Bellows Factor Calculator
Calculate exposure compensation for macro and close-up photography. When the lens is extended beyond infinity focus, additional exposure is needed.
Calculate bellows factor
Choose magnification for quick calculation, or extension for technical cameras
1:1 = life size, 1:2 = half size, 2:1 = twice life size
Bellows Factor
4.00×
Exposure compensation
+2.0 stops
Adjusted exposure examples:
If meteredf/8→ usef/4
If meteredf/11→ usef/5.6
If metered1/60s→ use1/15s
If metered1/30s→ use1/8s
From magnification
Factor = (1 + M)²
Where M = magnification ratio (1:1 = 1.0)
From extension
Factor = (E / f)²
Where E = total extension, f = focal length
Quick reference
| Magnification | Factor | Stops |
|---|---|---|
| 1:10(0.1×) | 1.21× | +0.3 |
| 1:4(0.25×) | 1.56× | +0.6 |
| 1:2(0.5×) | 2.25× | +1.2 |
| 1:1(1×) | 4× | +2 |
| 2:1(2×) | 9× | +3.2 |
| 3:1(3×) | 16× | +4 |
Log your macro exposures with Silverlog
Coming soon