As CEJ posted, you *will* need an ND filter, a strong one. How much of one depends on how long an exposure you want, and the light level. Worst case, let's say you want an exposure of 1 second or more, and your scene is in midday sun. At an ISO of 100, the "sunny f/16 rule" says that correct exposure is 1/ISO at f/16, so 1/100 @ f/16. Assuming I don't want diffraction effects to soften the result, I don't want to stop down any further. I'm going to need about seven stops of ND filter to reach 1 second:
0 1/120 (approx)
1 1/60
2 1/30
3 1/15
4 1/8
5 1/4
6 1/2
7 1
When I really want long exposures in daylight, I use a 10-stop ND filter, which allows me to shoot at f/8 and get shutter speeds well in excess of 1 second. I really need a six-stop as well, but it's not a high priority. |
