I've just glanced at a few threads that are many months old that compare the Pentax 80 and zoom with other scopes and fixed eyepieces. I'm aboout to purchase an 80 because of the great price, and have several Televue eyepieces that I use with my 85 that I plan to share between the two scopes. Has anyone done any side by side comparison of 80 to 85 mm scopes, including the Pentax, with fixed eyepieces (Televue would be nice)?? :flyaway:
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Pentax PF80 EDa and fixed eyepieces (1 Viewer)
- Thread starter Art Thorn
- Start date
I have never used (tried, but not really used in the field) a scope, but I have read a mixture of opinions on the Pentax scopes. I would like to know more from users regarding the quality of the scope's images. Is there really a quality control issue or is the scope a good high quality photography option? When I do purchase a scope, I would want the flexibility of being able to use a wide variety of standard eyepieces. It would be nice if a reputable review came out in the near future clearing Pentax of any possible quality issues
I think all things being equal, having a wide variety of eyepieces would be anyones deciding factor. Funny how I have never read where anyone complains about limited eyepiece selection for Leica, Zeiss or Swaro. What would a Leica with a Televue eyepiece be like? Maybe I missed something. Do these 3 companies make the 'best' eyepieces? Am I attaching too much importance to eyepiece selection?
Scott
I think all things being equal, having a wide variety of eyepieces would be anyones deciding factor. Funny how I have never read where anyone complains about limited eyepiece selection for Leica, Zeiss or Swaro. What would a Leica with a Televue eyepiece be like? Maybe I missed something. Do these 3 companies make the 'best' eyepieces? Am I attaching too much importance to eyepiece selection?
Scott
The other scopes you mention, Scott, don't have standard 1.25 eyepieces. I have heard that Swaro makes an adapter so that standard eyepieces can be used, but I don't know about the others.
I am interested in the Pentax quality issue also, because of the very mixed reviews, and so am asking, basically, are there problems with the zoom eyepiece (which always seems to be part of the equation) or with the objective, prisms,etc. I have not seen anyone compare the Pentax, with fixed eyepieces, with the other scopes, with fixed eyepieces (their own brands, for example).
I am interested in the Pentax quality issue also, because of the very mixed reviews, and so am asking, basically, are there problems with the zoom eyepiece (which always seems to be part of the equation) or with the objective, prisms,etc. I have not seen anyone compare the Pentax, with fixed eyepieces, with the other scopes, with fixed eyepieces (their own brands, for example).
Pentax Scope
I would say yes. I find a zoom eyepiece a must for birdwatchers. a Fixed eyepiece might have a wider FOV, even in some cases might be sharper, but it's just not enough, in many cases you'll need the extra reach while must of the time 20x is being used.
And back to your question, having one zoom eyepiece is enough and therefore selection is not really that a big thing..
I am, BTW, a very happy owner of the Pentax PF-80. I compared it more then once to other, high end scopes, and I think the price difference is no less then ridicules.
After going through some difficulties in the digiscoping area, I managed to understand the concept and I'm more then happy with the results.
birdeast said:
I would say yes. I find a zoom eyepiece a must for birdwatchers. a Fixed eyepiece might have a wider FOV, even in some cases might be sharper, but it's just not enough, in many cases you'll need the extra reach while must of the time 20x is being used.
And back to your question, having one zoom eyepiece is enough and therefore selection is not really that a big thing..
I am, BTW, a very happy owner of the Pentax PF-80. I compared it more then once to other, high end scopes, and I think the price difference is no less then ridicules.
After going through some difficulties in the digiscoping area, I managed to understand the concept and I'm more then happy with the results.
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Nigel G
Well-known member
I am also a very happy Pentax 80 owner. I make a point of not looking through other peoples scopes and that way I am certain to stay happy and concentrate on my birding rather than catalouges of expensive optics.
I have used the zoom both for general viewing and digiscoping for over a year and got some very satisfactory results. I have also recently purchased the Pentax XW20 (x26) fixed eyepiece primarily for digiscoping - its brighter, has a wider fov and allows less (almost no) zoom on the camera which should give a sharper image. I carry the second eyepiece in my camera bag the but the acqusition is still to new to say with confidence which will routinely be on the scope and which will be the spare.
I have used the zoom both for general viewing and digiscoping for over a year and got some very satisfactory results. I have also recently purchased the Pentax XW20 (x26) fixed eyepiece primarily for digiscoping - its brighter, has a wider fov and allows less (almost no) zoom on the camera which should give a sharper image. I carry the second eyepiece in my camera bag the but the acqusition is still to new to say with confidence which will routinely be on the scope and which will be the spare.
henry link
Well-known member
I borrowed a Pentax 80 about a year ago. It was not a good sample. Star testing showed pinching which caused a large spike in an in-focus star. Image quality was mediocre at best. I briefly compared the zoom eyepiece alone to a Zeiss and Swarovski zoom on my astro scope and found it inferior to both. At high magnification it had considerable lateral CA and also lost sharpness compared to the others. These problems might not be as visible on the Pentax scope. There is also a design flaw in the sizing of the prisms. Their apertures appear to be sized to clear the objective light cone at distant focus. At closer focus the change in position of the moving prism increasingly vignettes the objective so that the effective aperture of the scope is reduced to below 70mm at closest focus. This might be a common problem in scopes that use this type of focuser since bigger prisms add weight, size and cost. A good sample of this scope might still be attractive, but I wouldn't want the Pentax zoom eyepiece, which is expensive, heavy and optically not among the best.
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Robert Ellis
Larus marinus
Interesting Henry, as Pentax eyepieces are thought to be among the best by telescope folks. Too bad about the prism design, I guess I'll scratch the Pentax off my list, would've been nice to have a waterproof refractor that was a fine terrestrial and astronomical unit in one.
henry link
Well-known member
Robert, I don't think the zoom is in the same class with the XW eyepieces. It's difficult to evaluate the high power performance of zoom eyepieces on most birding scopes because at 60x the limiting factor is almost always the objective lens. I don't think you should scratch the Pentax off your list. As with all scopes, the key is getting a good sample.
Robert Ellis
Larus marinus
Whew, good. At this point I would be hard pressed to consider anything with a proprietary bayonet or otherwise limited mount. I was planning a nice set around the straight 80ED with a Williams diagonal and some Pentax XW eyepieces, straight through for birds and angled on the sky. The one 65ED I viewed was very nice though I had nothing to do a direct side by side with. I also might go absoultely nuts and eventually, very eventually for the money, be tempted spring for the 100ED if it is quality. Of course at that point I'd be in the range of some nice SCTs. All I can say is that I am glad I did not buy a cheap scope for the time being.
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henry link
Well-known member
Robert,
You won't be able to use a diagonal on the Pentax 80 and still reach focus. Probably not every astronomical eyepiece and barlow will work on it for the same reason.
You won't be able to use a diagonal on the Pentax 80 and still reach focus. Probably not every astronomical eyepiece and barlow will work on it for the same reason.
Robert Ellis
Larus marinus
Drat, not even with some "adjustments" to the back of the scope? I had been told locally that the Pentax could take a diagonal.
henry link
Well-known member
Robert, Don't take my word for it. I'm guilty of just assuming it can't work because of the 3"-4" focus difference. I'm sure you'll hear from someone who has actually tried it.
Robert Ellis
Larus marinus
Its okay, you aren't ruining my day. That purchase is still months if not more in the future. Even so, I coudl easily still want either the 80ed or 65ed for terrestrial use and stick to a dedicated space tube so that I only need one collection of eyepieces.
Wehr
Well-known member
henry link said:
The variation in optical quality of this kind of scopes is very amazing and seems mostly concern Pentax and Zeiss.
I cannot report any mentioned failure but your result at star testing. In my region all the birders use Zeiss or Leica and the Zeiss-adicted (almost the intire group) gave back their zooms after a short period of testing. Transmission was great, FOV was great but contrast was not.
I never heard that from Leica and about Pentax I never heard anything from our birders, because Pentax is rather unknown here.
I bought my angled Pentax 80 ED because of the ability to use standard eyepieces. My oculars are Zeiss Jena IF-Ww-Planokular F 23,26mm / 65°/ 6 lenses, Radian 18mm, Pentax XL 14mm, Pentax XL 10.5mm, Pentax XW 5mm, Radian 3mm and the big Pentax Zoom. For terrestrial observation the Radian 18mm is the best followed by the Zeiss, which is originally from a military instrument. The Radian 3mm is still useful, but pushes the scope beyond the limits and of course there are situations, where all oculars are better than the zoom (which is true for all brands).
Regarding the star test: I can provocate the same effect with my 4-inch APO refractor by not using a mirror, but the William Optics 45° Image Erecting Prism.
Walter
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Walter,
Variation in the optical quality of telescopes is unfortunately not limited to Zeiss and Pentax. All the brands suffer from it, even Leica and Swarovski. Some might vary less than others, but in all of them I have seen both very excellent and visibly poor units.
I'm sure you can simulate the effect of some aberrations by using an inferior-quality 45-degree erecting prism - indeed, sometimes the problems in birding scopes are due to the prism/s. Sometimes they come from misalignment, sometimes from pinched optics, and in the worse samples are usually a combination of many or all of the above. You might not find the variation quite as amazing if you were to test just how little the complex design needs to be off the optimum adjustment/dimensioning for the results to show readily.
However, the best samples can be remarkably free of aberrations, and even 45-degree prisms in birding scopes can be of such quality that virtually no prism-induced aberrations are visible in a star-test at magnifications up to 180x and beyond.
Also, a very good sample of a Zeiss 85 can have high contrast up to the 60x magnification, although I tend to agree that compared to some of the other top models the Zeiss scope does not excell in the contrast department.
Kimmo
Variation in the optical quality of telescopes is unfortunately not limited to Zeiss and Pentax. All the brands suffer from it, even Leica and Swarovski. Some might vary less than others, but in all of them I have seen both very excellent and visibly poor units.
I'm sure you can simulate the effect of some aberrations by using an inferior-quality 45-degree erecting prism - indeed, sometimes the problems in birding scopes are due to the prism/s. Sometimes they come from misalignment, sometimes from pinched optics, and in the worse samples are usually a combination of many or all of the above. You might not find the variation quite as amazing if you were to test just how little the complex design needs to be off the optimum adjustment/dimensioning for the results to show readily.
However, the best samples can be remarkably free of aberrations, and even 45-degree prisms in birding scopes can be of such quality that virtually no prism-induced aberrations are visible in a star-test at magnifications up to 180x and beyond.
Also, a very good sample of a Zeiss 85 can have high contrast up to the 60x magnification, although I tend to agree that compared to some of the other top models the Zeiss scope does not excell in the contrast department.
Kimmo
Well I now have the Pentax, with zoom, and have spent a bit of time comparing it to an excellent scope, my TV 85 with 9mm Nagler eyepiece. Yes, the TV equipment is better. The Pentax does show some CA, and some of it is in the eyepiece, because I put the zoom in the 85 and there it was. The Pentax, at 60x, does have slightly less contrast then the TV combo, and just perceptably poorer resolution. BUT, I paid 3x as much for the TV, and it's weight and lack of waterproofing make it difficult (or impossible) to use in the field. After trying the Pentax zoom in the 85, I was extremely pleased by its performance (the CA was very slight, not at all bothersome). So I won't be using my TV eyepieces with the Pentax - I'll be perfectly happy with the Pentax combo for birding. When I put it on a Carbon Gitzo tripod (which I also use for my camera), the total package weight is very acceptable. I would have to guess that I got a 'great' sample of both scope and eyepiece, because I would be surprised if any of the other top scopes could come much closer to matching the TV combo, and the price differences make me smile every time I visit the bank! So all of you Pentax users should be smiling too...
medinabrit
Well-known member
i,ll go along with you art . i have both 65 & 80 pentaxes both are exellent ,especially for the price ,i have at least a dozen eye pieces . mainly pentax & tv & they all come to focus in the pentaxes.i just got back from the UK every one who looked thru the 65 pf was quite impressed . i think that the one that kimo looked at must have been an exception . i recently dropped the 80 pf about 5 ft onto my deck & it still performed perfectly. a very sturdy piece of kit
brian
brian
