Second Focal Plane Question

[thefitter]

This was posted else where:

"...The main reason SFP is bad news is because its VERY hard to make a scope with consistent POI through the magnification range. Since most cheaper scopes opt for SFP its highly unlikely that the money has been invested to ensure that the poi doesn't move..."

I'm having trouble understanding it.

 

[mikecr]

Sounds like the solution is to avoid cheap scopes.
I agree
Are cheap FFP scopes 'good news'?

 

[thefitter]

Actually I was more refering to this part -

"...The main reason SFP is bad news is because its VERY hard to make a scope with consistent POI through the magnification range..."

 

[mikecr]

Well I've shot a box and full range of adjustments with Mk4 and NXS scopes, but it was always at max power(cuz that's the only power I shoot at). So I'll concede that I don't know about POA shifting w/power.

But even if I knew it was happening, I wouldn't give up a good SFP for FFP.
No way

 

[BoydAllen]

On paper, I generally shoot variables at their highest power. When I sight in a scope for field use, I sight in at the highest power and check zero, on an appropriate target, at the lowest. If it is going to be primarily used somewhere in between I verify zero at that setting as well. If there are significant discrepancies it goes back to the mfg. for repairs. In the past, I have used several SFP variable scopes for Calif. ground squirrel shooting at a variety of distances and power settings, with no problems. I guess that I must be lucky. I have only had one scope that had a problem of this sort. It was an old steel tube Weaver 3 x 9. Given that lower powers are generally used for closer shots, and that relative to varmint shooting, all big game targets are approximately the size of a barn. I think that in most cases, this is a non problem.

 

[6BRinNZ]

hey Fitter,

from memory S&B state something like that on their website (the first line)....what isn't quantified is the amount of POI change....i.e. assuming you are using quality SFP scopes would you even see it?

I guess you are asking more - what mechanically/optically between the two types makes it more difficult...that I can't answer.