What’s the difference between FFP and SFP?Let’s begin to understand what the difference is between the two systems before I begin to convince you that FFP is by far the best way to go.FFP stands for First Focal Plane and SFP stands for Second Focal Plane.When dealing with an assembly like a Rifle Scope, you will have 2 different Focal Planes. Why is this?Imagine the diagram below:
This is a visual representation of what happens when light waves enter in the optical assembly.
When you observe any source of light, you are observing a “point source of light.” This point source of light then disperses (represented by the two different lines above, it’s not just 2 lines it’s many different lines) and these dispersions are then captured by the lens, in our case the Objective Lens.
What our lens does is it focuses that point source of light and the waves coming from it behind the lens. And where this cone of light converges is called the Focal Plane.
FFP is First Focal Plane. The First Focal Plane is the Focal Plane right behind the Objective Lens.
It’s called the First Focal Plane because it is the First Focal Plane in the entire Rifle Scope Assembly.
First Focal Plane Scopes are called so because the lens with the reticle on it is on the First Focal Plane.
What does this mean?
Well if you see the diagram below, you’ll see that the First Focal Plane is in front of the magnification adjustment. This means that the reticle size will get bigger whenever you adjust the magnification.
SFP is Second Focal Plane. It gets it’s name the same way FFP gets its name: the reticle is placed on the Second Focal Plane of the assembly.
And this is what makes all the difference.
The Second Focal Plane is between the Ocular lens of the Rifle Scope and the magnification assembly. If the reticle is placed here, what’s going to happen to the reticle as you adjust the magnification?
That’s right, nothing. The reticle stays the exact same size, regardless of the adjustment in magnification.
What this difference really means.
This is in fact not a cool feature (in long range shooting) for one main reason which gives way to many other reasons: your measurements for Mil or MOA change every time you change magnification.
Now this is not some subjective preference, this is the truth: when your reticle doesn’t change size with the target as you increase/decrease magnification, you lose what the original Mil/MOA was and have to recalculate.
So the question becomes: what the f*** is the point of having variable magnification at all then?
I mean I guess you can just make the commitment to not change the variable magnification if you’re confident the current magnification will be good for your uses. But how do you know it will be?
And again I say: what’s the point of having variable magnification?
Let’s look at a real world example of this:
This target is at 100 yards (we’ll keep it simple). You know 1 Mil equals 3.6 inches at 100 yards right?
Nope. Zoom in a bit. The picture on the right this time.
1 Mil is still 1/1000th of any distance, so it’s 3.6 inches. But your reticle measurements have changed! Using a reticle as an aide has almost no use in this scenario now.
You can’t use the reticle to measure the targets length, unless you keep it at the original magnification. When you adjust it down, you then need to calculate all over again what each hash mark represents.
What really matters in a long range shot?
But none of this matters, if it doesn’t matter in a long range shot right?
Well what matters in a long range shot above all is the ability to be consistent. And using an SFP scope goes against this, literally every time you use it.
Good long range shooters are able to take the human element out of the shot. The more you have to add in human factors, the more risk you run into when making mistakes.
And if you have to calculate the different Mils and MOAs at different magnifications, you just amplify that factor.
Whereas when using an FFP scope, you literally have none of this risk. 1 Mil/1 MOA is the same regardless of the magnification adjustment you have set.
For tactical uses and hunting uses this has so many more advantages than an SFP scope. True, you may not need to adjust magnification every single time, especially in shorter range shots.
But accuracy depends on consistency first and foremost, and SFP scopes are inconsistent just by their own design.
Complex reticle design is a huge innovation for long range shooting.
Observe the reticle below:
This is what’s called a Christmas Tree reticle. We can use it to easily calculate holdovers for wind. Really useful at long range!
What’s even more useful is the subtensions these reticles come with. By that I mean the various hash marks have constant differences between them, like 0.5 Mil, 1 MOA, etc.
All you do is memorize what that is for your reticle, and you’re set when going out and shooting. SFP reticles don’t have this, and aren’t really that helpful for making calculations like this.
Applications Where SFP Is Beneficial
In short, SFP is usually advantageous at short range, and at low magnifications.
And I consider anything from 1-6 to be a low magnification setting.
Scopes like this are usually used for tactical applications, and don’t come with the advanced reticles we use in long range shooting. For this, having consistent measurements between the hash marks on the reticle isn’t as necessary.
And it could be more beneficial to not have the reticle get bigger at these short distances. When it gets bigger like this, it can obscure the target.
For tactical shooting this could be an issue. In long range applications, we like to see the target of course but it’s more about the adjustments we make on the turrets rather than seeing every detail of the target.
We don’t even have to make sure the reticle is even on the target with a long range shot, as long as the adjustments were made correctly. In tactical shooting, this isn’t the case.
What’s your say?
Objectively speaking, FFP is the better choice in a long range shot. And by long range, I mean any time you’re going over 100 yards.
Some might prefer the SFP because the reticle doesn’t obscure the target or because it’s cheaper. But again, these qualities are only really beneficial in a tactical shot.
Anytime you go over 6 magnification, FFP should be what you’re using.
Leave a comment below: which do you prefer, and why? What’s your biggest reason for not choosing the other?