(photo by Anne Archambault)
Anne and I recently had a chance to take a fine art long exposure photography workshop with Vancouver Photo Workshops. We’ve both been interested in long exposure photography for a while, and we’d already gotten some of the equipment (like 10-stop ND filters) to help us slow down the real world and blur our things like wave and waterfalls in broad daylight. As hoped, this workshop added to our bag of tricks.
The instructor was Marc Koegel. He has a great blog and since he’s been shooting long exposure photography for a while, he’s also full of great advice. He’s also been generous in sharing resources for the aspiring long exposure photographer.
Shooting Long Exposure
Marc had a lot of great guidance for us and took a ton of time to answer all sorts of questions. We spend half of both Saturday and Sunday talking about various aspects of long exposure photography. For me, the biggest take away was that long exposure photography is a means to the end of creating artistic images that inspire. Several people in the class mentioned that taking the workshop (including myself) was a way to help them produce more artistic photographs. Indeed, long exposure is a way of capturing a mood in movement that is imperceptible in our visual reality but that reaches us at a deep level. In this sense, it’s quite different than standard photography which aims to realistically and accurately the scene in front of us.
One of the really cool things about long exposure is the serendipity of it. Things happen when you’ve got the shutter open from thirty seconds to 30 minutes that you simply can’t account for. Marc showed us his image of the Brandenburg Gate where a limo pulled up while the shutter was open. The car helps make the image but could have never been staged. Clouds or water may not turn out how you think they will and that’s part of the magic.
Of course there were lots of interesting tips that we took away. Marc has an excellent blog at http://bulbexposures.com that provides detailed tutorials. We referred several times to the Long Exposure Tutorial which provided some excellent advice on gear, selecting the proper amount of ND stopping power, and some guidelines for shooting.
In terms of shooting, perhaps the best tip was to really bracket the shot. Marc suggested not only doing a plus/minus HDR style bracket, but also a time based bracket of 1,2,4, and 8 minute exposures to ensure you’ve captured what you need. The HDR style bracket will allow you to fill in detail if you need it in post.
2. Clouds and cloud Coverage
Generally, you’re looking for days where the sky is between 60-80% cloudy. These days will provide you with a good amount of cloud variation to allow for a sense of motion. Too much cloud cover and everything is just bland. Too little and you can’t make an interesting sky.
3. F-Stops and Diffraction
Another good reminder was about using your aperture wisely. Too many times you’ll be tempted to use a high f-stop to further slow down the shutter speed. I’ve done this countless times to slow my exposure time. However, it’s important to remember that high f-stops (higher than about f/14 really) will cause diffraction in the lens and will cause image quality and sharpness to suffer. If you can, shoot at between f/7.1 and f/11 to ensure appropriate sharpness.
4. Long Exposure Noise
When shooting long exposure, especially when doing it back to back, remember that heat can build up on your sensor and lead to sensor noise. For example, if you’ve taken six 5-minute shots back to back then you’ve had the shutter open for about 30 minutes non-stop. That’s going to build up heat on the sensor and cause an increase in noise, especially on hot days. So take that into account and try and give your sensor a chance to cool off and reduce noise.
I’ve read a bunch of articles on long exposure noise reduction. Marc recommends touse long exposure noise reduction for any shot longer than 8 minutes that on a crop sensor camera. He also recommends to avoid it all together on full frame cameras to avoid the associated lengthy delays. I’ve read articles pontificating both approaches. At this point, I think I’m in the camp that says most cameras that are under a year old probably have noise levels that make noise reduction more of a hassle than a benefit. You mileage may vary.
5. Test Shots and Exposure Time
When shooting long exposure images, use a test shot to help you determine your exposure time. From the test shot, you can compute the long exposure time for your ND filter with a simple table (see Marc’s bulbexposure.com tutorial) or smartphone application (available for all smartphone platforms). For example, if a “normal” exposure at f/11 is 1/60th of a second, the equivalent exposure with a 16 stop ND filter would be 18 minutes and 12 seconds.
6. Light Leaks
It turns out that as good as cameras are today, most still have small areas where light can leak in and ruin your long exposure images. Marc uses black tape to tape over his viewfinder and other strategic areas of his camera. This is also problematic for users of “plate” style 100mm x 100mm filters like Lee, Cokin, or Hitech since light can bounce between the filters and lens. In general, I think screw on filters probably do a better job of controlling potential light leaks, but are harder to take on and off for focusing and metering.
I’ve taken to simply covering my camera with my hat, both to prevent sun from entering my Cokin filter holder system as well as to cover the entire camera/lens system. This prevents heat buildup and helps prevent any additional light from ruining my shots.
I had a blast on this workshop. We visited some cool places and learned some great new techniques to really help our photography. While the tips were specific to long exposure photography, I think some are also applicable to everyday shooting. If you have the chance, I’d certainly recommend taking a look at what Marc is doing and his workshops at Vancouver Photo Workshops.