Luckly, I have overhere most of the days over the whole year beuatufully clear nights for testings, so I really enjoy in astronomy. My big love is using binoculars, and binoviewers on telescopes, and I have opportunitly to have most of binoculars which are very popular in astronomy over past approx 2 years.
In what I was based due testing times, was:
---sharpness (not necessarily to be sharp to extreme edges),
---and for me really annoying, false colours factor, while my eyes are VERY sensitive on chromatic abberations
---I do not care for other parameters
Tested binoculars were:
*** Pentax SP 8x40 WP
*** Pentax SP 20x60 WP
***Nikon 18x70 IF WP WF
***Carl Zeiss 15x60 GAT*
***BW3 series Hunter 8x56, 10x56
***BW3 series Hunter 8x56 ED, 10x56 ED, 12x56 ED
***BA8 Marine series 7x50, 10.5x70, 15x85 and 20x110
***BA8 Marine series 10x50, 15x70, 22x85
Testing Carl Zeiss 15x60 GAT*:
I was actually happy with mechanicall built quality, as well with nice optic look, with very smooth and precise optics surfaces, as well with central very smooth and precise focussing mechanism.
On daytime observations, for me, this bino have VERY annoying amount of false colours on most objects, especially on critical bright objects. I was dissapointed, very dissapointed! Also, tint of image is somewhat yellowish, which I do not like at all.
So expensive binoculars, with so bad image for my taste.
Yes, picture is sharp, but yellow tint of image and collour abberations bother me a LOT!!!
One more stuff I do not like here is, that eyepieces have VERY short eye releaf, and if I want see whole FOV (which is really big, approx 65-68 deg), I must touch all the time lenses with my eyelashes. In winter time, there is a lots of problems with lens fogging.
Under stars, becasue big FOV, views are really great, but contrast is not as I expected from expensive Zeiss premium bino, and stars are not so pinpoint like in Nikon 18x70 or Pentax 20x60. Light transmittion in Zeiss is not so good, even it is T* coated by Zeiss.
I must say, that I actually much more enjoy in looking through Marine 15x70, which I also do not prefeer, over the Zeiss 15x60 GAT*.
Testing Nikon 18x70 IF WP WF:
Nikon: yes,very nice looking bino, many years prefeered by many many astronomers worldwide. I wondered why is that so, so I buy one new to see what it can offer.
Mechanicall looking is very well, with very smooth and precise eyepiece focussing system. Lenses surfaces also very smooth looking and well made corrners of lenses if you look inside bino as much as you can see.
Here is one minus on daytime obervations about focussing system, while it does not cave central knob which is much more practicall.
In daytime observations,I was actually not happy at all with Nikon 18x70 IF WP WF, where it produce HUGE amount of false colours for my sensitive eyes, even more than already not good Zeiss 15x60 GAT*. Eye relaf is somewhat better than in Zeiss, but still too short for my taste. Picture it provide is just a bit yellowish/warmer, but not so much like in Zeiss.
Well, on nightime, it is really amazing, where plastic eyepiece eyegards are removed, I was blowned away with so pinpoint and sharp stars, and HUGE approx 72 deg FOV. Well, stars are very bad on edges, and not so big percentage FOV is usable, but I feel like I was in the space looking through Nikon, with the stars. Then I realise why astronomers like it.
But becasue short eye releaf, and bad image on daytime, I was not satisfied with it.
Testing Pentax SP series:
I was curious how these new series of Pentaxes performs, and my curiousity becomes from many threads I found written especially about 20x60 model, so I couldnt resist and ordered new Pentax SP 20x60 WP, and by the way, I buy new Pentax SP 8x40 WP, all to see how they perform. No matter if they were cheap or expensive, I must try them. Honestly, I was really skeptical about 20x60 model, becasue there is high magnification, small objectives, and not any ED or simillar glass inside (nor in the other testing binos I test). Also, there is small 3mm exit pupil, which I expected to produce not so satisfied images on daytime observations.
All I can say, I was amazed with their performance, as well with built quality. They are Made in China, but they are really amazing binoculars, and now you will se in what I am talking about!
On daytime observations, I was really scared that bino will have too much false colours on all objects, actually, I expect them very MUCH. And then, when I look through it.......BAM!
I was shocked! Where are false colours??? Wait.........just few looks more on very criticall objects on sea, ships, buildings, roofs, antennas............WOW!
I really did not expect that!!! For my very sensitive eyes, amount of false colours is VERY VERY low. Picture is very chrisp, and very sharp, with more neutral toned image, which I actaully prefeer.
What I discover on night observations, is that 20x60 model have very small pinpoint stars, with high contrast image, and very very low amount of chromatic abberations, barely visible just on very critical objects. Image sharpness of stars is present to almost very edge, but not to exteme edge. I actually forgot that this bino have only 44 deg FOV, but trust me, I did not perceived that at all becasue I was so amazed with its performance, and this does not bother me at all, no matter while I am a bit more lover of wider fields of view.
When we talk about mechanicall quality, they are very well built. Central focussing knob is very smooth and precise, which is huge advantage on daytime while you do not must focuss left and right eyepiece individually like in Nikon 18x70 or Marine series.
Thiese Pentaxes have something interesting in focussing mechanism: focussing system can be completly locked, all done just with one movement.
When eyeguards are in lowest position, position of image is a bit tricky becasue blackout effect, but all is very easily solved by screwing two-step rubber covered metal eyeguards.
Lenses of binos are very well polished with very smooth surface and eddges of all visible lenses (objectives and eyepeices) are precisely cutted, without any chipped corners, much better looking than Marine BA8 series or Hunters, and approx same quality of made like Nikon 18x70 have.
One more positive thing: 20x60 model is very light!
Switching to little 8x40 model, as expected, I found bino to have very chrisp image, with almost zero false colours even on daytime very critical objects. On stars, not so sharp on edges, with 54.4 FOV, as specified on Pentax pages, but still produce incredible picture of Milky Way stars, as well daytime objects with very chrisp image, and not so sharp edges (no bothered to me). Comparing Pentax 8x40 vs Hunter 8x56 ED, I could see more stars in Pentax, and Pentax have more pinpoint stars than bigger 8x56 ED Hunter, as well with Pentax I am able to resolve some stars which I can with 8x56 ED Hunter. Really unexpected. Contrast is also beter in Pentax.
Gripping and outher looking of new Pentax SP bino series, as well as optics, and price, is amazing, and IMO, unbeatable!
Testing Marine BA8 series:
These binoculars are really interesting.
There are two series inside BA8:
one are models 7x50, 10.5x70, 15x85 and 20x110,
and second models are 10x50, 15x70, 22x85 and 28x110.
I had them all, except 28x110.
These binos use 2 types of eyepieces, in which is main difference, except difference in size of objectives.
Models 7x50, 10.5x70, 15x85 and 20x110 were binos I really like a LOT, and becasue they produce very low amount of desturbing false colours, and have enough chrisp images with great eye releaf. On daytime observations, all are brilliant in any regard. One down side is that they are heavy. Mechanically very good made, but not as good as Pentax, Nikon and Zeiss, but still very very good.
What I can say, I was very, very happy with Marine series 7x50, 10.5x70, 15x85 and 20x110 modles, which are made in Kunming United Optics Corporation in China. All in all very good binoculars, with very low amount of false colours for my taste, with sharp and contrast images no to extreme edges, but still very satisfying, no matter if I use them in daytime or at the stars, always pleasure to use.
Models 10x50, 15x70, 22x85 I had, was not good for me, becasue many false colours on daytime, and short eye releaf for me. But, this amount of false colours are less than very expensive Nikon 18x70 and Zeiss 15x60 GAT* produce.
All these mentioned China binos are BA8 series from link
Testing BW3 Hunter series binoculars:
These are nice, compact, and very transportable, roof type binoculars, as well made in China, comes under various names like TS, Omegon....., and here is link
Central focussing system is good, not great or excellednt, and diopter adjustment is bad, and it could be easily broken when you want focus image little faster.
All in all, 8x56 and 8x56 ED models are best of series, and they provide really great images, where ED version is tad better, with bit brighter and chrisper image. Both have little amount of false colours, but not bothered at all, while I expected that that ED version would be much better than I saw. On stars, it is pleasure to use them, but none of them is good as Pentax 8x40 SP WP, which means Pentax resolve and show more stars, despite smaller aperture.
What is annoying for me here, that all of Hunters on very bright objects, on dusk or at stars, provide some spikes around observed object, and this is becasue roof prism nature.
10x56 and 12x56 models provide pictures with little lack of sharpness, and have too much false colours for my taste.
For my taste and purposes, as observer which prefers sharp, clean, and as much as possible image without false colours, my winners without doubt are Pentax SP 20x60, and its little brother Pentax SP 8x40.
These guys give me most satisfied images I ever had, of all observed objects, no matter if I observe on daytime or looking at stars.