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Scope Selection- FFP or SFP?

When selecting a rifle scope, a common decision that has to be made when selecting a variable magnification scope, is the location of the reticle. There are only two options, either on the first focal plane (FFP) or the second focal plane (SFP). Manufacturers place the reticle at a focal plane to assure a clear and sharp image. The difference is important to note and there are pros and cons to each.

Let’s start with first focal plane. When looking through an FFP scope, the reticle will change size with any change to the magnification- higher magnification, larger reticle- lower magnification, smaller reticle.  Stay with me now, as this means that the reticle remains the same size relative to the size of the target. In other words, as the image or target grows and shrinks, so will the reticle. Particularly useful with Mildot, Horus, or other reticles where the sub tensions are utilized for range finding or bullet drop compensation as they are accurate at any magnification setting. The downside to an FFP scope is that as magnification is increased, sometimes the reticle can block the sight picture possibly causing some guessing on your shot placement.

Now lets talk about the second focal plane (SFP). Reticles located on the second focal plane remain the same size when the magnification is adjusted up or down. Since only the target will grow or shrink as the magnification is changed, this of course, also means that the reticle does not remain the same size relative to the size of the target, so any sub tensions on the reticle are only accurate at a specific magnification setting, typically the maximum magnification.  To summarize, with a constant sized reticle in the second focal plane, a clearer sight picture is assured but using reticle sub tensions can only be done at one magnification setting.

In a rifle scope most of the magnification occurs just behind the turrets toward the eyepiece. The first focal plane is located forward between the turrets and the objective bell whereas the second focal plane is located between the turrets and the eyepiece, behind the magnification. This is why the reticle on the first focal plane is magnified along with the target and the second focal plane remains the same size in the view.

Selection of one over the other is often times personal preference and your needs. The most important take away is to know your scope, understand the difference in reticle placement and know how to take advantage of the features your scope provides.

 

 

 

 

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