• Welcome to BirdForum, the internet's largest birding community with thousands of members from all over the world. The forums are dedicated to wild birds, birding, binoculars and equipment and all that goes with it.

    Please register for an account to take part in the discussions in the forum, post your pictures in the gallery and more.
ZEISS DTI thermal imaging cameras. For more discoveries at night, and during the day.

Diopter Setting Consistency (1 Viewer)

P

pechelman

Active member
Has anyone noticed that they may have a different diopter setting from one pair of binoculars to another, or is it just me?

Even within the same brand \ line of binocular I find slight differences. Of course there are build tolerances to take into account, so that could explain the slight difference. However, what is most curious to me, is that some diopters have me firmly in the + side (e.g. habichts) while others in the - side (zeiss dialyt & 8x25 victory). I'm usually about +/-.7 from the zero marking on all of them.

Overall this surprises me as Id expect consistency in this setting from experience with other types of optical devices that sell individual screw on diopter correction lenses, and one needs to know their Rx before ordering. Then again, i dont see why it should matter if the setting is easily adjustable like on a binocular. But to be on either side of zero?

Not really worried about anything, just curious and wondering if others might share their experience with this.
 
pechelman said:
Has anyone noticed that they may have a different diopter setting from one pair of binoculars to another, or is it just me?

Even within the same brand \ line of binocular I find slight differences. Of course there are build tolerances to take into account, so that could explain the slight difference. However, what is most curious to me, is that some diopters have me firmly in the + side (e.g. habichts) while others in the - side (zeiss dialyt & 8x25 victory). I'm usually about +/-.7 from the zero marking on all of them.

Overall this surprises me as Id expect consistency in this setting from experience with other types of optical devices that sell individual screw on diopter correction lenses, and one needs to know their Rx before ordering. Then again, i dont see why it should matter if the setting is easily adjustable like on a binocular. But to be on either side of zero?

Not really worried about anything, just curious and wondering if others might share their experience with this.
Click to expand...

You are not “+/- .7.” They are just letting you know the range of the bino’: -7 diopters to +7 diopters. Also, it is fairly easy to see slight discrepancies, especially in less expensive instruments. I doubt you will see much in better quality instruments. It should be remembered that YOUR eyes will change a bit from day to day or even hour to hour. That’s just part of being human. Slight changes will occur because of what’s in your system and how you are feeling. Changes may be caused by:

Being tired, sleepy, fatigued, or ill. It could be caused by alcohol, caffeine, over the counter drugs, or even ... too much or not enough water. :cat:

Bill
 
Often there is no consistency even within the same line of binoculars. According to my experience the Swaro SVs are among the few binocular lines for which there is almost perfect consistency: you simply set the diopter to the value from your eye prescription and you are good to go. What's more there is not only consistency between different SV binoculars, but also the scale of the diopter compensation knob accurately indicates the true diopter value.
 
Last edited:
You are not “+/- .7.” They are just letting you know the range of the bino’: -7 diopters to +7 diopters
Click to expand...

The OP said 0.7 not 7; anyway -7d to +7d would be a huge range, and I am unsure there is any bino with such a compensation interval.
 
"you simply set the diopter setting to the value from your eye prescription and you are good to go."

That is only COMPLETELY TRUE if you live in a perfect world, are a robot, or have superman's control of your body. The deviation should definitely be slight AND your dioptric accommodation might make it imperceptible, but that's more a feature of biology than mechanics.

I am aware of what the OP said. That's why I gave it quotes. However, I just ignored the "." because I have never seen such a designation.

Bill
 
Last edited:
I always set the diopter compensation by using the standard method (left eye, right eye etc), but what I found out is that for all the SV binoculars that passed thru my hands the so obtained value coincided with the value in my eye prescription! That's my real experience in an admittedly imperfect world....
 
Thanks everyone for their replies. I can appreciate what is being said. Being aware that the human eye changes day to day, I still find it curious that on some binoculars I'm firmly in the minus range while on others in the plus range. And on those same binoculars, my setting required to get two focused images to each eye never varies much (or at all) day to day.

The use of a decimal in this case indicates a fraction of a turn to a full tick mark, which I have been assuming is equivalent to + or - 1.0. I have seen fractional diopter values listed by a well regarded optics manufacturer, listed as a decimal value, so I carried it along here. By saying I am "+/-.7" physically means that on ALL of my bins, my settings vary from within about ~three quarters of a rotation required to reach the first tick mark, on either side of the 0 indicated. And before we get into more semantics, yes, I am aware that three-quarters is not the same as .7, but i thought it might be a bit obnoxious/improper to say +/-.75 since I really dont have that much certainty in this "measurement".

Either way, sounds like I have my answer and my curiosity has been satisfied: There's little consistency for others as well.
 
Last edited:
I think it was meant to be +/-0.7 dioptres.

Some of the good binoculars, such as my Leica 8x32BA seem to have been set up very accurately.

But, yes, one's eyes change particularly with age and tiredness.
For, astronomy, even when young, I would go away for a minute and then refocus. It would nearly always be different to the previous setting.

On the other side, with age, accommodation decreases, so one needs to refocus quite often, and very accurate settings are useful.
Cheaper binoculars can have a lot of backlash, and are almost never correct anyway.

Some binoculars do indeed have +/- 7 dioptres available but usually only 5 or 4 is marked, with degree slashes, but stopping at about 5.

P.S.
The Leica correction lenses are marked 0.5 not .5
Minolta also have 0.5 correction lenses, not .5

P.P.S.
Maybe the Indians invented the zero, before a zero was in fact a dot, but I cannot remember who originally used these.
Before the zero or dot, it was difficult to make and record calculations.
 
Last edited:
PeterPS said:
I always set the diopter compensation by using the standard method (left eye, right eye etc), but what I found out is that for all the SV binoculars that passed thru my hands the so obtained value coincided with the value in my eye prescription! That's my real experience in an admittedly imperfect world....
Click to expand...

Hi, Peter:

You should definitely go with the prescription but that is only a solid AVERAGE AT THE TIME OF THE EXAM. You can’t go wrong if you realize it is only an average. If at 2 p.m. Friday, your optometrist gave your right eye a reading of -2 diopters and Saturday morning a reading of -2 diopters gave you a fuzzy image in that eye and you had to opt for turning the diopter ring to -1.5 diopters ... the world is still a good place to live and you are still entitled to a birthday because within a few hours you will undoubtedly be back to—or at least, passing through— -2 diopter land. This is covered fairly well on pages 24-26 of a book I know.

Also, keep in mind that the “standard method” is not ALWAYS the standard. A tiny sliver of instruments—the Steiner Peregrine for example—focuses RIGHT EYE FIRST. Yep, there’s one in every crowd. :cat:

Cheers,

Bill
 
Binastro said:
P.S.
The Leica correction lenses are marked 0.5 not .5
Minolta also have 0.5 correction lenses, not .5

P.P.S.
Maybe the Indians invented the zero, before a zero was in fact a dot, but I cannot remember who originally used these.
Before the zero or dot, it was difficult to make and record calculations.
Click to expand...

Good observation. Since a diopter is a unit of measurement in the metric system, it is standard to list the preceding zero. In standard/inch, it is directed by ASME/ANSI to omit the preceding zero. Since my head is usually buried in the standard/English/inch system, it was my fault for omitting that zero. While .5 does equal 0.5 most days, it may denote a difference to someone. Thanks for pointing that out.
 
In the past, I found very few inexpensive bins with the diopter properly calibrated at the zero setting, so I had to find the best setting by trial and error, and I then marked it with an extra fine point Sharpie (marker) for future reference.

In the present, I look at very few inexpensive bins, so I don't know if they've improved or not. When it comes to high-end bins, I find extremely little if any variation. Swarovski, Zeiss, Leica, Nikon top-end models seem to be properly set at the factory so that zero is zero.

I find that my best diopter setting _doesn't_ shift unless my prescription shifts. It doesn't shift from day to day or hour to hour. Thank goodness, or else I'd also need different glasses prescriptions! However, when my eyes are tired, or one is strained differently from the other (e.g. if I succumb to the bad habit of looking through a scope too long with one eye squinted shut), or are watering from cold/wind, I can be fooled into thinking that I benefit from a diopter adjustment. Yes, a different diopter can help a temporarily gimpy or watery eye, but I resist making such changes because the benefits are ephemeral and they only serve to impede getting my eyes back in synch and properly functioning.

--AP
 
I don't think being either side of 0 is of any special significance, if the real issue is just calibration of the dial itself. Like you I've always found myself near 0, usually a notch -, but on my old Trinovid BNs I was several notches +! I didn't care, just noted that for when I got it back after lending to someone else. When I finally had to send them in for service (after many years, a black spot of something got onto an internal lens) I mentioned this issue also, and they came back recalibrated better.

For what it's worth, I never have to adjust the diopter for myself from day to day once set. Only once when I was trying a bino with a physical defect, slippage in the diopter mechanism when focusing.
 
tenex said:
I don't think being either side of 0 is of any special significance, if the real issue is just calibration of the dial itself. Like you I've always found myself near 0, usually a notch -, but on my old Trinovid BNs I was several notches +! I didn't care, just noted that for when I got it back after lending to someone else. When I finally had to send them in for service (after many years, a black spot of something got onto an internal lens) I mentioned this issue also, and they came back recalibrated better.

For what it's worth, I never have to adjust the diopter for myself from day to day once set. Only once when I was trying a bino with a physical defect, slippage in the diopter mechanism when focusing.
Click to expand...

Methinks before there is a pile-on debunking what I said, I had better explain more thoroughly. SOME people may set their focus to their prescription and never look back. SOME OTHER folks may find themselves fiddling with the focus quite frequently. We are all different and have different sensitivities to focal shift.

A 10-year old may have as much as 14 diopters of accommodation, a 40-year old may top out at 4 diopters, and a 60-year old will PROBABLY top out at about 2 diopters. These are clinical test averages and not something pulled out of the air. Some claim a healthy eye will dilate to 7-7.1 millimeters, Yet, some youngsters will dilate to 9 millimeters. Also, an 80-year old SHOULD have no greater pupil than about 2 mm. But, some octogenarians will dilate past what their grandkids are mustering. In optics, “one size never fits all.”

Yep, some folks can “set and forget” their focus. That does not mean, however, their best and most relaxed focus remains constant, for that is rarely the case. It just means they are easily accommodating for those minor differences. There ... I feel better, now. :cat:

Just a thought,

Bill
 
I couldnt tell you what any of mine are set on, it's of no importance to me. I adjust it until I hit the best vision for me then it is hardly ever touched again. Theres just too many variable for me to try to make sure it's perfect. Between allergies, dust, wind and wearing lineless bifocals, it takes too long for perfection.

This is kind of like the reason BMW took the pounds per square inch markings off of oil pressure gauges a few years ago. Owners getting together and then complaining to the dealer if all of their pressures werent exactly the same.
 
perterra said:
I couldnt tell you what any of mine are set on, it's of no importance to me. I adjust it until I hit the best vision for me then it is hardly ever touched again. Theres just too many variable for me to try to make sure it's perfect. Between allergies, dust, wind and wearing lineless bifocals, it takes too long for perfection.

This is kind of like the reason BMW took the pounds per square inch markings off of oil pressure gauges a few years ago. Owners getting together and then complaining to the dealer if all of their pressures werent exactly the same.
Click to expand...


Of course, you would say that ... you're from Texas. Not only that ... from WEST TEXAS.

The Navy taught us to set them accurately and for a very good reason. BUT, I do as you do and have never missed a birthday because of it! :cat:

Bill

PS "dust, wind" ... in west Texas ? ... Nah, can't be!
 
Last edited:
WJC said:
Of course, you would say that ... you're from Texas. Not only that ... from WEST TEXAS.

The Navy taught us to set them accurately and for a very good reason. BUT, I do as you do and have never missed a birthday because of it! :cat:

Bill

PS "dust, wind" ... in west Texas ? ... Nah, can't be!
Click to expand...

Probably more north central than west, but I can see west Texas from here, and for ever wind from the west, we get a little more west Texas deposited here.
 
perterra said:
Nah, west of Dallas.
Click to expand...

Well, that's close enough for Government work to be called West Texas.|=)|

I adjust the diopter on my 1st use and after that I never think of it again - really don't know why I adjusted on my 1st use, as the focus knob always works great - could be my father talked about it many decades ago - anyway, I haven't found it necessary to do very many times in my life.
 
JoeJ said:
Well, that's close enough for Government work to be called West Texas.|=)|

I adjust the diopter on my 1st use and after that I never think of it again - really don't know why I adjusted on my 1st use, as the focus knob always works great - could be my father talked about it many decades ago - anyway, I haven't found it necessary to do very many times in my life.
Click to expand...

It is not critical to most people and most of the folks who get wrapped around the axle wanting to be certain they are EXACTLY at their prescription settings are unaware that THAT setting changes in small increments over large or small amounts of time and it is only their individual dioptric accommodation that makes the differences imperceptible.

Knowing your diopter setting remains the same from binocular to binocular is especially important for watchstanders on a warship in the middle of the ocean at midnight. That way, a person can be confident that the tiniest speck of light will be visible at the greatest possible distance. This could mean seconds more preparation time for an antiaircraft crew.

Bill

PS Isn’t the Dallas/Ft. Worth area part of Arkansas? :cat:
 
Last edited:
Warning! This thread is more than 6 years ago old.
It's likely that no further discussion is required, in which case we recommend starting a new thread. If however you feel your response is required you can still do so.

Similar threads

G
Leica, Zeiss & Swarovski binoculars compared: A personal report
2 3
Replies
42
Views
3K
Paultricounty
P
T
Zeiss SF 8x30 vs SFL 8x40
2
Replies
21
Views
1K
tian1227
T
chill6x6
SFL vs. Aurora...
Replies
6
Views
1K
chill6x6
chill6x6
D
Recommendation for a binocular
Replies
6
Views
407
MiddleRiver
MiddleRiver
R
Glare on the Habicht 8x30
2
Replies
25
Views
2K
Rg548
R

Users who are viewing this thread

Total: 2 (members: 0, guests: 2)
Back
Top