91 replies to this topic

[Jeelan]

hi Pinac, any chance to conduct further testing on the APM 70's?

 

cheers

Jeelan

[Pinac]

Yes, I have additional data from the last two days when the weather was better, need to verify but hope to write up second part of review tomorrow or Thu.

[Pinac]

Review of APM 70 ED Apo and 82 ED Apo – Part II

 

This is the follow-up to the first part of this review (see above, my earlier post within this thread).

In the meantime, I have had a chance to use the two APMs a few times both in daylight and at night under reasonable meteorigical conditions (no or very few clouds, relatively bright skies with lots of humidity in the air, allowing acceptable views of brighter objects but not ideal for fine deep sky objects or structures). I therefore consider my fndings preliminary and not definitive. Still, it looks as if there is sufficient interest in the 70 and / or 82 to justify this kind of preliminary review.

 

I used the two APMs mainly with the following eyepieces:

- Vixen 14mm SSW
- Kowa 14mm
- Nagler 11mm
- Kowa 9 mm
- DeLite 7mm
- DeLite 5mm,

 

and I did initially also use the APM 18mm UF a bit which came with the APMs.

 

I am aware that I prefer to use my BTs with somewhat higher magnifications than many other users do.

 

For use with other eyepieces, please read Mike’s („ZX12“) posts he has written about his experience in this thread and in another one, see in this forum:
- Thread „APM 70mm Apo binocular first impression“, posts 1, 5 and 18 about the use of
24 Pan UF and Delos 10mm, 14mm and 17.3mm
- This thread,  above post 27,  re 24 UF eyepieces in the APM 70.

 

In the beginning I engaged the APMs side by side and alongside the Vixen 70ED and Vixen 81, later more alongside the Kowa Highlander (the latter only with the 14mm and 9mm eyepieces, I don’t have the 21mm eps).

 

To start with a finding that I have mentioned before: in my eyes, the two APMs clearly outperform not only the Vixen 81 (non-ED), but also the Vixen 70ED in basically every relevant aspect of the optics: brightness, central sharpness, contrast, clarity of the image, off-axis sharpness, CA. The Vixen 81 is of course probably a „semi-Apo“ at most and sells as such at about half the price of the APM 82, whereas the Vixen 70 with its ED lenses sells at or above the price of both the APM 70 and 82.
Based on what I have seen so far, it seems to me that the APMs compete more „closely“ with the Kowa than with the Vixens. To buy today a Vixen 70ED and not an APM 70, I think the Vixen would have to be considerably cheaper than it is at the moment.

For me, the only very minor advantages of  the Vixens over the APMs are their slightly longer handles, and the pre-installed mount for a (Vixen or generic) red dot finder. The handle on the APMs is a bit short for larger hands, and I personally find it less than ideal that the screw holes for mounting a finder are actually placed on the handle itself.

But apart form these really minor features, the APMs are clearly the winner with their better optics.

 

With regard to mechanics, both Vixens and APMs allow a smooth operation of focusing and adjusting IPD. The APM have extendable dew shields, these on the Vixens are fixed.

As mentioned before, my specific samples of the APM have less than ideal clamping ring dimensions, meaning that eyepices sit a bit too loose in the APM 70 and a bit  too tight in the APM 82. To my surprise, this does not seem to affect image collimation in either model. The APM 70 with loosely fitted eyepieces shows a much better collimation (I am talking here about the alignment of the tubes) than either Vixen model, and the same is true also for the APM 82.

 

Some impressions gathered during a limited number of day and night time observations, when comparing the APM70 and/or 82 among themselves and with the Kowa:

 

- Daytime: The Highlander at 50x appears to have just a tad better central sharpness than the APM 82 at 52x, with the same Kowa 9mm eps used in both BTs (reading a large street sign 1.1 miles away that I have been trying to decipher for ages). However, the difference disappears further off-axis, and the APM shows even or better sharpness towards the edge of the fov. Both Kowa and APM 82 give a natural color rendering of the image.

 

Saturn: when seeing is ok,  at higher magnifications (80x) even the  APM 70 shows the increased brightness at the equator of the planet body. The Cassini – Division is not yet visible, maybe you can guess it, but this would probably need at least 100x or more (the 82 might be at a tiny advantage in brightness, see below). The Kowa offers the crispest view and best rendering of the gap between the planet and its rings.

 

Moon: Comparison APM 70 with Kowa at similar mag (APM 36x, Kowa 32x): similar sharpness and contrast (e.g. observing rupes recta), the Kowa seemed just a tiny bit  sharper in the center and better in CA in the outer areas of the field, but also in the APM color fringes were almost not noticeable, a very tiny yellow fringe at the moon edge was all. Image quality is very comparable between the Kowa and the APM 70.
In the APM 82, when using the 22mm ultraflat APM eyepiece I got a wonderfully sharp, crisp image of the 2/3s moon, I think the 82 produced one of the nicest images of the moon „hanging in space“ I have ever seen, with almost zero CA and only noticeable when the edge of the moon was in the outher parts of the fov.
In all three instruments, ghosting or other disturbing reflexes were not an issue.

 

Jupiter: the best, clearest and brightest view was in the Kowa. Moons very close to the planet body remain well visible. The 82 was next in brightness, not far from the Kowa, just maybe a tad less bright, but it also offered very good views.
Was the 70 as bright or almost as bright as the 82? I had the impression, if there was a diffference, it could not have been a big one. At any rate, the 70 seemed to show at least as clear a picture of the planet with its moons as the 82.
Features on the planet body (cloud bands) were well visible in all three instruments. if I had to rate them I would say that the Kowa was maybe just slightly ahead of the APMs due to its very hight central sharpness, but emphasis would be on „slighly ahead“).

 

Stars: on-axis, both APMs and the Kowa all show very nice pinpoint stars. Moving the eyes off-axis toward the edge, the APM70 performs best in my view, it shows the least blurriness, stars stay well defined almost up to about 80% outwards (ep Nagler 11mm). It seems to me that the APM 82 is almost as good as the 70 in this respect, maybe just slightly inferior, but I could be wrong (something to  be confirmed). The Kowa (I somehow expected that) exhibits clearly  the worst off-axis star images of the three, so the slightly better central sharpness of the Kowa is „compensated“ by inferior off-axis sharpness.
On several occasions, when comparing the Kowa to the APM 82 and then the latter to  the APM 70, I got the impression that the Kowa has a small advantage over the APM 82 when looking at faint stars barely visible., and I imagine that I experienced about the same small difference between the APM 82 and the 70. If I then compared the Kowa directly to the APM 70, the difference was still very small. In some instances, the difference resulted in me detecting an object just barely with averted vision in the APM70, while I could see the same object in the Kowa also when directly looking at it. As mentioned before, the difference between the two APM models is noticeably smaller than betwen the two Vixen models; depite the fact that the smaller of  the Vixens has ED lenses and the larger one doesn’t, the Vixen 81 is clearly brighter than the 70ED.  With the two ED Apo APM models, the difference is much less recognizable (which is in line with what Jeelan in post 53 above had expected).

 

Preliminary Assessment

Several ToDos remain on my list for future nights: testing resolution (double stars), observing deep sky objects, etc. etc, so it is too early at the moment to jump to definitive conclusions.
The following reflects my current thinking based on what I have been able to do so far.

 

Both APMs exceeded my expectations with their well designed and manufactured optics (please keep in mind that I had no previous experience with either the APM 100 or 120, owning only a few smaller binoculars from APM, and I admit I always felt some doubts about the rave reviews of the APM 100 and 120 in this and other forums).

Mechanically, the APMs are also nice instruments, even if quality control will in the future hopefully eliminate variations in the clamping ring dimensions which I experienced in the two samples I got (although I have to say that quality control at either Kowa or Vixen is also not perfect, and I had to send in instruments of both brands for service shortly after purchase). Everything else seems as good as I like it to be.

 

The Kowa remains a very fine instrument, no doubt, with superior central sharpness, a bright and crisp image, and its usability also in severe weather gives it a clear advantage for birders and other users who need a robust and water-/dustproof instrument.  The superior build and robustness come at a price though, literally. The Highlander is an expensive binocular, and it is much heavier than both APMs, and you can only use 3 dedicated eyepiece sets manufactured by Kowa and costing more than most other 1 ½ ’’ eyepieces.

 

This is where the APMs come in. The outperform the similarly sized Vixen BTs so clearly that I wonder whether Vixen will have to reduce prices to stay in the market (or maybe they hope that APM cannot build sufficient numbers of the new BTs at a decent quality to become a threat??).
Do they also threaten to take market share from Kowa ? Of course I cannot really predict, but I believe so. The APMs are quite close to the Kowa when it comes to optical performance, and they sell at about half the price of the Kowa. In terms of edge sharpness, they beat the Kowa quite clearly, the APM 70 being even better at this than the 82, and they offer an image quality comparable to the Kowa in most other practically relevant disciplines.

 

The image of the APM 82 is just a tad brighter than that of the APM 70, which is to be expected (30% more light gathering), so it reaches a bit „deeper into space“; how much precisiely remains to be verified.

 

The APM 70 is lighter and more compact than the APM 82, and it is well balanced on the tripod. The APM 82 is distinctly front-heavy which, as discussed in earlier posts, is not a problem, but I prefer to mount it on a „sliding shoe“ which allows me to adjust the center of gravity when mounting it on a tripod. With the APM 70, this is not an issue, it goes directly on the tripod or fork mount and turns smoothly in all dimensions.

 

Image definition of the APM 82 and APM 70 seems very comparable to me; the slight advantage in brightness of the 82 is „compensated“ by the slightly better edge sharpness of the 70.

 

Finally, which one to choose, the 70 or the 82 ?

 

My personal answer: the 70. Compact, light, easy to carry and handle, and with a performance quite close to the larger models or even better in select areas. Other forum members may choose differently based on other preferences.

 

At the moment, I got both. So will I get rid of the 82 ? Nothing is decided yet ...

 

Looking forward to hear about the experience of other users, esp. those coming to different conclusions (I am here to learn something, after all).

Pinac

 

EDIT Aug. 18/2017: one more detail.

The pointing feature on top of the carry handle works actually quite well on both APMs, better than on the Kowa. So when observing at magnifications in the 20-40x range, I didn't miss a red dot finder much (I plan to mount one anyway for higher mags), I ususally found my targets easily and fast.

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Edited by Pinac, 18 August 2017 - 12:38 AM.

[Mr. Bill]

Excellent review, Pinac.

 

I think down the road I might consider the 82 in the 90 degree version and that would allow comfortable observing at the zenith.

 

That would allow it to fit in neatly with the 100 and 70 45 oculars.

 

I'm not a "collector" and every optic has to fit in a unique nitche and not be duplication.

Edited by Mr. Bill, 17 August 2017 - 01:04 PM.

[jay.i]

Thanks for all of the detail, Pinac. I am curious - if one wanted a BT that has the ability to push upwards of 80-100x, would the 82mm be the only model capable of that with respectable brightness? I don't know that I could afford the 82mm right now but if I was going to get one APM BT, the 82mm is at the top of the list right now. The 70 would be nice and compact, easier to use, but I feel like I would rather get a used Fujinon 16x70 for bright low-power views, and then get an APM 82mm and use it for all power ranges, using the extra light to my advantage for objects that need higher power like OCs/GCs and planets.

[Pinac]

..... if one wanted a BT that has the ability to push upwards of 80-100x, would the 82mm be the only model capable of that with respectable brightness? ......

......

 

With my 5mm DeLites, I used the 70 up to 80x and the 82 up to 94x, and that worked quite well, both BTs seemed to still have some "reserves", which means you could probably use the 70 up to about 95x and the 82 up to about 110x and still get a decent image.

 

But beyond that, I think there is not much gain in even higher magnifications, the exit pupil getting smaller than about three quarters of a millimeter usually does not make much sense IMHO, even with excellent optics the "floaters" in your eyes put a limit at or above half a millimeter anyway for many people (esp. older ones), you just don't see more detail than with lower mag and slightly larger exit pupil.

 

So if you would like to go "upwards of 80-100" it might be advisable to go for a 100mm BT (maybe semi-Apo which are much cheaper than the ED version) instead of an 82. Maybe forum members with 100mm BTs can join in here?

 

Pinac

[Mr. Bill]

My lower limit on exit pupil is about 1.5mm....floater issues but also dim images.

 

I like my 11mm DeLite eps (2mm ep) in my 100 APOs for "high" power.

 

So this means the 70s to about 35x; after that the 100 APOs.

 

If I want more magnification than 50x I get at this point, I go "Cyclops."

 

I really like the 8 inch astrograph (f/4.45 with Paracorr) with the 13mm (2.9mm ep, 69x) and 10mm (2.24mm ep, 90x) Ethos.

 

After that, the 10 inch SCT or 12 inch Lightbridge.....

Edited by Mr. Bill, 17 August 2017 - 04:05 PM.

[jay.i]

I suppose I probably would not end up going beyond ~60x with the 82mm BT, which I've found to be a very versatile magnification. I don't want to buy 2 really short focal length eyepieces for 80-100x -- I'd rather double up on something I already have (or am soon to receive) like the 9mm Nagler, which provides 52x, a 1.57mm exit pupil, and a 1.57 degree TFoV. I think this is probably as far as I'd push it, as I prefer brighter images at lower power than dim images at high power. I would really love some 100mm BTs but I really would prefer to minimize CA as much as possible, so the Semi-Apo is... somewhat out of the question. I wondered what the difference was between the black "ED-SemiApo" model, the white/gray (more modern housing) Semi-Apo model, and the white/gray ED-Apo model. I have to think the more expensive Semi-Apo model is better, but... how much better?  I get the feeling I might appreciate the smaller ED-Apo model with FPL53... but hopefully you guys know something about the 100mm Semi-Apo that I don't.

Edited by yokken, 19 August 2017 - 09:25 AM.

[range88]

I got some ghost and glare problems in my 82, but that probably comes from my mod. I am able to use a 100° ep, so I guess that's the trade-off.

[Pinac]

My DIY way of mounting a red dot finder on the APM 82 (carry handle still usable with finder mounted).

Pinac

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Edited by Pinac, 20 August 2017 - 12:23 PM.

[andy79]

Thanks Pinac and all for the informed inputs to this thread. Being a total noob, I wonder what would be more rewarding in the long term for skygazing,one of APM binos or reflectors/refractors with much more magnifying potential in the same pricerange.
Seems that magnifications over 100x are a stretch with either APMs, and although two eyes are much more immersive(giving sensation of higher magnification as well) nut sure if the first money for looking at the sky should go on a catadioptric for example. I also need portability, from home, light pollution is very high. Thanks

[Pinac]

.... I wonder what would be more rewarding in the long term for skygazing,one of APM binos or reflectors/refractors with much more magnifying potential in the same pricerange.
....

....

 

 

Don't ask me, I am a binocular freak, and since I have the BTs (several pairs  ), my SCT and the other "one-eyed instruments" stay mostly in their boxes.

 

Of course it is sometimes nice to be able to go upwards of 100x, and that's when I switch to the Celestron SC, but at higher magnifications, you have to deal with issues such as how to follow your objects (manually or electronically) since they move at considerable speed. So you need a proper equipment for that which you can leave aside with the BTs for which I sturdy tripod and a solid mount are sufficient (my view).

 

Maybe the binoviewer can for certain uses be a viable compromise (I am currently testing the Swaro 95 BTX, which gives 35x and 60x magnifications, whether the image through one tube viewed with both eyes is still satisfactory in terms of sharpness, contrast and brightness). Not my area of expertise yet, still testing and learning.

 

To sum it up, I for myself clearly prefer the BTs with limited magnifying power over high mag monocular instruments. Some will see it like me, many will disagree.

 

Pinac

[jay.i]

I have yet to try any BT or binoviewer, but I'm very tempted to get a binoviewer before year end because I won't know if it works with my scope/scopes until I try it. I would prefer to go the binoviewer route since I could invest more money in a better scope. I can't use BTs for imaging, otherwise I would be all over the APM 82s. I'm having to live vicariously through Pinac, Bill, and Rich in the APM70 impressions thread.

[andy79]

Thanks Pinac forthe reply, fair enough. Clearly the high magnification would affect portability.
And as you (and yokken) mention, binoviewers seem a good "compromise".

[Pinac]

Just an alert to all those interested in the 70 (or the 82):

 

For extensive discussion of ghosting / stray-light issues etc. see the other thread in this forum:

"APM 70mm Apo binocular first impressions"

 

Maybe a moderator could combine the two threads into one for better clarity ?

 

Thanks. Pinac

[walle]

I have a APM 82 and just ordered a 100 APO from Farpoint and was wondering if anyone could recommend which filters work well with these bino’s. I’m thinking about Lumicon UHC or/and oxy111. Thanks

[ZX12]

I've had great results using the DGM NPB filter with the APM 70.

 

Dramatic difference on objects like the Veil Nebula.

 

Mike