Working out time on nd filters

ruffdog64

ruffdog64

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Harvey
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Can anyone point me in the direction of a link on how to work out exposure times when using nd filters please
 
What do you want to know? It depends on you ND number. Like with ND10 you can get really slow shutter speeds even on bright sunny days ;)
 
I've Yet to decide what to get I thought looking different filters and thier uses before deciding
 
Theres a chart here

First meter without the filter then work out, or use the chart, to slow shutter by the required number of stops
 
You need to get your head around the concept of "stops". It's really fundemental, and once you understand that a lot of other things become a lot easier to follow.

Shutter speed is easy, 1 stop difference is a doubling/halving of the shutter speed. This usually throws people with long exposures. Accepting that the difference between 1/2secons and 1 second is exactly the same photographically as the difference between 30 seconds and a minute can take a bit of getting used to. Normally it will be shutter speed that changes with ND filters. Aperture is a less automatically intuitive, I'll let you look that one up..

Then there's how you're going to use the filters. If you're just putting them on the front of the lens and metering through the filter there's nothing to change. The camera meter will be taking the ND filter(s) fitted into account. If you're going to meter without the filter and then add the filter afterwards (only really becessary with high ND filters or slow lenses), then you need to adjust with some mental arithmatic or refer to a table).
 
If you have an android phone there's a good app that you can use called Exposure Calculator that allows you to enter your metered reading then add or subtract up to 16 stops.
 
Or if you have an iPhone, there's an app called NDCalc...I use it and its very good and makes calculating exposures very easy indeed :)
 
The way I do it is just to count the number of clicks on the shutter speed dial.

For example, if you have a ten stops filter, and your camera is set to 1/3rd stop increments, then ten stops is 30 clicks.

All these extreme NDs vary a bit, from the marked exposure factor and even between batches. Like the Lee Big Stopper is about 10.5 stops, B+W ten stopper about the same. The one I use is the LightCraftWorkshop ND500, which is allegedly nine stops (as in x500 exposure factor) but mine checks out at 8.3 - so that's 25 clicks.
 
wow ,not just a piece of dark glass put on a lens and exposed for several minutes then!!:bonk: seriously thanks for all the help it will be put to good use,Harvey
 
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