Luger ST 7x50 Binoculars - opinions anyone

[Flying Eye]

Hi all,

Noticed a pair of these while looking for minimal magnification and maximum objective size; I've got a theory I'd like to test.

I can't find out if they are BAK4 or BK7.

Wondered if anyone had any first hand knowledge of the brand.

I spotted them at Amazon, and one or two other places.

They do another version which is infinity/auto focus and those were a lot less interesting to me.

Any thoughts anyone?

[Karen]

Hello Ian,

Those bins have bak7 prisms and the optics are possibly not fully coated. I would avoid.

specs are here

Buy Luger ST 7x50 Porro Binoculars | Outdoor Accessories & Camping Gear | All Outdoor Ltd | alloutdoor.co.uk in BINOCULARS > LUGER BINOCULARS > LUGER ST >

[BinocularSky]

It has a relatively small field of view (6.6 deg) for a 7x50, so the BK-7 prisms may not be an issue (you only really need BaK-4 for wide FoV -- see BinocularSky - Binocular Basics). It is fully multicoated. The aspheric lenses suggest that it may have good optics, pretty sharp across the field (but no guarantee). There are two things that may put me off it:

• Luger also hawks zoom binoculars -- always a warning sign!
  
• It is described as being good for lots of terrestrial uses, but astronomy isn't mentioned. The sometimes means that it has a bit of built in convergence, which is a pain for astronomy.
  

[Karen]

I may be wrong but it also looks like there is no diopter!

[Flying Eye]

Hello Ian,

Those bins have bak7 prisms and the optics are possibly not fully coated. I would avoid.

specs are here

Buy Luger ST 7x50 Porro Binoculars | Outdoor Accessories & Camping Gear | All Outdoor Ltd | alloutdoor.co.uk in BINOCULARS > LUGER BINOCULARS > LUGER ST >

Thanks Karen,

I'm a little lost; following the link you kindly provided, the page there says "Luger DIM full coating". So there must be something that leads you to suspect they may not be fully coated.

Given I am not very experienced with binocular technology yet, I'd be very grateful if you would tell me what you spotted (or didn't spot) that makes you suspect this potential problem with the coating, then I could be more aware of what to look out for as I continue to look for lower mag with large objectives.

Admittedly the BK-7 is mildly off putting, but I've also spotted this seems to happen with lower magnifications - I think I am right in saying Celestron do this switch below 10x too.

[BinocularSky]

Admittedly the BK-7 is mildly off putting,

Don't let it be. As I've said elsewhere, there are much more important considerations for binocular choice, such as crispness of focus, flatness of field, edge distortion, chromatic aberration, build quality, smoothness of focus ... The first binocular I ever used for astronomy, my father's Zeiss 10x50 Dekarem, had BK7 prisms and single-layer coatings — overall it was optically and mechanically superior, and hence better suited to astronomy, than most (if not all) of today's budget fully multi-coated efforts with BaK4 prisms.

[Flying Eye]

It has a relatively small field of view (6.6 deg) for a 7x50, so the BK-7 prisms may not be an issue (you only really need BaK-4 for wide FoV -- see BinocularSky - Binocular Basics). It is fully multicoated. The aspheric lenses suggest that it may have good optics, pretty sharp across the field (but no guarantee). There are two things that may put me off it:

• Luger also hawks zoom binoculars -- always a warning sign!
  
• It is described as being good for lots of terrestrial uses, but astronomy isn't mentioned. The sometimes means that it has a bit of built in convergence, which is a pain for astronomy.
  

Steve, thanks for an even clearer view of those particular areas. I was guessing (probably wrongly) that 6x 7x and 8x were giving a comparatively wide FOV, so BAK4 might be more desirable. I may have put a tad too much weight on that idea with hindsight!

I can see these may not be quite what I was hoping, despite being fairly close in quite a few respects. I've seen a few others so may well be asking for thoughts on those shortly.

I've got a specific idea in mind, and I'll probably post a new post for that. Need to marshal my thoughts on that enough to have it make sense to most people!

[Flying Eye]

I may be wrong but it also looks like there is no diopter!

Come on sleuth, how did you spot that? I'm amazed that your searches reveal things that mine don't appear to. I wonder what I am doing wrong? Maybe a course in binocular specification searching for newbies is called for?

That lack of diopter really would be a deal breaker for general use in this case, I seem to need to adjust fairly often as my eyes seem to change a bit over time. Is that even normal?

[BinocularSky]

I was guessing (probably wrongly) that 6x 7x and 8x were giving a comparatively wide FOV, so BAK4 might be more desirable. I may have put a tad too much weight on that idea with hindsight!

It all depends on the incident angle of the rays on the internally reflecting surface of the prism. If it is less than about 41* for any of the rays, then BaK-4 starts becoming useful, but only for the periphery, not the centre, of the field of view.

I've got a specific idea in mind, and I'll probably post a new post for that. Need to marshal my thoughts on that enough to have it make sense to most people!

I was going to suggest that, if you gave us a clue, you might get some half-way helpful suggestions.

[Karen]

Come on sleuth, how did you spot that? I'm amazed that your searches reveal things that mine don't appear to. I wonder what I am doing wrong? Maybe a course in binocular specification searching for newbies is called for?

That lack of diopter really would be a deal breaker for general use in this case, I seem to need to adjust fairly often as my eyes seem to change a bit over time. Is that even normal?

It's just that on close examination of the picture the eyepieces seem to be identical and I can't see any sign of diopter markings. As I said I may be wrong but it may be worth checking before purchase.

[Flying Eye]

I see what you mean now you've pointed it out Karen, thanks very much indeed. Another thing learned and to be on the look out for.

It's hard to imagine anyone setting out to make binoculars and not including diopter adjustment in this day and age. That won't mean it can't happen though. I mean look at the fixed (as in moulded in) spotting scopes on too many of a certain manufacturer's telescopes (beginning with C). Who would ever have thought that a good idea, especially when the moulded in item does not appear to work at all for rather a lot of folk?

[BinocularSky]

It's just that on close examination of the picture the eyepieces seem to be identical and I can't see any sign of diopter markings. As I said I may be wrong but it may be worth checking before purchase.

The dioptre markings, if any, are usually on the other side of the eyepiece (so you can see them when you hold the binocular away from your eyes. However, you are correct that it's worth checking -- I mean, this outfit does hawk "focus-free" (i.e. not focusable) efforts.