SLC headache (1 Viewer)

[Skippa]

Hi,

I have a pair of 8x42 slc's that I've had for about 6 months now. They give me a headache after using. Sometime I feel my eyes are blurred after using them for a while.
I've tried playing with interpupillary distance and dipotor settings with no difference.

Any suggestions? Its very frustrating.

Thanks,
Skippa

 

[delia todd]

Hi Skippa and a warm welcome to you from all the Staff and Moderators.

Oh dear... I'm sorry to hear you're having such problems with your binoculars, hopefully someone can give you some advice and will be along soon. Just wondering if a visit to an optician might help too? You've so many beautiful birds to look at, it's a shame you can't make the most of them at the moment.

I'm sure you will enjoy it here and I look forward to hearing your news.

 

[SUPPRESSOR]

Hi,

I have a pair of 8x42 slc's that I've had for about 6 months now. They give me a headache after using. Sometime I feel my eyes are blurred after using them for a while.
I've tried playing with interpupillary distance and dipotor settings with no difference.

Any suggestions? Its very frustrating.

Thanks,
Skippa

Need the collimation checking.

 

[jan van daalen]

Hi,

I have a pair of 8x42 slc's that I've had for about 6 months now. They give me a headache after using. Sometime I feel my eyes are blurred after using them for a while.
I've tried playing with interpupillary distance and dipotor settings with no difference.

Any suggestions? Its very frustrating.

Thanks,
Skippa

Hi Skippa,

Welcome to BF.
The diopter setting would be the first thing on my mind. You do know that the neutral position of the diopter setting with the SLC is not in the middle but sideways, marked with a triangle?
The second thing could be that the bin is out of collimation which means the right and left tube are not inline. You can check that by looking with both eyes through the SLC , close one eye open it and close the other eye. When the "picture" moves your bin is out of collimation. Even the slightest collinmation error gives one a headache.
In that case The SLC has to go to Swaro and they will take care of you.
Let us know how it ends.

Jan

 

[Binastro]

Hi Skippa and welcome.

Sounds like the binocular is out of collimation.

It could possibly be that your eye prescription has changed, perhaps prism correction.

Regards,
B.

 

[Skippa]

Thanks for all the responses. I've worked out that the middle eyecup setting it just a touch to close, while the fully extended eyecup position is to far.

I've been using them on the middle setting as it gives me the sharpest edge. But any slight movement and I get black shadowing.

Could this cause headaches? From eye strain?

Do I need a binocular with eyecups that have the correct setting for me maybe?

Thanks,

 

[PYRTLE]

Additionally, were they new and had you tried a pair before hand, I would also initially suggest faulty collimation.

 

[KC Foggin]

Very sorry to hear about your problems with your Bins.

Hi there and a warm welcome to you .
We're glad you found us and please join in wherever you like

 

[Skippa]

Yes I purchased them new last year.

I tried the 10x42 version. They have a shorter eye relief Ive seen?

I've tried the collimation test of focusing on a horizontal line and moving my eyes back to see if the line distorts. They seem fine, however, I'm aware that the brain can see imperfections I'm unaware of so not a precise indicator.

Thanks,

 

[jring]

I've tried the collimation test of focusing on a horizontal line and moving my eyes back to see if the line distorts. They seem fine, however, I'm aware that the brain can see imperfections I'm unaware of so not a precise indicator.

Hi,

first of all, welcome to birdforum!

I don't really know that test for collimation - and it sounds like it only checks for the tubes being out of sync in up/down direction but not left/right.

So maybe try what Jan recommended or do it the stargazer's way and focus on a bright star, then defocus one eye completely with the diopter full to one side and observe the star again. The out of focus tube will show the star as a pale disc, the in focus tube as a bright dot. You want the bright dot to be in the center of the disc, if it is not, your bins are out of collimation.

Incorrect diopter setting might also give a headache after a long time, but slightly out of collimation is easier to miss.

Joachim

 

[Skippa]

When I focus a star (off hand, I don't have a tripod) and then turn the diopter all the way one way or the other while still staring at the star, the star drifts to the left edge of the burry blob (blob is more oval then round?) My eyes will eventually start to try and realign the star in the blob and shift it momentarily.

Thanks

 

[jring]

Hi,

this sounds like the two tubes are out of alignment in horizontal direction - also the fact that the diffraction pattern is oval might mean some astigmatism in the tube which the diopter acts on.

Can you try to move the diopter to the opposite end of the range and check whether the main axis of the elliptic "blob" flips 90 degrees? That would prove astigmatism.

All in all, since you have a Swaro which is still under warranty, you should talk to your vendor to arrange for a visit to Absam - unfortunately only your bins get to go...

Joachim

 

[Skippa]

I did try the diopter in both directions. Same in either direction.

I contacted swaro and they want me to get someone else to have a look and see if it effects them the same way.

I've had a bad run with these, when I first received them, I noticed the rings that screw in and hold the objective lenses in has two spots for a tool to drive on, it had clearly slipped on assembly and burred the black finish off down to steal. Did not effect the bins but for $2090 AUD I was not impressed.

Swaro were not stressed at all.

Thanks,

 

[jring]

I contacted swaro and they want me to get someone else to have a look and see if it effects them the same way.

That indeed makes sense as the astigmatism (if there is any, if the direction of the ellipse does not flip, it is a bit doubtful) can also happen in your eyes (although since you cannot defocus at will, you can't see the out of focus diffraction patterns - just stars looking like little crosses instead of dots and general blurriness).

Also a slight squint can make a marginal instrument not work for one user...
I was on a vacation with some friends and looked through one pair of bins in the group and couldn't get the images to merge. Everybody else said they were ok... so one of my friends (who happens to be an ophthalmologist) looked me deep in the eyes and said Joachim, you have a slight squint (which is correct - I even had glasses for that with a prism prescription as a kid) but nowadays I can merge the images just fine, with or without bins - except for that single pair which probably was a bit out of collimation but was still ok for those without my slight squint...

Joachim

 

[Maljunulo]

Would you please share your definition of "squint"?

Thanks

 

[jring]

Would you please share your definition of "squint"?

Thanks

Hi,

as in cross-eyed?

Joachim

 

[Maljunulo]

Thank you.

It must be slight if you can truly fuse images.

 

[Binastro]

I can only speak from personal experience.

In later years I have needed prism correction, but only for my reading glasses.
This varies slightly over time, i.e. every one or two years, and is sometimes zero.

For computer, T.V. and distance glasses I have not needed prism correction.

The prism correction is achieved I think by two means.
Prism correction in the glass, or by altering the separation of the centres of the two lenses, i.e. decentring the lenses.

There are some binoculars that I feel unhappy using. These are usually cheaper binoculars where I think there is small or moderate miscollimation.
In general high quality binoculars are delivered new with good collimation.
But any binocular that is dropped could be knocked out of alignment.

The Swarovski binocular mentioned here could be out of alignment.
But maybe get other binocular users to check.

Regards,
B.

 

[Binastro]

The person checking the binocular should have the same IPD, inter pupillary distance, as the binocular could be conditionally aligned rather than collimated.

B.