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Eyepiece ? |
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Blackbird
Optics Apprentice Joined: February/10/2007 Location: United States Status: Offline Points: 284 |
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Posted: February/23/2007 at 15:18 |
I am considering purchasing a Pentax PF-80 ED and have some questions about eyepieces. What eyepiece would best suit me for looking at 6mm. holes (on paper) at 500 yards? Would the 20-60X zoom eyepiece be my best choice or a straight power? All opinions welcome!
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anweis
Optics Master Joined: January/29/2006 Status: Offline Points: 1148 |
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Friday afternoon was sunny, so i decided to go at the spot where many birds of prey take a rest while migrating through this area. I was lucky, there was one Red-shouldered hawk there, perched on a limb, across the lake. I had a "cherry sample" handpicked Swarovski HD 80mm with the zoom eyepiece on it, mounted on a humongous Gitzo tripod ($800). I could see that the bird was a Red-shouldered, but i wanted to see more detail. So i used the zoom at 40x, 50x, and 60x. I could barely see the bill (about 15 mm in size, grey and yellow in color), but the brown spots on the chest were quite visible. I remembered that i had the rangefinder (Leica 1200) in the car, so i measured the distance to the hawk: 344 meters. I could see the eyes of the hawk, about 6 mm in size, but only because they where black in an area of pale rusty feathers. Long story short: you will not see 6mm holes at 500 yards with any scope, with any eyepiece, unless you use those splatter targets that show neon green dots where the bullet hits them. The Pentax zoom is one of the best zooms on the market today. Well worth the price. Edited by anweis |
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www.technika.nu
Optics Journeyman Joined: August/02/2005 Location: Sweden Status: Offline Points: 611 |
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Anweis is right, at that distance you can never count on seeing any bulletholes. However in rare occasions with a strong sun behind the targets you will be able to see them. I have seen 6,5mm bulletholes at 700 meters, but only that one day ( behind the targets there where the sea)
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1stscope
Optics GrassHopper Joined: January/14/2007 Status: Offline Points: 66 |
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The Pentax gets very good reviews, and the ability to use standard eyepieces gives you a chance to see what you want. Dedicated astronomical scopes will give you the best chance for viewing small things at a distance, they're designed to be used closer to optical limits, but seeing conditions will usually be the limiting factor.
http://www.buytelescopes.com/product.asp?display=reviews& ;pid=2026
Pentax PF-80 ED Spotting Scope
Having said this, in side-by-side comparison, the Swarovski, as has been said by others before, has a yellowish hue in the overall image. This seems to give the impression that the image is brighter than it actually is. I didn't prefer this. The Pentax and the Leica did not have this yellowish hue. In particular, the Pentax's color fidelity was astounding.
Betterviewdesired.com rates the Pentax as the current reference standard above both the Swarovski and the Leica. I'm tempted to agree. The images through the Pentax possess a high "wow" factor.
Finally, the Pentax costs about $500-$600 less.
For many years the Tele Vue Ranger 70 mm ED scope has been the BVD Reference Standard for optical performance. The Ranger, at 70 mm, is brighter and sharper than any of the conventional 80 mm scopes I have tested, with the exception of the new Pentax 80 mm ED....
So, to sum all this up, the Tele Vue 85 easily sets a new standard for optical performance in a scope compact enough (barely) to take into the field after birds. Would I carry it? Probably not. At 11 or 12 pounds with a usable tripod it is just too heavy. On the other hand, if I were going, for instance, hawk (or Grasshopper Sparrow) hunting on the Kennebunk Plains, or shore birding on Bolivar Flats, or looking for pelagic birds blown in close by a storm off Two Lights—anywhere I could set it up within 100 yards of the car—then I would definitely pack it and a full range of eyepieces or whichever zoom (Tele Vue or Pentax) I ended up with....And, even now, every time I look at a bird through one of the exceptional conventional spotting scopes I have to use, I will be thinking: "I wonder what this would look like through the Tele Vue 85? I wonder what this bird really looks like?"
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1stscope
Optics GrassHopper Joined: January/14/2007 Status: Offline Points: 66 |
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I think that the article below has been posted here before. Anyway, it also goes over lower cost scopes.
http://www.6mmbr.com/spotterreview.html Premium Spotting Scopes in Review And the Winner Is...
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1stscope
Optics GrassHopper Joined: January/14/2007 Status: Offline Points: 66 |
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As noted in a reply in another thread I have a 'junk' 50mm telescope that someone gave me, and after a bit of work I've been able to see the shadows of one of it's moons on Jupiter, at 120x. That's using my shortest eyepiece, but even if I had a shorter one or a barlow that's getting close the limits for a telescope of that aperture. Assuming it's Jupiter's largest moon the shadow would be roughly 1.6 arc seconds, compared to a .30 caliber bullet hole at 600 yds which would be about 3 arc seconds.
So, as suggested in some of the replys, one would need very good resolution even for a high contrast image at that distance, very good contrast if it's say a hole in the black (my 50mm scope doesn't appear to even be fully coated so contrast is low in some situations), and just as important very good seeing conditions. More aperture gets you better resolution but at some point it becomes more senitive to seeing conditions than a smaller scope (I have an 8in reflector that is usually unusable for daytime viewing at higher magnification). Better coatings / baffling/ etc. gets you better contrast, but you can sometimes brute force an image with better resolution from a larger aperture than with a better, smaller scope. An astronomical scope will be a better low cost bet for viewing such an image, but it will be bulky, take more research, testing and maybe some tuning to get a good low cost model, and won't typically provide up/down left/right corrected views that people usually want. |
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