On September 22, 2108, Markus Ludes had announced two new small porro binoculars. Originally planned as individual focus instruments, further work and some discussions on the CN forum have now led to a central focus design, and prototypes have been presented for both a 8x30 ED and a 6x30 model.
During about ten days, I had a chance to review the two instruments.
Hereafter, I briefly name the specs of the two binoculars, describe how I reviewed them and with which other binoculars I have compared them, before I explain my findings and discuss my conclusions.
I tried to obtain my findings as objectively as possible (not easy when your eye apparatus is heavily involved), but my (preliminary) conclusions are of course subjective and personal.
Specifications:
8x30 ED
Objective diameter: 30 mm
True aperture (measured): 30mm
Magnification: 8 x
Exit pupil: 3.75 mm
Eye relief (acc. to spec): 18.2 mm
Useful eye relief (measured from rim of folded eyecup): 12.5mm
External diameter of eyecup (measured): 40mm
IPD: 57 - 72 mm (measured)
RFOV (acc. to spec): 8.1 degrees = 142 m
AFOV (acc. to spec): 65 degrees
Close focus (measured): 5.03 m
Focus type: IF
Prism system: Porro I
Waterproof (acc. to spec): yes
Weight (measured, with eyepiece cover and objective caps): 620 g
Made in: China (Kunming United Optics)
____________
6x30
Objective diameter: 30 mm
True aperture (measured): 30mm
Magnification: 6 x
Exit pupil: 5 mm
Eye relief (acc. to spec): 18.5 mm
Useful eye relief (measured from rim of folded eyecup): 12 mm
External diameter of eyecup (measured): 40mm
IPD: 57 - 72 mm (measured)
RFOV (acc. to spec): 9.3 degrees = 163 m
AFOV (acc. to spec): 56 degrees
Close focus (measured): 2.38 m
Focus type: IF
Prism system: Porro I
Waterproof (acc. to spec): yes
Weight (measured, with eyepiece cover and objective caps): 591 g
Made in: China (Kunming United Optics)
How these reviews were done
After initial inspection of both binoculars, I measured their weight, their range of IPD, the external width of the eyecups, their true aperture, their useful eye relief (with a dynameter), and their close focus.
I then used both binoculars during daytime, twilight and at night, both freehand and mounted on tripod, outside in the fields to assess their optical characteristics, comparing them with other binoculars (see below).
Then I reviewed both for stray-light, flare and ghosting performance, thereby also using LED flashlights.
I also used the USAF 1951 to compare central sharpness with other binoculars.
While the 8x30 ED obviously faces a lot of competition from competing same size porro and roof binoculars, finding the right instruments to compare the 6x30 model was less easy because there are not many good 6x30 / 6x32 models left on the market. I finally settled on using the following selection which I had at my disposal:
- Vixen SG 6.5x32 (roof prism)
- Vixen Atrek Light 6x30 (porro)
- Bushnell Natureview 6x30 (porro)
- Swarovski Habicht 6x30 (porro), discontinued
The Vixen SG and the Habicht would definitely be much more expensive than the APM 6x30, the Vixen Atrek and the Bushnell both clearly cheaper.
For October, the Kowa BD II 6.5x32 XD with 10 degrees RFOV has been announced, which would certainly also be interesting to compare, but is not available yet.
To compare the 8x30 ED model, I chose the following competitors:
- Swarovski Habicht 8x30 (porro)
- Nikon E II 8x30 (porro)
- Vixen Ultima 8x32 (porro)
- Carl Zeiss Jena Jenoptem 8x30
The two APM prototypes – 8x30 ED, 6x30 - share many mechanical and optical characteristics and therefore the reviews below sound in large parts similar. I have tried to write them in a way that allows reading only one of them and skipping the other.
Review of the 8x30 ED
GENERAL INSPECTION; FIRST IMPRESSIONS
External Finish and Build Quality: excellent. The leatherette fits perfectly, everything appears solid and well finished. The 8x30 looks like and feels like a miniature of the larger 7x50 / 10x50 APM MS ED models. There are no “gaps” between metal parts or metal and rubber parts. Pleasant haptics. Grip appears good both dry and wet.
Ergonomics: the binocular is well balanced and fits extremely well into my (smallish) hands, holding it reminds me of the Nikon E II, the feeling is better than with the Habicht. The Index finger rests easily on the focus wheel. Because of its compact dimensions, the 8x30 appears heavier than it actually is, and solid. Very pleasant experience.
MECHANICS
The central hinge is relatively stiff, which is to my liking, the range of adjustment is okay.
Eye cups: they are of the fold down type. As Markus mentioned, the rubber is a bit stiff and will be changed against a softer material. But even in the prototype version, I found the eyecups quite comfortable on my eye sockets and nose. I have a relatively narrow IPD (61mm) and therefore liked the external diameter of the eyecups (40mm).
Focus mechanism: the central focusing works precisely and smoothly, with no play, the focus wheel turns evenly and consistently, neither too stiff nor too loose. There is plenty of extra travel beyond infinity.
The bridge is well built, pressing one side of it down does make the bridge rock just slightly, but I found this acceptable. There is no rocking when turning the focus wheel.
Diopter adjustment: It sits on the right eyepiece, the „0“ mark indicates almost precisely true zero dpt. Operation is again smooth and with no play, but the adjustment wheel turns too easily and therefore an unintended adjustment is often the result (this can easily be corrected in the production version).
OPTICS IN GENERAL
Inspecting the instrument from the eyepiece side: the quality of antireflection coatings appears high, even compared to very good instruments such as Nikon EII or Habicht.
The exit pupils are minimally truncated. There are no false pupils. Some other bright structures, reflections etc. around the exit pupil appear, but overall not too bad. Vignetting appears moderate.
Inspecting the instrument from the front end: again, the quality of coatings appears high. Blackening inside the tubes is less than perfect, but this is a prototype and so the final model may show a different picture.
“Einblickverhalten”: How easy is it to find a comfortable placement of the eyepieces against your eye sockets allowing you to easily view the entire field of view with no shadows, “kidney beaning”, or similar effects in the image? I found that so-called “ease of view” to be very good!!
Eye relief: the spec say 18.2mm, but as Markus has pointed out, with the eyelens sitting quite deep and the folddown eyecup design, this may be tight for eyeglass wearers. I measured a “useful” eye relief from the rim of the folded eyecup of about 12.5mm. Using my glasses, which I usually don’t wear when observing, I could just, just see more or less the entire FOV. So it is a bit tight.
Effective Aperture: it is it identical with the diameter of the objectives, so aperture is not stopped down internally, and that is good news.
Close focus: for the 8x30 ED, I measured 5.03 m. Not great, but then, a porro binocular has never been ideal for very close observations anyway (because of their lateral offset), that’s really the domain of the roof prism binoculars, unless you use the Porro with one eye only (or unless you use a particular design such as in the Pentax Papilio).
IMAGE QUALITY
Size FOV: the spec say 142m, which is nice for a 8x30. Of course, you cannot compare it to the Nikon E II with its 8.8 degree FOV. But the field in the APM is still of a good size and allows getting a nice overview when observing.
Central sharpness, contrast, “brilliance” of the image: I found the 8x30 ED really good!! Markus indicated it was better than some Japanese competitors, and I have no doubt about that. On the USAF, it almost reached the performance of very good glasses such as the Habicht or the Nikon EII. Also, I found contrast and sharpness in the center of the image as good as in the CZJ Jenoptem. It easily outperforms the Vixen Ultima.
Overall, the image appears bright and clear.
Off-axis sharpness:
Preliminary remark: I think you should be aware that this is not a flat field instrument!! Don’t expect image characteristics like in the large MS ED APO binos from APM (7x50, 10x50, etc.).
Markus mentioned that the 8x30 ED “suffers from a quite obvious poor edge”, and I think he exaggerated. I found it not as bad as I had expected. Putting it side by side to the Jenoptem (or the Vixen Ultima) would give the APM a clear advantage, so if you don’t mount the 8x30 ED on tripod, you may find its edge sharpness quite satisfactory. It’s about as good as in the Habicht 8x30, which is more than satisfactory for most people.
The size of the sweet spot is okay, blurring starts just lightly at about 65% out from the center and then gets clearly worse from about 80%, although some of it is due to field curvature.
The 8x30 ED may therefore in the end be less useful for astronomy than for birding and general nature observation. But in my view, it is not a “loser”, as you could think based on Markus’ remarks. I like it quite a bit.
Distortion appears almost non-existent, still, panning shows no significant globe effect.
On the other hand, there is a little bit of field curvature (see remark under the 6x30).
Chromatic aberration: here, the 8x30 ED really shines! Very little in the center of the image, and also towards the edge, it never becomes an issue. Good job!
Stray-light etc.: good performance for such a compact binocular. My favorite test (observing across a river against a low standing sun, with the glittery water below and the sun above the line of sight) reveals no major issues, there are various sorts of reflections, flares, etc., but observation never gets totally obstructed. Some veiling glare, but okay.
Twilight performance: observing at dusk against a dark forest while the sky is still slightly lit after sunset: there still was sufficient image contrast, the image never got totally “washed out”.
Ghosting (tested on bright light sources, e.g. moon at night or streetlight, and on point-like LED): nothing significant.
Flares, Spikes: no issues.
Color fidelity: the image tone is just a tiny bit (and I mean tiny!) warmer than e.g. in the Habicht (which is known to be cool), quite similar to the Nikon EII. Paper test reveals good color fidelity.
Review of the 6x30
GENERAL INSPECTION; FIRST IMPRESSIONS
External Finish and Build Quality: excellent. The leatherette fits perfectly, everything appears solid and well finished. The 6x30 looks like and feels like a miniature of the larger 7x50 / 10x50 APM MS ED models. There are no “gaps” between metal parts or metal and rubber parts. Pleasant haptics. Grip appears good both dry and wet.
Ergonomics: the binocular is well balanced and fits extremely well into my (smallish) hands, holding it reminds me of the Nikon E II, the feeling is better than with other small Porros. The Index finger rests easily on the focus wheel. Because of its compact dimensions, the 6x30 appears heavier than it actually is, and solid. Very pleasant experience!
MECHANICS
The central hinge is relatively stiff, which is to my liking, the range of adjustment is okay.
Eye cups: they are of the fold down type. As Markus mentioned, the rubber is a bit stiff and will be changed against a softer material. But even in the prototype version, I found the eyecups quite comfortable on my eye sockets and nose. I have a relatively narrow IPD (61mm) and therefore liked the external diameter of the eyecups (40mm).
Focus mechanism: the central focusing works precisely and smoothly, with no play, the focus wheel turns evenly and consistently, neither to stiff nor to loose. There is sufficient extra travel beyond infinity.
The bridge is well built, pressing one side of it down does make the bridge rock just slightly, but I found this acceptable. There is no rocking when turning the focus wheel.
Diopter adjustment: It sits on the right eyepiece, the „0“ mark indicates almost precisely true zero dpt. Operation is again smooth and with no play, but the adjustment wheel turns too easily and therefore an unintended adjustment is often the result (this can easily be corrected in the production version).
OPTICS IN GENERAL
Inspecting the instrument from the eyepiece side: the quality of antireflection coatings appears high, even compared to very good instruments such as Nikon EII or Habicht.
The exit pupils are truncated, the left one quite clearly, the right one less so (this may be less a design problem than a quality control issue). There are no false pupils but some other bright structures, reflections etc. around the exit pupil, but overall not too bad. Vignetting appears moderate.
Inspecting the instrument from the front end: again, the quality of coatings appears high. Blackening inside the tubes is less than perfect, but this is a prototype and so the final model may show a different picture.
“Einblickverhalten”: How easy is it to find a comfortable placement of the eyepieces against your eye sockets allowing you to easily view the entire field of view with no shadows, “kidney beaning”, or similar effects in the image? I found that so-called “ease of view” to be very good!!
Eye relief: the spec say 18.5mm, but as Markus has pointed out, with the eyelens sitting quite deep and the folddown eyecup design, this may be tight for eyeglass wearers. I measured a “useful” eye relief from the rim of the folded eyecup of about 12mm. Using my glasses, which I usually don’t wear when observing, I could just, just see more or less the entire FOV. So it is a bit tight.
Effective Aperture: it is it identical with the diameter of the objectives, so aperture is not stopped down internally, and that is good news.
Close focus: for the 6x30, I measured 2.38 m. Not superb perhaps, but okay, and a porro binocular has never been ideal for very close observations anyway (because of their lateral offset), that’s really the domain of the roof prism binoculars unless you use the Porro with one eye only (or unless you use a particular design such as in the Pentax Papilio).
IMAGE QUALITY
Size FOV: 9.3 degrees = 163m is a nice size! This is why most people will be interested in the 6x30 configuration, it allows to get wider images than almost any other 7x or 8x binocular. With 9.3 degrees, you will not see entire star constellations as in the very wide-field so-called starfield binos (e.g. Vixen SG 2.1x42), but I find those only useful under a really dark sky, and even there, they don’t go “deep enough” for my taste. The 6x magnification goes much deeper, so I like objects like the Double Cluster or the Pleiades much better in the APM, where their brilliance becomes better visible.
Central sharpness, contrast, “brilliance” of the image: I found the 6x30 very good, even better than the 8x30 ED!! I found contrast and sharpness in the center of the image as good as in the clearly more expensive Vixen SG 6.5x32, and it easily outperformed the Vixen Atrek and the Bushnell. Image brightness is also very nice.
Off-axis sharpness:
Preliminary remark: I think you should be aware that this is not a flat field instrument!! Don’t expect image characteristics like in the large MS ED APO binos from APM (7x50, 10x50, etc.).
Markus mentioned that the 6x30 had a “nice and very well corrected FOV” and was “sharp almost all over the field”.
I found that true, keeping in mind that I could not and should not expect edge performance like in a flat-field EL SV or SF.
Putting it side by side with the Vixen SG 6.5x32, the APM, it was hard to say which of the two had the better edge sharpness. The size of the sweet spot is nice, point-like stars in most of the image, blurring starts gently at about 80% out from the center and then gets worse only at the very edge. But see below regarding field curvature.
Distortion appears almost non-existent; still, there is no significant globe effect when panning.
On the other hand, there is a significant amount of field curvature in the 6x30. What is its effect?
If you observe the center of the image and use the focusing to get the image sharp in the center, you may find the very edge blurred; if you then turn the focus wheel and the edge gets sharp (now the center gets blurred), then you have field curvature.
I found the amount of it surprising, and this is a pity, because it masks the fact that “normal” edge blurriness (from astigmatism etc.) is almost non-existent. Field curvature was more pronounced on the right side of the image than in the left (in both tubes of an irregular shape), and clearly more present than in the 8x30ED. For me perhaps the only disappointment in this otherwise very well made binocular, but I don’t know whether this can/will be improved in the final production version (Markus isn't convinced that field curvature is that big an issue).
Chromatic aberration: no issue, as Markus had mentioned. Very little in the center of the image, and also towards the edge, it never becomes a significant issue.
Stray-light etc.: good performance for such a compact binocular, and the 6x30 apeears here even a level better than the 8x30 ED. My favorite test (observing across a river against a low standing sun, with the glittery water below and the sun above the line of sight) reveals no major issues, there are various sorts of reflections but observation never gets totally obstructed. Some veiling when sunshine directly on the front lenses, but still okay.
Twilight performance: observing at dusk against a dark forest while the sky is still slightly lit after sunset: there still was sufficient image contrast, the image never got totally “washed out”.
Ghosting (tested on bright light sources, e.g. moon at night or streetlight): nothing significant.
Flares, Spikes: the left tube showed spikes like in a roof prism binocular, and this was surprising. Almost certainly not a design issue, but the result of insufficient quality control at KUO. I expect this not to be an issue in the final production version.
Color fidelity: the image tone is just slightly warmer than e.g. in the Habicht (which is known to be cool), quite similar to the Nikon EII. Paper test reveals good color fidelity.
PRELIMINARY CONCLUSIONS
Four years ago, allbinos closed their review of the Nikon 7x50 IF SP WP with the words:
quote
“In 20-30 years’ time, when there are only plastic roof prism instruments available on the market, a solid, timeless pair of binoculars with Porro prisms will sell like hot cakes.”
unquote
This came back into my mind when I reviewed the two APM prototypes. I generally like the Porro design, and while there are still plenty of cheap Porro binoculars on the market, good small Porro binoculars with a metal body and high performance optics are becoming rarer all the time.
The two APMs will be a welcome addition to the current binocular universe. I have been waiting for something like the compact 6x30 not only for astro, but also for my daily walks with the dog, where I often feel 8x or even 7x too much when the pulse is going fast. But If Markus launches both, I would also want to get the 8x30.
For what it’s worth.
Pinac
Attached Thumbnails
Edited by Pinac, 11 September 2019 - 11:07 AM.
