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Kowa BDII-XD - september 2019 (2 Viewers)
- Thread starter Boris Flaccus
- Start date
dries1
Member
Kowa 8X32
Just received these today, initial impressions are the build quality seems good, optics - in collimation, good color rendition, a bit of CA at the field stop, (this does not bother me) a bit of a small sweet spot but more on this later. It is not a FL or an EII but it is a very portable glass and light for those who need light weight at a modest price.
As a followup to this post.
Focus is very fast, but the dampening and travel is firm and deliberate. Not a flat field per say but to stay in the field of focus requires fine tuning, it does not take much movement on the focus wheel to go out of focus. (as an edit to my previous findings the sweet spot is fairly good), better than I initially thought. So far a very small 8X32, it seems to be a good value.
Andy W.
Just received these today, initial impressions are the build quality seems good, optics - in collimation, good color rendition, a bit of CA at the field stop, (this does not bother me) a bit of a small sweet spot but more on this later. It is not a FL or an EII but it is a very portable glass and light for those who need light weight at a modest price.
As a followup to this post.
Focus is very fast, but the dampening and travel is firm and deliberate. Not a flat field per say but to stay in the field of focus requires fine tuning, it does not take much movement on the focus wheel to go out of focus. (as an edit to my previous findings the sweet spot is fairly good), better than I initially thought. So far a very small 8X32, it seems to be a good value.
Andy W.
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wdc
Well-known member
Thanks for the quick and concise review Andy. My question of course pertains to eye relief, which I think we are on opposite ends of the issue. In your spare time, would you mind trying 'em with a pair of reading glasses, or sunglasses, to see if the entire field is available? I'd appreciate it. Thanks.
-Bill
-Bill
Steve O4B
Optics4Birding.com
Thanks for the quick and concise review, Andy.
With regards to the out of focus edges, can they be refocused or is the lack of focus more due to astigmatism? I've found with a lot of 8x32s, including the 8x32 Victory T*FL which I owned for a bit, that eye placement is hypercritical due to astigmatism. If it is introduced distortion (e.g. pincushion or what have you) that blurs the edges, I don't seem to notice the eye placement issue as being so pronounced.
Also, of slightly less importance, is the focus-knob metal? I always liked the metal, knurled knob of the Genesis series; I still find it the most please focus I've used.
Justin
How do these stack up?
Any thoughts on low light performance with these? Currently considering the Kowa BD ii in 8x32 or 8x42, Maven b3 8x30, Meopro 8x42, or Vortex Viper 8x42. Hoping to upgrade from an older Diamondback 10x42 that I gifted to a family member, and this will be my only glass for awhile.
How do you think these stack up in the sub $500 range?
Thanks in advance,
Sage
Any thoughts on low light performance with these? Currently considering the Kowa BD ii in 8x32 or 8x42, Maven b3 8x30, Meopro 8x42, or Vortex Viper 8x42. Hoping to upgrade from an older Diamondback 10x42 that I gifted to a family member, and this will be my only glass for awhile.
How do you think these stack up in the sub $500 range?
Thanks in advance,
Sage
Steve O4B
Optics4Birding.com
Hi Sage,
For need low light performance, I would avoid all 30mm or 32mm binoculars in favor of the 42mm models. A 42mm binocular will receive about 70% more light than a 32mm binocular. That's a little more than 2/3 of a f/stop. So, given equivalent glass and coatings, the 42 will be the better choice.
Between an 8x42 and a 10x42 of the same binocular series, the 10x will give you better low light performance. If you don't believe me, do the test. The reason for this is physiological as well as optical. All 42mm binoculars receive the same amount of light in any given circumstance. The objective lens doesn't know which eyepiece the binocular has. The 8x delivers more total light to your eyes because of the wider field of view - you have photons coming from more things, but it delivers the same amount of light from the bird as the 10x. The problem is that the photons from the extra field of view of the 8x reach your retinas and tell your brain that there is more light, so your brain doesn't dilate your pupils as quickly. That means you get less light from the bird with the 8x. When your pupil diameter maxes out with the 10x, the pupils would still be only partially dilated with the 8x. This is the effect called twilight factor.
Steve. Nice explanation of Twilight Factor. I have never heard it explained in that way but it sounds logical. Good advice on the 32mm versus 42mm also. Interesting that a 42mm brings in 70% more light. I was using the Kowa BD II XD's 6.5x32 today and the big FOV is impressive. When I went back and forth the between the Kowa and my Nikon 8x32 EDG II the Nikon's FOV seemed small. With it's close focus and huge FOV and great DOF the Kowa's are really good for insects and butterflies and fast moving close up birding. You can catch a lot of stuff on the edge of the FOV by movement. I was hiking in Yellowstone National Park and I met a couple that were observing butterflies and it was quite interesting how many different species of butterflies there were in the small area they were observing in. I never realized there were so many SMALL species of butterflies with different wing colorations. They had a field book of butterflies and showed me 5 or 6 different species while I was there. It was interesting. The Kowa's big FOV is good for that because you are mostly looking down at the ground and you need a big FOV. For Sagew I have used the Kowa's at dusk and for a 32mm binocular I feel they are very bright but like Steve says they won't compare with a high quality 42mm. If you are going to use your binocular a lot in low light you should probably get a 42mm. As Steve says a 10x42 is better in low light and will show you more detail than an 8x42 but will be harder to hold steady and of course have a smaller FOV.
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Very Nice Wide Angle Binocular for the Money!
I got my Kowa BD II 6.5x32 today. I am very impressed with them. 6.5x is pretty nice when you have a 10 degree FOV. There is quite a bit of WOW factor even at 6.5x which doesn't happen with the smaller FOV binoculars at this low of a magnification. The edges soften up a bit but as Dries said they have a pretty big sweetspot and they are very sharp on-axis. They handle CA quite well even at the edge and they handle glare quite well for such a small binocular. The focuser is very smooth without slack or any stickiness. They seem to be very bright also so I assume they have good coatings. Of course the 6.5x magnification gives you good DOF and they are very easy to hold steady even noticeably easier than a 7x. I think they perform well above their price point and they are the first binocular less than 8x that I actually like. Kowa did a good job on these. I agree with Dries that they are a very good value for $400.00.
I got my Kowa BD II 6.5x32 today. I am very impressed with them. 6.5x is pretty nice when you have a 10 degree FOV. There is quite a bit of WOW factor even at 6.5x which doesn't happen with the smaller FOV binoculars at this low of a magnification. The edges soften up a bit but as Dries said they have a pretty big sweetspot and they are very sharp on-axis. They handle CA quite well even at the edge and they handle glare quite well for such a small binocular. The focuser is very smooth without slack or any stickiness. They seem to be very bright also so I assume they have good coatings. Of course the 6.5x magnification gives you good DOF and they are very easy to hold steady even noticeably easier than a 7x. I think they perform well above their price point and they are the first binocular less than 8x that I actually like. Kowa did a good job on these. I agree with Dries that they are a very good value for $400.00.
Chosun Juan
Given to Fly
Lee I'm sure you'll appreciate the 140% FOV Area of the 6.5x32 versus the rather pedestrian Zeiss 8x42 SF
lol :-OChosun :gh:
Lee I'm sure you'll appreciate the 140% FOV Area of the 6.5x32 versus the rather pedestrian Zeiss 8x42 SF
Chosun :gh:
Absolutely CJ. I can foresee that fov being great for so many different activities and look forward to it immensely. But see post 122 where I explain that fov isn't the only criterion on which to judge a bino :-O
Lee
Chosun Juan
Given to Fly
Lee - I'm going to introduce you to a new Industry Metric - VOV
"Volume of View" :eek!:
This takes account of the dof - a fn of magnification.
Here the 6.5x32 Kowa BDII-XD has fully 174% of the VOV of the Zeiss 8x42 SF. Team Blue simply can't compete ! :eek!:
As you can see 174% is no small difference ....... :cat:
Chosun :gh:
Surely the Kowa has a bigger VOV than that CJ? But sadly you are getting your personal accommodation all mixed up with your 'circles of confusion' :-O
VOV is a nice idea but it is too dependent on accommodation and how you define depth of field, and anyway the little Kowa needs no help of this kind. Both me and Troubadoris are looking forward to this model.
It is quite lightweight too so it would be friendly to your shoulder.
Lee
Chosun Juan
Given to Fly
Lee - you've got to get with times - VOV is where the Industry is at daddio ! :hippy:
:smoke:I assure you my figures are correct |
|174% is enough to throw shade at the SF :cat:
It's a completely independent fn of mag. .......... the only accommodation you have to worry about is that which keeps the rain off Troubadoris and provides tea and croissants for brekkie ! :-O
Chosun :gh:
Lee - you've got to get with times - VOV is where the Industry is at daddio ! :hippy:
I assure you my figures are correct |
174% is enough to throw shade at the SF :cat:
It's a completely independent fn of mag. .......... the only accommodation you have to worry about is that which keeps the rain off Troubadoris and provides tea and croissants for brekkie ! :-O
Chosun :gh:
Daddio made me smile. I think I last heard that in 1969 :-O
If I can change the brekkie order to either coffee with croissants or tea with toast then I am totally convinced. The VOV should be enough to accommodate the egos of Trump/Johnsson and Putin combined!
Can't wait to try this model out.
Lee
Thanks for report Andy! Looks like a nice little binocular..
Steve O4B
Optics4Birding.com
Thanks, Dennis,
For light reception, you calculate with relative areas. Since π drops out and the diameters have the same ratio as the radii, just square the larger diameter and divide by the square of the smaller diameter to get the increase:
42^2/32^2 = 1764/1024 =1.723, so actually more than 72% more light.
Good equation, Steve. That is very helpful. Chosun, you are correct about the DOF on the Kowa's. It is really helpful when spotting birds and insects. It is almost like you have a 100 yard DOF where everything is in focus.
