You may have seen two acronyms floating around while shopping for rifle scopes, they are SFP and FFP. SFP is second focal plane, and FFP is first focal plane. Both refer to the focal plane that the reticles exist in. This applies only to variable power scopes. A fixed power scope, a red dot, or holographic doesn’t have a focal plane you should be concerned about. FFP and SFP have their strengths and weaknesses, and like almost any scope consideration you have to focus on what the scope and the rifle is for.
First Focal Plane
First focal plane scopes are the newer reticle option for scoped rifles. First focal plane scopes are more specifically designed for tactical shooters and hunters where the distance to target changes and is often unknown. FFP scopes place the reticle in front of the erector.
The main takeaway in terms of the difference between the two focal planes is the fact that first focal plane reticles do not grow or shrink in size as magnification increases, but it appears they do. The reticle is being magnified to match the magnification of the target. The reason this is important to tactical shooters is varied. First and foremost tactical shooters and hunter tend to use mil scales to calculate bullet drop and wind calls.
On a first focal plane scope, the mil scale is the same at 2x as it is on 10x. So the scale is always the same. Tactical shooters are also speed based shooters. Meaning they may not have time to calculate the difference in magnification and the difference it makes in mil scales.
First focal plane scopes do have a few issues. First and foremost at higher magnification ranges these scopes tend to have less clarity. They are also considerably more expensive than scopes in the second focal plane. Also, first focal plane scopes cannot reach the same levels of magnification as a second focal plane scope, however, for tactical shooters and hunters, this isn’t a large concern because they don’t need massive levels of magnification.
There are a few myths floating around regarding first focal plane scopes. The biggest is that FFP scopes are weaker and break easier. This isn’t true, though, it may have been at one time, but first focal planes are just as tough as second focal planes scopes.
Second Focal Plane
Second focal plane scopes are the old standard. Second focal plane scopes take the reticle and place it behind the erector. And right next to the magnification ring on most optics. This affects the reticle by keeping it the exact same size as you move through different magnification ranges. This makes it difficult to use Mil or MOA scales at variable magnifications. These MIL and MOA scales are only accurate at one specific power.
Most SFP scopes have an accurate scale at their highest power, I say most because some oddballs have the true reticle size at an odd magnification. So always consult your scope’s manual.
Second focal plane scopes are primarily designed with long range shooters and short range hunters in mind. Hunters who are are covering a hundred yards or less at any given time, and are not equipped with reticles featuring a MIL or MOA drop reticle.
Benchrest long range shooters typically want to pull every little bit of magnification out of their scopes. So they choose second focal plane scopes which can easily have 50 power magnification ranges. They also prefer the ability to have as thin a reticle as possible, which second focal plane scopes can provide.
To use a second focal plane scope with a mil dot reticle at a lowered magnification you have to do a bit of math. The basic rule that as the magnification levels go down the value of the reticle goes up. A scope with a magnification level of twelve at six power means the mil scale will be doubled.
FFP or SFP decisions, decisions..
I tend to prefer the first focal plane. I feel it’s more versatile for my shooting needs. I like the fact the scale stays the same regardless of the magnification I am using. It means less thinking for me and more shooting. I am slightly biased due to my own scope experiences being almost exclusively FFP. With that said SFP scopes are still quality pieces of gear and are much more affordable for those willing to do the extra work, or for shooting at the bench.