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Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: May/14/2008 at 15:49
jeremill View Drop Down
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I also have a pair of Steiner Predator Pro 10x26 and have noticed with extended viewing I experience severe eye fatigue.  Is this because I have astigmatism, the magnification or is this a problem with Steiner lens.
 
 
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Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: May/14/2008 at 18:37
lucznik View Drop Down
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Most likely it is because you are using a 10x26 (with its very small 2.6mm exit pupil) for extended viewing. 

Although all of the issues you address can exacerbate the problem, in reality any binocular with such a small exit pupil regardless of brand, magnification, and/or your eyesight issues, is going to give you eyestrain if you use it for extended viewing.

You need to get yourself a quality binocular sporting at least a 4mm exit pupil.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: May/14/2008 at 18:48
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I would add get away from the Steiner, they are just sub par optics anyway.  There are lots better options out there for better prices.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: May/15/2008 at 10:49
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Originally posted by supertool73 supertool73 wrote:

I would add get away from the Steiner, they are just sub par optics anyway.  There are lots better options out there for better prices.
 
I totally agree with that. I have not seen the new split bridge Peregrine XP. Not that i care...
 
 
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: May/15/2008 at 12:31
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a 6 or 7 power binocular is MUCH more stable and so much easier on the eyes.
 
if you need 10x for extended viewing, i recommend a tripod.
 
i only use 6 or 7 power, because i get bad fatigue w/ higher powers.
 
my 2 cents.
 
J
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: May/15/2008 at 19:35
sparke View Drop Down
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Hi guys,

I'm new in this field and to the forum, but I'm getting into the basics these days. Seems to me the guys are obviously right that the small exit pupil is causing the eye fatigue. I looked around a bit for something good in the same price range, and came up with the Vortex Diamondback 8x42, which has an exit pupil of 5.25mm - they cost 200 bucks on Amazon. From what I've seen (well, really just read) Vortex seem to be good at making equipment for rougher conditions... Any opinions?

Hope this helps, but have to admit I'm really writing as much for myself as to help. I just started writing a little bit about binoculars, doing some reviews etc, but for now I just say what I say based on technical specifications and reading around. I'm looking forward to getting into some discussions here and learning - and hopefully testing - a bit along the way!


Are (Norway)
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Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: May/16/2008 at 03:01
Roy Finn View Drop Down
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Yet another reason your could be experiencing eye fatigue is the bino is out of vertical or horizontal collimation. Just a thought. Also, and just as important, is to make sure your bino's diopter setting is set-up perfectly. This will cause eye fatigue as much as other issues will. Each barrel must be set for your own eyes to eliminate eye fatigue. You can find the correct diopter proceedure under the "FAQ" section. IT is by nature if the open bridge design that open bridge design are more skeptical to alignment problems than piano hinge designs, meaning they are more fragile to misalignment.
 
Roy
 


Edited by Roy Finn - May/16/2008 at 04:27
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: May/16/2008 at 08:56
jonbravado View Drop Down
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what roy said is spot on. could be a combination of things too.

 
J
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: May/16/2008 at 16:28
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Originally posted by anweis anweis wrote:

 
I have not seen the new split bridge Peregrine XP. Not that i care...
 
The one sample I handled was superb optically.  I thought it was basically on par with the "big 3" alpha class roof prism bins, as best I could tell looking at resolution targets inside a store and looking at artificial point sources of light.  I thought it had a very comfortable feel to it as well, with gel-filled sections in the armor.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: May/22/2008 at 10:24
windstrings View Drop Down
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The "biggest" issue may be the depth of field of a 10X... although the other issues discussed all carry weight...
I'm assuming your glasses are perfectly clear when your eyes are fresh.. if not, obviously troubleshoot that before going further.

With that being said.. the more a lens is in the telephoto mode or rather "higher power", the less depth of field you will have as far as seeing things close and far and it all being in focus.
Most of the time when your looking into the distance at a target, the peripheral part of the lens will be touching on objects much closer such as nearby trees or limbs or even the grass in front of you etc.
Not only are cheap lenses poor at the edges, but as you are in a 10X lense, the focus itself will be poor too.....

So your eyes are constantly attempting to compensate and focus what it see's as it views the whole picture your lens is offering.
Theoretically, if you only looked dead center and didn't let your attention drift to the outer parts of vision, you shouldn't have eye strain.
But in the real world, you "look around" while looking through your glasses and then determine where to move your glasses too so as to see the new target dead center.
This " moving around" plays havoc on your focusing muscles in your eyes as they attempt to go a good job.

Steiner makes a glass that is in focus for everything from 20 feet out, its an 8 X 30 and only about 200.00.     Try one, .... for cheap glass, you may find it serves you better.

If you want to get into the swarovski quality you will pay many times more but get much more clarity out to the edge of vision, but there are still limitations with depth of field issues when dealing with high power lenses.

Having a larger exit pupil will make it so you have more room for error as far as exactly where your eye has to be placed behind the optic for proper or good viewing and that will help some too.. .but its not an all in all fix for the depth of field issue.

Look at all the parameters of the bino you are choosing as depth of field changes based on size of lens etc... but basically the "shorter" the bino is from front to end, the better the depth of field will be, and unfortunately, the higher power lenses get really long.

I found that dropping from an 10X to just 8.5 has quite a difference in depth of field.. dropping even more in power for a given lens will have even better results.

If you really don't want to buy more glass, another option would be to get a tripod or some way to rest your bino's.
Objects moving around all the time also gets you into those outer edges of the glass as mentioned where viewing is more strainful as well as affords eyestrain trying to lock onto an object thats constantly moving around..... again, dropping in power will also bring more stability in that area too, but to save some bucks, you may try to stabilize your binos first, but of course that will do nothing for your depth of field issues, but I'm betting the combinied issues discussed are bringing the total eye strain, removing just one issue will be a help but I fear it will only prolong the time before you arrive at eye strain.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: May/22/2008 at 14:07
lucznik View Drop Down
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Originally posted by windstrings windstrings wrote:

The "biggest" issue may be the depth of field of a 10X... although the other issues discussed all carry weight...
I'm assuming your glasses are perfectly clear when your eyes are fresh.. if not, obviously troubleshoot that before going further.

With that being said.. the more a lens is in the telephoto mode or rather "higher power", the less depth of field you will have as far as seeing things close and far and it all being in focus.
Most of the time when your looking into the distance at a target, the peripheral part of the lens will be touching on objects much closer such as nearby trees or limbs or even the grass in front of you etc.
Not only are cheap lenses poor at the edges, but as you are in a 10X lense, the focus itself will be poor too.....

So your eyes are constantly attempting to compensate and focus what it see's as it views the whole picture your lens is offering.
Theoretically, if you only looked dead center and didn't let your attention drift to the outer parts of vision, you shouldn't have eye strain.
But in the real world, you "look around" while looking through your glasses and then determine where to move your glasses too so as to see the new target dead center.
This " moving around" plays havoc on your focusing muscles in your eyes as they attempt to go a good job.

Steiner makes a glass that is in focus for everything from 20 feet out, its an 8 X 30 and only about 200.00.     Try one, .... for cheap glass, you may find it serves you better.

If you want to get into the swarovski quality you will pay many times more but get much more clarity out to the edge of vision, but there are still limitations with depth of field issues when dealing with high power lenses.

Having a larger exit pupil will make it so you have more room for error as far as exactly where your eye has to be placed behind the optic for proper or good viewing and that will help some too.. .but its not an all in all fix for the depth of field issue.

Look at all the parameters of the bino you are choosing as depth of field changes based on size of lens etc... but basically the "shorter" the bino is from front to end, the better the depth of field will be, and unfortunately, the higher power lenses get really long.

I found that dropping from an 10X to just 8.5 has quite a difference in depth of field.. dropping even more in power for a given lens will have even better results.

If you really don't want to buy more glass, another option would be to get a tripod or some way to rest your bino's.
Objects moving around all the time also gets you into those outer edges of the glass as mentioned where viewing is more strainful as well as affords eyestrain trying to lock onto an object thats constantly moving around..... again, dropping in power will also bring more stability in that area too, but to save some bucks, you may try to stabilize your binos first, but of course that will do nothing for your depth of field issues, but I'm betting the combinied issues discussed are bringing the total eye strain, removing just one issue will be a help but I fear it will only prolong the time before you arrive at eye strain.


You are confusing a number of issues in your logic.

First, the ability of the eye to "roam around" is a good thing.  Your eyes do this naturally all day everyday.  You can't tire your eyes out or "play havoc with your focusing muscles" by looking around. Quite the contrary, trying to look dead center all the time without allowing your eyes to roam is what is unnatural and tiring.  If your assertion were correct, then having a very low exit pupil number would actually prove more comfortable as the only option would be to just look straight forward. The small exit pupil's inability to allow your eyes to roam about the image is precisely what makes compact binoculars uncomfortable to use for long periods of time.

Second, edge clarity has nothing to do with depth of field.  They are separate concerns - though both are important. Depth of field is a function of magnification and involves how much is in focus from near to far. Edge clarity is a function of glass/manufacturing quality (or lack thereof) and involves how much remains in focus from one side of the FoV to the other. Increasing depth of field does not necessarily improve edge clarity nor vice versa.  A lack of edge clarity (which is what you describe) certainly could cause eyestrain as too little of the FoV is in focus but, increasing depth of field won't help this problem.

So too, depth of field is not a function of binocular length.  If so, the 10x Swarovski EL (with a published-by-Swarovski  length of 158 mm (6.22 inches) would have greater depth of field than the 8.5x EL with its published-by-Swarovski length of 165 mm (6.5 inches)  I have two 8x42mm binoculars, a Leupold Golden Ring and a Bushnell Discoverer.   The Discoverer is significantly shorter than the Leupold but, they do not exhibit identifiable differences in depth of field.  Neither, for that matter, do my two 8x mini-binoculars. 

Some quality issues can appear to have an effect on depth of field in that a well made binocular with excellent, crisp, focus is going to keep more in focus than a cheaply made piece of crap binocular and will therefore appear to have greater depth of field.  This is not entirely true however.  Each binocular (assuming they are of the same magnification) actually still has the same depth of field, it's just that the cheap one is bad all around and so that depth is unusable.  This is a quality issue.  Take that same cheap binocular and polish its lenses to a usable quality and then re-coat and remount them and it will show the same depth of field as the high-quality binocular - even though everything else about it's manufacture remains the same.





Edited by lucznik - May/22/2008 at 14:09
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: May/22/2008 at 14:36
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Sorry for not being more clear... seems the more you say, the more you can be misunderstood instead of the other way around.. I know they are two different issues about edge clarity and depth of field, but I'm trying to not get tangled in technical truths but rather in real life use truths.... edge clarity as far as what the eye sees can be either or a combination.... note I did speak about one or the other or both and how alliviating just one issue would help, but not solve the other.

Anytime the eye has to focus an imperfect picture, it works... to much of that and its like opening and closing your hand 1000 times in a row.. if its not used to it, it gets tired as the muscle cells reach exhaustion.

True, moving the eye around is natural and keeps it limber, but its "un-natural" to have an unfocused world all the time or at least a world that keeps changing and have to keep refocusing it.

Its similar to getting used to progressive lens glasses.... gives you a headache until the brain learns where the sweet spots are in the glass.

Putting glasses on and off does the same thing as the brain cannot automatically know how to accommodate the muscles until trial and error... but then the muscles are again exhausted.

I'm speaking more in medical terms of "why" the eye does what it does.

All things being equal..... the shorter the unit, the easier it is the accomplish depth of field... if you have a unit thats shorter with better depth of field than a longer unit, its because other expensive factors have overridden the basics.
Look at any telephoto shot of a camera and you will notice the foreground and the distance are out of focus, unless its an infinity shot, then its only the foreground.
Take any two pair of identical binoculars "identical" with the exception that one is a 10X and the other is some lesser power.... see which  one has the better depth of field.... I don't think it will "ever" be the one with more power.
By physics... "usually" that lesser power will be shorter.

But at any rate.... an Auto-focus binocular can be very comfortable and easy on the eyes if your happy with the clarity.

I used a military steiner 8 X 30 for years AF and was ecstatic with them as they never tormented my eyes as the whole world was always clear without having to turn dials and focus. Set the diopter one time and your done.

NO, they are not like my EL's but neither to they cost like them either.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: May/22/2008 at 16:25
lucznik View Drop Down
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Originally posted by windstrings windstrings wrote:

...I'm trying to not get tangled in technical truths but rather in real life use truths...
Only by understanding these "technical truths" can you effectively address and rectify the cause(s) of the "real life use" problems being experienced.  Otherwise you take shots in the dark at a solution and the one you eventually find may not be attributable to the reason(s) you think.  Thus you might recommend something to someone else because it worked for you only to have them end up dissappointed because the feature that you thought solved the problem didn't really deserve the credit.
 
Originally posted by windstrings windstrings wrote:

Anytime the eye has to focus an imperfect picture, it works... to much of that and its like opening and closing your hand 1000 times in a row.. if its not used to it, it gets tired as the muscle cells reach exhaustion... 
...an Auto-focus binocular can be very comfortable and easy on the eyes if your happy with the clarity.
What you say approaches truth but, is still a bit confused.  The so called "auto focus" (or as Steiner coins it "Sports Focus") binocular relies heavily on the eyes' ability to accomodate for differences in near/far vision.  Age, visual accuity, etc. can serve to make this less possible for any given individual.   Generally, Individual Focus (IF) binoculars perform their best when:
  • the user knows that they will be looking at things at intermediate distances and will not be alternating between looking both extemely near and extremely far - in which case each ocular barrel will require additional re-focussing, which will likely prove extremely tedious.
  • the user knows that they will not be looking in areas of heavy/dense cover trying to pick out detail behind and/or within foliage or other obstruction(s.)

It is important to understand that all other things being identical,  an IF binocular does not inherently offer greater depth of field (DoF) than a Central Focus (CF) binocular.  DoF is a function of magnification.   In this example, the glass is not different, and the light has no idea what mechanical process was used to guide it to the retina. Properly focussed, the CF binocular is adjusted to each individual eye just as certainly as is the IF binocular. The difference being that the CF binocular has a mechanism that allows for the easy switching between near/far extremes and the selective focusing of items in front of, in between, and/or behind partial obstructions (branches, foliage, fences, people etc.) that the other lacks.


Originally posted by windstrings windstrings wrote:

True, moving the eye around is natural and keeps it limber, but its "un-natural" to have an unfocused world all the time or at least a world that keeps changing and have to keep refocusing it.
  This again is a function of binocular's (or other optics's) quality, not DoF nor of the specific focussing mechanism.
 

Originally posted by windstrings windstrings wrote:

 All things being equal..... the shorter the unit, the easier it is the accomplish depth of field... if you have a unit thats shorter with better depth of field than a longer unit, its because other expensive factors have overridden the basics.
I think you mis-typed something here because, as written, this statement is self-contradictory.
 
 
Originally posted by windstrings windstrings wrote:

 Take any two pair of identical binoculars "identical" with the exception that one is a 10X and the other is some lesser power.... see which  one has the better depth of field.... I don't think it will "ever" be the one with more power.
This statement is true - because DoF is a function of magnification.
 
 
Originally posted by windstrings windstrings wrote:

 By physics... "usually" that lesser power will be shorter.
This statement is not.  Just as a small sampling:
  • Leupold Gold Ring 10x=6.0"  8x = 6.0"
  • Leupold Acadia 10x=6.0"  8x=5.8"
  • Leupold Cascade (P) 10x=5.0"  8x=5.0"
  • Leupold Cascade (R) 10x=5.5"  8x=5.5"
  • Bushnell Elite 10x=5.25"  8x=5.25"
  • Zeiss Victory FL 10x=6.8"  8x=6.8"
  • Zeiss Conquest 10x=5.6"  8x=5.6"
  • Leica Ultravid 10x=5.8"  8x=5.6"
  • Swarovski EL 10x=6.2"  8.5x=6.5"
  • Swarovski SLC 10x=5.8"  7x=6.5"
Thus we see that the lower mag/higher DoF binocular CAN be shorter as in the case with the Leica Ultravid and the Leupold Acadia but, it can also be LONGER as in the case with the Swarovski EL and Swarovski SLC.  Most often however, they appear to be pretty much the same length. 


Originally posted by windstrings windstrings wrote:

 But at any rate.... an Auto-focus binocular can be very comfortable and easy on the eyes if your happy with the clarity.
  That's a HUGE "if."

Originally posted by windstrings windstrings wrote:

 I used a military steiner 8 X 30 for years AF and was ecstatic with them as they never tormented my eyes as the whole world was always clear without having to turn dials and focus. Set the diopter one time and your done.
  I've used IF binoculars before and have never found the "set it one time and you're done" line to be true. I'm sure some people (with younger eyes that lack visual accuity problems) might find them perfectly satisfactory.  If you are one of those people, more power to you.
 
However, having said that, if such a system was really all that good, why has almost every manufacturer in the world gone to producing only Center Focus (CF) models? Does any major manufacturer currently even make IF binoculars in their high-end lines?  I don't believe they do.  In fact, not even Steiner does.  All of their top-of-the-line stuff is now CF.  Only their budget/mid-range porro prism stuff has the IF mechanism. 
 


Edited by lucznik - May/22/2008 at 16:52
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yep... your right.. I mixed my words.. sorry....

When I used those bino's I loved them and thought they were the best in the world and my eyes never got tired.... but then I lost them in a move across country and so went to buy some more.... only then did I learn about the better clarity... less smoky look at distances, better minute detail etc of the higher end glasses....

I'm afraid to go back and even try a pair of those anymore.. but they did the job at the time and I never knew the difference in fact found my elk hunting area by spotting an elk a whole mountain away as he walked upon the edge of a crest.... from then on.. thats where we hunted every year as it proved a good spot.....

I only say that to say indeed those did the trick... .many folks dog the AF and I wonder if they honestly have ever tried them....

If I only had a couple two or three hundred to spend and no more, I would seriously consider them again.... but instead I bought EL's.
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