Riflescopes: First Focal Plane or Second?

Where the reticle is positioned in the scope affects how you see it and use it as you dial the magnification up and down.

Riflescopes: First Focal Plane or Second?

Regardless of a reticle’s location, its focus is adjusted at the ocular end of the scope, here with a fast-focus eyepiece.

In my youth, many hunters still used iron sights, though the gremlins that had plagued scopes for most of a century were being chased off in quick succession.

In 1949, Leupold had become the first U.S. manufacturer with leak-proof scopes, nitrogen-filled to nix fogging. The trend from steel tubes to alloy continued into the 1950s. Constantly centered reticles followed. I remember horsehair reticles, thick as Grecian pillars in the field of view, that broke of their own great weight under recoil — and T.K. Lee’s .008-inch dot on almost invisible strands of black widow spider web that didn’t break. 

Horsehair and spider webs have since been replaced by wire. Leupold’s popular Duplex reticle, with bold outer and fine inner sections, came from .0012-inch platinum wire flattened to .0004-inch. Premier Reticle Ltd., which has sold reticles to most major scope-makers, twisted ribbon wire to form a “plex.” Another way to make reticles is by photo-etching metal foil .0007-inch thick. Chemicals strip all but the desired form. Foil must be glued to the mount; wire can be soldered. Both seem delicate, but their light weight, like a spider web’s, means little inertia. So they withstand sharp recoil.

More powerful hunting and sniping cartridges prompted increasingly brutal tests for scopes. “At Bushnell, scopes pulled from the line are checked with the equivalent of 10,000 shots from a .375 H&H,” a company insider told me. “Honestly, though, a scope that endures a hundred hits is good for thousands.”

Stateside, most reticles so tortured are in the scope’s second, or rear, focal plane. But European shooters have long favored first- or front-plane reticles. SFP vs. FFP. What’s the difference? As to recoil tolerance, there’s none. But reticle placement does affect what you see in a variable scope.

So, What’s the Difference?

An SFP reticle is placed behind the erector assembly. Erector lenses turn the upside-down image formed by front lenses right-side up (hence the name). The assembly also includes magnifying glass. An FFP reticle sits ahead of the erector tube, though not necessarily near the front of the scope. Depending on the internal design and the scope’s external profile, an FFP reticle may lie just forward of the turret. 

The SFP reticle appears the same across the power range of a variable scope. It doesn’t change in apparent dimensions when you dial from 3X to 9X or from 16X to 4X. On hunting rifles, I like SFP reticles.

An FFP reticle changes in apparent size when you dial magnification up and down. Depending on its design, it can hide small targets at long range when you increase power to … well, hit small targets at long range! Conversely, an FFP reticle can become hard to pick up quickly when magnification is dialed down for urgent shots at big game in cover — just when you need a bold reticle! But that characteristic is also in the FFP’s favor for some kinds of shooting. Its dimensions remain the same relative to the target at all power settings. So the spans defined by hash marks and dots on range-finding reticles have the same value at any magnification. Even simple reticles — a dot, plex or post — can be used to estimate distance or to shade for bullet drop or drift if you know how much the dot or post covers, or subtends. With an FFP, subtention is constant across power ranges.

FFP reticles are quickly getting traction stateside as shooters buy more powerful scopes with broader magnification ranges. For decades after Leupold introduced its Vari-X 3-9X in 1961, competitive shooters and hunters were happy with “three-times” range (top magnification three times the bottom). Then a four-times scope appeared, and the race was on. Five-, six-, even eight- and 10-times ranges have followed, in bigger, ever heavier scopes. The practicality of adding such breadth is a topic for another time. But these scopes arrived with growing interest in long-range shooting — at targets and, controversially, at game.

These days, long-range matches include targets of various sizes at mixed ranges. Shooters must determine range, then adjust for bullet drop, and often for wind drift, too. As nearly all matches are timed, shooters like to do as much of this pre-shot prep while “in the scope,” as do predator hunters at extended range. Reticles marked in minutes or mils for ranging also help with shading (“Kentucky windage”) in response to shifting conditions and off-center shots. FFP reticles make sense because shooters can dial to any power without fretting about how it will affect the reticle’s relationship to the target. It doesn’t.

SFP reticles marked for ranging can be calibrated for an accurate read at only one power setting. Typically that’s the top magnification. But in a few high-power scopes, accurate registry is at 10X. Before buying a variable with a range-finding SFP reticle, you’ll want to know this number!

Long shots at predators out West beg high magnification scopes, increasingly available with FFP reticles.
Long shots at predators out West beg high magnification scopes, increasingly available with FFP reticles.

Long-Range Magnification

The top magnification of some scopes is too high even for long-range competition. At 30X, surely 40X, field of view is so small, finding a distant plate on a sagebrush hillside is difficult. Recoil can bump it far out of the field. Even at 24X, mirage can blur and “float” a target so it seems submerged in an ocean swell. At ranges shy of 1,000 yards or so, such magnification is hardly ever helpful. So many shooters use the “half-power” rule to make high-power scopes more versatile. At half the top magnification, marks on an SFP reticle span twice the specified measure. For example, at 12X in a 6-24X variable, a 1-mil span is 2 mils wide. Halving power gives a dot or bracket twice the value. An easy rule to remember and apply.

Besides holding an edge with marked reticles in long-range competition and predator hunting, the FFP location eliminates reticle shift as you change magnification. An FFP reticle is forever stationary, in front of the erector assembly’s moving parts. An SFP reticle isn’t so isolated. To be fair, detectable shifts in point of impact due to SFP reticle movement are now very rare.

SFP Reticle Proving Grounds

I once tested point-of-impact shift with power changes in 27 scopes with SFP reticles. From 1-4X to 6.5-20X, they represented 14 brand names and all price categories. They were mounted on a variety of rifles, .22 Rimfire to .30 Magnum, fired from sandbags. 

Three scopes showed 1 to 1.5 inches change in point of impact when power was dialed from the low end to the high. That’s significant, if not alarming in a hunting scope. Six scopes registered changes of .5- to .75-inch — insignificant, in my view, as natural shot dispersion and human error can easily open groups that much. No detectable change was noted in the other 18 scopes. There was no clear correlation between retail price or magnification with point-of-impact shift.

That test was conducted over 20 years ago. Since then, manufacturing tolerances have tightened, especially for high-power scopes. A Swarovski engineer told me: “Tolerances for our 4-16X and 6-24X scopes are smaller than for less powerful variables.” More than any other major scope-maker, Swarovski has held to SFP reticles — though its sister brand Kahles catalogs FFP models. 

To clear your mind of unclean suspicions regarding reticle shift, you need only leave that scope at one power setting. Scopes on my rifles for deer and elk might as well be super-glued at 4X. Hunting predators in open places, where deliberate shots from prone or sitting are the rule and the animals small, 7X or perhaps 8X makes sense. I seldom fire at game so far that ranging marks on a reticle are useful. 

Fixed-Power Scopes

Leupold once made a lovely 7.5X. Not long ago another caught my eye: the Spectra 7.5x50mm by GPO, or German Precision Optics. It’s engineered in Germany by people who cut their professional teeth at Zeiss and Meopta. Components are German, too. “Our scopes are top-tier, but priced 20 percent lower than comparable models from Germany,” said Mike Jensen, president of stateside distributor GPO USA. 

At this writing, the 7.5x50i is one of 22 riflescopes on the GPO roster. Nearly all are variables. Most, like the 7.5X, feature 30mm tubes. Exceptions: 1-inch 3-9x42mm and 4-12x42mm models, and three 34mm “tactical” scopes. Variables have power ranges of three, four, five, six and eight times. I was able to snare a 7.5x50i on loan.

This scope has a 7mm exit pupil, as big as the human eye can use, even at night. Its 4 inches of eye relief and a 15-foot field at 100 yards make for fast aim. There’s plenty of magnification for a prone poke at a coyote 300 yards off. ED glass yields diamond-sharp images, color-true to the edge. The lighted dot is at the junction of fine wires, with three bars at 3, 6 and 9 o’clock (the German No. 4 reticle). Dot size and the “weight” of wires and bars are just right, to my eye. An eight-position turret-side dial runs the dot, powered by a CR2032 battery. Forget to switch it off? After three hours of no adjustment, the dot loses patience and goes black, saving battery life. Used down to 15 percent of its capacity, the dot will blink three times when on, then glow normally. 

Windage and elevation dials have .1-mil graduations, each .36-inch at 100 yards. MOA dials are an option. Clicks are uniform and crisp. The dials can be set to read “0” after zeroing, for quick reference and return. The fast-focus eyepiece is marked, so if turned accidentally can be quickly re-adjusted. 

The 7.5x50mm Spectra weighs 21.7 ounces — not heavy for an illuminated scope with a 50mm front lens. Its 15.5-inch alloy tube is handsomely finished matte-black. No marks showed after I’d wrung it out shooting “around the square” at 100 yards to test W/E repeatability. After 80 clicks of adjustment in four directions, the last shots fell within 1.25 inches of the first. A penny shy of $630, this 7.5X GPO impresses me as a real bargain in a sight for almost any open-country hunting rifle. It’s light enough to complement a “walking varminter,” with a reticle and an exit pupil that help you hit in the dimmest conditions.

Variable-Power Scopes Dominate

Still, variable scopes dominate the market. You might think most makers with a lot of skin in the industry would offer both FFP and SFP reticle placement. Some do. Leupold, Vortex, Zeiss and Burris come to mind. Logically, high-power target scopes with reticles marked in minutes and mils would have FFP reticles, while hunting variables of modest modification would have SFP reticles. But you can find both options in both types of scopes — even your choice of FFP or SFP in a single model. 

While FFP reticles are becoming more popular, SFP reticles still outnumber them in scopes sold stateside. Swarovski has stuck with SFP placement even in its 3.5X-22X Z8i with a tiered reticle. It’s on my long-range Remington 700 in 7mm Rem. Mag. and has excelled on steel targets to 1,000 yards. 

At my last count, Vortex lists a dozen FFP scopes in its long roster of 1-inch, 30mm and 34mm models. Two 30mm Viper PST Gen IIs — the 3-15x44mm and 5-15x50mm — are offered with either FFP or SFP reticles. The 34mm Razor HD Gen II 4.5-27x56mm and 6-36x56mm are of FFP design, but also the 1-10x24mm and Viper PST Gen II 2-10x32mm with a 30mm tube.

Zeiss has two new LRP S5s with FFP reticles: a 3.6-18x50mm and a 5-25x56mm. They join 4-25x50mm and 6-36x56mm S3 FFP models. All have 34mm tubes. Zeiss Victory V8 and Conquest V6 and V4 scopes are of SFP design.

Leupold’s Mark 6 1-6x20mm and 3-18x44mm scopes feature FFP reticles and 34mm tubes. So does the Mark 8 1.1-8x24mm. Perversely, the Mark 5HD 3.6-18x44mm and 5.5-25x56mm, also of the FFP clan, are built on 35mm tubes, as is the Mark 8 3.5-5x56mm. Leupold catalogs its 30mm 4.5-14x50mm and 8.5-25x50mm VX-3i LRP scopes with FFP reticles.

The Czech firm Meopta offers its superb MeoPro Optika6 with 30mm tubes and FFP reticles in 1-6x24mm, 3-18x50mm, 4.5-27x50mm and 5-30x56mm models. All except the 5-30X are also available with SFP reticles.

FFP or SFP for predator hunting? You choose. The selection of both has never been better!


Comments on this site are submitted by users and are not endorsed by nor do they reflect the views or opinions of COLE Publishing, Inc. Comments are moderated before being posted.