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Opticron MMS 160 - Image stabilized handheld scope (1 Viewer)

A 26mm aperture and 160mm focal length, if that is what it is, is not fast.
In fact it comes within even Conrady standards maybe.

I was using my 2016 Canon 8x25 IS last night and unfortunately it is a lemon. Made in Japan.
I was looking at Jupiter.
The IS is jittery. There is bad and strange false colour, lots of it, and maybe astigmatism or the IS part is not properly aligned. Jupiter is cross shaped with blue and red ends at 90 degrees to each other. Most peculiar. I don't think it is my eyes.

The 2014 sample is brilliant.

So one really has to try any optics one buys, as bad examples turn up.
Generally I have had very good Canon IS results over almost 20 years. But it is only fair to report this very poor example.
 
I will check on the close focus distance.

No factual idea on why the small aperture except to suggest that Opticron was trying to keep it smaller and lighter. Size and weight seem to be concerns, from what I have read, with some of the Canon models. I have only ever tried the 8x25.

Binastro,

Thank you. Would you have another explanation for the change in edge performance with the same eyepiece?
 
Hi,

thanks for the review - sounds interesting. The question is what is the reason for the not so hot edge performance. Can you get the edge sharp by refocussing or not.

In the former case it's field curvature and a lot of that is expected in an instrument with such a short focal length - field curvature is governed by focal length rather than focal ratio. The only way around it is additional corrector lenses aka field flatteners.

The focal ratio is just shy of f6 which is actually quite typical for spotters. Keeping the focal ratio sane and the focal length and thus physical length small is probably the reason for the tiny aperture. But since the focal ratio is similar to bigger spotters, so is the exit pupil for a given EP (EP fl/body fr).

If you cannot focus the edge, it's not only FC but might also be coma, astigmatism or a combination of both.

Can you give a ballpark percentage for the sweet spot?

Joachim
 
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Frank: Thanks for the update and information. More detail on the nature of the edge degradation would also be appreciated.

mayoayo: The brochure lists close focus as 9.8 feet.

I agree that focal ratio seems typical and similar to MM3/4 spotting scopes. I wonder if edge performance is related to prism design and coatings. I noticed that while it is listed as fully multi-coated, there is no mention of prism material, type of coatings, and whether or not it is phase corrected.

Alan
 
Hi,

edge performance is not usually related to prisms (except maybe vignetting due to too small prisms).

The shape of the device implies Schmidt-Pechan prisms - due to the small aperture and the slow focal ratio in comparison to binocular objectives, prisms from those could be used...

Joachim
 
With this version of IS I think that the maximum aperture is 30mm.
Maybe improved versions or different systems could be used with larger apertures.

The Canon 8x25 IS uses a different IS system to the larger Canon IS binoculars.
 
The edge performance is definitely field curvature and can be refocused. How many diopters difference seems to be more of the issue. Apparent sweet spot size with this eyepiece is approximately 75%.

Close focusing distance for my eyes with this eyepiece is approximately 8 feet.

Let me know if there are any other questions.
 
Hi Pete,

thanks for the info - since I haven't found a dealer for your products over here in germany yet (preferably near Frankfurt), I assume mail order directly from you is an option too?

And while we're at it, you asked if there was interest in an astro adapter for the SDLv2 zoom some time ago - has this materialized? If yes, I'd like one in the package...

Joachim
 
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Would MMS 160 work with 40933 HR2 eyepiece?
If yes, what are magnifications?

P.S.
I also have a Japan eyepiece in the old grey box marked 20-60x D=60. 16-48x D=50.
The eyepiece is marked ZOOM 50S in green and 60S in red with 18x 48x in green letters in the window and 20x 60x in red letters in the window.
But no makers name.
It is smaller diameter than the HR2 with a smaller attachment.
It may be Opticron.

The smaller eyepiece seems to have the wider apparent field at the highest magnification, but a considerably smaller field at the lowest magnification. Maybe the smaller eyepiece focal lengths are smaller?

It may be that the HR2 eyepiece can be used on the MMS 160 with an adapter.
What about the smaller ZOOM eyepiece?
 
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Binastro,

I couldn't find anything to that effect on the Opticron's MMS 160 page but I do remember reading it somewhere. I will see if I can find it.

Edit:

Found it. Listed as HR instead of HR2 but it shows 8-24x.
 
Thanks Frank.
8x to 24x would be useful but dim at 24x. It may need an adapter.

Yesterday I tried the 60 to 80 year old Broadhurst Clarkson HAWK 18x 23.5mm black leather drawtube scope with 3 drawtubes. 6 inches long collapsed.
It is very dim even in sunshine.
But it it is dirty inside, probably never cleaned. Also the relay lenses, eyepiece and objective are all uncoated.
No CA. Field only about 1.6 degrees.
It is really unsteady as it is too small to balance properly. The long drawtube scopes are much steadier.

The rear tube unscrewed makes a 30x magnifier. The bigger versions are much brighter and 20x.

The coated MMS 160 will be a brighter scope.
 
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Binastro: I was initially surprised by the field of view numbers for zoom eyepieces, but it seems that in general zooms are not par-focal with magnification and that the apparent field of view is smallest at low magnification. The one exception I've used is the Nagler 3mm-6mm zoom which has fairly consistent 50 degree apparent field and is par-focal over the magnification range.

Pete: Good news. I'm looking forward to trying out the MMS 160. I noticed that B&H has it up on their site with a 7-14 day availability.

Frank: Have you tried it with zoom eyepiece? How effective is IS and how is brightness at say 15x?

Thanks,
Alan
 
Joachim - yes, you can order from us but a better option might be to order by phone from our German distributor Vendemos (vendemos.eu). They don't have stock or samples yet but I'm sure they would be happy to help.

I can make sure to send the 1.25" adapter - it didn't really work as a project to be honest but you are welcome to try one for me :)

Cheers, Pete
 
Alan,

I did try it briefly with the SDL V2 but not the HDF. I will use both more extensively over the weekend and let you know.

I can say I was very pleased with the IS at 11x with the HDF fixed mag eyepiece.
 
Hi Alan.
It is to be expected of zoom eyepieces as the field is determined by the field lens.
At say 8mm fl the apparent field can be large, but at say 24mm fl it will be small unless the field lens was very large.

Nagler tries hard to have parfocal eyepieces but this is an extra constraint that others forget about.

I have the Nagler 3mm-6mm zoom and it is very good. It deliberately has a medium field to maintain quality.
With such small focal lengths it is easy to maintain the field size.
Also I use some 82 degree eyepieces. These help a lot with fixed tripods. Some are over 30 years old now.
 
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Alan,

I did try the MMS 160 with the HDF zoom this weekend extensively....and just now I set it to 15x to specifically answer your questions.

I did not find the brightness levels objectionable. I wouldn't call it "bright" but I wouldn't call it "dim" at that particular setting either. The IS works well all the way up to 21x.
 
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