Parallax vs Focus

[FTRshooter]

Yeah, I keep reading that stupid canard and can't figure out why people keep repeating it. My current hypothesis is that this is a requirement for lesser optics because of backlash due to substandard knobs. It certainly is NOT something one does with a March scope. I even have a large wheel on the side-focus knobs of my March scopes to help with focus because of arthritis in my left hand. It also provides with increased granularity of focus. I am told these scopes are highly favored by air gunners because of the high magnification and the ease of focus and we know of focus becomes a lot more critical at closer distances.

So the next time I read about someone having to go to infinity and then back down to the proper distance, that will be a signal that we're talking about inferior optics.

 

[Bart B]

I think such reasoning is not knowing how and why the scope mechanics position lenses and the tolerances involved.

 

[Orange Dust]

OK Guys, now I am confused. Thought I learned something, maybe I didn't. My Kahles doesn't seem to have any backlash, and you can turn it from either direction and end up in the same place. My Vortex's, not so much. Does not surprise me.

 

[FTRshooter]

I would have been surprised if your Kahles had that issue; it's a pretty high quality optics. It's not a March, but it's not bad.

 

[Orange Dust]

I would have been surprised if your Kahles had that issue; it's a pretty high quality optics. It's not a March, but it's not bad.

Easy big guy

 

[Bart B]

Even if all the mechanical tolerances were zero, the few percent tolerances in lens focal length can cause the side knob set to 200 yards to position the moving lenses to focus several yards either side.

Got a Nightforce high end variable some years ago that when the focus was set at 200 yards, it was parallax free at 100 yards. Called Nightforce to let them know and they asked how I was able to discern that. Told them I used a monocular to magnify the reticle and target image 7 times to see small parallax errors. Returned the scope.

 

[WildBillG]

Bat B and FTRshooter PLEASE go back to the first page of this thread and read what Catshooter wrote. He explains why you must on all side focus scopes start at infinity and dial down. It does not matter how good your scope is or how poor. With AO scopes you do not have to worry just turn to your target distance.
OrangeDust all of my side focus scopes can be turned in either direction to. It is just that in order for a side focus scope to function properly you must go to infinity or past and turn down. I guess it is a bit of a pain but that is a draw back of side focus.

 

[dfanonymous]

Idk how there such idiocy going on a year(s) old thread.

 

[Orange Dust]

Bat B and FTRshooter PLEASE go back to the first page of this thread and read what Catshooter wrote. He explains why you must on all side focus scopes start at infinity and dial down. It does not matter how good your scope is or how poor. With AO scopes you do not have to worry just turn to your target distance.
OrangeDust all of my side focus scopes can be turned in either direction to. It is just that in order for a side focus scope to function properly you must go to infinity or past and turn down. I guess it is a bit of a pain but that is a draw back of side focus.

More than willing to learn to do it right. Need good intel as to what that is. Been turning down from infinity since first reading this thread. Just saying i cant tell it makes a difference on my k525i.

 

[FTRshooter]

Bat B and FTRshooter PLEASE go back to the first page of this thread and read what Catshooter wrote. He explains why you must on all side focus scopes start at infinity and dial down. It does not matter how good your scope is or how poor. With AO scopes you do not have to worry just turn to your target distance.
OrangeDust all of my side focus scopes can be turned in either direction to. It is just that in order for a side focus scope to function properly you must go to infinity or past and turn down. I guess it is a bit of a pain but that is a draw back of side focus.

WildBillG, Please understand that I don't care a whit what the Tabby Murderer said 17 years ago. I checked directly with March's chief engineer and I elected to go with what he says about his scopes.

 

[WildBillG]

OrangeDust I don't think could tell a difference. I think there is chance the side focus can change a little while shooting due to design from what I gathered.
FTRshooter if you truly believe that this sticky is a lie ask Len to remove it. You better have 100% proof though on the off chance you may be wrong. Remember one thing though you pay extra for side focus on a scope do you think companies will tell you there is a down side to it. If I am wrong so what I took an extra second to focus my scope. If you are wrong you could cost a guy a match or trophy of a life time. Please go prove that what Catshooter wrote is wrong beyond a doubt and create a sticky on it.

 

[FTRshooter]

FTRshooter if you truly believe that this sticky is a lie ask Len to remove it. You better have 100% proof though on the off chance you may be wrong. Remember one thing though you pay extra for side focus on a scope do you think companies will tell you there is a down side to it. If I am wrong so what I took an extra second to focus my scope. If you are wrong you could cost a guy a match or trophy of a life time. Please go prove that what Catshooter wrote is wrong beyond a doubt and create a sticky on it.

I don't have a problem with the stickied thread. I'm sure that problem as reported 17 years ago is still valid for inferior optics. I specifically stated that was NOT an issue in my March scopes and that was confirmed by March themselves.

Just so you know, I carefully chose my screen name here, selecting to reflect my avocation. I am a long-time rifle competitor and I shoot F-class matches at 1000 yards regularly, at the local, state, regional and world level; I have medals and plaques to prove I can usually it the target.

BTW, you can't prove a negative.

 

[WildBillG]

I am lost on proving a negative. How ever I am happy for you with all of your success and I hope it continues for you. Neither of us know for sure though which scopes are equal to your March scopes. I feel better telling others to focus the way Catshooter explained as there is no harm in it. This is just one of those subjects I guess where we will have to agree to disagree for now at least.

 

[Orange Dust]

I have proven in my own mind this backlash thing is true with my vortex scopes. When i got my kahles i played with it to see what would happen if i just went to the yardage from whereever. This scope also is the only one i own that the marks match my eyes. I couldnt tell any difference just going to it instead of from infinity. Been doing it anyway because it seems like the thing to do. One thing about this scope is windage is on the left and paralax on the top under elevation. Setup makes it easy to dial windage and i like it. Sacrifice is paralax not so easy to get to.dont know difference of internals vs side mount, but i really like the scope. Wish i knew for sure if it matters on this scope.