Safe shutter speed: how slow can you hand-hold?
A safe shutter speed is the slowest you can hand-hold before your own shake blurs the frame. Blur has two causes: you moved or the subject moved. Safe shutter speeds and stabilisation only deal with the first. Neither helps with a toddler running across the room.
1. How to work out a safe shutter speed
The traditional guide is the reciprocal rule:
Slowest safe shutter = 1 ÷ equivalent focal length, in seconds
- 50mm on full frame → 1/50s or faster
- 200mm on full frame → 1/200s or faster
- 50mm on APS-C (75mm equivalent) → 1/75s or faster. Use the equivalent, not the number on the lens.
A longer lens magnifies the same wobble more.
On a smaller sensor, convert first. Equivalent focal length = marked focal length × crop factor, and crop factor = 43.3mm full-frame diagonal ÷ your format's diagonal:
| Format | Crop factor | A 35mm behaves like | Safe shutter |
|---|---|---|---|
| Full frame (36×24mm) | 1.0× | 35mm | 1/35s → set 1/40s |
| APS-C (Sony / Nikon / Fujifilm) | 1.5× | 52.5mm | 1/52.5s → 1/60s |
| APS-C (Canon) | 1.6× | 56mm | 1/56s → 1/60s |
| Micro Four Thirds | 2.0× | 70mm | 1/70s → 1/80s |
The result usually falls between two settings; no dial has 1/52.5s. Always round to the faster one. It is a floor, and half a stop of margin costs nothing. Full conversion in the focal length and angle of view guide.
2. Safe shutter speed by focal length
1 ÷ equivalent focal length, worked out. First the computed value, then after the arrow the nearest faster setting:
| Marked focal length | Full frame (1.0×) | APS-C (1.5×) | MFT (2.0×) |
|---|---|---|---|
| 14mm | 1/14s → 1/15s | 21mm eq., 1/21s → 1/25s | 28mm eq., 1/28s → 1/30s |
| 24mm | 1/24s → 1/25s | 36mm eq., 1/36s → 1/40s | 48mm eq., 1/48s → 1/50s |
| 35mm | 1/35s → 1/40s | 52.5mm eq., 1/52.5s → 1/60s | 70mm eq., 1/70s → 1/80s |
| 50mm | 1/50s → 1/50s | 75mm eq., 1/75s → 1/80s | 100mm eq., 1/100s → 1/100s |
| 85mm | 1/85s → 1/100s | 127.5mm eq., 1/127.5s → 1/160s | 170mm eq., 1/170s → 1/200s |
| 135mm | 1/135s → 1/160s | 202.5mm eq., 1/202.5s → 1/250s | 270mm eq., 1/270s → 1/320s |
| 200mm | 1/200s → 1/200s | 300mm eq., 1/300s → 1/320s | 400mm eq., 1/400s → 1/400s |
Phones work the same way with their quoted equivalent. Most main cameras are 24–26mm equivalent, so 1/25s to 1/30s.
Zlens turns the phone into the camera console: live view, remote settings, RAW transfer. Android first, coming soon.
About Zlens and supported cameras3. Tightening the rule for digital
The rule comes from film and assumed a modest print at normal viewing distance. Pixel-peeping at 100% is far harsher. In practice:
| Situation | Adjustment |
|---|---|
| High-resolution body (40MP+) | 1–2 stops faster than the rule |
| Social media only | The rule is about right |
| Awkward stance / one hand | 1 stop faster |
| Large prints | 2 stops faster, or use a tripod |
Test yourself once. Find a finely textured wall, stand as you normally do, and shoot three frames at each speed down from the rule: 1/50s, 1/25s, 1/13s, 1/6s. At 100%, the first speed that smears is your floor. It varies by person and by how tired you are, but once measured you stop guessing.
4. What stabilisation buys
Manufacturers' "X stops" come from a standardised test. Knock some off for real use:
| Type | Claimed | Realistic |
|---|---|---|
| Lens stabilisation (OIS/VR/IS) | 3–5 stops | 2–3 stops |
| In-body 5-axis (IBIS) | 5–8 stops | 3–4 stops |
| Body + lens co-operative | up to 8 stops | 4–5 stops |
Stabilisation lowers the safe shutter speed; it does not abolish it. n stops means the shutter time can be multiplied by 2ⁿ. On full frame:
| Effective compensation | 50mm (from 1/50s) | 200mm (from 1/200s) |
|---|---|---|
| 0 stops | 1/50s | 1/200s |
| 2 stops (×4) | 0.08s ≈ 1/13s | 0.02s = 1/50s |
| 3 stops (×8) | 0.16s ≈ 1/6s | 0.04s = 1/25s |
| 4 stops (×16) | 0.32s ≈ 1/3s | 0.08s ≈ 1/13s |
| 5 stops (×32) | 0.64s ≈ 0.6s | 0.16s ≈ 1/6s |
These rows use the realistic figures. Reaching the last row still takes a steady stance, a controlled breath and a short burst to pick the sharpest frame.
Two limits. Most bodies want stabilisation off on a tripod: with nothing to correct, the system can hunt and add blur, though some recent bodies detect a tripod themselves. And stabilisation only fixes camera shake.
5. Camera shake and subject motion are different things
Once the subject moves, the safe shutter speed no longer applies. It models your hands, not their legs. Speed and direction decide now:
| Subject | To freeze it |
|---|---|
| Someone walking | 1/125s |
| Running child or pet | 1/500s |
| Birds in flight, sport | 1/1000s or faster |
| Cars crossing the frame | 1/1000s or faster |
At the same speed, crossing the frame needs a faster shutter than coming towards you, because it covers more of the sensor.
If you want blur, like silky water or light trails, go the other way: tripod, base ISO, aperture stopped down, and a neutral density filter if it is still too bright. For how the settings trade, see the exposure triangle.
Telling them apart: zoom to 100%. If everything, static background included, smears one way, that is shake: go above the safe shutter speed or turn stabilisation on. If only the subject is soft, it moved, and only a faster shutter fixes that.
6. FAQ
What is a safe shutter speed?
No single number; it follows the equivalent focal length. Slowest safe shutter = 1 ÷ equivalent focal length in seconds: 1/50s for 50mm on full frame, 1/200s for 200mm. A 50mm on APS-C (1.5×) is 75mm equivalent, so 1/80s; on Micro Four Thirds (2.0×) it is 100mm equivalent, so 1/100s. Round to the faster setting, and add 1–2 stops for a high-resolution body, a big print or an awkward stance.
Do I still need a safe shutter speed if my lens has stabilisation?
Yes. Stabilisation lowers the floor by n stops, multiplying the shutter time by 2ⁿ; it doesn't remove it. A 50mm on full frame starts at 1/50s, and three working stops take you to 0.16s, about 1/6s. It only corrects camera shake, so a moving subject still needs a fast shutter.
Why is my photo still blurred with stabilisation on?
Most likely the subject moved, which stabilisation can't fix. The other usual suspect is leaving it on while on a tripod. If the whole frame is smeared, it is shake; if only the moving subject is, the shutter was too slow.
Must I switch stabilisation off on a tripod?
On most older and mid-range bodies, yes, since the system can oscillate with nothing to correct. Some recent models detect a tripod and switch it off themselves; check your manual.
How do I set up a long exposure?
Tripod, base ISO, aperture around f/8–f/11, then set the time in shutter priority or manual. In daylight, anything past a second or so needs a neutral density filter. Fire with the self-timer or a remote so pressing the button doesn't shake the camera.