Televue Panoptic 27mm eyecup vs eye relief

[Chipela]

Hello,

I was looking at the specs and images of Televue Panoptic 27mm (not going to buy one, no no no ). Anyway, what made me wonder is that it has a generous 19mm eye relief but the eyecup doesn't seem to reach too far from the surface of the eye lense, just a few mms. My reference is the Delos design where the eyecup unfolds but in addition to that I can extend the barrel ~15mm and get excellent protection against light entering the eyecup.

So how is it, is there some mechanism giving more protection or does one need to buy an eyecup extender or something similar?

Thanks for any info,

Chipela

 

[John]

Eye relief is measured from the centre of the top surface of the eye lens. The top surface of the eyelens with the Panoptics, and many other widefield eyepieces is actually concave so the central point can be a few mm below the point where the eyecup is fitted so the actual physical eye relief from the eyepiece top can be less than the specced eye relief. Eye lenses can be recessed as well, which also "eats up" some of the eye relief.

Tele Vue do actually market an eyecup/eyeguard extender for folks that feel they need a deeper eyecup on their fixed eyecup models. The 27mm Panoptic is one of the models that this accessory fits:

http://www.televue.com/engine/TV3b_page.asp?id=158

[alan potts]

I use the 35mm and the 41mm Panoptics and I don't find any problems with the eyecups and stray light, maybe the 41mm could do with being a bit longer if I had any lights about but I don't see there would be any requirement to need a larger eyecup on the 27mm in any situation

[Chipela]

Thanks a lot for the info!