March 36-55x52 EP-Zoom Scope - Anyone Have One?

[South Pender]

I was able to snag one of these used recently at a great price and have had a chance to look it over in some detail. I think it's going to be a good acquisition, but there's one thing I noticed about it that I'm confused about. So I'm hoping someone can clarify this for me.

The zoom function is in the eyepiece, and when you change the zoom from 55 power down to 36 power, the eyepiece comes out just under one inch. So the scope is longer at 36 power than at 55 power. In addition, the eye relief is less at 55 power than at 36 power, and so the combined effect is that you have to move your head forward when set at 55 power--because the eyepiece has moved in about an inch and the eye relief is less.

Seems to me that it should be the reverse of this--that is, when the eyepiece is in its innermost position (55 power), the eye relief should be greater to compensate.

So, if someone has this scope and can explain this, I'd really appreciate it.

 

[Turbulent Turtle]

The March EP scopes are interesting designs. Essentially the zoom function is in the eyepiece instead of the erector tube and thus you are zooming in on the picture of the second focal plane. I just grabbed a loupe that I have on my desk and I observe that the image provided by the loupe increases in magnification as it gets closer to the object.

 

[Fred Bohl]

Yes I have one love it and it functions as you have described.

Seems to me that it should be the reverse of this--that is, when the eyepiece is in its innermost position (55 power), the eye relief should be greater to compensate.

Wouldn't it be nice, but probably a future feature that I could not afford. I'm happy to have the benefits of the eye piece zoom versus erector cell zoom and can tolerate the eye relief position shift with zoom.

I observe that the image provided by the loupe increases in magnification as it gets closer to the object.

TT's reply informs us how a loupe (aka magnifier) works and the eyepiece of the EP Zoom is a form magnifier/loupe.

Also if you have observed, the diopter correction function on scopes works the same in that +diopter corrections move the eyepiece toward the turrets and reduce apparent eye relief while -diopter corrections move the eyepiece away from the turrets and increase apparent eye relief both slightly though. Further note that for fixed power March 40x, 50x, and 60x the eye relief gets shorter with power 80mm, 78mm and 77.5mm respectively (at 0 diopter). These are small side effects of the optical design of the scope and the magnitude of these effects are determined by how much of the burden of power desired is placed on the eyepiece. In the case of our 36-55x EP zoom, the basis is the 50x with a special eyepiece of effectively 0.72 to 1.1 power.