Thread: Should parallax and focus coincide ?

In the weekend, I had the opportunity to use a Zeiss Conquest 6.5-20x50. It would focus up beautiful and sharp at 100m but there was a lot of parallax apparent (5-10 cm). Adjusting the parallax knob to minimise reticle movement gave quite a blurry image - I couldn't see the scoring rings and could barely make out the aim point.

Is this a fault in the scope or a "feature" of my eye ?

I've had cataract surgery and got an intraocular lens, which is fixed focus. It has been set about 0.5 diopter short sighted to make it easier to read. For me, the "side focus" is good for getting a sharp image, while control of parallax error is a lower priority. Other shooters over about 50 will also have reduced accommodation and a naturally long sighted person would have difficulty focusing up close. Does anyone else notice a discrepancy between focus and parallax ?

Question again: Should a scope be built so that sharp focus and minimal parallax occur at the same range or does this depend on the shooter's eye too ?

I have trouble at 100 with my eye focusing on either the recticl or target with the other being blurry. particulary when tired . At 200 i don't have this problem.
Focusing and paralax are close but not perfect at short ranges and spot on further out on my scope. Probably my eyes

Some scopes brands are worse than others, even same brand/model scopes seperated only by a few places in their serial number can be different. Some are well focussed when the parallax is adjusted out, and others start to get fuzzy when at that adjustment. Try adjusting your eyepiece/ocular lens to get your target/crosshair focus right at 100/200yrds then try again.

Every pair of geovids i have seen has their focus ring in a different position for 100 and 500yrds. I dont know what that means but just wanted to mention it.

Did you focus the reticle to your eye before using the scope (adjustment at rear of scope) and then adjust parralax (side knob) if not then thats probably your problem

I thought you looked at the sky and focused the reticle? what I have all ways done in the past then forgot about it.

I thought adjusting the ocular only adjusted the reticle focus? and if not what power and parallax settings should I use while setting the ocular?

Im pretty sure its my eyes it only happens when been concentrating on groups for a while and or not enough sleep.

Originally Posted by Cyclist

Did you focus the reticle to your eye before using the scope (adjustment at rear of scope) and then adjust parralax (side knob) if not then thats probably your problem

I'd say that's a common prob for newbies

yeah you should focus the eye peice on a white wall etc but it can help fix parrelex issues it you set the parrelex then tinker with the eyepice focus......but if the cross goes out of focus the scope is no good for you.... My sightrons have been great ...set the focus and parralex is fine

Thanks Leathel and everyone else.

It sounds as if it would be good to start the scope setup by:
1) adjust the parallax ring to get rid of crosshair movement when you move your eye, using an object a long way out eg > 1000m and regard that as infinity for the parallax even if the ring has a bit more travel available
2) then use the ocular to make the reticle sharp, which is all it does. You do this while looking way into the distance, eg at a blue sky and telling your eye to look far. This is so your eye is focussing at infinity. A short sighted person can't focus out to infinity of course and a long sighted person who relaxes their eye will focus beyond infinity. I'm not sure of the consequences of this but it must work out reasonably well as a lot of people are short sighted and don't notice any problems. If you then try to focus your eye closer, like by thinking about the end of the barrel or reading a book, I expect the reticle would go out of focus. At higher powers, over 10x and shorter distances either the reticle or the target is in focus but not both.
3) if you have a parallax adjustment then you can bring a short range target back into focus and also minimise parallax, hopefully at the same range.

I usualy set at 100 first then test further out as 100 is often more criticle for focus.... but yes that is what I do.