L’illuminamento è il flusso luminoso totale incidente su una superficie per unità di area.
1 ph = 10,000 cd/m² 
1 cd/m² = 0 ph 
Esempio: 
Convert 15 Foto in Candele per metro quadrato:
15 ph = 150,000 cd/m² 
| Foto | Candele per metro quadrato | 
|---|---|
| 0.01 ph | 100 cd/m² | 
| 0.1 ph | 1,000 cd/m² | 
| 1 ph | 10,000 cd/m² | 
| 2 ph | 20,000 cd/m² | 
| 3 ph | 30,000 cd/m² | 
| 5 ph | 50,000 cd/m² | 
| 10 ph | 100,000 cd/m² | 
| 20 ph | 200,000 cd/m² | 
| 30 ph | 300,000 cd/m² | 
| 40 ph | 400,000 cd/m² | 
| 50 ph | 500,000 cd/m² | 
| 60 ph | 600,000 cd/m² | 
| 70 ph | 700,000 cd/m² | 
| 80 ph | 800,000 cd/m² | 
| 90 ph | 900,000 cd/m² | 
| 100 ph | 1,000,000 cd/m² | 
| 250 ph | 2,500,000 cd/m² | 
| 500 ph | 5,000,000 cd/m² | 
| 750 ph | 7,500,000 cd/m² | 
| 1000 ph | 10,000,000 cd/m² | 
| 10000 ph | 100,000,000 cd/m² | 
| 100000 ph | 1,000,000,000 cd/m² |