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yosemites 6x30 vs 8x30? (1 Viewer)
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Kevin Purcell
Well-known member
Terrible compared to what? Another decent $89 porro? 
I don't find "flare" control to be terrible in either the 6x30 or 8x30 but the bin is vulnerable to veiling glare stray light especially when viewing above the horizontal.
I think this is because to upper prism can see the lower outside edge of the objectives so there is a stray light path. This shows up when it catches bright light (which most of the time it doesn't).
You can see this if you view the Yosemite from the objective end with the hinge downward outside (uniform bright light helps). You can look in through (from your point of view) the upper right and upper left of the objectives into the prism housing.
I think there was a trade off in prism size (bigger) and baffling that allows this to happen but for horizontal viewing that is looking at the ground you tend not to get much light in at that angle. If you look up at a significant angle (30 to 45 degrees) at a tree surrounded by sky you can see this effect. It's not a direct path to the eyepiece or the optical path but I suspect with some multiple scattering you get veiling glare: reducing the contrast across a portion of the field.
The effect is the same in both 6x30 and 8x30 as the optics are essentially the same: with the same size enclosure and worse eye relief I suspect only the eyepiece focal length (and associated aperture stop, perhaps) have changed. And that wouldn't affect this sort of stray light issue.
BTW, unlike some other comments about the 8x30 being ussuitable for use with eyeglasses. I find the 8x30 with its specified 14mm eye relief that sounds too low works fine for me (just see the full FOV) with my eyeglasses (which are quite close fitting).
Aside from that the 8x30 has a larger AFOV but a smaller FOV and the image is a little dimmer as might be expected. The larger image and the reduced brightness both make the 8x seem less sharp than the 6x. But it's still a decent performer.
I don't find "flare" control to be terrible in either the 6x30 or 8x30 but the bin is vulnerable to veiling glare stray light especially when viewing above the horizontal.
I think this is because to upper prism can see the lower outside edge of the objectives so there is a stray light path. This shows up when it catches bright light (which most of the time it doesn't).
You can see this if you view the Yosemite from the objective end with the hinge downward outside (uniform bright light helps). You can look in through (from your point of view) the upper right and upper left of the objectives into the prism housing.
I think there was a trade off in prism size (bigger) and baffling that allows this to happen but for horizontal viewing that is looking at the ground you tend not to get much light in at that angle. If you look up at a significant angle (30 to 45 degrees) at a tree surrounded by sky you can see this effect. It's not a direct path to the eyepiece or the optical path but I suspect with some multiple scattering you get veiling glare: reducing the contrast across a portion of the field.
The effect is the same in both 6x30 and 8x30 as the optics are essentially the same: with the same size enclosure and worse eye relief I suspect only the eyepiece focal length (and associated aperture stop, perhaps) have changed. And that wouldn't affect this sort of stray light issue.
BTW, unlike some other comments about the 8x30 being ussuitable for use with eyeglasses. I find the 8x30 with its specified 14mm eye relief that sounds too low works fine for me (just see the full FOV) with my eyeglasses (which are quite close fitting).
Aside from that the 8x30 has a larger AFOV but a smaller FOV and the image is a little dimmer as might be expected. The larger image and the reduced brightness both make the 8x seem less sharp than the 6x. But it's still a decent performer.
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Kevin,
Some weeks ago I got the chance to try the Yosemite 8x30. I have earlier praised the 6x30 and considered it to be the best ever made binocular in it's size and pricerange. I don't compared them side by side, but my impression was that the 8x30 had an optical quality in par to the 6x30. Very sharp and brilliant image. I tried it under bright light conditions in a store.
As usual with higher power and larger apparant field of view I experienced the edge sharpness to be inferior to the 6x30. I am quite demanding about eye relief and found the 8x30 to not be adequate for me with eyeglasses on, while the 6x30 is great.
As with the 6x30 I could notice that the aperture is stopped down. These glasses have around 28mm true aperture, and therefore actually perform like 6x28/8x28 binoculars.
However they are both great binoculars for the price and I will highly recommend them to anyone who wants a budget binocular with an optical performance rivalling some several times more expensive binoculars.
Regards, Patric
Some weeks ago I got the chance to try the Yosemite 8x30. I have earlier praised the 6x30 and considered it to be the best ever made binocular in it's size and pricerange. I don't compared them side by side, but my impression was that the 8x30 had an optical quality in par to the 6x30. Very sharp and brilliant image. I tried it under bright light conditions in a store.
As usual with higher power and larger apparant field of view I experienced the edge sharpness to be inferior to the 6x30. I am quite demanding about eye relief and found the 8x30 to not be adequate for me with eyeglasses on, while the 6x30 is great.
As with the 6x30 I could notice that the aperture is stopped down. These glasses have around 28mm true aperture, and therefore actually perform like 6x28/8x28 binoculars.
However they are both great binoculars for the price and I will highly recommend them to anyone who wants a budget binocular with an optical performance rivalling some several times more expensive binoculars.
Regards, Patric
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Kevin Purcell
Well-known member
Swepat: I concur.
That's what I was trying to say in my post. I've noticed with a few bins that brightness can easily change the perception of the bins. I think both are equally sharp but the smaller and brighter image in the 6x looks "better". But optically they're very close.
Nice to get another data point on the eyeglasses with the 8x30. Their spec ER is right at the edge (well, below the edge) so it seems if you have close fitting glasses then they may work. But as you find (and Otto McDiesel found too) it doesn't work for some. If I tried another pair of glasses which are less close fitting I find I can't see the field stop at the top or bottom of the field but I still find the bin useful. This is an area each eyeglass wearer has to try out for themselves.
That's what I was trying to say in my post. I've noticed with a few bins that brightness can easily change the perception of the bins. I think both are equally sharp but the smaller and brighter image in the 6x looks "better". But optically they're very close.
Nice to get another data point on the eyeglasses with the 8x30. Their spec ER is right at the edge (well, below the edge) so it seems if you have close fitting glasses then they may work. But as you find (and Otto McDiesel found too) it doesn't work for some. If I tried another pair of glasses which are less close fitting I find I can't see the field stop at the top or bottom of the field but I still find the bin useful. This is an area each eyeglass wearer has to try out for themselves.
Steve C
Well-known member
I have both 6x and 8x Yosemites. I've spent quite a bit of time lately with them, the Swift Eaglet 7x36 and a Vortex Fury 6.5x32 I have and the Promaster ELX ED I recently bought.
The flare control issue, in my 6x30 was handled by cutting an inch or so thick band from a bicycle innertube and placing this over the eyepieces. Slide it far enough down the eyepiece, and the last bit of it will fold over 90* and essentially extend the length of the eyecup. No more flare for me with that slight extension. The flare issue never raised it's head for me with the 8x30. I would say my 6x30 is just a perciptible bit sharper and brighter than the 8x. The image on the 8x however looks to be a little larger than 2x larger than the 6x. My 8x would be a better choice for those who think that 6x is not enough. The 6x is however brighter in a gloomy gray day or in twilight.
I don't wear glasses so the eye relief isn't an issue for me. Having said that, wearing either my reading glasses (which I do need) or sunglasses, the 6x and 8x both seem to let me see the whole fov.
I would say that Swedepat is correct in his assement that they are very nearly equal in optical performance. The difference being only in a larger image for the 8x. Both are the best deal out there for value as relates to price. Next is the Promaster ELX ED and Hawke Frontier ED.
I think one of the issues with that class of price binocular will likely show itself as having a lilttle flare. I really only shows (to me anyway) when panning in the general direction of the sun.
The flare control issue, in my 6x30 was handled by cutting an inch or so thick band from a bicycle innertube and placing this over the eyepieces. Slide it far enough down the eyepiece, and the last bit of it will fold over 90* and essentially extend the length of the eyecup. No more flare for me with that slight extension. The flare issue never raised it's head for me with the 8x30. I would say my 6x30 is just a perciptible bit sharper and brighter than the 8x. The image on the 8x however looks to be a little larger than 2x larger than the 6x. My 8x would be a better choice for those who think that 6x is not enough. The 6x is however brighter in a gloomy gray day or in twilight.
I don't wear glasses so the eye relief isn't an issue for me. Having said that, wearing either my reading glasses (which I do need) or sunglasses, the 6x and 8x both seem to let me see the whole fov.
I would say that Swedepat is correct in his assement that they are very nearly equal in optical performance. The difference being only in a larger image for the 8x. Both are the best deal out there for value as relates to price. Next is the Promaster ELX ED and Hawke Frontier ED.
I think one of the issues with that class of price binocular will likely show itself as having a lilttle flare. I really only shows (to me anyway) when panning in the general direction of the sun.
Kevin Purcell
Well-known member
You know that's rather odd but it's more to do with visual system and the poor ability we have for guessing visual angles e.g. how big is the moon? how big is compared to the thumbnail at arms length? It's about 1/2 degrees (and these two items are about to same size!).
6x30 has 420 ft./1000 yds FOV == 8 degrees so AFOV is 48 degrees
8x30 has 393 ft./1000 yds FOV == 7.5 degrees so AFOV is 60 degrees
As you can see in angular measure no where near twice as large (it's 25% bigger AFOV).
But it feels much bigger. I know what Steve is saying.
But people are really sensitive to this change in FOV. Go to 40 degrees and people will complain of looking down a toilet roll. Get up to 65 degrees (like the Frontier or Diamondback) and it's wow this is wide angle - filling my field of vision! I think that's the trick ... it's getting so much closer to the eye's useful wide field that you don't see much improvement beyond that.
The visual system is a funny thing
Steve C
Well-known member
Whoa!!
I didn't mean to say the image looked double in size. Here's the math 8x-6x=2x (that 2x, not double). The 6x Yosemite I have compared to the 8x I have looks more like maybe a 5.75x rather than 6x when compared to the 8x. Or maybe the 8x looks like 8.25x. That kind of difference.
I didn't mean to say the image looked double in size. Here's the math 8x-6x=2x (that 2x, not double). The 6x Yosemite I have compared to the 8x I have looks more like maybe a 5.75x rather than 6x when compared to the 8x. Or maybe the 8x looks like 8.25x. That kind of difference.
Tero
Retired
Kevin, did you come to like the 8x30s overall?
I still have my 8x40 porros, even used them today, but the Yosemites probably would work as well. I like the 3D effectof my current porros. My last ones caused some confusion in my brain, even one event of eye strain, Nikon Action series.
I still have my 8x40 porros, even used them today, but the Yosemites probably would work as well. I like the 3D effectof my current porros. My last ones caused some confusion in my brain, even one event of eye strain, Nikon Action series.
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Kevin Purcell
Well-known member
I'm not following you Steve ...
Oh wait. I get it. D'oh.
That's a rather odd nomenclature to use given that 2x usually means doubling
Tero: The 30ish bins occupy one end of the shelf ... the 40ish bins are at the other. It all depends how I feel but recently I've been more biased to the 40ish stuff. Though I've been tending to grab the Yosemite 8x30 recently for a quick look out the window. I need to do compare the 8x30ish bins I have. I think I rather like all of the bins I have right now to a greater or lesser extent.
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henry link
Well-known member
It's possible that the Yosemites' actual magnifications may not be quite as specified. I evaluated an 8x30 back in June ( http://www.birdforum.net/showthread.php?t=116600 ), but unfortunately didn't bother to measure the true magnification.
The effective eye relief of the 8x30 model could be longer. It's limited by the design of the eyepiece housing rather than the optics because the eyelens is recessed more than necessary.
The effective eye relief of the 8x30 model could be longer. It's limited by the design of the eyepiece housing rather than the optics because the eyelens is recessed more than necessary.
Steve C
Well-known member
Henry
Or anybody else who might know.
I wonder what the actual acceptable magnification range for a glass at the price level of the Yosemite might be. For example might the 6x range from 5.5-6.5x and the 8x range from 7.5-8.5x? I sort of assigned what I see in the two I have to normal variations in manufacturing tolerance. As in I may have a <6x, or a >8x. But I readily admit that is an assumption on my part. Both are eminently usable binoculars.
Or anybody else who might know.
I wonder what the actual acceptable magnification range for a glass at the price level of the Yosemite might be. For example might the 6x range from 5.5-6.5x and the 8x range from 7.5-8.5x? I sort of assigned what I see in the two I have to normal variations in manufacturing tolerance. As in I may have a <6x, or a >8x. But I readily admit that is an assumption on my part. Both are eminently usable binoculars.
Surveyor
The more I understand, the more I understand why I
Steve;
The ISO guide lines for Standard Optics is +/-5% magnigication with +/- 2% relative to the barrels. For High Performance Instruments (sport optics don't fit although the alphas are usually close) the figures are 4% and 1.5%.
Hope that helps.
Best,
Ron
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English is my second language so I may have called "flare" waht sould have called ghost image.; I actualy thought that two are the same. First day I received yosemite I tested them looking through window and as anyone else was impressed but at first dusk and then in the evening i could see ghost image of every neon and street light outside field of view; this is what I think is ghost image. In the field in the last dying minutes of daylight ghost images of every tree shadow were interfering with the image.
So my question was, was this problem the same or rectified with 8x30 yosemite?
I have cheap baigish 8x30 which doesn't have this problem but doesn't have all other nice characteristics of yosemites.
So my question was, was this problem the same or rectified with 8x30 yosemite?
I have cheap baigish 8x30 which doesn't have this problem but doesn't have all other nice characteristics of yosemites.
Steve C
Well-known member
Buff,
Right across the street from my house is the equipment yard of a local excavation service. They are doing a little night work and they have a couple of big portable stand lights going that are too bright to look directly at. These are about 200 yards away. There are three city street lights that can be seen from where I was. There are mumerous house lights, night lights, etc about the neighborhood.
The only way I can get either of the two Yosemites to perform as you describe is to get close enough th the really bright work lights, to get the effect you describe. Also if I get the nearest streetlight on one side of the field and the work lights on the other, there is a little of your ghosting phenemon visible. But if the bright light is a degree or two away from the edge of the field,that condition is not there. It is only the very brightest lights that ghost. The worst one of the two is the 8x. I would not reject either on on this basis. The better Promaster is not so afflicted.
I didn't get any stray ghost effect from twilight shadows only.
So, there it is from my view through my binoculars. I do tend to wonder if you Yosemite is an abberation. Maybe mine are. Don't know if this helps or not. |=)|
Right across the street from my house is the equipment yard of a local excavation service. They are doing a little night work and they have a couple of big portable stand lights going that are too bright to look directly at. These are about 200 yards away. There are three city street lights that can be seen from where I was. There are mumerous house lights, night lights, etc about the neighborhood.
The only way I can get either of the two Yosemites to perform as you describe is to get close enough th the really bright work lights, to get the effect you describe. Also if I get the nearest streetlight on one side of the field and the work lights on the other, there is a little of your ghosting phenemon visible. But if the bright light is a degree or two away from the edge of the field,that condition is not there. It is only the very brightest lights that ghost. The worst one of the two is the 8x. I would not reject either on on this basis. The better Promaster is not so afflicted.
I didn't get any stray ghost effect from twilight shadows only.
So, there it is from my view through my binoculars. I do tend to wonder if you Yosemite is an abberation. Maybe mine are. Don't know if this helps or not. |=)|
Kevin Purcell
Well-known member
Hah! Your English is fine
In fact that's what I call flare too (like the sun on older camera lenses).
Unfortunately a lot (more) people use "flare" to mean "glare" specifically what's called "veiling glare" in the camera business: an overall reduction in contrast across a portion of the field.
And so I assumed the latter. Bad assumption. Pardonez moi.
I wrote a thread on these various terms: generally on-axis problems (and discrete problems are "flare" or more specifically "ghost images" and both on-axis and off-axis light gives "veiling glare".
You can get ghost images (reflections between the elements) in the Yosemite. I've seen them on a couple of occasions but it's rather infrequent. The only reporducible case was with a magliite used in candle mode (with an exposed bulb). That test, like the street-light test, is quite harsh for this bin. In normal (birding/terrestrial) use I find the sun is the only bright light source around and it has some veiling glare problems close to the sun.
The ghost image problem is a function of the quality (effectiveness) of the AR coatings on the optics. For example, the Diamondback seems rather more susceptible to ghost images (something I only noticed after using them for a while ... it's not mentioned in my review) so I rank it's AR coatings as good but not the best.
So to answer your original question: it's the same on both 6x30 and 8x30 but in neither case do I find it terrible (but I don't look at bright lights at night).
Kevin,
I assume the reason may be that we experience the area of the apparant field? A 25% larger AFOV means a 56% larger apparant area (don't know if that is a correct expression). Which is significantly larger.
Regards, Patric
