Optics guides
Every explainer we have written, in one place: 42 guides on rifle scopes, red dots and LPVOs, binoculars, rangefinders, thermal and bore sighting. No product pitches here, just the fundamentals in plain English. When you are ready to buy, each section links to the matching buying guide.
Rifle scopes
Setting one up, and the four specs that confuse everyone. Shopping? See our best rifle scopes.
- How to sight in a rifle scope Bore sight, start at 25 yards, then fire a group and adjust to it.
- How to mount a rifle scope Levelling, eye relief, squaring the reticle and torque, in order.
- How to adjust a rifle scope Every dial explained, and which way to turn each one.
- Rifle scope numbers explained (3-9x40) Magnification x objective, plus tube size, MOA clicks and focal plane.
- FFP vs SFP Why first-focal-plane holds stay true at any magnification.
- MOA vs MRAD What each click is worth, and why neither is better.
- MOA / MRAD calculator Enter your distance and miss, get the exact MOA, mils and clicks to dial.
- Mil dot ranging calculator Enter a known target size and the mils it spans, get the distance.
- What parallax is Why the reticle seems to shift, and when it actually matters.
- Rimfire vs centerfire scope Why a rimfire scope uses a 50-yard parallax setting.
- What distance to zero a .22 Zero at 50 yards, and the published data showing what 25, 75 and 100 cost you.
Red dots and LPVOs
The 1x speed question, and where magnification earns its weight. Shopping? See our best red dot sights.
- How to sight in a red dot Zero distances for a rifle and a pistol, and why astigmatism is your eye.
- Red dot vs iron sights Target focus, both eyes open, and why co-witness backups exist.
- How to zero AR-15 iron sights Front post for elevation, rear for windage: FORS, and the 25/300 battle zero.
- Red dot vs holographic How each projects its reticle, and what it costs in battery.
- Green dot vs red dot Why the eye sees green brighter, and when that is worth the premium.
- MOA dot size: 2 vs 3 vs 6 MOA How much of the target each dot covers, and why bigger is not less accurate.
- Red dot size at distance calculator Enter a MOA dot size and range to see how many inches it covers.
- Red dot vs reflex A reflex sight is a type of red dot; the real choice is reflex vs holographic vs prism.
- Prism scope vs red dot A magnified etched reticle against a 1x projected dot, and which suits astigmatism.
- EOTech vs Aimpoint Holographic window and reticle against red dot battery life and weight.
- What does LPVO stand for Low Power Variable Optic, word by word, and how it works.
- LPVO vs red dot Reach and holdovers against speed, weight and battery life.
- LPVO vs red dot magnifier One variable optic against a modular dot-plus-3x setup.
Binoculars
Reading the numbers, choosing a size, and looking after the glass. Shopping? See our best hunting binoculars.
- How to choose binoculars The specs that matter: exit pupil, eye relief, field of view.
- What binocular numbers mean 10x42 decoded: magnification first, objective lens second.
- 8x42 vs 10x42 Field of view and shake against reach. Birding vs hunting.
- How to focus binoculars The two-step method: set the dioptre once, then the wheel.
- How to clean binoculars Blow off grit first. The order is what prevents scratches.
- Roof prism vs porro prism Why roof prisms cost more to make the same image.
- Monocular vs binocular Half the size and weight against depth and comfort.
- Spotting scope vs binoculars Wide handheld scanning against high-magnification detail on a tripod.
- When were binoculars invented From Lippershey in 1608 to the porro and roof prism.
Rangefinders
Golf and hunting units are not interchangeable. Here is why. Shopping? See our best hunting rangefinders.
- Hunting vs golf rangefinder First-target vs last-target priority, and why swapping fails.
- Rangefinder for bow hunting Angle-compensated bow mode and pre-ranging your lanes.
- What is slope on a golf rangefinder How it adjusts for uphill shots, and when it is not legal.
- Golf GPS vs laser rangefinder Point-to-pin precision against a full map of the hole.
Thermal and night vision
Seeing heat versus amplifying light, and which one finds game. Shopping? See our best thermal scopes.
- Thermal vs night vision Thermal reads heat in total darkness; night vision needs light.
Bore sighting
Getting on paper before you burn ammunition. Shopping? See our best laser bore sights.
- What is bore sighting Aligning the scope with the barrel, in plain English.
- How to bore sight a scope By eye through the bore, or with a laser bore sight.
Crossbow scopes
Speed-calibrated reticles for bolt drop, and setting them up. Shopping? See our best crossbow scopes.
- How to sight in a crossbow scope Zero at 20 yards, then set the speed dial to your bolt velocity.
- Crossbow scope vs red dot Magnified bolt-drop holdovers against 1x speed up close.
We tell you when a guide is research-based rather than a hands-on test, and we note the limits. Every award and superlative is verified against a primary source before it is published. See how we evaluate.