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APM MS 20x80 ED - A Brief Comparative Review

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#1 Pinac

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Posted 11 February 2018 - 09:35 AM

APM MS 20x80 ED – A Brief Comparative Review

 

Part 1 of 3

 

 

Introduction

 

This is a brief comparative review of the new APM MS 20x80 ED binocular. After a brief look at the current market of 20x binos, I compare the APM with what I hope is in some way a representative selection of 20x80 instruments.

To keep things simple, I only took into account the straight-through, fixed-eyepiece, non-zoom binoculars and left all the 45 degree and 90 degree binocular telescopes, as well as the straight-through Docter Aspectem (with vario-zoom eyepiece set to 20x), which is in a league of its own, aside.
 

This is a preliminary review. Conditions for night sky observations have been abysmal during the last few months, and the next few weeks seem not to improve dramatically. So I will follow up this first review, which is based on daytime observations, in-house tests and a very limited time under a less than perfect night sky, with further findings once this becomes possible (at that time I will also try to compare the APM 20x80 ED with the 20x70 ED model).

 

The market of 20x binoculars

 

Of the thirty or so 20x binocular models I have come across in a brief search (see attached Overview “20x Binoculars”), almost all (26) have the configuration 20x80, only 2 are 20x70, another 2 are 20x60 (stabilized Zeiss, Pentax) and one is 20x56 (Nikon Monarch 5).

Of course, the above is not a reliable count; not only will there be other brands and models that I have not immediately found, but of the 20x80 models, many are one and the same optics, just slightly differently packed (and sometimes not even that, only differently branded).
 

15, i.e. a majority, of the 20x80 binos in the list feature a central focusing mechanism, 11 have individual focusing.

Missing from the list are the Vixen ARK 20x80 and the (identical) Opticron WP Observation 20x80 - Vixen has apparently discontinued selling the ARK, and Opticron on their website lists theirs as „Sold Out“.
 

Nevertheless, 20x80 seems to be a popular size. Why?
 

First, it will be interesting to discuss why 20x80 seems so much more popular than 20x70. Only Celestron and APM are today offering a size 20x70 bino (APM only in an ED version, since the former Lunt MS have been phased out). Comparing the new 20x80 ED from APM with APM’s 20x70 ED model, at first glance their image characteristics are very similar with identical FOVs, the 20x80 appears just marginally brighter, and it is of course about 500g heavier and also a bit larger than the 20x70. Why does everybody go for 20x80?
Holger Merlitz recently wrote that for astro uses, an exit pupil of 5mm would be the best compromise, so that 20x100 or 16x80 would be better options than 20x80. Nevertheless, 20x80 is sold everywhere.
 

Second, if you look at the high end of the 20x80 market, for only little more money, several models of (non-ED) binocular telescopes become available that not only allow to change eyepieces / magnifications, but also offer the more comfortable 45 degree or 90 degree viewing configuration. So why would anybody spend close to € 900 for a straight-through, fixed-eyepiece 20x80 model with all its limitations? Are ease of handling, and less weight, simpler mount/tripods options etc. the important factors? Questions awaiting an answer.
 

The cheapest of the 20x80 binoculars in the attached list are sold below $ 100, the most expensive above $ 1’200. A large number costs between about $150 and $350. The new APM ED figures at the upper end of the price scale, only the Steiner and the Newcon cost even more. The non-ED version of the APM is in good company with the Helios LightQuest HR and the Omegon Argus at the upper third of the range.
 

I have tried not to speculate too much as to which of the different brands and models are in fact similar or even identical in optical design and performance. I am confident that, e.g., the Omegon Argus and the non-ED APM MS are basically identical instruments. Many others are identical or very similar in their specifications and seem often only slightly modified versions of a basic design/build. Still others look extremely similar from the outside with identical dimensions, shape, mechanical elements etc. (Celestron Skymaster basic version and Opticron Oregon) but have very different „interiors“ and perform quite differently, so appearances are sometimes deceiving.

Attached Thumbnails

  • Market fo 20x Binoculars.png

Edited by Pinac, 11 February 2018 - 10:03 AM.

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#2 Pinac

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Posted 11 February 2018 - 09:38 AM

APM MS 20x80 ED – A Brief Comparative Review

 

Part 2 of 3

 

 

The six binoculars in  this review

 

I hope that my selection of six different models may allow for a meaningful comparison.
Two are from the lower end of the price spectrum (below €200, the basic Skymaster and the Opticron), two from the middle to upper range (over €200 to below €700, the Omegon and the Skymaster Pro) and two from the highest section (over €800, Steiner and APM ED). It would have been useful to add something mid-priced like the Helios LightQuest HR or an Oberwerk Deluxe III to the group, but that was not possible.
 

Three of the binos feature IF, and three CF focusing; this was not intended but just happened to be so. For astro use, CF has no advantage in my opinion, and I personally prefer IF.

 

Rating the APM 20x80 ED and comparing it to its five competitors
(cf. attached table)


GENERAL

At first glance, only the mark “ED” in red distinguishes the new APM from its non-ED brother (or from the similar Omegon). As those latter models, it is well built and finished, with pleasant haptics. It and the Omegon are the largest of the binos in this review, and also the heaviest, since they are the only ones with a magnesium body. The others, including the Steiner, have a plastic body (which is not necessarily a bad thing; esp. Steiner with its huge military markets has lots of experience with plastic housings and covers its best models with a 30-year warranty).

The Steiner, with its green armour and “military look” is somewhat an outsider among astro binos, and I might not have come across it if some optics shops had not recently offered it for a substantial discount on the UVP.

While the Steiner comes with a relatively solid useful bag and the others with some sort of standard bags as well, the APM is accompanied by a very nice, new “trendy” bag, much nicer than the previous typically Chinese bag for the non-ED version or for the Omegon.

 

All contestants except the Omegon APM are fitted with a central metal bar with a  vertical tripod adapter; the Omegon comes with a standard tripod adapter hat is screwed into the front end of the hinge, same as for all Lunt and APM binos. The new APM, however, comes with a novelty (see pictures provided recently by Markus Ludes): a relatively short metal bar that is screwed into the font end of the hinge, on which a long movable vertical tripod adapter is attached that allows to nicely balance the APM on its center of gravity depending on which angle you are observing at, as if it also had a central metal bar like the others, but removable; so if you want to use the APM with other forms of mounts (Berlebach or so), you can easily do that.


MECHANICS

Folding or unfolding the hinge is sufficiently stiff on the tested APM, similar to the Opticron. While the Omegon and the two Skymasters have a moderately stiff central hinge, the Steiner’s hinge is too stiff and needs quite some force to adjust.

With my relatively narrow IPD, I have come to fold down the eyecups on all binos to achieve a more comfortable viewing position, which worked well on all tested models except for the Steiner, which has eyecups that are labelled “foldable”, but I have never managed to really fold them down (this has consequences for eye placement and ease of view, see below).
 

On the APM, Omegon and Steiner, each eyepiece if focused individually, easy to turn on the APM and Omegon, quite stiff on the Steiner. The Skymaster, Skymaster Pro and Opticron have central focusing with satisfactory precision on the mechanism and little rocking of the bridge. On all instruments, the “0” mark corresponds reasonably well to 0 dpt.
 

All binos are specified “waterproof”, except the Opticron. Opticron does not mention whether they consider the Oregon at least splashproof or not.

 

OPTICS

All instruments exhibit little vignetting.

The APM and the Steiner both have nice and relatively dark areas around the exit pupils with no false pupils. The Opticron also shows some brightness around the EP, but no false pupils.
The Omegon and the two Skymasters clearly exhibit one or several false pupils, beside some bright structures and reflections around the EP.
 

Collimation / alignment was good on all reviewed binoculars.
 

Comfortable eye placement and ease of viewing the entire field of view is good on all, except the Steiner. The latter has eyecups that are okay form a comfort point of view, but that I am not able to fold down, which keeps me from seeing the entire field of view.

The APM, Omegon and Opticron all have RFOVs of roughly 3.3 degrees, translating into 57-58m. The Skymaster is labelled 3.7 degrees = 65m, but that difference is hardly visible in my eyes. The Skymaster Pro has a RFOV of 3.2 degrees, the Steiner only 3.0 degrees = 53m, but because of the configuration of the eyecups and possibly some other reason, the field of view in the Steiner appears even narrower than specified.
 

Eye relief appears okay on all binoculars in the review (I observe without glasses, so spectacle wearers should verify this statement for themselves).
 

Now, as to the “pièce de résistance”, i.e. the image produced by the reviewed binoculars:
 

The APM shows very good central sharpness and contrast, it appeared better than in the other binos, except perhaps the Steiner, which shows similarly good sharpness on axis.
The Omegon and the Opticron appear slightly less sharp on axis, but still good, whereas the two Skymasters fill the “bottom ranks” in this discipline.

A note here about the Skymaster and the Skymaster Pro: the only clearly recognizable difference I found between the two consists of a brighter image in the Pro version; in all other respects, the Pro did not do substantially better than the basic Skymaster.
 

In the APM, the central sharpness covers a nice wide area and only starts deteriorating at about 80-90% going from the center of the image towards the edge, and beyond that, peripheral sharpness is still quite good.
The same is true for the Steiner (but you have to take into account the narrower FOV of the Steiner!).
The Omegon is reasonably sharp within about 60%, the Skymasters deteriorate much faster (40%) and also show very blurred peripheral parts of the image.
A positive surprise for me here was the Opticron: it has quite a wide sharp part of the FOV, I would estimate at least 80% going outwards, and beyond that still showed satisfactory peripheral sharpness.
 

The APM exhibits little CA, almost none for my eyes in the center, and only a little bit colour further out. The ED glass here really makes for a substantial difference, esp. when compared to the (non-ED) Omegon.
The Steiner is almost as good, the Skymasters and the Opticron show some – not much – CA, but this is visible also at the center, whereas the Omegon disappointed me with considerable CA throughout. I have to say that this was not a “stable” finding, a lot depends on your eye placement behind the EP, but still, the Omegon appears to be the most delicate in that respect.
 

The image of the APM is brilliant and bright and shows colours naturally, my eyes could not detect any significant tint.
Brightness is also good in the other binos except the basic Skymaster, which has not a very brilliant image.
Moreover, in my eyes all except the APM and the Steiner show some form of tint or hue: quite pronounced in the Opticron is a reddish/pinkish sort of tint, which does not seem to affect brightness much but appears to slightly diminish contrast on some objects.

The two Skymasters and the Omegon all exhibit a little “warmth” in their image (I could have used the word “yellow”, but that might be misinterpreted as a strong tint, which it is not).
 

Reflections from bright objects outside the field of view / stray-light suppression / ghosting:
{{ Note: this was tested using a bright focused LED pocket light; tests on the night sky remain to be performed once possible (weather) }}

The Steiner performs best in this: no significant ghosting, and little reflections.

The APM and Omegon show a little ghosting and some reflections, even some glaring veil (but this should not be overvalued, since objects on the night sky, including the moon, are less bright than the LED source used here).

The Opticron and the two Skymasters exhibit some ghosting of bright objects and considerable amounts of reflections (when panned around a bright light source), but again that needs to be verified under “natural viewing conditions”.
 

The APM 20x80 ED: VERY BRIEF IMPRESSIONS FROM THE NIGHT SKY
 

Moon: Wonderful sharp and bright in the APM; the almost total absence of colour fringes makes this a very pleasant view, the usual greenish fringe at one edge and orange fringe at the other edge of the moon disk as seen in many binos are missing. This makes the moon stand out even more against a dark background! Almost too bright.
 

M42: conditions not ideal, sky too bright and also humid, but shape of nebula clear and distinctly visible. EdZ once wrote that with a 20x80 “…you can sometimes pick out all four stars in the Trapezium, the closest being 8.7”…” (CN post Sep.17, 2004).
I tried under less than perfect conditions and could clearly separate A and D from C; B was at the limit, I thought I could see it, but maybe that’s only because I knew it was there, so the sighting of B was not a reliable finding.
The Omegon and Steiner showed 3 stars, slightly less clear than the APM. The others clearly showed 2 stars, maybe 3. Again, viewing conditions were not great.
 

 

IN LIEU OF A SUMMARY REGARDING THE OPTICS

 

APM ED: bright, sharp, almost no CA, difference to Omegon Argus (or the non-ED APM as well) is significant, also in terms of sharpness and contrast. Image brilliant, high colour fidelity.
 

OMEGON ARGUS: brighter and much sharper than the Celestrons, central sharpness good and comparable almost with Steiner, but sweet spot smaller, edge sharpness mediocre. Significant CA. Image slightly warm.
 

SKYMASTERS: tiny sweet spot, the Pro clearly brighter than the standard model, both a bit yellowish image, sharpness only slightly better in the Pro, edge sharpness nothing to write home about. Quite a bit of CA.
 

OPTICRON: size and shape seem to indicate basically same product as Celestron, but internal and optics actually quite different. Relatively bright, brighter than even Skymaster Pro, central sharpness good and the best among the cheap participants, but not quite as good as APM and slightly behind the Steiner. Contrast is not as good as in the Omegon. Much wider sweet spot than the others, edge sharpness actually quite good, better than most others.  Slightly reddish / pinkish tint or hue. Some CA.
 

STEINER: FOV seems much narrower than expected and specified, but this is in part due to the eyecups which cannot really be folded down properly. Good central sharpness, almost as good as APM, relatively good edge sharpness, brightness okay but not very brilliant image. A bit of a tunnel vision effect.

Attached Files


Edited by Pinac, 11 February 2018 - 09:51 AM.

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#3 Pinac

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Posted 11 February 2018 - 09:39 AM

APM MS 20x80 ED – A Brief Comparative Review

 

Part 3 of 3

 

PRELIMINARY CONCLUSIONS
{{To be followed with more detailed night sky observations and a comparison with size 20x70}}

 

Not surprisingly, the APM ED offers overall the best performance of the reviewed group of 20x80 binoculars. I don’t think you would currently find a better 20x80 astro bino (my guess is that the Newcon 20x80 sold by a Canadian company for a lot of money is in fact substantially identical with the Omegon Argus or APM non-ED).

APM continues to feed the market with innovative quality instruments, and I hope they keep doing so. However, they do not come cheap. But if you can afford the APM, this is likely to be the bino of choice.

The next best thing might be the Omegon Argus (or the non-ED APM), but the roughly € 200 less will be felt in a clearly lower performance.

Among the cheap options, the Opticron Oregon has positively surprised me. I would prefer it over the universal Celestrons.

 

The Steiner seems a bit of a costly outsider, but its narrow FOV aside, it is well built, does have sturdy mechanics and good optics.

 

 

For what it’s worth.
Pinac

 

below from right: APM - Omegon - SkyMaster - Opticron - SkyMaster Pro - Steiner

Attached Thumbnails

  • IMG_9645.PNG

Edited by Pinac, 11 February 2018 - 09:57 AM.

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#4 garret

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Posted 11 February 2018 - 11:17 AM

Many thanks for your review Pinac, owning so many binoculars is very expensive. 

 

Questions:

How good are the anti reflection coatings? are they fully multi coating including the prism?

How about internal baffling and darkening?

 

 

APM continues to feed the market with innovative quality instruments, and I hope they keep doing so. However, they do not come cheap. But if you can afford the APM, this is likely to be the bino of choice

APM's  pricing is changing with the season, currently the 70mm ED binocular series is selling for 609 euro's, including 19% tax, I bet you have the 80mm series for 700 euro by the end of the year.

 

Garret vd Veen



#5 Pinac

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Posted 11 February 2018 - 11:41 AM

Thanks Garrett.

Yes, I spend a lot on binos (you might consider me a "pathological collector"), but I drive an Opel instead of a Mercedes, and I have neither been to the Maledives nor the Seychelles nor Barbados ....

wink.gif
 

I cannot comment on APM's pricing policy. Currently, they are moving shop and offices, so things may be a bit different anyway for a while.

 

As far as I know, the APMs are FMC in the real sense of the word , i.e. on all optical surfaces. Markus Ludes might confirm or correct me. Baffling and darkening are well executed, see for yourself in the attached image (green reflections are from the lamp illuminating the tube for the photo).

 

Pinac

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Edited by Pinac, 11 February 2018 - 11:50 AM.

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#6 Mad Matt

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Posted 11 February 2018 - 05:10 PM

Many thanks Pinac! Excellent review! I can’t wait to here you impressions when you get the APM und some really dark skies! 👍😁

#7 Pinac

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Posted 12 February 2018 - 01:04 AM

Thanks, Matt. I can‘t wait either.

I think the last few months, the weather gods have been upset by something - maybe you have not been good lately? wink.gif


Edited by Pinac, 12 February 2018 - 01:04 AM.


#8 Mad Matt

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Posted 12 February 2018 - 03:23 AM

Thanks, Matt. I can‘t wait either.

I think the last few months, the weather gods have been upset by something - maybe you have not been good lately? wink.gif

It wasn't me... I have been a good boy and have been eating all of my dinner smile.gif


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#9 Gyna

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Posted 12 February 2018 - 06:48 AM

Thank you Pinac,

great review. Too bad you didn't consider the CBS Tordalk 22x80 in your test...! Seriously, I'm still waiting for a modern center focus 20x80 with the APM ED quality and price tag. Marcus Ludes, can you ear me?!?

 

Marco



#10 TORSTI

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Posted 17 February 2018 - 01:29 AM

Nice review, thanks. I,m also the one who is waiting your dark sky impressions. Last week i got ms16x80ed, but still waiting tripod for it. 

 

Jyrki



#11 Pinac

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Posted 17 February 2018 - 02:08 AM

Thanks  Jyrki.

Will update my report once possible (raining again today here... frown.gif )

And:

Looking forward to hearing from you about your 16x80 - should be a pretty impressive glass !

 

Pinac



#12 TORSTI

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Posted 17 February 2018 - 03:08 AM

Hi. I will try to tell something about it, when the weather(again)favor, and the tripod is here. I tried it handheld, and it was almost impossible to keep it steady, due the weight/mag. But, what i saw, looks very promising. My first, and only bino before this, was Fuji 10x70fmt-sx. That was really great instrument. I sold it over ten years ago. Never really understanding why? I hope that this will be even better than Fuji.

 

Jyrki



#13 Magellanico

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Posted 17 February 2018 - 11:17 AM

Thank you for your review.

BTW, have you tested the true working aperture?


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#14 Rich V.

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Posted 17 February 2018 - 02:17 PM

This report was a great read, Pinac.  Thanks for your efforts.  bow.gif

 

I see in your long list of binos that you have a Nikon 18x70; how do the 20x80EDs compare with them?   Edge of field correction and on-axis sharpness in particular.   From my experience with the 70mm EDs, I already expect the 80mm APMs will show much less CA and have a better corrected FOV.  wink.gif

 

Rich



#15 Rich V.

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Posted 17 February 2018 - 02:48 PM

Thank you for your review.

BTW, have you tested the true working aperture?

The 70mm EDs measure the full 70mm aperture; I'd expect the same from the 80s of this series.

 

Rich



#16 Pinac

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Posted 17 February 2018 - 05:30 PM

.....

BTW, have you tested the true working aperture?

 

I didn‘t.

The reason is simple (and in line with what Rich wrote): Marcus couldn‘t show his face here at CN anymore if the 80 series didn‘t work at full aperture ...lol.gif , and so I did not have to test.

But maybe I will test sometime, just to get that hint of doubt out of the way which you triggered with your question wink.gif


Edited by Pinac, 17 February 2018 - 05:31 PM.

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#17 Pinac

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Posted 17 February 2018 - 05:33 PM

This report was a great read, Pinac.  Thanks for your efforts.  bow.gif

 

I see in your long list of binos that you have a Nikon 18x70; how do the 20x80EDs compare with them?   Edge of field correction and on-axis sharpness in particular.   From my experience with the 70mm EDs, I already expect the 80mm APMs will show much less CA and have a better corrected FOV.  wink.gif

 

Rich

 

Thank you, Rich.

 

Let me get back on that.

 

Pinac


Edited by Pinac, 17 February 2018 - 05:33 PM.


#18 Pinac

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Posted 18 February 2018 - 12:40 PM

Thank you for your review.

BTW, have you tested the true working aperture?


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#19 Pinac

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Posted 18 February 2018 - 12:41 PM

Thank you for your review.

BTW, have you tested the true working aperture?

 

APM MS 20x80 ED: see photo.

Is it 80mm, or 79mm ? Anyway, the APM virtually operates at full aperture - do I hear a sigh of relief from Markus  ?...smile.gif

 

80mm, by the way, is also what the Omegon works at. And the Celestron SkyMaster Pro. Well done !

 

Not the standard Skymaster, though: just 73mm.

 

The Steiner - expensive outsider - reaches disappointing 75mm. I would not have expected that.

 

The cheapest, Opticron Oregon, brings up the rear: 70mm (but still, it's image qualities, especially brightness, and edge sharpness,  convince me much more than the two Celestrons).

 

For what it's worth.
Pinac

Attached Thumbnails

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Edited by Pinac, 18 February 2018 - 12:50 PM.

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#20 mmx_4

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Posted 19 February 2018 - 10:35 PM

thanks for nice review .

Can you measure eye relief ?

17mm from frame (as in many other binoculars) or from lens (as in Zeiss) ?


Edited by mmx_4, 19 February 2018 - 10:37 PM.


#21 range88

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Posted 20 February 2018 - 01:58 AM

This is a truly informative article though the result does not surprise me.



#22 Riccardo_italy

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Posted 20 February 2018 - 03:27 AM

80mm, by the way, is also what the Omegon works at. And the Celestron SkyMaster Pro. Well done !

 

I had the Skymaster PRO 70mm. I can confirm, they also work at full aperture; beautiful, well-constructed and reasonably priced binoculars. However I returned them - too much CA for daytime use.


Edited by Riccardo_italy, 20 February 2018 - 03:28 AM.


#23 Pinac

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Posted 20 February 2018 - 04:40 AM

thanks for nice review .

Can you measure eye relief ?

17mm from frame (as in many other binoculars) or from lens (as in Zeiss) ?

I assume the 17mm are measured from the surface of eyelens.

 

From the rim of the eyecup (when folded down), I measure 13.5mm, with a margin of error of +/- 0.5mm.

 

You could gain another maybe 2mm - 2.5mm by fully removing the rubber eyecup - I have done that on my APM 28x110.

 

Pinac


Edited by Pinac, 20 February 2018 - 04:40 AM.

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#24 Pinac

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Posted 05 March 2018 - 10:49 AM

The following is just a brief follow-up on the original review of the APM MS 20x80 ED, after spending a little bit more time with it - and with its smaller brother, the APM MS 20x70 ED - under the night sky.

 

A few key data (figures correspond to APM’s spec, except where stated “measured”):

 

APM MS 20x80 ED
Eye relief acc. to spec: 16mm // measured w. folded eyecup: 13.5mm
IPD: 57-74mm (measured)
RFOV: 3.3 degrees = 58m
AFOW: 66 degrees
True aperture: 80mm (measured)
Length: 30cm
Weight (measured, with eyepiece cover and objective caps): 2’731g

 

APM MS 20x70 ED
Eye relief acc. to spec: 16mm // measured w. folded eyecup: 15mm
IPD: 57-74mm (measured)
RFOV: 3.3 degrees = 58m
AFOW: 66 degrees
True aperture: 70mm (measured)
Length: 28.6cm
Weight (measured, with eyepiece cover and objective caps): 2’143g

 

This means the 70 is about half an inch shorter, but 1.3 pounds lighter than  the 80.

 

Unfortunately, weather conditions have still been less than ideal here lately; not only were there many more “cloudynights” than in other years during the same period, the cloudless sky was also overall not as dark and clear, and during the few nights it was, the moon was shining really bright. Take this into consideration when reading the following.

 

The performance of the APM 80 ED confirmed the initial positive impression. Bright, sharp image with little CA – off-axis sharpness fine for most of the field of view, except maybe the 10-15% furthest out.

The 70 has – not surprisingly - very similar image characteristics, I would rate the two equal in terms of edge sharpness.

 

I got the impression, however, that the 80 shows a tad less CA. This may be due to the slightly larger exit pupil than in the 70, which may allow an easier eye placement behind the eyepiece, more than to anything else; hard to say. The difference is not great, but I think it is there. At night, this is of course not extremely important, since CA is only a real issue on bright objects such as the moon.

 

But also the 70 produces a very nice image of the moon. I usually check, when the phase is right, a few structures on the surface of the moon which I use when comparing large binos. Typical ones are Vallis Alpes (7.5 N / 7.0 E), best seen on nights 7-9 after new moon, or night 7 after full moon, and Rupes Recta (22.0 S / 7.7 W), seen best on nights 8-9 after new moon, or night 7 after full moon).
Although Vallis Alpes was easy to spot and well visible in both instruments, it seemed to me that it appeared just a little bit clearer and more distinct in the 80 than in the 70, but if the difference was not just my imagination but real, it was definitely not much.

 

It was slightly windy that night, and turbulence was high. But then, just for a moment, the wind stopped, and I saw Rupes recta in the APM 80, just for a short time, but clear. When I switched  to the 70, I couldn’t identify it anymore, and later, things became again more blurred than earlier that night, and also the 80 did not show Rupes Recta anymore.

Up to now, I had only been able to identify Rupes Recta in 25x100, 28x110 or in my BTs, but never in a 20x binocular.
However, in 2008, there was a discussion here on CN (including at that time EdZ) as to what size instrument is required to identify Rupes Recta, see:
 

https://www.cloudyni...-in-binoculars/

Reading this thread, I learned that Rupes Recta should in fact be accessible in a 20x80 bino, based on the experience of the other users in the quoted thread. This was new to me, buit it meant that my spotting of the great wall was perhaps not pure imagination. It would be interesting to hear what other forum members think.

 

Despite the mediocre atmospheric conditions, I tried to observe some deep sky objects, such as M42 (Orion Nebula): Here, a difference in brightness between the 80 and the 70 was almost imperceptible; moreover, there seemed to be no clear difference between the two instruments in the amount of structure you can see in the nebula. After a while, I realized that some of the faint stars around M42, which are just barely visible in the 70, appear a bit more pronounced in the 80. But overall, there was no clear “advantage” of the 80 over the 70 when observing the nebula itself. This seems interesting since the 80 has 33 % more light gathering aperture, so you might expect to see more of a difference.

The same could be said for M31 (Andromeda). Also here, a really dark clear sky with low humidity and little light pollution might perhaps have revealed details in the 80 more clearly than in the 70. I just did not have these conditions, so I don’t really know.

 

M45 (Plejades), Mel 25 (Hyades) an M44 (Praesepe): overall a very similar impression. Crisp nice clusters, the 3.3 degree FOV in both instruments is just wide enough to give a beautiful image against the background sky (certainly even more impressive under very dark skies); no discernible difference in the number of visible stars (overall impression, not counting).

 

fwiw.
Pinac

 

image: APM MS 20x80 ED (left), APM MS 20x70 ED (right)

Attached Thumbnails

  • IMG_9655.PNG

Edited by Pinac, 05 March 2018 - 10:53 AM.

  • Mad Matt, plyscope, Stellarfire and 1 other like this

#25 garret

garret

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Posted 05 March 2018 - 11:54 AM

Almost no difference between them...so skip the 80mm; its 100 Euro and 588 grams more and take the 16 x 70 instead...you get the same apparent field but the true field is wider: 4.1 degree and the 16x has 4 mm more eyerelief, its like a 16x70 Fujinon but for 1/2 the price smile.gif

 

Garrett


Edited by garret, 05 March 2018 - 11:58 AM.



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