Re: article I wrote about choosing a rifle scope
Jay,
I realise that you wrote this article for non-techies that want a basic understanding of what a scope does, so it has to be written in simple terms and cannot be exact in every detail.
Nevertheless, there are a couple things that made me flinch while reading and that I think should be corrected before presenting this to a crowd seeking advice on scopes.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Opticsspecialist</div><div class="ubbcode-body">Parallax error applies to variable power scopes. Parallax is determined by the distance to the objective, the exit pupil size and relation of the eye to the tube of the scope. The reticle is on one of the lens inside your scope.</div></div>
Parallax has nothing to do with variable or fixed magnification. The maximum amount of parallax error is determined by the ratio between the object distance and the parallax free distance, and the optical system itself (not limited to magnification and exit pupil size).
The reticle is usually not placed on a <span style="font-style: italic">lens</span> that is part of the image-forming optics, but rather on an additional flat glass if it’s not a wire reticle.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Opticsspecialist</div><div class="ubbcode-body">Objective size is also important. Your objective must be large enough to accommodate a good field of view and give you good low light performance if that’s what you need, allow you to mount your scope to your rifle reasonably; most people like to mount the scope as low as possible.</div></div>
Objective size is not directly related to FOV, this is a common misunderstanding. If anything, a smaller objective size would lend itself to designing a scope with larger FOV, because it is easier to get an image that is well corrected to the edges with a big focal length/objective size ratio (f-number). If scopes with different objective sizes from the same series provide different FOV, this is an indirect effect.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Opticsspecialist</div><div class="ubbcode-body">Resolution is the measure of how much light comes into the objective lens and exits the ocular lens. The better the scope the more light gets let through, resulting in sharper images and better picture in low light.</div></div>
This is probably just a mixup while composing the text and you accidently swapped <span style="font-style: italic">resolution</span> for <span style="font-style: italic">transmission</span>.