Binocular ramblings (1 Viewer)

Have been having a slight eye problem lately. I have a left dominant eye, so focusing with the left is fine and even if the right is not quite on the mark, I do not always adjust the diopter for every bird. But, if I do, I adjust that separately for the right eye. Then I look agian, with both eyes. Soemething is still not right, so I refocus. There never seems to be a perfect focus setting for both eyes. Looking with just one eye, there is. It is not so bad in bright light, but on cloudy days. And I do not have any easier time with close objects with 8x than 10x. Far away objects are fine.

Is there something funny with my eyes?

Tero said:

Have been having a slight eye problem lately. I have a left dominant eye, so focusing with the left is fine and even if the right is not quite on the mark, I do not always adjust the diopter for every bird. But, if I do, I adjust that separately for the right eye. Then I look agian, with both eyes. Soemething is still not right, so I refocus. There never seems to be a perfect focus setting for both eyes. Looking with just one eye, there is. It is not so bad in bright light, but on cloudy days. And I do not have any easier time with close objects with 8x than 10x. Far away objects are fine.

Is there something funny with my eyes?

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Tero, have you tried to find out when you have this problem. I notice I have more problems focussing them both when my eyes are tired. (That does not necessarily mean I am tired as a person, but I have strained the eyes a lot.) I had been told by an optician that I have what he called slight hidden cross-eyes. Normally my brain compensates for that and all is fine, but when the eyes (or that part of the brain) are tired, I have problems focussing both eyes. To me, it usually does not show up when I use binoculars, but when I am reading, which, of course, also means being in the close range where it all is more critical.

Thanks, sounds a bit similar. Duh, the brain, of course, it must be the brain. It is not a constant effect, just like you described, depends on when.

These are interesting binocular ramblings. I have some eye problems myself. Most notably, my eyes are not properly "collimated". An optometrist verified this and recommended adding a prism to my prescription, but I didn;t like it because it made my eyes feel weird. So I never got that done on any glasses since then. So basically, since my eyes are not properly aligned, I have some problems drawing the binocular images together into one image. This is especially noticable from 10 ft. in, and in binoculars that have wide spaced objectives -- like porros. Even full sized roof prism models do this to me. The only binocular not to do it are the B&L Custom Compact 7x36 and the Pentax Papilios. Both of these are reverse porro designs that have very close set objectives. Plus the Papilios have convergent objectives that narrow down with close focusing. To tell you the truth, I am thinking of returning the Alpen Apex 8x42s I purchased recently because I am getting slightly dual image from 10 ft in -- plus, the IPD is barely adequate. I can see just about everything I want with the Custom Compacts. They have 26mm objectives but seem as bright as any full-size bincular except when twilght approaches. They have very good optics, a relatively wide field and sharp images out to the edge. They focus down to 7 ft. They need to be treated more gently than a fully armored waterproof roof, but the benefits seem to outweigh the advantages of a roof prism I can afford.

Rambling on, I have a theory that if you experiment with any binocular, you are going to start seeing little things wrong with it. You might start having some nagging doubts that you need a better bin. Yet whenever I have been actually out birding with any decent binocular, I have paid much less attention to the binocular and much more to the birds. Most of us like to take out our binocs and fondle them and look at things across the room, read the contents list from cereal boxes, and look at mountains to see what the resolution is like and so forth, but I think it might be asking for trouble if I do this too much.

Well said, Trashbird. I think we're all victims of the Great Marketing Con, as much with our bins as with our cars, freezers, PC's, shoes etc. One used to say "hey, I'm out watching birds, having a great time. For this I use my binoculars". Now we say "hey, I'm out birding, but I'm not completely satisfied, because I feel my bins might not be perfect in all respects, and there may be a better pair out there on a website/in a store/etc.". And the con is, as there's an ever-increasing range of similar products out there all infitesimally differentiated, of course the pair we have aren't absolutely perfect, because, as you say, if you fiddle with your bins for long enough, you'll find something about them that may be improved on an alternative pair. I'm not preaching, I've been daft enough to spend a small fortune on bins, and have now got two pairs of top-ends which are far more than anyone really needs, and which I certainly didn't need. The birds remain the same. So now I merely laugh at myself, resolve not to spend anymore hard-earned moo-lah on unnecessary optics, and enjoy the birds. Off to try and find a reported Laughing Gull this weekend. We don't get a lot of them in Ireland. Can't wait.

The reverse porros have worked well for me as well. I should look to see if any 30mm models are available. Are these reverse porros?
http://www.eagleoptics.com/index.asp?dept=1&type=19&purch=1&pid=63

I noticed that I am actually more comfortable with my glasses when viewing close objects through binoculars. With disant birds, makes no difference, glasses or not. My glasses are about 1.0 0r so, so I see distance pretty well on a bright day without the glasses. I need them mainly to read.

Tero said:

The reverse porros have worked well for me as well. I should look to see if any 30mm models are available. Are these reverse porros?
http://www.eagleoptics.com/index.asp?dept=1&type=19&purch=1&pid=63

I noticed that I am actually more comfortable with my glasses when viewing close objects through binoculars. With disant birds, makes no difference, glasses or not. My glasses are about 1.0 0r so, so I see distance pretty well on a bright day without the glasses. I need them mainly to read.

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Tero,

Yes it is a reverse Porro design. There is less sense of depth with a reverse Porro than with a roof prism glass, which is less than with a standard Porro.

I am going to propose that above $300, improvements in binocular features become harder to discern as the price rises. A $600 glass may not be twice as good as a $300, however you may try to quantify it, but it is most certainly better. Your optimization of features, your purse and your physical needs meet the design compromise of the manufacturer. That is your sweet spot.

I would add that a $100 binocular, good for the price, is not a good binocular.

Happy bird watching,
Arthur Pinewood :brains:

I did not find a lot of 8x30 or 10x30 reverse porro models listed by any makers. The smaller roof prisms are popular, lots of 30-36mm models but not as wide FOV as porros.

Tero said:

I did not find a lot of 8x30 or 10x30 reverse porro models listed by any makers. The smaller roof prisms are popular, lots of 30-36mm models but not as wide FOV as porros.

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Tero,

For any given power, and objective size, increasing the FOV requires larger prisms. For the sake of fashion, roof prism binoculars have slim lines and smaller prisms. The advantages of roof prism binoculars are that the design lends itself to waterproofing, shock resistance, shorter length and lighter weight, but at greater expense. Close tolerances in the manufacture of the roof prism, phase coating, and more difficulty in assembly add to the cost.

The bottom line is you get more optically for your money with a Porro prism binocular, but they require more care and are larger.

Happy bird watching,
Arthur Pinewood

Yes, I have a large clunky favorite porro for winter, 8x40. Mostly I like it as it is easy with glasses on. Many porros ignore glasses wearers, mine are Nikons, Action EX.

I have some compacts as well, both 8x25 and 10x25 reverse porros, but neither works for me with glasses. They require an eye glass much closer to the eye.

The B&L Custom Compact 7x26 are the best reverse-porros I know of. 7x26 gives you an exit pupil of 3.7mm as opposed to a 3.75mm of an 8x30 (which is a pretty popular configuration). The Bushnell Natureview 8x30 are a reverse porro-prism design, but the optics nowhere near the Custom Compacts. But other than the Natureview, I know of no other reverse-porro designs in an 8x30 configuration. The intended purpose of the reverse-porro is to make the binocs more compact. They just happen to be good for people like me with wonky eyes.

I used to have a pair of Pentax 7x35 PCF III that I sold to my Dad. I still enjoy birding with those when I visit him (the fact that he lives in Portal, AZ next to Cave Creek Canyon probably helps too). The Pentax porro design puts the objectives lower and closer together -- so that may be why I like them. It also may very well be that my wonky eyes do better with lower powers rather than 8-10x. And the Pentaxes have a better inner IPD than most.

Anyway, that's the view from here.

trashbird said:

...
These are interesting binocular ramblings. I have some eye problems myself. Most notably, my eyes are not properly "collimated". An optometrist verified this and recommended adding a prism to my prescription, but I didn;t like it because it made my eyes feel weird.

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Hmmm. Sounds like you have difficulty with convergence, which is a muscle control problem.

<klip>

Most of us like to take out our binocs and fondle them and look at things across the room, read the contents list from cereal boxes, and look at mountains to see what the resolution is like and so forth, but I think it might be asking for trouble if I do this too much.

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I do it too, and draw the same conclusion. My wife calls it Binocular Attention Disorder (BAD).

Ed

Cont. with my eye/brain problem, see above:
I did some testing with my porros. I think I can live with the problem, though I think I don't get it with roof prisms.

IT TOOK ME HALF A YEAR, but I figured I need to adjust the diopter at an average distance and leave it there. Then I focus on the bird etc with my POOR eye, my worse eye. The good eye will then work out some slight adjustments. It works OK for 5 minutes, then I need to take a break and go back to looking after half a minute.

OK, did some more testing, with porros and roof prisms. To my eyes the roof prisms are definitely easier on the eyes for close viewing and long viewing. To me the roof prism view appears "flat", but not sure what that means to others. It looks similar to my old SLR camera 50mm lens. But the 8x40 porros are unbeatable at finding the bird first, mine anyway. Field of view is quite a bit more than my 10x36 roofs. So with warblers, once we get some, I will go with the porros.

OK, another Binocular purchase has been made. Not that I need any, 2 pairs of decent ones plus some pocket versions are enough for anyone.

No info will be given on what, as this is going to be a gift to me. I don't really get to test them till May. The kids get to wrap them once I check that there is no need to return the product.

But for summer, and perhaps winter, I have gone back to the 10x side, and roof prisms. I will use porros for warblers, I have a bigger FOV.

Tero said:

OK, did some more testing, with porros and roof prisms. To my eyes the roof prisms are definitely easier on the eyes for close viewing and long viewing. To me the roof prism view appears "flat", but not sure what that means to others. It looks similar to my old SLR camera 50mm lens. But the 8x40 porros are unbeatable at finding the bird first, mine anyway. Field of view is quite a bit more than my 10x36 roofs. So with warblers, once we get some, I will go with the porros.

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You might consider that the ease on your eyes is an individual binocular thing instead of a prism design thing. A cheaper made or misaligned anything can be bad on the eyes.

Yes, that occured to me, the porros are not perfectly aligned. When you look to a far away object, the image is a better round shape, and close by the parts separate. It does not bother me except when required to look at things for long period. At some point I will look at warranty service.

Tero said:

Yes, that occured to me, the porros are not perfectly aligned. When you look to a far away object, the image is a better round shape, and close by the parts separate. It does not bother me except when required to look at things for long period. At some point I will look at warranty service.

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Perfect collimation of oculars is, IMO, more important than any other characteristic. Even marginal optics look pretty good when collimation is dead on. Regardless of optical quality, poor collimation will strain your eyes, exhaust the brain, and ruin the image.

Next in line is an effective diopter that compensates across the entire viewing range. My aging eyes can detect a difference as small as 1/8 diopter and I dare say many reviews are negatively skewed by an improperly adjusted diopter.

John

I have checked all my binoculars for roundness of image. As I have never quite seen badly collimated bins, lately, I have not mastered any collimating tests. I understand the tests, but my results are inconclusive.

Anyway, all of mine give a perfect round image at long distance, except the 8x Nikon Action porros. It is not that badly off, so I may use them for a while. If I complain to Nikon and they agree, all they will do is replace them with another pair. It may improve things, may not. It would probably not get worse with a new pair.

I can’t really complain about eye strain, but there were some focusing issues at close distance (see messages earlier above).

Nearly all my binoclulars give a slight figure 8 image (the standard binocular silhouette in movies!) at close distance. It is the most obvious with the Nikon porros. And the least, or none at all, with some small inverse porros. The lenses are so close together, that I would not expect it there.

Tero said:

I have checked all my binoculars for roundness of image. As I have never quite seen badly collimated bins, lately, I have not mastered any collimating tests. I understand the tests, but my results are inconclusive.

Anyway, all of mine give a perfect round image at long distance, except the 8x Nikon Action porros. It is not that badly off, so I may use them for a while. If I complain to Nikon and they agree, all they will do is replace them with another pair. It may improve things, may not. It would probably not get worse with a new pair.

I can’t really complain about eye strain, but there were some focusing issues at close distance (see messages earlier above).

Nearly all my binoclulars give a slight figure 8 image (the standard binocular silhouette in movies!) at close distance. It is the most obvious with the Nikon porros. And the least, or none at all, with some small inverse porros. The lenses are so close together, that I would not expect it there.

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I read somewhere and have observed myself that the "roundness" of the individual image in a binoc differes from porro to roof prism. Porros give slightly oval images that are wider than they are tall, and roofs give slightly oval images that are taller than they are wide. I think this has something to do with the prism itself -- but I can't remember. It's possible that it's an illusion like how roof images sometimes appear larger than porros of the same configuration.

I have also noticed that binocular images look better when each individual image has better edge sharpness. I think this is because when the individual images merge, the "center" of the binocular image is not the exact center of the individual images.