Originally Posted by Sam Vimes
Interesting thought, especially when you consider the blaze of glory that the Lightstream arrived in only to be discarded very quickly when many complained of PX error.
I can only comment on the one and only FFP scope I own, a Weaver 3-9x40 Tactical. I use it on my hunting rig and wouldn't do so if I thought that I was getting more PX error than a SFP scope. I do have to make one qualifying statement though. I very, very rarely take a hunting shot less than around 20 yards. However, when using it at the club on shorter range targets I've yet to notice any excessive PX error.
The problem with the Lightstream has little to do with more parallax error than other scopes, it's really down to the huge field of view which is almost twice that of a Bushnell 6500 on the same magnification.
What this does is allow the shooters head to come off the centre of the scope more than other scopes before the picture is lost which gives the impression of more parallax error.
When comparing the two with exactly the same head movement (5mm off centre) the parallax error is pretty much the same.