Opticron 2.5X booster. (1 Viewer)

Binoseeker

Mostly using spectacles (myopic) with binoculars.

• Dec 23, 2014

• #1

I bought an opticron 2.5x booster to check it out.
With the 48-50-ish adapter it fits perfectly to my meopta
S2 HD 82 scope & Mc Kinley 8x42 bin, after putting some thin
selfadhesive flocking material on the inside of the adapter
to reduce inner diameter slightly.

When i look through the ocular, holding it in my hand, the centre
part is slightly out of focus, then there is a "ring" around it that is
sharp, and then it gets slightly out of focus to the edge, should it
be like this, usually optics at least is sharp in the centre ?

I like the mechanical design, with exchangeable adaptors, twist up
eye cup, it feels solid.

I will get back to you about optical performance when put on the scope
& bin in a couple of days.

Anders

 

C

Cluster

Well-known member

• Dec 23, 2014

• #2

Perhaps it's the same thing that I have seen on more than one new binocular, a donut shaped sweet-spot, just as you describe. Having set up the centre of the view for the best focus and sharpness, panning away from the focussed object I see an improvement in the contrast/sharpness then it softens as usual.
My present Hawke Endurance has a hint of this, one of two that I bought, I kept the donut sweet-spot shaped one because this gave (by far) the widest sweet-spot. I returned a 7x42 for this as it was too noticeable in one barrel. the replacement that they sent to me was identical. Now thinking about it, I'd bet that it was the same one returned. That went back too.

Dave..

 

T

typo

Well-known member

• Dec 23, 2014

• #3

Anders,

I've only played with a couple of these briefly over at Opticron's Luton HQ and I seem to remember it was necessary to adjust the distance between the booster and the eye lens to get the best result. While the resulting sweet spots were small, both boosters certainly performed well enough to confirm the resolution deficiencies in one binocular I spotted previously. Are you sure the problem is with the booster?

David

 

Binoseeker

Mostly using spectacles (myopic) with binoculars.

• Dec 23, 2014

• #4

Dave, thanks for your reply.
I usually take a note of the serial number, just in case, when returning stuff so i can check if they return the same sample to me.

The opticron booster don't have a focuser so i can't check the sweetspot by refocusing s t s. Some people here on BF have the Bushnell booster, and others, which seems to be of the same type, maybe one of the owners can tell us if it displays the same optical donut behaviour while handheld, please.

Anders

 

Binoseeker

Mostly using spectacles (myopic) with binoculars.

• Dec 23, 2014

• #5

David, thanks for your reply.
I am not sure there is any problem with it, i am just asking since it look funny when out of focus in the centre.
Maybe it is not correct to check a booster handheld ?
Well, i guess there are a lot of boosters here on BF.
The swaro type should have good performance, maybe it is out of focus in the centre also, a donut, handheld ?

Anders

 

T

typo

Well-known member

• Dec 23, 2014

• #6

Anders,

I might be wrong but I presumed the Opticron booster was some variation of a Barlow lens and shouldn't work in isolation... but I don't think I tried.

David

 

Binoseeker

Mostly using spectacles (myopic) with binoculars.

• Dec 23, 2014

• #7

David,

Here is some info on the swaro booster...it seems to function well on its own...

http://scopeviews.co.uk/SwaroBooster.htm

And here is the zeiss one...can also be used separately...

http://www.zeiss.se/sports-optics/en_se/nature/binoculars/binoculars-accessories.html

 

Last edited: Dec 23, 2014

T

typo

Well-known member

• Dec 23, 2014

• #8

Anders,

I know any monocular (or binocular) can be used to boost magnification. I just don't know if the Opticron UTA works that way. Hopefully one of the Opticron guys can help out. Do you see the doughnut effect when used with the Meopta/McKinley?

David

 

H

henry link

Well-known member

• Dec 23, 2014

• #9

I have the Bushnell Elite 2.5x "Doubler", which appears to be very similar or identical to the Opticron. It's a roof prism monocular with fixed focus.

I think the ring of good focus around a fuzzy center results from the center coming to focus a little beyond infinity, so it's not focusable by a normal eye. Field curvature brings the focus for distant objects to a plane that the eye can handle in a ring around the center. I think you'll notice that closer objects can be brought to focus nearer the edge as the field curvature increases.

This really isn't a problem when the device is used to boost the magnification of a binocular, since all the focusing is done by the binocular and it has plenty of focus adjustment to compensate for the slightly de-focused booster.

Henry

 

Binoseeker

Mostly using spectacles (myopic) with binoculars.

• Dec 24, 2014

• #10

Henry, your description is similar to my experience.

Here are some photos taken with my iphone, looks a bit dark, don't have much light now on the chart but it will give you a feeling of how it works :
- Booster alone maybe half a meter from chart.
- Booster on Meopta S2 scope at 30x gives 75x in total, at 10m distance.
- Booster on Meopta S2 scope at 60x gives 150x in total, at 10m distance.

I haven't had time to look outside with it, it is dark outside when getting home from work...

When looking only through the booster, at 2m distance, the image looks sharper at the edge, when increasing the distance the sharpness area moves towards the center, donut shape, when looking at say 60 m distance the image is sharp only at the center.


Merry Christmas !

Anders

 

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Last edited: Dec 24, 2014

Binoseeker

Mostly using spectacles (myopic) with binoculars.

• Dec 24, 2014

• #11

Interfaces...

Well, as said earlier, I used the opticron UTA adapter ring no. 40948, with some self-adhesive thin flocking material mounted on the inside to reduce internal diameter so now it fits very well onto the eyepiece on the meopta S2 HD scope, and on my McKinley 8x42 binocular.
I put on some tape on the eyepiece, just below the twist up eye cup, to increase diameter to give more support for the adapter ring all the way s t s.

I took one of the adapter rings, that came with the iphone 4/4s digiscoping adapter, the ring for BD/SV/YF-binoculars, and removed the thick flocking material, and put on some self-adhesive thin flocking material instead, to increase inner diameter, so now it fits perfectly on the opticron UTA eye piece so now it is easier to digiscope through the booster with my iphone 4/4s.

With flocking materiel I mean black velvet/velour like fabric. I bought this EAN 8427973067076, to try it out, mounted inside a home made longer sunshade extender for my scope. The self-adhesive fabric is made by Sadipal, no 06707, cost 90 SEK. , size 100x45cm.

http://en.sadipal.com/upload/producte/self-adhesive-velvet.pdf


Anders

 

Last edited: Dec 24, 2014

H

henry link

Well-known member

• Dec 24, 2014

• #12

Binoseeker said:

Henry, your description is similar to my experience.
When looking only through the booster, at 2m distance, the image looks sharper at the edge, when increasing the distance the sharpness area moves towards the center, donut shape, when looking at say 60 m distance the image is sharp only at the center.


Merry Christmas !

Anders

Click to expand...

Hi Anders,

That sounds like the same field curvature effects I see, except yours apparently works better for your eyes since I can never focus the center even for objects at infinity.

Merry Christmas to you!

Henry