Goy the above scope in a used rifle deal. Seems pretty clear glass but when focusing the image
get larger or small as the eyepiece is turned.

What is with that?

Hip

quote:

Originally posted by Hipshoot:
Goy the above scope in a used rifle deal. Seems pretty clear glass but when focusing the image
get larger or small as the eyepiece is turned.

What is with that?

Hip

Is the eyepiece dragging on the power ring and turning it slightly when trying to focus?

quote:

Originally posted by eagle27:

quote:

Originally posted by Hipshoot:
Goy the above scope in a used rifle deal. Seems pretty clear glass but when focusing the image
get larger or small as the eyepiece is turned.

What is with that?

Hip

Is the eyepiece dragging on the power ring and turning it slightly when trying to focus?

No it is not moving the power ring! It has a focus ring at the rear of the eyepiece. When it is moved in or out it makes the image bigger or smaller similar to a magnafying glass. Out-larger---In-Smaller.

Changing the focus always changes the power slightly but you're the first person I've heard say they could see it happening.

I had to deal with the problem when evaluating field of views and eye relief for my book. With Euro-focus scopes I would set it on the midpoint but had to make do with my own corrected vision (supposedly better than 20/20) when dealing with slow threads.

Sorry, I wanted to change field of views to fields of view but the window locked up and won't resave

I had a few Nikko Sterling scopes over the years but never noticed anything like you describe. Does the reticule/crosshair change in size when focusing or just the image view?

The reticule DOES change in size.

I like the scope and the optics are nice and clear.

It is just that I have never seen that before and I own/have owned about 50 scopes mostly Leupold some Weavers, Lymans, B&L, Redfields, Bushnells and some other Japanese scopes.

I guess you've got Euro focus on that scope. Twisting that quickly would make noticing the change more likely. I've had the odd Nikko Stirling scope (and shotgun - it's a brand as Australian as Bushnell is American) but mine had the old slow adjustments.

It's really no big deal except that I think some makers may shrink the picture when taking their field-of-view measurements. This is inevitable where variables such as some 2-7x really only extend to 6.5x.

It's called "focus breathing" when it happens on photographic lenses.

Almost all lenses suffer from it to some extent, but obviously it is subject to the exact design and more expensive lenses tend to be much better in this regard (and many others) than cheap ones.

I don't know about now, but years ago when I had a better handle on these things, Nikko Sterling were about the cheapest junk on the market.

Thanks for the responses Guys!

Hip

quote:

Originally posted by Peter Connan:
It's called "focus breathing" when it happens on photographic lenses.

Almost all lenses suffer from it to some extent, but obviously it is subject to the exact design and more expensive lenses tend to be much better in this regard (and many others) than cheap ones.

I don't know about now, but years ago when I had a better handle on these things, Nikko Sterling were about the cheapest junk on the market.

You must have had good scopes, generally, Peter.

Nikko Stirling (correct spelling) were cheap and cheerful but I've seen worse. We have one from about 1975 that I really like because of its 'egg-shaped' ocular, which gives field-blending redolent of the old Nickel and Zeiss scopes.

Since the mid-60s, at least, they've been image-movement, of course, and you know what I think of that - NS, Nikon or Zeiss, its all junk.

quote:

Originally posted by sambarman338:
You must have had good scopes, generally, Peter.

Generally I have always felt good optics are worth spending money on. I have not had many, as most of my rifles are iron-sighted and I don't speculate on firearms. I keep them.

Furthermore, I freely admit that I hunt relatively easy terrain most of the time, and I don't really have any hard-kicking scoped rifles. I tend to like smaller calibers except for dangerous game, and for dangerous game I prefer a ghost-ring peep.

I have never owned a non-image-moving scope and have only seen issues with two. One was a Nikko Sterling on a .44-40. I suspect the mounts were a factor in the scope's demise.

The other one was a Lynx (which is a local brand) which failed on a .22LR, was repaired and failed again.

Personally I don't buy anything cheaper than a Leupold.

I've only had a couple of image-movement scopes go bad without their getting bent, Peter, and one those was a Nikko Stirling. Generally, though, they seem to have a reasonable reputation here.

My cousin in the country has had heaps of dearer-brand scopes pack it in, though, including three or four Weavers. I'm not sure why he continued to buy them, come to think of it. His latest casualty was that Burris variable I wrote of, which got dropped. I bent the first Japanese alloy scope I owned but wonder now if a German dural model may have fared better.

If I had to put a scope on any rifle that even might have to be used against dangerous game, I would search the world for a still-good, reticle-movement European scope and get a competent gunsmith to install it, whatever that cost.