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EL 8.5x42 WB eyepiece convex or concave? (1 Viewer)

John Frink

Well-known member
Hey, Swaro-geeks, take a look at this one. Here's a photo of an EL 8.5x42 WB for sale on the big auction site, and the reflections in the eyepice seem to suggest that the outermost lens surface is convex. Serial number is L7315nnnnn. My own 8.5x42 is L7334nnnnn, and the outer eyepiece lenses are concave. Is this photo an optical illusion? Or did Swarovski change their eyepiece design in mid-2003?

John
 

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Not sure.
Sometimes craters on the Moon look like domes.
It depends which direction the lighting comes from.
One might tell from the shape of the reflections here.

Of course if one had the binocular one could just put a spherometer on it.
 
I suspect the outer ocular lens surface is flat, as it is in most all binoculars.

The objective may be flat or maybe convex, it depends.

Jerry
 
I suspect the outer ocular lens surface is flat, as it is in most all binoculars.

The objective may be flat or maybe convex, it depends.

Jerry

A friend has ~2010 8.5x42 ELs and I have ~2012 10x42 EL SVs and both have concave outer surfaces to the outermost ocular lens.

On that auction listing it sure looks convex, but hard to say if it's just an illusion.
 
A friend has ~2010 8.5x42 ELs and I have ~2012 10x42 EL SVs and both have concave outer surfaces to the outermost ocular lens.

On that auction listing it sure looks convex, but hard to say if it's just an illusion.

You are correct, I just checked mine, the 8.5 EL has a concave ocular.
Good time to give my oculars a cleaning with the lenspen.

As you know, it really does not mean anything.

Jerry
 
You are correct, I just checked mine, the 8.5 EL has a concave ocular.
Good time to give my oculars a cleaning with the lenspen.

As you know, it really does not mean anything.

Jerry

No but convex would be interesting, not sure I've seen that on any "premium" bins before. I guess you'd need more built in depth to the eye cups even in their lowered position to keep the oculars clean.
 
I seem to recall seeing elsewhere reference to the Swaro EL 8.5x42 having concave oculars, but I cannot tell on mine with certainty. However this may be of interest http://scopeviews.co.uk/Swaro10x42SLCHD.htm, see under "Optics Eyepieces?

The 2015 ISO (ISO 14132-1:2015(en)) has the following statement:

"4.2.8
eye relief
distance from the vertex of the last optical surface to the exit pupil of the telescopic system measured along the optical axis"

This can only mean that oculars cannot be concave �� ????
 
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The Swarovski eye cups are removable so I took one off my 7x42SLC B and looked closely at the ocular and it looked to me like its top element was slightly concave.Then I checked my little 8x30 CL Companion. The ocular is small but it also looked to me like its top element is slightly concave.

Now, this is not exactly a rigorous test, but anybody with these binoculars can do it; so I held the stiff edge of a piece of writing paper across the diameters of the top elements of the oculars of both of these binoculars and they still appeared concave to me.

The eye cups of my Zeiss Victory 7x42 T* FL, Leica 8x42 Ultravid Blackline and Nikon 10x32 EDG are all removable so I checked the top elements of their oculars for curvature. They all appeared flat to me although the Zeiss and Nikon have metal casings that extend above the glass of the top elements so I could not use the paper edge "test" on them. The paper edge "test" on the Leica agreed with what I saw with my eyes.

For what it is worth.:smoke:

Bob
 
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