JGo9: Take A Look Through My Viewfinder: Using A 10 Stop ND Filter

If you follow me on Flickr you know that recently I've purchased a 10 stop ND filter and I've bee using it frequently. I've recently been getting a few questions on how to use it, after all the filter is extremely dark and can be a bit tricky.

The particular ND filter that I got is a B+W slim 3.0 filter. The slim part of the filter cuts down and helps to prevent vignetting. It personally took me a while to figure out how the number of stops are indicated in the names of the various ND filters that are available. The higher the number the darker the filter. For a 10 stop you need to look for 3.0.

900 second exposure @ f11 and ISO 100

So what's all the fuss about 10 stop ND filters? Well just take a look above! ND filters allow you to take some really long exposures, even during the day. So what does that allow you to do? Well it is great for getting smooth silky water, streaking clouds, make water look glassy, get some great reflections, capture intense colors, need I go on?

Taking shots with a 10 stop ND filter can be a bit tricky. Remember the filter will often times make what you see through your eye piece pitch black. So lets cover the steps I take when shooting with the filter:

Shooting on a tripod is a must, I don't care who steady of a hand you have.
Frame your shot, set your focus, and meter your shot in AV mode with your f value set at the desired value.
Turn off Auto Focus and make sure you have IS of VR turned off.
Be sure you have your camera set to work with your remote.
Switch your camera mode to Manual where you'll set the f value to the same value that you used to meter your shot in AV (or aperture mode) and most of the time you'll be setting your exposure to bulb.
Be sure to set your exposure 10 stops longer than the exposure your camera metered at in AV mode. I'll explain later how to calculate the 10 stops.
Now carefully put your filter on and be sure to not move the focus ring or change your framing. This can be easier said than done.
Then I typically switch to LiveView to minimize vibration.
Last but not least I cover the eye piece on the back of the camera to not allow light in that may destroy your shot, especially when doing a long exposure shot. I usually use a microfiber cloth to do so.
Then take your picture, and sit back and enjoy the beauty in front of you. I find myself typically looking for my ext shot.

120 second exposure, f 11, ISO 100

My camera (Canon T1i) keeps track of the length of the exposure for me on the LCD display, which is a nice feature. If your camera doesn't, try your watch or phone to keep track of the exposure length, as it is very important to getting a properly exposed shot.

OK now to tackle the tricky thing of determining what exposure to use when taking shots with a 10 stop ND filter on. This was something I was very concerned about before I bought my filter, so I did some searching online to see what I could find. Well I ran across an article on a Manfrotto website. It has a chart that shows the metered exposure (remember this is the exposure the camera gave us in AV mode) and then you find the column that applies to the number of stops of the ND filter you are using and it will tell you what your exposure needs to be. Some times you'll find that your exposure is not listed but typically it's in the middle of what is listed so just split the difference between the slower and longer times on the chart. I've really relied on this chart and have found it very useful! Here is the link to it: http://manfrottoschoolofxcellence.com/2011/03/24/timo-frey-long-exposures-and-nd-filters/

I hope this helps and trust me I don't think you'll regret the purchase of a 10 stop ND filter. It can really open up a whole new world of possibilities!