...Anyway, our own WesBob has them in stock in his Canada-based store, and can ship to the USA:https://airgunarcheryfun.ca/immersive-optics-14x50-1450md-1450mde/
I'm looking for a scope for a particular purpose. What I would like:1) 14.4x or adjustable magnification up to at least 15x.2) SFP with standard 10x mil-dots.3) Deep depth of field. A little blur is OK, but I want no discernible parallax error from 25yds to 55 yds. Without adjusting the parallax setting. So non-AO or AO is OK.Any suggestions? I don't want to order a bunch of scopes to try. Maybe a scope like that is not possible.So far none of my scopes really cut it. Since I'm not confident in finding that scope, right now I'm making some apertures to go on the ocular to force alignment and reduce the parallax error.
Get used to shooting at blurry targets.FWIW- There is an airgun FT class in the UK where you are NOT allowed to touch your scope once the match starts.Set it and forget it. I believe that most competitors set their scopes around 30 yards and just adjust. Not for me. I like to see every detail of what I am shooting at.-Y
Quote from: Cableaddict on November 19, 2021, 06:55:41 PM...Anyway, our own WesBob has them in stock in his Canada-based store, and can ship to the USA:https://airgunarcheryfun.ca/immersive-optics-14x50-1450md-1450mde/I prefer at least 14.4x and standard mil-dots. Otherwise, I'm interested in hearing your report on it's DOF.
The increase in depth of field should bring with it less parallax error
The increase in depth of field should bring with it less parallax error .... Unfortunately, it comes with a small exit pupil, making head position critical.... If you think about it, that is likely why you observed the popularity of small objective lenses.... Their small exit pupil forces you to have a better head position, again minimizing parallax.... but the penalty is a dimmer image....
Check this out. I found a parallax error calculator online:https://www.lelandwest.com/parallax-error-calculator.cfm?Action=1&CFID=3444076&CFTOKEN=f44dd23ee5903419-5BDAD640-9592-4F79-FBF0F9CAD8AC07C4&jsessionid=2CDFF2B291FA89EB2CF48F5FF43DACEF.cfusionInterestingly, the scope's magnification is not part of the formula. What I find REALLY odd is that there is no mention of distance between the ocular and the objective. That's definitely a factor in DOF. (Maybe that creates the magnification, in conjunction with the ocular / objective ratio? )- So does this mean that this error is NOT one-to-one tied to DOF focus? I'm still having trouble conceptualizing with this.=============================================Formula:Parallax error in millimeters (Pmm): ( 0.5 x D x ( Abs ( R - P ) ) / P where D = Objective diameter in millimetersR = range to targetP = fixed parallax setting of scopeParallax error in inches (Pin): Pmm x 0.0393701Parallax error in Minutes of Angle: Pin / 1.047 / ( R / 100 )Parallax error in Milliradians: Pin / 3.6 / ( R / 100 )
Check this out. I found a parallax error calculator online:...Interestingly, the scope's magnification is not part of the formula. ...
Double the power, dof is halved. Double the exit pupil diameter, dof is halved.These two factors compete in any one instrument as eyepiece focal length is changed. Halving the eyepiece focal length doubles magnification and halves the exit pupil diameter. And so the depth of focus remains the same.
I cannot confirm this to be true, but my feeling is that parallax error is consistent with depth of field, which means you want a small diameter objective relative to the focal length of the objective......
Some people talk about a scope having "forgiving" parallax and how they can just set it one point and not touch it for shooting targets at different distances. Well, this is not actually true. The scope's DoF is large, so it looks like your targets at various distances are focused, but you'll still have parallax error because technically the error is only gone at one specific setting for a target at a given distance. In f/22 image, which bottle cap is perfectly focused? Now the bottle cap below or above that one is still pretty sharp, but if this were a rifle scope, either of those bottle caps would still show parallax error. You need to adjust your parallax either way. UNLESS... your target is "at infinity" for your scope...That would mean the distance at which you're shooting is far enough away that the in-focus (and parallax-free portion of your sight picture) covers a large enough physical distance. Let's pretend the in-focus area of your scope covers maybe 1/8th inch within your scope's sight picture. An 1/8th-inch portion of your picture at 100 yards might be a foot. But an 1/8th-inch portion of your picture at 1,200 yards might be 200 yards.
It would appear that parallax error depends on the accuracy of adjusting your scopes focus to the actual target distance.... which is actually HELPED by a short depth of field....
...If you're shooting a pcp, hence no recoil, why not just add some kind of tube to your ocular, maybe 3" long, with a rubber ring at the back?This would help keep your eye centered, and maybe even prevent some sun reflections at the same time.Heck, this would be even BETTER than a short eye-relief scops, since you eye is still cenetered, but further back, so orientation errors are even further prevented.