Help with Parallax & Image Focus

[BoydAllen]

The part where he tells the reader to lock down the eyepiece adjustment and never touch it again is at best an oversimplification. Some have been so impressed with the other information that they were wary of violating that edict.

 

[4xforfun]

deal with the issue of the focus on the rear objective.


My Best, John

Just an FYI...this lens is called the occular lens if I am not mistaken.

Thanks,
Tod

 

[Buzzardab]

It's funny that this topic comes up after we just had this same discussion this morning at the gun club after we shot 1000 yd silloet match Sunday. My son came up to watch the match after turkey huntin in the am and seeing one of the regulars didn't show there was an opening on the bench.He sat at the bench after I shot getting ready to shoot a bank of animals and asked me why the dot moved off the animal when he moved around behind the scope. I said you must be touching the stock and he said he wasn't.
So I looked thru and saw the cross hair movement myself with the side focused crystal clear. I called sigh torn and asked about it and they said I need to adjust ocular and parallex together to stop the cross hair movement,gonna mess with that at the next match,I am sure it mattears way mor at 1000 then normal hunting yard ages.

 

[msinc]

There's an old saying..."the longer you make those child support payments, the more the kid will start to look just like you..." I don't know if that is true or not, but it sure has seemed to me, in my experience, that the more you pay for a scope the more you can see when it starts to get dark and the less parallax problems you will have. I believe that high quality, highly corrected lenses have smaller parallax parameters.
I always have to set the side focus on a known range and then take out the parallax with the occular diopter adjustment to get it right. My eyesight is not terrible though {I only need 1.25 reading glasses} and that could sure be the difference.
The last scope Unertl made for the USMC was a real pain to get set, but once it was spot on with the parallax adjustment there was none from zero to 1200 meters. That scope focused by turning the objective and once set you locked it with a jam ring. I have never had to "re-adjust" the one I have.
My hunting rifle has a Zeiss Diavari that only has the occular adjustment, again, once set for me I haven't touched it. Nice to have feature on a hunting scope when you don't really need to be worrying about parallax.
Maybe I am dreaming, maybe my eyesight is way better than I thought and maybe I just paid way too much for these scopes, but I don't chase parallax like I do with lesser grade optics.

 

[BoydAllen]

The issue becomes more obvious at higher magnifications, because you can detect smaller amounts of parallax more easily. In short range benchrest the lowest power of scope that is commonly used is 36x. When we are trying to shoot as small as possible, every little thing counts a lot more than it ever would in the field. The only reason that I have written about this is to let people know that a particular kind of adjustment problem can be fixed, and that they should not be concerned about trying something a little different to solve their problem.