View Full Version : Scope magnification question 9x vs 9x

04-13-2012, 9:41 AM
Hi all, finally got the 2 girls on the range at the same time AND noticed a big difference in magnification between their scopes - any thoughts would be appreciated.

1) Leupold VX-II 3-9X50mm Matte/Duplex
2) Nikon ProStaff Rimfire 3-9x40mm w/BDC 150 Reticle

Was at the 50 yard station, and had sighted in my .22LR using scope #2 at 9x magnification. Decided to be lazy and not move the Lead Sled over to the 100 yard target to re-check my 30-06.

The 30-06 is using #1 and at 9x the sight picture and magnification was greatly reduced [target looked further away].

What gives? Didn't think the 50mm vs 40mm would make a difference, and if anything the result [in my mind] would be reversed. I know my 50mm camera lens is different than my 200mm [with the 50mm having a wider FOV].

What am I missing?


04-13-2012, 9:52 AM
Does #1 have a wider FOV? My guess is it may appear like it magnifies less because it takes up less of the FOV?

Just a wild guess though, I am by no means an optics expert.

HK Dave
04-13-2012, 10:02 AM
It's the other way around, all things being equal the 50mm would have a wider field of view than the 40mm.

When you compare camera lenses... the 50mm-200mm in a camera lens is something equated to the 3-9x of the riflescope. In other words, you're talking about zoom, not the size of the front objective.

The other thing to keep in mind, when a manufacturer says 9x, it doesn't necessarily mean 9x... it's just an approximation. Same thing applies to camera lenses btw. ;)

What you were probably experiencing was a mixture of everything i just said.

04-13-2012, 10:25 AM
Thanks for the extra brain power!

My Leupold
FOV at 100 yards:
3x - 32.3'
9x - 14'

My Nikon
FOV at 100 yards:
3x - 33.28'
9x - 11.3'

Looking at the above numbers . . . the Nikon is "tighter/closer" at 9x and "wider/further" at 3x. So with the Nikon, the target size will appear larger at 9x and smaller at 3x than the Leupold. Correct? ;)

04-13-2012, 11:30 AM
The target size will be the same. However, you will see "more" of it and if the crosshairs are slightly different the target may appear smaller or larger in reference to them.

Also, the 9X listed usually isn't the actual magnification. As an example my leupold 3-9 is actually 3.8 to 8.5.