Join for FREE
It only takes a minute!
Zeiss - Always on the lookout for something special – Shop now

Welcome to BirdForum.
BirdForum is the net's largest birding community, dedicated to wild birds and birding, and is absolutely FREE! You are most welcome to register for an account, which allows you to take part in lively discussions in the forum, post your pictures in the gallery and more.

Kowa 883 with 25/60 and 1.6 Extender Center Shadow

Reply
 
Thread Tools Rate Thread
Old Friday 3rd January 2020, 01:39   #1
wcerveny
Registered User

 
Join Date: Dec 2019
Location: Marblehead, Ohio
Posts: 4
Kowa 883 with 25/60 and 1.6 Extender Center Shadow

Please excuse me if this is a dumb question but I am very new to birding and spotting scopes. I just purchased a Kowa 883 with the 25-60 eyepiece and the 1.6 tele extender. When using the 25-60 without the extender I am having great results however when using the extender at about 70 or higher power I am seeing a circular shadow at the center of the eyepiece. It seems no matter where I place my eye at these higher magnifications I can not see an image without the circle shadow. I have adjusted the eye cup all the way down up and in between.
It almost seems like I can not get my eye close enough to the lens to get rid of the shadow.

Thanks in advance.

Bill
wcerveny is offline  
Reply With Quote
Old Friday 3rd January 2020, 07:10   #2
jring
Registered User

 
Join Date: Aug 2015
Location: Germany
Posts: 2,261
Hi,

what you describe is called kidneybeaning and is usually caused by the eye being too close to the eyepiece. Can you try to fully extend the eyecup or position your eye even farther away?

Joachim
jring is offline  
Reply With Quote
Old Friday 3rd January 2020, 23:52   #3
wcerveny
Registered User

 
Join Date: Dec 2019
Location: Marblehead, Ohio
Posts: 4
Thank you for your response. I did a little reading on the kidney bean effect and please correct me if I am not properly informed. The effect can be kidney bean shaped or round and it can be from the eye being too close or also too far away. Mine appears to be too far away at higher magnification with the 1.6 extender. I can not get the eye close enough to eliminate the dark circular shadow. So perhaps the best thing is to return the 1.6 and be satisfied with the 25-60 Kowa unless you may have some other suggestions Joachim.

Thanks,

Bill
wcerveny is offline  
Reply With Quote
Old Saturday 4th January 2020, 03:47   #4
Alexis Powell
Registered User

 
Join Date: Dec 2003
Location: LY+DG counties, Kansas, USA
Posts: 3,308
I agree with Joachim, I think your eye is too close. I use the same equipment as you and I have no problems. I wear glasses, so my eye is not very close to the ocular.

--AP
Alexis Powell is offline  
Reply With Quote
Old Thursday 6th February 2020, 21:34   #5
mskb
Registered User

 
Join Date: Aug 2018
Location: Massachusetts
Posts: 164
Hey Bill, Congratulations on the scope. Did you figure this out? You do mention you have varied your eye cup height and still unable to resolve the shadow issue. So I wonder if it is something else other than the eye relief. Any chance you could post / link to an image of the shadow you are mentioning?

Last edited by mskb : Thursday 6th February 2020 at 21:51.
mskb is online now  
Reply With Quote
Old Friday 7th February 2020, 14:22   #6
wcerveny
Registered User

 
Join Date: Dec 2019
Location: Marblehead, Ohio
Posts: 4
Unfortunately I am unable to post any picture as I returned the scope and eyepiece.
I was still within the 30 day return period on the purchase.
I am happy to report that the new scope and eyepiece that were sent to replace the originals are working fine for me now.
wcerveny is offline  
Reply With Quote
Old Friday 7th February 2020, 21:23   #7
mskb
Registered User

 
Join Date: Aug 2018
Location: Massachusetts
Posts: 164
Thanks Bill! Glad things worked out well!
mskb is online now  
Reply With Quote
Advertisement
Reply


Thread Tools
Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is Off
HTML code is Off

{googleads}

Fatbirder's Top 1000 Birding Websites

Help support BirdForum

Page generated in 0.15816402 seconds with 21 queries
All times are GMT. The time now is 03:25.