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SF vs AO parallax adjustments

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tjtjwdad View Drop Down
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    Posted: January/01/2010 at 14:25
To all,
 
Whats the plus/minus of one vs the other regarding clarity, resolution and parallax adjustments.  It seems to me the AO scopes just look better thru the glass and adjustment is finer/more precise where as the SF scopes the adjustment is more sensitive.  The ERGO of the SF for righthand shooters is a nice attribute.
 
Thx,
 
Jim
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8shots View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 8shots Quote  Post ReplyReply Direct Link To This Post Posted: January/04/2010 at 02:03
My understanding is that the AO has less lenses and are therefore more clear and robust. The SF is again easier to reach for quick adjustments.
As I allways maintain, nothing is all gain. You win on one end, but lose on the other.
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koshkin View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote koshkin Quote  Post ReplyReply Direct Link To This Post Posted: January/04/2010 at 03:26
If properly executed, it makes no difference aside from the location of the controls.

With that in mind, in principle, side focus scope is easier to make truly robust than an AO scope, since with SF the moving components are fully internal.  With AO, the fine threads on the front of the scope can be vulnerable to impact.

AO does not add any additional optical elements.  SF does add one more lens (typically).  In principle, that can have a detrimental effect on image quality.  However, with modern coatings and proper optical design, one extra optical element makes no discernible difference whatsoever.

With AO, the mechanics are simpler and there is a little more leverage for the adjustment, so it is easier to make an accurate fine adjustment.  

With SF, I have seen a number of scopes in the past that have backlash issues.  Better makers seem to have taken care of the problem though.

If you are trying to mount the scope as low as possible, AO scopes have a larger outside objective diameter, so they often have to sit a little higher.

Lastly, AO scopes ar eusually easire to manipulate for lefties than SF ones.

ILya
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tjtjwdad View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tjtjwdad Quote  Post ReplyReply Direct Link To This Post Posted: January/04/2010 at 09:32
Koshkin, 8-shots;
 
Thanks a lot.  ERGO wise, I prefer the SF over the AO.  Recently I just purchased a Swarovski 6-18 scope that was heavily discounted and I almost passed it up since it had the AO but since this going a bench-type varmint rifle the AO really isn't an issue for me.
Playing with it in the store the parallax controls just seemed more refined/precise than the SF. 
 
As far as the comparision I mentioned, I use to have a Nikon Monarch 6.5-20x44 with AO that was replaced under warranty with a 6-24x50 with SF.  The 6.5-20 was clear thru its entire zoom range.  The 6-24 is not.  Around 18-20x the picture starts getting fuzzy/hazy and dark although the reticle is still sharp.  I can clear it up using the eye piece but then the reticle isn't as sharp (which is a no-go for me) or I can move the SF adjustment and clear it up but then I see just a slight amount of parallax.  Truthfully, its kinda annoying.  I don't recall of having this issue on the 6.5-20x44
 
Thanks to each for the replies.
 
Jim
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