HDRI ND Filter Values

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