Question about focusing my scope

[gunsrfun1]

Hello - I looked on the web for this Q&A but can't seem to find anything, so I thought I'd give THR a try. You guys always come through.

A friend gave me a BSA 8x32 (44mm) scope with parallax adjustment to use for some general purposes. I know this isn't a high-end scope, but it will do for now.

Optics are clear, although it's no Leupold or Nikon. At 8x, I focused the eyepiece so that both the reticle and the target (about 100 yards away) are clear. I am finding that as I increase the power, the reticle stays sharp, but the target starts getting slowly more blurry.

I know that at 100 yards there is only so much magnification you can use anyway, but I notice the target starts to lose focus at ~ 10x or so and gets progressively worse.

My questions are as follows:

1) Generally speaking, is it normal for a variable scope, with focus set at a certain power, to make the target less sharp (the target, not the reticle) as you increase the power?
2) If so, how do you decide at what power to set the focus on, since the whole purpose of a variable scope is to have different magnifications.

I may be missing some basic points on setting up a variable scope, so let me know if so.

Thanks.

 

[NeuseRvrRat]

this is common, especially on cheap scopes like BSA

set the power wherever you want

 

[wally]

this is common, especially on cheap scopes like BSA

True, but you need to adjust the diopter to set eyepiece focus on the reticle first. Set the AO focus to infinity, look up at some clouds with the scope and adjust the diopter to have crisp reticle immediately with your vision still focused at "infinity" (eyes relaxed).

Then put the scope on the desired power and adjust the AO to focus the target.

Generally same as using a zoom lens on a camera -- its best you focus at the longest zoom (highest magnification) where depth of field is smallest thus focus accuracy is greatest, then at lower magnifications any focus shift is usually "hidden" by the improved depth of field.

 

[adelbridge]

The yardage indicated on the parallax adjustment is often a ball park figure, especially on entry level product. Adjust the parallax to work for your vision.

 

[TIMC]

The yardage indicated on the parallax adjustment is often a ball park figure, especially on entry level product. Adjust the parallax to work for your vision.

Noe of my leupold even have numbers on the parallax adjustment, they are really not needed. Parallax is gone when the targe becomes clear. A good scope should be crystal clear even on maximum magnification at 100 yards.

 

[jim243]

You use the dioplor adjustment on the back objective of the scope to adjust the focus on the retical, the ring just forward of the rear objective to adjust the power of the scope and the bell on the front objective to adjust for the focus on the target.

Jim

 

[gunsrfun1]

OK so getting back to my original question: I think you are all saying that once I have my scope focused properly, it should hold focus throughout the range of magnifications. And that the reason my scope isn't doing that is probably due to the relative low quality of the scope.

Is that correct?

 

[David Clark]

That is not what they said at all. The more power you use the finer you have to adj. your parallax and don't go by the number on the AO. You adj the back of the scope just for the cross hairs looking at a white wall or such just for your eyes, then when you get it to the power you want you adj. the parellax. If you adj. the power to 32 at say 100 yds. and then adj the parallax to be clear it should be good at all the lower settings.
Dave

 

[jmorris]

They are also talking about two different adjustments one, that you make at the rear of your scope, the other you make with the knob on the left side of the turret.

 

[jmr40]

Good advice but, FYI 8X32 refers to a fixed power scope or binocular with 8 power magnification and a 32mm front objective. The correct way to describe it would be to say 8-32X44. It will reduce confusion.

 

[rcmodel]

See post #3 again.

Focus the scope while it is set on max power and AO set on infinity, by bringing the rifle up and quickly looking through it.

Keep adjusting the eyepiece focus until the reticule is sharp & clear while looking at the sky at max power as soon as you look through it.

DO NOT continue to stare through the scope while screwing the eye piece in & out looking for a clear setting.

Your eye will try to adjust to the out of focus condition faster then you can screw the lens in & out and you will never get-r-done.

rc