Rifle Scopes Unmarked parallax/side-focus any use?

[dbooksta]

I just got a Sightron SIII SS 8-32x56 LR MD and was surprised to find that the side-focus does not have distance markings. Obviously I got a scope in this power for precision target work at known distances, so doesn't the lack of calibration on the parallax ruin that?

The manual simply says, "SIII LR Series Side Focus Models do not have a distance scale and should be adjusted until the image is clear and parallax free."

What is a user supposed to do: fiddle with the side focus while moving his head side to side until the reticle stops moving with respect to the target?

 

[paulyosh]

Re: Unmarked parallax/side-focus any use?

Exactly. I treat the numbers on a parallax knob like BDC markings - they'll get you close, but the markings definitely shouldn't be relied on for precision work.

 

[sirhrmechanic]

Re: Unmarked parallax/side-focus any use?

Agree with PaulYosh.

My Mk4 is also unmarked. I did put a mark, though, on the dial that lets me line up exactly 100 yds for sighting in and quals at a known distance.

Cheers, Sirhr.

 

[300WSM]

Re: Unmarked parallax/side-focus any use?

never used the numbers. ...ever. The knob rotation is so short why bother. Just keep your eye up to the scope and turn it til it's "focused".

 

[sobrbiker883]

Re: Unmarked parallax/side-focus any use?

"Any use?" actually I have more respect for unmarked knobs than marked knobs because marked knobs are never right.

I'm usually looking through the scope while adjusting, not at the turret anyway.......On my adjustable objectives (ERGO) I turn it until I'm parallax free, and on my Tpal I know that I move the bottom of the knob away if targets are further, and closer if the targets are closer.

 

[jdgray]

Re: Unmarked parallax/side-focus any use?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: dbooksta</div><div class="ubbcode-body">What is a user supposed to do: fiddle with the side focus while moving his head side to side until the reticle stops moving with respect to the target? </div></div>

Yep!! And with a Leupold, you must start at infinity, and dial it in without backing up a bit, if you go by. Not sure if any other makers have backlash issues like Leupy, but thats how I gotta do it

Now my Bushnell Elite 3200 with AO, has number values on it that are spot on, and you can use it to range with, its so close.

 

[Quickdraw40]

Re: Unmarked parallax/side-focus any use?

NF's do not have any yardage markings.

 

[LoneWolfUSMC]

Re: Unmarked parallax/side-focus any use?

I like the marks to get me close. If I am punching holes at a specific range, then I will fine tune it to eliminate parallax.

Otherwise I get it close and gas on.

Don't get wrapped around the axle about dialing out parallax. Worry about a solid consistent cheek weld. It will do you more good when engaging multiples at different ranges than any fancy parallax knob.

 

[sobrbiker883]

Re: Unmarked parallax/side-focus any use?

Good point. Proper execution of the fundamentals, including a repeatable cheek weld will alleviate almost all of the issues associated with parallax, and regarding parallax: it is better to have the parallax set for a distance shorter than the target than shooting a target inside the parallax adjustment.

I think the design of adjustable objectives shines in this area, I can usually set my scope for the shortest target then carry on without touching it-its been my experience that side focus scopes for some reason are less forgiving on distance variation (as far as clear sight picture is concerned).

 

[dbooksta]

Re: Unmarked parallax/side-focus any use?

Sure, if I have a perfectly repeatable cheek weld and cant then parallax adjustment isn't a factor. But I doubt I'm that consistent. And if I'm up around 32x magnification then even minimal slop in my eye alignment with parallax set incorrectly is going to affect my groups. I bought this power so that I could specifically rule out sight picture errors as a factor when testing for accuracy.

And everyone who makes it sound like setting the side-focus is easy, can you explain what exactly you do? I don't see changes in "focus" -- as in blurry vs clear images -- once I'm dialed past 100 yards or so, even though there is a decent range of side-focus travel after that point. And for me it's excruciating to align on a target at a new distance and then add a sequence of wobbling my head side to side to confirm I'm parallax free before I get back to the rest of the business of releasing a good shot.

So what are the conventions and standards on this? Do you good target shooters just have such repeatable eye alignment that parallax doesn't factor in? Or is parallax such a small factor even at high magnification that you can be misdialed by half or twice the actual distance and it's still not going to take you more than a small fraction of an MOA off in the worst case?

 

[sobrbiker883]

Re: Unmarked parallax/side-focus any use?

If you are shooting 32X for accuracy you have time to check for parallax, the elimination of which is the real function of that turret, not the clarity of the sight picture.
At that power I hope you have a mirage band.

Your post presents an interesting incongruity, in that you bought an expensive 32X scope to eliminate sight piture errors, and are going to great pains to eliminate such, but its too excruciating to check for parallax the old fashoined way (moving your head).......

Good luck with your endeavors.

 

[AK10mm]

Re: Unmarked parallax/side-focus any use?

If you have to agonize over this,I suggest you sell it and buy one that IS MARKED.I have an SIII 6-24 unmarked and no problems.My Zeiss Victory 6-24 is marked,in meters,but I never look at the markings,I use the same cheekweld(try practicing this also)and turn it until it is focused.When I'm shooting Rockchucks,one may be at 237yds and my next target could be at 425yds,so much for markings,EH?

 

[pupdawg]

Re: Unmarked parallax/side-focus any use?

dbooksta - You get on the rifle and move your head up and down slightly while looking through the scope and turning the parallax adjustment until NO reticle movement is apparent with regards to the target. That sounds pretty easy to me.

In some scopes, the parallax might be adjusted out totally at a given target distance yet the picture may or may not seem as sharp or focused. Just turning the parallax adjustment until the picture seems "focused" might not be the point at where it is parallax free.

 

[salmonaxe]

Re: Unmarked parallax/side-focus any use?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: sobrbiker883</div><div class="ubbcode-body">
I think the design of adjustable objectives shines in this area, I can usually set my scope for the shortest target then carry on without touching it-its been my experience that side focus scopes for some reason are less forgiving on distance variation (as far as clear sight picture is concerned). </div></div>

I've noticed this myself. I've always wondered if an optics expert could explain why this is the case. Of course all but one of my AO scopes are USO...

 

[jdgray]

Re: Unmarked parallax/side-focus any use?

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">I don't see changes in "focus" -- as in blurry vs clear images </div></div>

My VXIII works that way, when the image is sharp, the parallax is gone at the same point. Maybe you have a scope problem, cause its really a only a few second procedure of bobbing and weaving

Good luck!!

 

[MBass300]

Re: Unmarked parallax/side-focus any use?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: sobrbiker883</div><div class="ubbcode-body">"Any use?" actually I have more respect for unmarked knobs than marked knobs because marked knobs are never right.

I'm usually looking through the scope while adjusting, not at the turret anyway.......On my adjustable objectives (ERGO) I turn it until I'm parallax free, and on my Tpal I know that I move the bottom of the knob away if targets are further, and closer if the targets are closer. </div></div>

If you are using the scope for range work, you will probably be shooting at 1 target at a given range, so there is no need to adjust for parallax from one shot to the next. Set it once, and you're good for as long as you're shooting that distance.

Of course, if you want to be able to make a quick adjustment while shooting to a "mark", why not make your own marks? One afternoon, spend a little time dialing out the parallax at varying distances and make your own marks at each range setting. For range use, you can start witha 50yd mark, a 100yd, a 200yd, etc.. This will ultimately be more accurate than if your scope had "factory" markings. In the field, it's a different story, as game rarely appears at exactly 100yds or 300yds, so you will need to fine tune it anyway.

 

[dbooksta]

Re: Unmarked parallax/side-focus any use?

This is my first foray into more powerful scopes. My cheap Nikon Buckmasters 4.5-14x40 has a calibrated side-focus, so I was assuming more powerful and expensive scopes would also have that feature.

Granted I've never stopped to verify how close the Nikon side-focus markings are, but in principle this should not be difficult for a factory to set since they know the geometry of their lenses and reticles. And if the turret is marked then I can check it once when I first buy the scope -- just like I check the mil-dot/power alignment -- and either return it or mark a correction if it's off.

OTOH, since apparently plenty of top-of-the-line high-power scopes don't have calibrated side-focus turrets I guess my assumptions about this whole matter are off. Yes, for true target work I have time to correct parallax by trial-and-error dodging-and-weaving every time I change distance. But I got a mil-dot scope so that if I wanted to I could use it for ranging and hold-overs. I guess I could calibrate side-focus myself and try to mark the turret or carry a "parallax dope" card. But why shouldn't every high-power model come with a calibrated turret that could be adjusted just like the reticle turrets so we only have to do this once?

 

[LoneWolfUSMC]

Re: Unmarked parallax/side-focus any use?

Here is my suggestion.

When you get behind the scope, turn the parallax turret until the target is as well focused as you can get it. Then without disturbing the rifle move your noggin around behind the scope and look for the crosshair to "wobble" over the target. Continue to adjust the turret until the crosshair doesn't wobble. If it gets worse, turn it the other way.

As another poster stated if you are having a mental block because of the lack of marks....then mark it. Silver Sharpies work wonders.

As for the real world. This is why I prefer the AO on my SN-3. If I have time I will set the parallax. If not, I will leave it at 100 or 200 depending on the range for that stage.

As I said before, consistent cheek weld will alleviate most of the parallax issues. If you are not able to get a consistent cheek weld you need to work on that before you worry about marks on the scope.

 

[sobrbiker883]

Re: Unmarked parallax/side-focus any use?

I believe that mechanically (and I may be wrong here) if a scope has a side focus that actually works as marked that once the diopter is adjusted off -0-, then all bets are off as far as the marking, focus and parallax elimination coinciding are concerned.

I wear prescription glassed, so I may just be used to never having the AO/SF work wkhere they are marked.

On my silhouette rifles I do mark where they are parallax free for the four distances matches are shot at. For practical precision rifles, maybe I will mark mine for major yardages.

 

[dbooksta]

Re: Unmarked parallax/side-focus any use?

Thanks everyone for their guidance and advice.

ALCON: I had a good discussion today with Alan Orr, technical expert at Sightron. He confirmed several observations made in this thread:

1. It's far more important to get the diopter adjusted correctly first. And changes there would render any side-focus calibration incorrect.

2. If your diopter is set correctly so the reticle is in focus, then your sight picture will be parallax-free if and only if the target is in focus. Therefore you don't have to bob and weave to confirm parallax is dialed out if you believe your eyepiece is focused on the reticle and the scope is focused on your target.

3. Side-focus knobs have very limited range of motion and thus aren't suited to precision marking anyway. If you really want detailed focus control you should get an AO, which may have two full turns from the low to the high end (on a much larger dial).

4. And, of course, if you focus on the fundamentals -- especially consistent cheek weld and eye alignment -- parallax won't be a factor anyway.