Anyone with opticron aspheric 8x40

[johnnyp]

Hi All

Have recently purchased a pair of the opticron aspheric 8x40 and am very pleased on the whole. They do suffer from internal reflection on the moon or anything very bright but i believe this is normal?

When holding the binos at arms length the exit pupils are not perfectly round but slightly uniformly cut off in the top right of each exit. (hope that makes sense!)

Am i losing some light because of this? or all the opticron aspherics like this? I would appreciate your thoughts

cheers

John

[johnnyp]

bump

[argonaut]

What you are seeing is the prisms intruding into the light path. I doubt you will be losing anything. The 8x40 aspherics give you a nice 5mm exit pupil.

I use my 8x42's for nice wide field viewing.

Enjoy the binoculars.

Hope this helps a little.

[johnnyp]

What you are seeing is the prisms intruding into the light path. I doubt you will be losing anything. The 8x40 aspherics give you a nice 5mm exit pupil.

I use my 8x42's for nice wide field viewing.

Enjoy the binoculars.

Hope this helps a little.

Thanks for the reply, thats good to know. are you using the aspherics yourself? what are the internal reflections(not exactly sure of the term) like on bright objects? such as the moon

cheers

[argonaut]

Hi John,

It's probably light reflected from the porroprisms. It does bounce around quite a bit. The Moon is very very bright.Venus also is another candidate. Not sure exactly what you are seeing though.

It also depends form where you are viewing. When I view from my backyard I also suffer from reflections,depending on which binocular I'm useing. It's all down to optical coatings and blackening inside the binocular.

Aspheric lens systems are difficult to make and very expensive to get right.Just look at some photographic lenses which use aspheric systems. I presume you have a very flat field.

My 8x42's are Vortex Razors.