Maple57: I’m a guy who knows nothing about this ‘depth of field’ stuff, aside from a couple posts of yours. When looking online, how do I tell if a scope has decent depth of field? Thanks.
Well the reality of it is that manufacturers will not generally quantify depth of field since it is hard to quantify.
Technically depth of field is an infinity thin plane at exactly the ideal focus distance.
Everything is technically out of focus both before and after that thin theoretical plane. The question is by how much? That is somewhat subjective but obvious to the eye just the same.
The only advice I can really offer is to evaluate scopes you are considering side by side (use a premium scope as a bench mark) and know what to look for. For some guys that's a tree, I can see the tree, that's good enough... This guy will never be a precision rifle shooter. You need to see fine detail both before and after the ideal point of focus as far as possible. Then you can read mirage.
Unless it screams at you, things like chromatic aberration are to me nothing you want to pay much attention to as it will reveal itself in many other ways.
The most important thing to look for is detail in something with poor contract like bark on a tree or grain in a telephone pole.
You might also pull a couple optical resolution charts off the internet and print them. Maybe print a couple on grey paper to reduce the contrast. Post them at some distance away and evaluate them.
Look for sharpness, but more importantly how difficult it is to get the scope to focus acceptably well. Some scopes will never really focus they will just get better or worse but never good.
All too many scopes will fail badly at this simple test. Vortex Diamondback Tactical is the worst I have seen. Burris XTRii is better but not but 3 times the price better. Hence the XTRiii.
Hopefully you know some guys with scopes you might be considering so you can have a peek through theirs, or you can go to a store that stocks what you might be interested in.
And one final thought... Give no extra point to any FFP scope with more than 4X zoom... Anything below 4X from the max will render the reticle useless. FFP scopes should at least have an illuminated reticle to counter this point.
I wouldn't sweat it too much. It's not something that manufacturers can easily quantify. Do your research and buy the best scope you can afford.
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Money alone will NOT solve this problem.
Short scopes with big lenses and high magnification are typically problematic regardless of price. Regardless of price.
Think about the sharpness of refraction angles... Bring lenses closer and the angles get exaggerated and DOF is reduced automatically... Optical fact.
Scope manufacturers are about making sales. They will slut themselves out to anyone with a credit card and go to great lengths to help you feel great about dropping $4000 on a scope that sucks, but you would never admit to for the simple fact that you paid $4000 for it. Besides fan boys who don't know the difference will tell you that you are crazy to bash it, so that might make you feel like you didn't get raped.
A solid benchmark for nice glass is Kahles 5-25, but there is better out there if you are fussy. I would say needlessly better, but better just the same if a got that kinda cash.
The real question with scope selection is short of a Kahles 5-25, what is really good enough?
