Fieldscope III 60 HD vs. Pentax 80 ED (1 Viewer)

I look forward to reading this, Henry - many thanks.

Thanks Henry,

That will provide very interesting results indeed. If I may add anything, do you think comparing flare is possible in a reliable sort of way? Also, which Nikon do you have, the MC or the MC II? I don't think their difference is necessarily noticeable in the areas you'll measure, but the MC II does have somewhat improved edge resolution and different eye-relief curve, so the optics must have changed slightly from the MC.

Looking forward to your report.

Kimmo

Thank you so much for doing this, Henry. Really looking forward to the results. Any chance you could also include the Televue (Vixen, Meade, etc) 8-24mm zoom?

Zack

Kimmo and Zack,

The Nikon zoom I have is the original MC. Sorry Zack, I don't know anybody locally who has a Televue/Vixen zoom I could borrow to test.

I just examined the interiors of the Nikon, Swarovski and Zeiss zooms at their shortest focal lengths, looking for internal reflections close enough to the exit pupil to cause flare. At its shortest focal length the Nikon has a relatively bright ring about 4-5mm in diameter (measured by placing a ruler across the eyelens). That one is small enough to perhaps allow some flare to enter the eye under the right lighting conditions. The Zeiss has several bright rings, but the smallest is 7mm. The Swarovski is quite well baffled with a dim ring at about 12mm and a bright one at about 17mm. Is this the sort of "flare" you mean, Kimmo, or have you experienced flare from the eyepiece glass itself? Virtually all the flare I have seen has come from internal surfaces near the exit pupil edge. I've never noticed any flare with any of these zooms used in the Stowaway which has a thoroughly baffled tube so that the area between the exit pupil and the first eyepiece internal reflection is completely black. I'll try to look for it.

Henry

kabsetz said:

Henry,

I know this is a bit (but not entirely) off-topic for this thread, but would you care to provide us with a detailed comparison of the Pentax, Leica, Zeiss and Nikon zooms since you are in the unique position of being able to test them all in the same scope, and what is more, a scope that is undoubtedly better than any of the scopes the zooms are made for.

I, for one, would be most interested and grateful.

Kimmo

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Hi Kimmo,

I've read lots of the reviews on Alula and loved them. I agree with most of what is there. After reading your review on the Nikon Fieldscope III ED I wondered if you really liked the scope or not? Wasn't sure? I will be performing my own tests this weekend with a Nikon Fieldscope III ED 60 with Nikon 30X WA eyepiece vs. The Pentax 65 ED with a Pentax 12mm XW (the highest end Pentax eyepiece). Any of your knowledge or informative comments on this would be great. I am doing this amateur review for the eyeglass wearers that want a small scope and cant use a zoom. Any predictions on which will outperform the other?

Anyone else's comments on this would be aprecciated as well.

Thanks in the future,
Carlos

Henry,

Thanks for your observations. What I mean by flare are, on closer reflection (pun intended) perhaps two things. One is whether or not there are perceptible differences in flare in the image when you are viewing daytime or nightime objects with the Stowaway. You basically answered that above, saying no. Maybe the moon would be the acid test, but if you have not noticed any flare in daytime use, then the eyepieces are likely all good in this respect. The other phenomenon, which is not actually flare but also results from unwanted reflections in the eyepiece, is the brightening or coloring of the image periphery (the very edge). The Nikon MC (I) especially at smallest magnification had a distinct yellow ring around the periphery, which has pretty much been cleaned away from MC II. I think the ring came from reflections from the field lens edge reaching the eye, as the edge was not blackened and not covered enough by the field stop.

Carlos,

I actually do like the Fieldscope III, it is just that I'm in general pretty lukewarm towards small scopes as the bigger ones perform (in my view) so much better. Among the 60-65mm variety, I like the Swaro best and Nikon second among the ones I have tested. For eyeglass-users the Swaro zoom is tons better, otherwise their differences are not great at all.

The one advantage of small scopes is that their quality seems to be somewhat more consistent, so the lemon-cherry spread may not be so wide.

I am quite convinced that the old wisdom according to which small scopes perform better in poor seeing is a false interpretation of observable differences which arise when you compare a small scope which comes closer to its diffraction-limited performance (i.e. has fewer aberration) against a large one which has more aberrations, but in steady seeing can nevertheless outresolve the smaller scope.

When I have compared scopes of different sizes which star-test similarly (have similar overall aberration totals) there has been no advantage to the smaller scope in poor seeing. This is a bit off-topic, but relevant to the 60-65 vs. 77-85 dilemma.

I'm glad you've enjoyed my reviews.

Kimmo

help with Nikon zoom eyepieces

Dear Henry and Kimmo,

In light of your recent posts on flare in zoom eyepieces I am hoping that you can help me with a problem. I currently have in my possession two Nikon MC II zoom eyepieces, one of which I shall keep. I have until tomorrow (Friday) to decide which of the two it shall be. It has, however, been extremely difficult for me to judge between the two: alternating back and forth between them on the same scope is not very productive. After reading your posts, I examined the interiors of the two eyepieces and found the following: in both, there is an initial, slender, bright inner ring; that slender ring is followed by an area of darkness; that area of darkness is in turn followed by a broader, bright ring. In one eyepiece, however, the area of darkness between the two bright rings is slightly larger (broader or wider), which then gives the outer ring in that eyepiece a slightly more well-defined appearance. Is the difference between the interiors of the eyepieces significant in determining which of the two is the better choice? Are there are other ways of testing the eyepieces that you can recommend?

I would be truly grateful for your feedback in this area.

Thank you.

Best,
Avron

Avron,

I set up a situation to see if I could detect a flare problem from the smallest reflection ring I see at maximum magnificationin with my Nikon MC zoom. I pointed the Stowaway at a dark tree trunk about 5 degrees from the sun. I could actually see sunlight falling on the interior of the telescope tube. There was no obvious flare in the image but there did seem to be a slight loss of contrast through the Nikon zoom compared to the very well baffled Swarovski zoom. It's possible that at a lower light level with my eye opened wider I might see some flare in very difficult light, but I think this kind of flare (an out of focus reflection at the edge of the field) is much more likely to come from the prism housing, focusing element or telescope tube rather than the eyepiece.

Perhaps Kimmo will have something to suggest, but I think if comparing the two eyepieces on your scope at both high and low magnification doesn't produce any difference you can see, then probably there isn't one.

BTW, Kimmo I do see the yellow ring at low power now that you mention it.

Henry

Hello Henry,

Thank you for your quick response. Unhappily, it appears that I failed to be clear in my first post. Please let me try again. When I looked at the two Nikon MC II eyepieces, I did so with each of them removed from the scope, holding them side by side in my hands, with the zoom set to 60x in both. It was under those conditions that I noticed the difference in the patterns of light that I could see in each of them: moving outwards from the center, in each there was, first, a slender bright ring, followed by an area of darkness, and, finally, a broader, bright outer ring. But, again, what struck me was that in one eyepiece the area of darkness between the two bright rings was slightly larger, giving the bright outer ring in that eyepiece a slightly more well-defined appearance. It was in light of the difference between the two eyepieces when viewed independently of the scope that I wondered whether the difference between their interiors made one the better choice.

I apologize for the extra work that I have caused you. If the above is significant in any way, I would be grateful if you would let me know.

Thanks.

Avron

Avron,

Sorry I didn't directly address what you see inside the eyepieces. I doubt that there is any significance, but I am surprised that you see any difference at all since the construction should be identical. What you see might indicate that the moving field lens in one was placed a little farther away from the rest of the elements than in the other. Try placing one eyepiece to one eye and the other eyepiece to the other eye and check to see if the two field circles are exactly the same size. Now try each on the scope and check to see if the real fields are identical by noting objects at the very edge of the field in one compared to the other. One could have slightly more magnification than the other which may either make its field circle a little larger or its real field smaller at "60X" and might change the internal appearance. If this is true I'd go for the one with the higher magnification if everything elso is equal. Also check the reflections you see coming back from the coatings. If one eyepiece has darker coating reflections it's light transmission may be a little higher.

Henry

Henry,

I'm sorry I have made you aware of a flaw (albeit minor) that you were blissfully ignorant of before. Now you'll have to buy the MC II.

Avron,

Being an obsessive sort, I have when I had the chance, compared a bunch of zooms in order to purchase "the best one". I tested them with a booster, which yielded no reliably repeatable differences between the dozen or so I had at hand. I thought some of them were perhaps marginally sharper than others, but even now I could not swear there were any real differences. So, in this respect, I feel confident in saying that compared to unit-to-unit differences in the scopes themselves, differences in eyepieces are insignificant when it comes to resolution. I did not even try to assess differences in flare or light transmission. However, what I focused on was ease of view. I did note that some specimen were slightly easier to view with than others, and the best one, the one I finally settled on, was both imaginably sharper and repeatably and reliably easier and more relaxed to view with. My eye was happier with it, and I found it snapping to focus a bit better. I have a similar experience with Leica zoom eyepieces, although that time it was a friend of mine who was doing the choosing, and I must admit that although he was sure one of them was better than the others, I was back then not convinced that there was a real difference. So, if I were you I would pretty much ignore everything else and just do A/B swaps and try to see if I found one more relaxing and natural to view with than the other. If not, toss a coin. I think it is conceivable that with lens elements as small as they are in the zooms and with a 1mm exit pupil, the light bundle entering the eye which forms the area of the sharpest central image travels through a very tiny area of glass, and if this area is slightly less smoothly ground in one lens than in another, the smoother figure might give a more relaxing view.

Kimmo

Henry,

Thank you for the advice on checking the field circles, real fields, and the reflections from coatings in the two eyepieces. The fields in each seem identical, at least to me. If I understand your suggestion about reflections coming from the coatings, then the two eyepieces are distinct, with one certainly having darker reflections than the other. It is interesting that this might translate into higher light transmission. (I assume here that you are referring to the circles of light and dark that one can see simply by looking at the eyepiece when it is not attached to the scope.) It is also interesting that eyepiece with the darker reflections is the one whose the reflections are less well defined. It is not possible for me to tell whether this translates into increased brightness or sharpness in practice, possibly due to the very clear, bright weather in Toronto the last few days.

Kimmo,

Following your suggestions, I have a sense, although not a strong one, that one eyepiece is marginally easier to snap to focus than the other. I am not sure that it is a more relaxing eyepiece overall. Interestingly, it is the piece with the darker reflections coming from the coatings. One of the reasons that I am experimenting with the eyepieces is that, on one occasion, when comparing two Nikon eyepieces in the same scope, the optical differences were quite pronounced. One seemed to have what was either greater contrast or color saturation, while the other seemed clearly sharper. How does one choose in such a case? And I very much appreciate your comment about obsessive sorts: after a day of going back and forth between the two eyepieces, it is a miracle that my scope has any of its thread left.

Thanks to both of you. If you have additional comments, I’d be delighted to hear them.

All the best,
Avron

The reflections I mean are the tiny mirror like reflections returning from the glass surface; for instance the reflection of a window over your shoulder as you look at the eyepiece. These reflections are the light being rejected by the glass surface, so the darker they are the less light is being rejected and more is being transmitted through the glass. I have read that different batches of the same multi-coating may vary from a loss of .2% per surface to .5%. In a complex eyepiece with 8 to 10 surfaces that might result in a 2%-3% difference. Barely visible if vislble at all, but perhaps a little bit of a reason for choosing one over the other. I've found Nikon coatings to be pretty consistent.

Hello Henry,

I have just now had the opportunity to try to evaluate the two Nikon eyepieces in light of your having corrected my misunderstanding of your previous response. I do hope that I have it right this time. With a window at my back, I viewed the reflections from the window in the two eyepieces simultaneously. I made sure that in each eyepiece I was able to see the same image reflected, a view of two houses across the street (one with red brick, one with yellow brick). I was also able to see the sky above them. The difference in what eyepiece showed was quite astonishinf. In one eyepiece, the colors of the houses and sky were rendered quite faithfully. In the other eyepiece, the colors were significantly darker and had an overall greenish hue or tinge. I do not know whether the greenish tinge is a product of (and is what you meant by) the darker reflection that one eyepiece might produce or whether it is a separate phenomenon. Is there anything that you can tell me about this?

I appreciate your patience as I learn about ways of carefully checking optics.

Thank you.

Avron

Avron,

The green tint is normal for Nikon multi-coatings. Your description of the other eyepiece reads like the outside glass surface isn't coated at all. Very odd! I'd go for the dark one.

Henry

I have the Nikon Fieldscope III 60 ED and love it. I chose this over the Nikon 78 because of its design and the fact that it was waterproof. Nikon has since come out with a similar scope design in an 82 mm scope. The 82 will have the advantage of brightness and image size which are both important in digiscoping. If digiscoping is important to you, the fixed eyepiece 30 (38 on the 82 mm) X WA is needed. It is a fairly compact scope for 82 mm.

kabsetz said:

Carlos,

I actually do like the Fieldscope III, it is just that I'm in general pretty lukewarm towards small scopes as the bigger ones perform (in my view) so much better. Among the 60-65mm variety, I like the Swaro best and Nikon second among the ones I have tested. For eyeglass-users the Swaro zoom is tons better, otherwise their differences are not great at all.

The one advantage of small scopes is that their quality seems to be somewhat more consistent, so the lemon-cherry spread may not be so wide.

I am quite convinced that the old wisdom according to which small scopes perform better in poor seeing is a false interpretation of observable differences which arise when you compare a small scope which comes closer to its diffraction-limited performance (i.e. has fewer aberration) against a large one which has more aberrations, but in steady seeing can nevertheless outresolve the smaller scope.

When I have compared scopes of different sizes which star-test similarly (have similar overall aberration totals) there has been no advantage to the smaller scope in poor seeing. This is a bit off-topic, but relevant to the 60-65 vs. 77-85 dilemma.

I'm glad you've enjoyed my reviews.

Kimmo

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Hi Kimmo,

Thanks for all the great advice.

First impressions with Nikon 60 ED Fieldscope III vs. Pentax 65 ED- Yes the Nikon Fieldscope III ED is amazing. And The Pentax 65 ED is not too shabby but eye placement in the Penxtax XW 14mm eyepiece (even with lots of eye relief) is crucial. Still, I did not like the Pentax eyepiece it's a lot bulk for the lack of performance in comparisson to the small Nikon 30X WA MC. Still the Pentax performed well and held it's own for the money but the colors, contrast, sharpness was about an extra 15% difference. I think the Nikon is about 15% more expensive than the Pentax and you get that in the the optics as well.

Thank you very much,
Carlos

Dave B Smith said:

I have the Nikon Fieldscope III 60 ED and love it. I chose this over the Nikon 78 because of its design and the fact that it was waterproof. Nikon has since come out with a similar scope design in an 82 mm scope. The 82 will have the advantage of brightness and image size which are both important in digiscoping. If digiscoping is important to you, the fixed eyepiece 30 (38 on the 82 mm) X WA is needed. It is a fairly compact scope for 82 mm.

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Hi - my son has the ED82 and it is a particularly fine scope - so compact compared with other top makes. The EDIII is a very bright scope, though - I doubt in the vast majority of cases the eye would tell the difference except at extremes of light level.

scampo said:

I really am thinking you need to try these scopes. The eye-relief is hardly an issue at all unless you wear spectacles of a certain style. My son has the Nikon, I have the Zeiss, my brother the Swaro. They all have pros and cons - even the Swaro does not excel except on price and, if you like it, the rubberised coating.

The Zeiss is my favourite birding scope with its uniquely wide zoom, the Nikon is the best in terms of edge to edge sharpness and its magnificently faithful view; the Swaro is contrasty and sharp.

I think the Pentax is very good value but I've heard it's heavy. That matters on a long walk without doubt. I doubt you'll make a satisfying decision without trying them out first, but buying blind I'd go for the Zeiss 65 or 85.

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Thanks. Oh, yes, I'll try them when I can get to a dealer again (not easy here). I did try them when I initially picked out the scope I wanted, but things changed when I got the Pentax as a gift (as I was looking in a lower price range). I will try them again before I make a final decision. However, without a lot of experience, I can only trust myself so far. Reviews and expert opinions are important to me. It's been a while since I revisited this thread. My current bent is to go for the Nikon 82, but I need to see it alongside the Pentax before I make my final decision.

Dave B Smith said:

I have the Nikon Fieldscope III 60 ED and love it. I chose this over the Nikon 78 because of its design and the fact that it was waterproof. Nikon has since come out with a similar scope design in an 82 mm scope. The 82 will have the advantage of brightness and image size which are both important in digiscoping. If digiscoping is important to you, the fixed eyepiece 30 (38 on the 82 mm) X WA is needed. It is a fairly compact scope for 82 mm.

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Thanks for the input, especially as regards the eyepiece. I'm leaning toward the angled Nikon 82, though, and I'm a bit concerned that I'll have a hard time aiming the 30x eyepiece (eye relief is an issue for me re: the zooms).