Eye relief

[dawson]

I read all these threads where people talk about eye relief and i've had to look on wikipedia to try and understand it, which i think i now do.

But what factors affect eye relief? Is it simply the field of view of the eye piece and the size of the exit pupil on the eye piece? Do manufacturers quote the eye relief of their eye pieces?

Thanks

James

[T A WOW]

I'm not sure what exactly effects the eye relief of any given EP other than its designed to have a certain amount. Most manufactures will state what it is usually. If not a simple google search would probably tell you.

[Rusty Strings]

Manufacturers at the pricier end certainly quote eye relief as it can make or break how effective the eyepiece is for spectacle wearers

[Guest Tweedledum]

Hi There,

 

Its basically the distance from the top of the eyepiece to the point where the eye can still see a full field of view. so if you are a glasses wearer you do not need to have your glasses squished!...

 

Other factors also like age! check these links out and have a play..Remember to set the second link to visual not camera..

 

http://www.stargazing.net/naa/scopemath.htm

 

http://www.12dstring.me.uk/fov.htm

[angusw2]

As I understand it its the fundamental design of the eyepiece that affects eye relief. The eye lens needs to be a good size and the apparent field of view is the angle that the light rays exit the eye lens to form the image. The larger the eye lens the further from the eye lens the rays come to a focus and the greater the eye relief. That's why an eyepiece like a Nagler 3.5mm has an eye lens of about 17mm diameter, and an unfortunate pricetag to go with it! 

Angus

[Guest CodnorPaul]

Now that sounds like a man bitten with the Ethos bug after Saturday night

[Guest Tweedledum]

An eyepiece does not need to be expensive to have good eye relief. One of the best I owned was an 8mm BST explorer, excellent eye relief for less than £50.

[Cazz]

I'm perhaps just a bit strange, well perhaps not just a bit lol, but the eyepieces I seem to get on best with are good quality plossels.

I do wear glasses and have an astigmatism in my right eye, which means I get on better wearing my glasses whilst observing. Or perhaps I'm just still very inexperienced.

[Guest Wayne]

Damian - I agree the 8mm bst explorer is fab.

If you know what I mean lol :-)

[Guest Tweedledum]

Hi Wayne,

 

Its just a cracking ep, when you get it out of the box there is such a lot of glass and screw up eyecup is the biz, glad it has a good home!

[Guest Wayne]

Thanks damian. It gets a lot of use. Let's hope the whether stays good. :-)