Kowa 1.6 Extender (1 Viewer)

[SUPPRESSOR]

Thinking of getting one for my 883. How much field of view does one give up ie a lot ,quite a bit or not too much!
Any info much appreciated .
Pete.

 

[DRodrigues]

As the AFOVs aren't supposed to change, you get resulting FOVs dividing those you have now by 1.6...

 

[SUPPRESSOR]

Ok ,thanks for that.

 

[wolfbirder]

I bought one for my 883 but rarely use it, the depth or field of view is inevitably shallower and I found it hard to use when birds were moving. Good though if a bird is stationery .

 

[hoan]

I bought one for my 883 but rarely use it, the depth or field of view is inevitably shallower and I found it hard to use when birds were moving. Good though if a bird is stationery .

Hi wolfbirder,
Did you try the "cable tie trick" on your 883? With this tierap trick, even with the 1.6x extender set at 40x, I can find and follow easily the heron, osprey and bald eagle in flight.

 

[SUPPRESSOR]

Yes, I think it could be one of those things that when it's on you wished it was off and visa versa!!
Peter.

 

[b_reynolds_ak]

I use one my 773 and it is absolutely fantastic. I can only imagine it would be that much better on the 88mm. Of course you lose some fov, but if you need to really observe details from miles away, it is invaluable.

 

[Hauksen]

Hi,

I use one my 773 and it is absolutely fantastic. I can only imagine it would be that much better on the 88mm. Of course you lose some fov, but if you need to really observe details from miles away, it is invaluable.

I use one for the 883, and I'm not happy at all because the rather fast "slow" focus drive of the 883 makes it really hard to get the subject correctly into focus. (That's basically what Wolfbirder was saying too.)

I've only used it for astronomical observation so far, not for birding, so I my impression might be slightly biased.

The dual-speed focuser on the 883 really is poorly configured in my opinion - the speed of the "slow" drive is markedly faster than what I would consider perfect for a single-speed system without the extender, when on a dual-speed system, it really should be slower.

Regards,

Henning

 

[Tringa45]

Hi,

I use one for the 883, and I'm not happy at all because the rather fast "slow" focus drive of the 883 makes it really hard to get the subject correctly into focus. (That's basically what Wolfbirder was saying too.)

I've only used it for astronomical observation so far, not for birding, so I my impression might be slightly biased.

The dual-speed focuser on the 883 really is poorly configured in my opinion - the speed of the "slow" drive is markedly faster than what I would consider perfect for a single-speed system without the extender, when on a dual-speed system, it really should be slower.

Regards,

Henning

Yes indeed, Henning. The slow/fast ratio is 3:1 and if the coarse focus is right for 25x it should be about six times slower for 60x because of the reduced depth of field. The 1,6x extender would necessitate a further reduction of two and a half times.

I believe some rack and pinion or Crayford focussers for astronomical scopes have a slow/fast ratio of 10:1.

John

 

[paddy7]

The extender is invaluable in some settings, and a bit of a pain in others. Of course, firstly, your mag starts at 40x with it installed. The FoV does drop, and i never use it for sea-watching, where you would think the distances would benefit the extender - but no.
Estuaries, shore-lines, big, open environments, scanning mountainsides though - great. It takes about 2-3 mins to install or remove, so i generally have an idea before i go out whether its a 1.6 day or not.
Also - better in days of little wind or other condition likely to cause instability, particularly if using at full zoom.
Although i may not use it more than 20-30% of the time, i wouldn't be without one.

 

[Hauksen]

Hi John,

Yes indeed, Henning. The slow/fast ratio is 3:1 and if the coarse focus is right for 25x it should be about six times slower for 60x because of the reduced depth of field. The 1,6x extender would necessitate a further reduction of two and a half times.

Thanks a lot for confirming my suspicion!

My very first look through a Kowa 883 ever was at an exhibition, and I told the Kowa salesman there, "I love the view, but the fine focuser is too fast". He immediately and smoothly replied, "But there's no slack or lost motion at all" ... and the smoothness of his delivery told me he gets that comment from his customers all the time.

I saw that some people 3D-print long levers for finely focusing rifle scopes, so maybe I'll try something like that on the 883. As so often, the challenge will be stowage when not in use ... providing the actual functionality will be straightforward

Regards,

Henning

 

[BoldenEagle]

I saw that some people 3D-print long levers for finely focusing rifle scopes, so maybe I'll try something like that on the 883. As so often, the challenge will be stowage when not in use ...

I have been thinking of something like that also.

Please let us know if you will come up some solution for this "fine tuning the not so fine focusing"!

Regards,

Juhani

 

[SUPPRESSOR]

Yes, I think it could be one of those things that when it's on you wished it was off and visa versa!!
Peter.

I decided to purchase the 1.6 extender which arrived today and then spent the afternoon on bodmin moor with it. Pleasantly surprised with its performance so much so that I shall keep it on most of the time.
Pete.

 

[BoldenEagle]

I decided to purchase the 1.6 extender which arrived today and then spent the afternoon on bodmin moor with it. Pleasantly surprised with its performance so much so that I shall keep it on most of the time.
Pete.

Way to go. I think that if not getting the extender, one will not get the full benefit that 883 is able to provide.

Allthough in my opinion, the highest magnifications are only useful at relatively bright conditions and without too much heat haze. If the scope body is a good sample, there is definitely more details to be seen if conditions are favourably and at least I don't feel that 40x mag. as the minimum is too much for, say finding birds in flight. So for me the worst things with the extender really are just the inevitable small exit pupil at the high mags., and the far too fast fine focusing gear of the scope.

But there's also a way to some degree overcome the brightness loss at the high magnifications: go digiscoping and adjust the camera exposure and you will pull out details and colours that you couldn't see at all with naked eye. Of course this doesn't work well with bif but for many stationary cases I have been pleasantly suprised how much difference there can be.

Regards,

Juhani

 

[SUPPRESSOR]

Way to go. I think that if not getting the extender, one will not get the full benefit that 883 is able to provide.

Allthough in my opinion, the highest magnifications are only useful at relatively bright conditions and without too much heat haze. If the scope body is a good sample, there is definitely more details to be seen if conditions are favourably and at least I don't feel that 40x mag. as the minimum is too much for, say finding birds in flight. So for me the worst things with the extender really are just the inevitable small exit pupil at the high mags., and the far too fast fine focusing gear of the scope.

But there's also a way to some degree overcome the brightness loss at the high magnifications: go digiscoping and adjust the camera exposure and you will pull out details and colours that you couldn't see at all with naked eye. Of course this doesn't work well with bif but for many stationary cases I have been pleasantly suprised how much difference there can be.

Regards,

Juhani

Yes, I agree with all of that. I also like the fact that with the extender on the field of view does not feel pinched.
Have used the scope a few times now and it just feels normal and great for reading bird rings too.
Peter

 

[SjerPlover]

Perfect for reading the code of coulor ringed birds when circumstances (e.x. behaviour of the bird and weather conditions) allow.