FFP vs SFP Rifle Scopes Explained: Which Focal Plane Do You Need?

In a first focal plane (FFP) scope the reticle grows and shrinks as you zoom, so its holdover and ranging marks are correct at every magnification. In a second focal plane (SFP) scope the reticle stays the same size, which keeps it bold at low power, but its marks are only correct at one magnification, usually the highest.

Choose FFP if you hold over or measure with the reticle at different magnifications. Choose SFP if you zero once, shoot at one power, or want an LPVO that behaves like a red dot at 1x. Here is how the difference works and where each one wins.

How the two designs work

A variable scope has two image planes where a reticle can sit. The first is in front of the zoom (erector) lenses, so the reticle is magnified along with the target. The second is behind them, so the target is magnified but the reticle is not.

• FFP: reticle and target grow together. Everything the reticle measures stays in proportion, so it gives the same answer at 2x, 5x or 10x.
• SFP (also called rear focal plane): the reticle looks the same size at all powers. The target grows behind it, so the angle each mark covers changes as you zoom.

Side by side

The SFP arithmetic you need to know

An SFP reticle's marks are only true at the calibrated power. Below that power, each mark covers more angle, in proportion. On a scope calibrated at 6x:

• at 6x, a 2 MOA hash mark covers 2 MOA;
• at 3x, the same mark covers 4 MOA (6 ÷ 3 = 2 times as much);
• at 2x, it covers 6 MOA (6 ÷ 2 = 3 times as much).

So if you use a bullet-drop mark at 3x on an SFP scope calibrated at 6x, you will hold for a much longer distance than the mark says. That is why SFP shooters are told to "hold at max power". The manual will tell you the calibrated power, so check it. For what each unit covers at distance, see the MOA at distance chart.

When FFP wins

• You hold over, or measure a miss, at whatever power the scope happens to be on. The marks always mean what they say.
• You range targets with the reticle, or shoot long range with a mil or MOA grid.
• You run a 1-8x or 1-10x LPVO at mid powers, where an SFP reticle's holds would be wrong.

When SFP wins

• LPVOs used like a red dot. At 1x an SFP reticle stays bold and fast; an FFP reticle can shrink to a fine wire, and you rely on the illuminated centre. That is why many of the best-value 1-6x LPVOs are SFP.
• Zero-and-hold hunting. A stalker who zeroes at 100 m and holds centre on the chest never uses the reticle to measure, so SFP costs nothing.
• Low light. A constant, heavier reticle is easier to see against a dark animal in shadow at low power.

Comparing both in one family

The clearest way to see the difference is to compare the same scope in both planes. SIG makes the TANGO-MSR 1-6x24 in both: the SFP version with the MSR BDC6 reticle and the FFP version. SIG lists both with a 30 mm tube, 11 brightness settings and 1/2 MOA clicks, so the focal plane is the main difference. The same applies to the TANGO-MSR Compact 1-10x24, sold in SFP and FFP versions.

The LPVO question

For a 1-6x used with both eyes open at 1x and at 6x for distance, SFP is usually the better buy, ideally with a daylight-visible illuminated centre. A distance-marked reticle such as the ACSS (see what is the ACSS reticle) works the same way: use its holds at the calibrated power.

For a 1-8x or 1-10x where you will genuinely hold over at 4x or 5x, FFP starts to earn its premium. The best FFP LPVOs deal with the tiny 1x reticle with a very bright centre: EOTech's diffraction-grating "Daylight Bright" SR5 on the Vudu 1-10x28, and Primary Arms' Red Dot Bright on the PLxC. There is more on this in what is an LPVO?

Compare both types in our LPVO range and the full rifle scope collection. Every listing states its focal plane.

Frequently asked questions

Is FFP better than SFP?

Neither is better in every case. FFP is better if you use reticle marks at different magnifications; SFP is better if you want a bold reticle at low power and zero-and-hold simplicity.

At what magnification is an SFP reticle accurate?

At its calibrated power, which is usually the maximum. The manufacturer's manual states it. At any other power the marks cover a different angle.

Should a deer stalking scope be FFP?

Usually not. Most stalkers zero at 100 m and hold on the chest inside 200 m, so the reticle is never used to measure. SFP gives a heavier, easier-to-see reticle in poor light, often for less money.

Why are FFP scopes more expensive?

The reticle sits in front of the zoom lenses, so it has to be made very precisely and stay perfectly centred as it is magnified. That tighter tolerance usually adds cost.