from a base setting of -1 dioptre. The change can happen in a random way - possible from three times a day to once every 3 days.

This is probably due to the eye muscles becoming less flexible so I have learned to live with it. It's certainly affected by the the lighting conditions and if I have been reading or using a screen. I also think that it is both eyes.

If it is your eyes, then I suggest that you forget about dioptre markings except to set it initially to the centre of your range so that you won't be far of any setting you require. Then just adjust it when you feel it has changed. You will find that after a short time you will do this as normal. Don't become obsessed with the markings on the dioptre ring - your eyes will tell you the setting you need

I know that many people set their dioptre and never change it as l did, but l wonder how many also think that once set, it never needs to be changed when in fact, in their case, it might well need to be changed.

In order to check if it is your binoculars I suggest that you really need to try to borrow some other binoculars to see if it happens with those.

Stan

Stan,

Your statement that "If I use a Bushnell 8x42, the diopter is set to 0 all the time." suggests it's the 8x30 Nikon at fault. The consistent +1/-1 setting is so weird though--hard for me to imagine a mechanical problem that would do quite that.

Lee's advice, "One way to determine if it is your eyes or the binoculars that are 'changing' would be to set your dioptre in the usual way and then put the bins down and don't use them for a few hours and then do the dioptre check again. If you need to change the dioptre again then it would sound as though your eyes are changing." is very good. I can't imagine a mechanical problem where the mechanism would slip while the binocular was left to lay undisturbed.

Ron

I had a similar problem with a pair of binoculars about a year ago, it turned out that I had adjusted the ipd for comfort rather than optical accuracy - I don't get on with large eye cups. Fundamentally one or both eyes were not centred correctly, add in my lack of optical accomodation and that was enough to cause the problem. It was perhaps good that they didn't blackout when not perfectly aligned, but in this case it would have helped.

It took a fair amount of self discipline to get used to using my eyes rather than the shape of my skull to adjust and use those bins.

Can't remember which ones they were now, as I have cut down on the bins I use, but not my Nikons, my EIIs are fine. I havn't had that problem with any other binocular.

My eyesight has changed over the last 20 years so that most bins are now set to 0 dioptre adjustment, rather than one click off which simplifies things.

ronh said:

Stan,

Your statement that "If I use a Bushnell 8x42, the diopter is set to 0 all the time." suggests it's the 8x30 Nikon at fault. The consistent +1/-1 setting is so weird though--hard for me to imagine a mechanical problem that would do quite that.

Click to expand...

Please can you tell where l said that?

Stan

iveljay said:

I had a similar problem with a pair of binoculars about a year ago, it turned out that I had adjusted the ipd for comfort rather than optical accuracy - I don't get on with large eye cups. Fundamentally one or both eyes were not centred correctly, add in my lack of optical accomodation and that was enough to cause the problem. It was perhaps good that they didn't blackout when not perfectly aligned, but in this case it would have helped.

It took a fair amount of self discipline to get used to using my eyes rather than the shape of my skull to adjust and use those bins.

Can't remember which ones they were now, as I have cut down on the bins I use, but not my Nikons, my EIIs are fine. I havn't had that problem with any other binocular.

My eyesight has changed over the last 20 years so that most bins are now set to 0 dioptre adjustment, rather than one click off which simplifies things.

Click to expand...

I have always set my binocular IPD by view and not by eye IPD. However, when I have checked the measure after having used the binoculars, the IPD's are the same anyway.

l have just checked my wife's Nikon M7 8x30 and have no problem setting the IPD by view or measurement and they are both the same.

My problem is definitely to do with the eyes, so all I am suggesting to Sagus
is that he should not assume that his problem is the binoculars.

Stan

My Canon 18x50 IS has neither had the dioptre or the focus changed in about ten years, even though my eyes have changed a little. I use it only for distance observation.
Similarly the PST H alpha telescope has never had the focus or wavelength setting changed in over ten years.
I use the curved field of the 12.5mm Kelner eyepiece for fine adjustments.

I think it is because of the Canon 2.8mm exit pupil and f/10 for the scope.

My dioptre does change over the day, but not enough to affect the above two instruments.

Stan,
I'm sorry, you did not say that. The original poster, Sygus, did.

Sygus,
I meant my comment for you.

Ron

Stanbo said:

Not necessarily as those lighting conditions don't change, whereas when viewing in daylight there are changes happening all the time.

Click to expand...

By street light I meant a street lamp (sorry for my poor english). So yes, I use the bins in daylight, at different times of the day, with different lighting conditions (sunny / cloudy...).
I haven't touched the focus knob for more than a week, and the diopter adjustment is still ok...

ronh said:

Your statement that "If I use a Bushnell 8x42, the diopter is set to 0 all the time." suggests it's the 8x30 Nikon at fault. The consistent +1/-1 setting is so weird though--hard for me to imagine a mechanical problem that would do quite that.

Click to expand...

ronh said:

Sygus, I meant my comment for you.

Click to expand...

Yes, I figured
That's odd indeed. Could this problem be related to a loose lens, or to the focusing system ?