19 Mar 2022
The following table shows virtual exposure times when using Neutral Density (ND) filters while capturing HDRI images.
As ND filters can be stacked, the total Exposure Value (EV) can be increase. Here I’m using ND8, ND64 and ND1000 which gives a good range of EV values between 3 and 19 stops.
The formula for calculating this virtual exposure time is.
1 / (shutterspeed * pow(2, EV)
For example, if using a shutter speed of 1/8000th and an ND8, the result would be.
1 / (8000 * pow (2, 3)) = 0.000015625
Shutter Speed is given as a fraction of second, while all the other values are expressed in seconds.
shutter speed | no ND (EV 0) | ND8 (EV 3) | ND64 (EV 6) | ND1000 (EV 10) | ND1000 + ND8 (EV 13) | ND1000 + ND64 (EV 16) | ND1000 + ND64 + ND8 (EV 19) |
---|---|---|---|---|---|---|---|
8000.0 | 0.000125000 | 0.000015625 | 0.000001953125 | 0.0000001220703125 | 0.00000001525878906 | 0.000000001907348633 | 0.0000000002384185791 |
4000.0 | 0.000250000 | 0.00003125 | 0.00000390625 | 0.000000244140625 | 0.00000003051757813 | 0.000000003814697266 | 0.0000000004768371582 |
2000.0 | 0.000500000 | 0.0000625 | 0.0000078125 | 0.00000048828125 | 0.00000006103515625 | 0.000000007629394531 | 0.0000000009536743164 |
1000.0 | 0.001000000 | 0.000125 | 0.000015625 | 0.0000009765625 | 0.0000001220703125 | 0.00000001525878906 | 0.000000001907348633 |
500.0 | 0.002000000 | 0.00025 | 0.00003125 | 0.000001953125 | 0.000000244140625 | 0.00000003051757813 | 0.000000003814697266 |
250.0 | 0.004000000 | 0.0005 | 0.0000625 | 0.00000390625 | 0.00000048828125 | 0.00000006103515625 | 0.000000007629394531 |
125.0 | 0.008000000 | 0.001 | 0.000125 | 0.0000078125 | 0.0000009765625 | 0.0000001220703125 | 0.00000001525878906 |
60.0 | 0.016666667 | 0.002083333333 | 0.0002604166667 | 0.00001627604167 | 0.000002034505208 | 0.000000254313151 | 0.00000003178914388 |
30.0 | 0.033333333 | 0.004166666667 | 0.0005208333333 | 0.00003255208333 | 0.000004069010417 | 0.0000005086263021 | 0.00000006357828776 |
15.0 | 0.066666667 | 0.008333333333 | 0.001041666667 | 0.00006510416667 | 0.000008138020833 | 0.000001017252604 | 0.0000001271565755 |
8.0 | 0.125000000 | 0.015625 | 0.001953125 | 0.0001220703125 | 0.00001525878906 | 0.000001907348633 | 0.0000002384185791 |
4.0 | 0.250000000 | 0.03125 | 0.00390625 | 0.000244140625 | 0.00003051757813 | 0.000003814697266 | 0.0000004768371582 |
2.0 | 0.500000000 | 0.0625 | 0.0078125 | 0.00048828125 | 0.00006103515625 | 0.000007629394531 | 0.0000009536743164 |
1.0 | 1.000000000 | 0.125 | 0.015625 | 0.0009765625 | 0.0001220703125 | 0.00001525878906 | 0.000001907348633 |
0.5 | 2.000000000 | 0.25 | 0.03125 | 0.001953125 | 0.000244140625 | 0.00003051757813 | 0.000003814697266 |
0.25 | 4.000000000 | 0.5 | 0.0625 | 0.00390625 | 0.00048828125 | 0.00006103515625 | 0.000007629394531 |
0.125 | 8.000000000 | 1 | 0.125 | 0.0078125 | 0.0009765625 | 0.0001220703125 | 0.00001525878906 |
0.06667 | 15.000000000 | 1.875 | 0.234375 | 0.0146484375 | 0.001831054688 | 0.0002288818359 | 0.00002861022949 |
0.03333 | 30.000000000 | 3.75 | 0.46875 | 0.029296875 | 0.003662109375 | 0.0004577636719 | 0.00005722045898 |