883 (1 Viewer)

[Tringa45]

I wouldn't deny that there is an occasional 883 lemon, but think that a false impression of Kowa's consistency has arisen.
When Jan Meijerink of Twentse Vogelwerkgroep tested a number of 883s back in 2008, they were not only all much better than the Zeiss Diascope 85, but more consistent too.
Perhaps I have been lucky with my 883. It star tests well and when I measured resolution a few years back, I could resolve group 2, element 5 on a USAF 1951 chart at 23 m. That translates to 1,42 arcseconds. Diffraction limited is 1,32", but I might have managed 2,5 a few cm farther back or 2,6 a few cm closer.

John

PS: There are a few new tests here Twentse Vogelwerkgroep. Go to "Testrapporten" and use Google translate for the Dutch (KIjkers = binoculars).

 

[Ownthenight]

I wouldn't deny that there is an occasional 883 lemon, but think that a false impression of Kowa's consistency has arisen.
When Jan Meijerink of Twentse Vogelwerkgroep tested a number of 883s back in 2008, they were not only all much better than the Zeiss Diascope 85, but more consistent too.
Perhaps I have been lucky with my 883. It star tests well and when I measured resolution a few years back, I could resolve group 2, element 5 on a USAF 1951 chart at 23 m. That translates to 1,42 arcseconds. Diffraction limited is 1,32", but I might have managed 2,5 a few cm farther back or 2,6 a few cm closer.

John

PS: There are a few new tests here Twentse Vogelwerkgroep. Go to "Testrapporten" and use Google translate for the Dutch (KIjkers = binoculars).

Good Dutch folk... Well since I started this thread, my 883 has arrived... And although I am too much of an amateur to take pictures, I believe it star tested absolutely perfect...and I mean perrrrfect. The lines couldn't be any more concentric than they were...it was so amazing, that I thought I was doing something wrong. I don't have a 1951 yet... But redbubble dot com had some that I wanted to get... I wanted to get one that's printed on metal... I'm not sure about whether it will be pixelated or not...
I purchased one on paper as a gift for a fella at my Optics retailer... He said it was nice... I was wanting to get one of the much larger ones, I think it's 24x24" something like that...
.... anyway, thank you for your reply.

 

[Tringa45]

Good Dutch folk... Well since I started this thread, my 883 has arrived... And although I am too much of an amateur to take pictures, I believe it star tested absolutely perfect...and I mean perrrrfect. The lines couldn't be any more concentric than they were...it was so amazing, that I thought I was doing something wrong. I don't have a 1951 yet... But redbubble dot com had some that I wanted to get... I wanted to get one that's printed on metal... I'm not sure about whether it will be pixelated or not...
I purchased one on paper as a gift for a fella at my Optics retailer... He said it was nice... I was wanting to get one of the much larger ones, I think it's 24x24" something like that...
.... anyway, thank you for your reply.

Well, if your 883 is star testing so well, you probably don't need to repeat the test on a USAF 1951 chart.
If you're still interested though, there is a credit card sized plastic card available from Edmund Optics (Order #38-710), which would do the job for a mere €7.
You would have to illuminate it well. I overlooked this and paid nearly €100 for a glass slide, which has to be backlit.
I don't know why you would want anything big. My 883 was resolving 6,35 line pairs /mm at 23 m distance!

John

PS: I received a lot of help on resolution testing from bidforum member, typo, who hasn't been seen much recently. If you need any help you can PM me.

 

[Ownthenight]

Well, if your 883 is star testing so well, you probably don't need to repeat the test on a USAF 1951 chart.
If you're still interested though, there is a credit card sized plastic card available from Edmund Optics (Order #38-710), which would do the job for a mere €7.
You would have to illuminate it well. I overlooked this and paid nearly €100 for a glass slide, which has to be backlit.
I don't know why you would want anything big. My 883 was resolving 6,35 line pairs /mm at 23 m distance!

John

PS: I received a lot of help on resolution testing from bidforum member, typo, who hasn't been seen much recently. If you need any help you can PM me.

Thanks.... I wanted the huge one for super long distance... Mainly for riflescopes... This was all just tentative fantasizing... Yes, I suppose I could be more realistic with what I planned to get...

I guess, if I wanted real results; I'd need a more 'regulation' size, and follow the formula... You're absolutely right about that.