Nikon MRAD Reticle ZOOMS When Focussing Eyepiece??

[Riflman]

Okay, so I thought I knew a bit about scopes, but I have never seen this before.

I have a Nikon Black x1000 6-24x50mm MRAD scope, and when I adjust the fast focus eyepiece, the reticle dramatically ZOOMS in and out. What's more it's very easy to turn and could easily move with a slight rub on clothing. It seems to me that this would change my ranging, POI, and EVERYTHING. Am I wrong?

My Nightforce NXS 5.5-22x56mm does NOT do this. Nor do any other scopes I own.

 

[ckaberna]

Research 1st focal plane! Not familiar with that scope at all.

 

[Riflman]

Research 1st focal plane! Not familiar with that scope at all.

I don't think I was being clear. The reticle zooms only when changing the fast focus on the eyepiece....as in when you focus the reticle.

The reticle does NOT change in size when zooming in or out using the power ring.

 

[ckaberna]

I don't think I was being clear. The reticle zooms only when changing the fast focus on the eyepiece. As in when you focus the reticle. It does NOT change in size when zooming in or out using the power ring.

New one on me? I’m sure somebody will chime in with experience in that.

 

[jb1000br]

This is normal...will change apparent mag with a big diopter change. NF diopter changes at slower rate (finer adjustment) so it would not be as noticable.

 

[Riflman]

I checked a bunch of my other scopes, and didn't see that. I will test it, but has to make a difference in the calibration of the reticle. If the scope is calibrated to range at 12x (or 11x on the NF), then the reticle cannot change in size. In this Nikon, it is a massive difference in size between the has marks from one end of the diopter adjustment to the other. It's not that there is more diopter adjustment, because the reticle stays in focus for a good part of the throw, but the reticle still grows and shrinks. If it was calibrated at 0 diopter and I change the fast focus (I need reading glasses), then the calibration is FUBAR. At least that's what my brain is telling me.

 

[Turbulent Turtle]

I checked a bunch of my other scopes, and didn't see that. I will test it, but has to make a difference in the calibration of the reticle. If the scope is calibrated to range at 12x (or 11x on the NF), then the reticle cannot change in size. In this Nikon, it is a massive difference in size between the has marks from one end of the diopter adjustment to the other. It's not that there is more diopter adjustment, because the reticle stays in focus for a good part of the throw, but the reticle still grows and shrinks. If it was calibrated at 0 diopter and I change the fast focus (I need reading glasses), then the calibration is FUBAR. At least that's what my brain is telling me.

Don't listen to your brain, it's feeding you a false narrative.

The diopter adjustment doesn't have anything to do with changing the "calibration" of the reticle. Let me explain.

Your scope is a second focal plane design, which means that it focuses the image from the objective, AFTER it has gone through the erector/zoom lenses, onto the place where the reticle is located thus forming one image. This merged image (or focal plane) is what your ocular lens is looking at and the diopter adjustment of that ocular lens is there to set the focus of that lens with respect to that focal plane. So even if the reticle appears to increase or decrease, it's staying the same size relative to the remainder of the image or put another way, the entire second focal plane is increasing or decreasing. BTW, the ranging and so on, should be done at 18X to match the reticle size.

I'm still puzzled by your statement about the reticle growing and shrinking so much and yet being in focus all the time. That does seem to be the province of a first focal plane scope, but since you said you have a Black X1000 6-24X50 MRAD, that is a second focal plane scope. Now if you had said you have a Black FX1000 6-24X50 MRAD, things would be different as that is a first focal plane scope.

 

[Riflman]

Hi Denys.

It's definitely a X1000, but I will take it to the range, shoot a group using one of the has marks, then change the eyepiece focus and try again. It *is* a very wide range of zoom on the eyepiece. Perhaps I will try filming it with my iphone. Thanks.

 

[Turbulent Turtle]

Hi Denys.

It's definitely a X1000, but I will take it to the range, shoot a group using one of the has marks, then change the eyepiece focus and try again. It *is* a very wide range of zoom on the eyepiece. Perhaps I will try filming it with my iphone. Thanks.

The wide range of zoom on the eyepiece is surprising. There are relatively few riflescopes with eyepiece zoom; the one with which I am most familiar is the March 40-60 EP Zoom, which you can see here:
http://marchoptics.com/shop/brand_march-optics/secondfocalplane/40-60x52mm-ep-zoom-scope

The principle of operation is that the eyepiece itself pulls out or goes in, unlike a regular zoom riflescope where the zoom setting is all internal. You see, in order to change the focal length of a lens, you actually have to move the lens back and forth, which makes the eyepiece go out or come back in.

The advantage of the EP Zoom is that the image formed by the internal lenses is never disturbed and the point of aim never shifts when you zoom in an out like in a regular variable reiflescope. The eyepiece zoom only increases and decreases the totally formed image at the second focal plane. On the other hand, because the eyepiece moves, that may affect the position behind the riflescope.

So, if the focal length of the eyepiece was actually changing, the eyepiece would grow of shrink, because there's not a lot of room in there to do it internally. My Kowa spotting scope, like many of the higher quality ones, has interchangeable eyepieces. I have two for my Kowa; a 27X Long Eye Relief, and a 20-60X zoom.. The latter is over twice the length of the former; because it has a 3X zoom built-in. The zoom is all internal to the eyepiece, but it's a much bigger unit and on a riflescope, it would wipe out most of the eye relief.

I look forward to the iPhone video that you will try to produce. This is an interesting issue. BTW, have you talked with NikonUSA about this?

 

[Zero333]

I can see the reticle change thickness when working the diopter adjustment, but it's shouldn't zoom in or out.