There are few things that seem to confuse more rifle shooters than the difference between first and second focal plane scopes. Lots of people know there's a cost difference between the two and that hunters generally prefer SFP scopes, but not everyone really knows why. While the differences and benefits of each aren't really complicated, it helps to see it visually, so let's do that.
Here are a couple of internal views of a typical rifle scope . . .
Courtesy LongRangeShooting.com
First or second focal plane really only refers to where inside the scope the reticle is located. It's either in the first focal position, in front of the scope's erector system nearer the objective lens or in the second focal position closer to the ocular lens. That's it. It's that simple.
But what does that mean in a practical sense?
Your view of the reticle in a FFP scope will vary as you zoom in and out. The higher the magnification, the larger the reticle appears and the easier it is to see the hashmarks or "subtensions." The other important factor is those hashmarks -- whether they represent minute of angle or milliradians -- are accurate no matter what magnification you're using.
In a second focal plane scope, the reticle always looks the same, whether you're at minimum or maximum magnification. A lot of reticles in SFP hunting scopes are simple duplex reticles, but if the reticle in your SFP scope has hashmarks (either in MOA or mils) they're only accurate at one magnification level, usually the maximum.
While a FFP reticle can be thin and harder to see at low magnification levels and low light conditions, a SFP reticle is always easy to pick up. But if you rely on your hashmarks for elevation or windage adjustments, you're going to have to do some mental math if you're mot at maximum magnification. Lots of hunters make it easy on themselves by sticking to half magnification. So if your SFP scope has a reticle with MOA subtensions at 12X, those marks will represent 2 MOA at 6X.
First focal plane scopes tend to be more expensive. They generally have more complex reticles that require more precise positioning inside the scope. But they're generally quicker and simpler to make holdover and windage adjustments on the fly. That's generally a better choice for competition or "tactical" shooters and those who hunt at longer ranges.
For must hunters who generally shoot at distances from 100 to 300 yards, the simplicity, lighter weight, and reduced cost of a SFP scope will make more sense. You can hunt with a first focal plane scope and you can compete and shoot long range with a second focal plane scope. Neither one is "better" than the other. But knowing the differences between the two and how they work should let you make a better choice when it's time to buy.
