Focusing Techniques

Sharp focus is one of the most satisfying aspects of film photography — and one of the most frustrating when you get it wrong. Unlike digital, you can't check focus on the back of the camera. You commit, wait for development, and hope.

This guide covers focusing methods for different camera types and situations, from basic split-prism focusing to zone focusing and hyperfocal techniques.

SLR Focusing

Single-lens reflex cameras show you exactly what the lens sees through a mirror system. This makes focusing relatively intuitive, but there are techniques to improve accuracy.

Split-Prism Focusing

Most SLR viewfinders have a split-prism focusing aid in the centre — a circle divided horizontally where out-of-focus subjects appear misaligned.

How to use it:

1. Place the split-prism on an edge or line in your subject (vertical lines work best)
2. Turn the focus ring until the two halves align perfectly
3. The subject is now in focus

Microprism Collar

The shimmering ring around the split-prism shows a "sparkling" effect when out of focus that settles when focus is achieved. Useful when:

• The split-prism blacks out
• Your subject lacks clear lines
• You prefer the visual feedback

Ground Glass

The outer area of the viewfinder is ground glass — you can focus here by eye, like focusing a magnifying glass. Less precise than aids but works at any aperture.

Rangefinder Focusing

Rangefinder cameras use a separate optical system to measure distance. A secondary image appears in the viewfinder centre that you align with the main image.

The Rangefinder Patch

In the centre of a rangefinder viewfinder, you'll see a bright rectangular patch showing a secondary image. This image shifts as you turn the focus ring.

How to use it:

1. Place the patch on your subject
2. Turn the focus ring until the two images align (become one)
3. Subject is in focus

What to align:

• Vertical edges work best (door frames, faces, lamp posts)
• Horizontal edges work but are less precise
• High-contrast edges are easier to see

Rangefinder Advantages

• Focus in low light (the rangefinder patch is bright)
• No mirror blackout during exposure
• Accurate with wide-angle lenses (where SLR focusing is harder)
• Compact camera bodies

Rangefinder Limitations

• Framelines approximate — actual frame edges may differ slightly
• Parallax at close distances (what you see isn't quite what the lens sees)
• Long telephoto lenses are impractical (base length limits accuracy)
• Can't see depth of field preview

Zone Focusing

Zone focusing means pre-setting focus to a distance and shooting without adjusting. It's fast, reliable, and essential for street photography.

How It Works

1. Set a working aperture (f/8 or f/11 typically)
2. Set focus to a chosen distance (2-3 metres is common for street work)
3. Use the depth of field scale on your lens to see what range is sharp
4. Shoot subjects within that range without touching focus

Reading Depth of Field Scales

Most manual focus lenses have a depth of field scale — paired numbers on either side of the focus index mark.

Example with a 50mm lens at f/8, focused at 3m: Look at where the "8" marks fall on the distance scale. Everything between those marks is acceptably sharp — perhaps 2m to 5m.

Zone Focusing in Practice

Street photography setup:

• 35mm or 50mm lens
• f/8 or f/11 aperture
• Focus set to 2.5-3 metres
• Sharp zone roughly 1.5m to 5m

You can now shoot without touching focus. If someone walks into your zone, raise the camera and shoot. This is far faster than focus-then-shoot.

Hyperfocal Distance

Hyperfocal focusing maximises depth of field for a given aperture. Focus at the hyperfocal distance and everything from half that distance to infinity is acceptably sharp.

Calculating Hyperfocal Distance

The formula is complex, but for practical purposes:

Values for 35mm film, circle of confusion ~0.03mm

How to use hyperfocal:

1. Set your aperture
2. Focus at the hyperfocal distance for that aperture
3. Everything from half that distance to infinity is sharp

Landscape Application

For maximum sharpness in landscapes:

1. Find the hyperfocal distance for your lens and aperture
2. Focus at that distance using the distance scale or live measurement
3. Foreground and background will both be acceptably sharp

Example: 35mm lens at f/11, hyperfocal ~3.6m. Focus at 3.6m. Sharp from ~1.8m to infinity.

Scale Focusing

When you can't see through the viewfinder (shooting from the hip, camera over head), use the distance scale:

1. Estimate distance to subject
2. Set focus ring to that distance
3. Use a small aperture for margin of error
4. Shoot

This requires practice estimating distances, but it becomes intuitive.

Focus and Recompose

A common technique with centre-point focusing:

1. Place the focus point on your subject
2. Lock focus (half-press shutter or use focus lock)
3. Recompose to your desired framing
4. Shoot

Tips for Sharp Focus

For SLRs

• Use the split-prism — It's more accurate than eyeballing the ground glass
• Check your diopter — Most SLRs have diopter adjustment. If the viewfinder image is fuzzy, adjust until framelines are sharp. The diopter adjustment is usually a small dial or slider next to the viewfinder eyepiece. Turn it while looking through the viewfinder until the focusing screen (or framelines) appears sharp to your eye
• Focus on eyes — In portraits, always focus on the near eye. A sharp eye forgives other softness

For Rangefinders

• Align vertical edges — They're easier to see than horizontal
• Clean the viewfinder — Haze makes the rangefinder patch hard to see
• Practice in good light — The rangefinder patch is harder to see in dim conditions

General Tips

• Stop down for safety — When in doubt, f/8 gives you margin for error
• Pre-focus before the moment — Don't fumble with focus when the shot happens
• Learn your distances — Practice estimating 2m, 3m, 5m. Walk it off until it's instinctive

Common Focusing Mistakes

Focusing too slowly By the time you've achieved perfect focus, the moment has passed. Practice speed, accept "good enough" for moving subjects.

Trusting infinity too much "Infinity" on a lens scale isn't always perfectly at the hard stop. Test your lenses and mark true infinity if needed.

Ignoring depth of field Wide apertures have razor-thin focus planes. If you're shooting at f/2, focus accuracy is critical. At f/11, it's forgiving.

Not checking the viewfinder image Even with perfect focus technique, a dirty viewfinder or misadjusted diopter means you're not seeing accurately.

Summary

• SLRs: Use the split-prism or microprism for precision
• Rangefinders: Align the patch on vertical edges
• Zone focusing: Pre-set distance and aperture, shoot without adjusting
• Hyperfocal: Maximise depth of field for landscapes
• When in doubt: Stop down and give yourself margin

Focus becomes automatic with practice. After a few hundred frames, you'll focus accurately without conscious thought — your hands will know where the ring needs to be.