Recent content by dcjs

You simply cannot establish a POI with so few rounds with the accuracy people expect. I know people try to do it all the time, but 3 shot groups just don't cut it. You may get lucky, but you may just as well be further off than you would expect. Questioning your scope's tracking because the...

All that means is that the reticle with field lens has to be positioned exactly in the right axial location in order to remain in focus throughout the magnification range, but the same is true for a SFP scope, which also has a first focal plane that has to remain in focus throughout the...

Can you prove that invisible pink unicorns do not exist, or is that just a belief of yours? All I can tell you is that there is no difference in the optical layout of FFP vs. FFP as a matter of principle that has to do with the number of elements. The numbers vary depending on the individual...

Urban scope legend.

As for aberrations, there's about half a dozen different ones that would be interesting to an expert. You keep asking for "aberration" (singular) and seem to think that it is somehow related to diffraction (which usually doesn't play any significant role in a scope to start with). This is where...

No it is not, for the reason I explained in the linked post. The erector "looks" at an image that is upside down (the image created by the objective system in the first focal plane), that's why it has to move counter to what intuition tells you. I understand your puzzlement, because I used to...

You are making a few simplified assumptions that about camera lenses (which only consist of an objective) that do not apply to scopes (which consist of an objective, an erector system with a certain (possibly variable) magnification and an ocular). A few points in no particular order: FoV...

No, the text is correct, see explanation here: http://www.snipershide.com/shooting/snipers-hide-rifle-scopes/188037-reticle-travel-within-scope.html#post2470771

Those are ERA-TAC rings by Recknagel. They are available as seperate rings or one-piece mount and with normal bolt/nut attachment or QD levers. Pretty much the default choice for heavy duty picatinny mounts in Germany/Europe. ERA-TAC one-piece mounts

http://www.snipershide.com/shooting/snipers-hide-rifle-scopes/180815-questions-about-updated-2012-2013-premier-1-8x4-other-1-8-options.html#post2399691

Premier 5-25x56 ist available with MOA reticle and knobs.

Very well put. This is one of those cases where physics trumps "common sense". Springs do not "tire" from being subjected to a constant force like a muscle would, they tire from compression/expansion cycles. So by "relieving" the erector spring after shooting, you're actually doing it a...

Yes. You are "scanning" the upside down image in the first focal plane with the erector so to speak. Move the erector up (physically) to point the reticle at a lower point on (upside down) target. this will cause you to raise the reticle up to your target (together with the gun this time) and...

That's exactly right. Also, you can visualize the tunneling this way. If you calculate from high towards low power and generate your graph, you will reach the maximum FoV at some point before minimum magnification is reached. From that point on, the graph will just be a horizontal line until...