Focus to infinity for short-sighted users (1 Viewer)

[hopster]

I have been looking at a lot of the top quality binoculars over the last few months and have discovered that short-sighted people (with negative prescriptions) may need to be aware of an issue. In some cases you might not be able to get to infinity (i.e. star gazing) comfortably without glasses because the focuser gets very close to or hits the end stop due to a lack of leeway. I much prefer to use binoculars without glasses, and sometimes also with winged eye cups, to stop stray light entering from the sides.

My prescription is ≈ -2.5 in both eyes. The binoculars that I have noticed this on are the following (all 8x42s):

• Leica Noctivid (2 examples the same)
• Kahles Helias S (= late Swarovski SLC)
• Swarovski NL pure
• Zeiss HT(though the focuser probably needed servicing on this one)

So all very nice optics otherwise! Zeiss SF & FL T and Opticron Aurora and Swaro EL 8.5x42 were OK.

I have also tried two of the problematic ones (Noctivid & HT) in 10x42 and they are both better though still a bit too close for comfort. I suspect this is not a coincidence but due to the different optical or focusing design required at the larger magnification.

It may be good to get a kind of database going about this to help people in advance before they buy without checking and get disappointed. On another thread, user etc said:

I am at -5.25D. I get binos which have enough overdrive past infinity so I can use them without eyeglasses.
Zeiss 10x54 HT is pretty good, So is Swaro EL 8.5x42 and probably 10x42.. EL 12x50 has -7D of correction.

So HT (at least in 10x) and EL seem to be good candidates from this point of view.

 

[etc]

At -2.5D, you can get anything. I think it's hard to find something that does not comply with this.
All Leicas go to at -4D, Swaro EL 8.5x42 to -6D, 10x56 SLC to -8D.. Zeiss 8x42 SF to -6D.
There is a database here but I am not convinced it's fully accurate after reviewing it (specifically I do not believe any Leica is at -5D).

The PINACOLLECTION – Binoculars Today

 

[hopster]

At -2.5D, you can get anything. I think it's hard to find something that does not comply with this.
All Leicas go to at -4D, Swaro EL 8.5x42 to -6D, 10x56 SLC to -8D.. Zeiss 8x42 SF to -6D.
There is a database here but I am not convinced it's fully accurate after reviewing it (specifically I do not believe any Leica is at -5D).

The PINACOLLECTION – Binoculars Today

The two Leica Noctivid 8x I looked at were not going to make -4D (they were struggling to get to -3D) but the 10x might have.

 

[etc]

It's really sad. I think Leica is the best built binocular out of all the Alphas but completely inadequate in terms focus past infinity.

 

[kimmik]

was the diopter set to 0 on the noctivid? mine (and presumably all) noctivid easily makes 4D with the diopter at 0. with the diopter at 4, there is still a tiny bit over overdrive so 4.5/5D max total correction is about right.

 

[Canip]

There is a database here but I am not convinced it's fully accurate

It isn‘t fully accurate, and can‘t be.

The values are marked as estimates.

And:
I have found - a bit unexpectedly - sample variation up to 1 dpt and more between several samples of the same model.

So these values are meant as indications only.

 

[hopster]

was the diopter set to 0 on the noctivid? mine (and presumably all) noctivid easily makes 4D with the diopter at 0. with the diopter at 4, there is still a tiny bit over overdrive so 4.5/5D max total correction is about right.

Yes it was, my eyes are almost identical in terms of myopia. Is yours 8x or 10x?

 

[eronald]

Does Leica do the adjusment as a service request these days? I know an independent repair guy who sais he could do it - sadly Brexit happened