Here's a statement so obvious that it almost isn't worth the breath it takes to say it; photography depends on light.
Well, duh!! Of course that's true. And to create a technically good picture all you need to do is stay within a set of prescribed boundaries (sensor or film sensitivity, aperture, shutter speed, so on). Any modern camera is designed to do just that, automagically adjust itself to stay rigidly within those boundaries and produce a great photo of your morning latte, smiling dog, or breath taking sunset. But what happens when you step outside those boundaries?
Well, true be told, it ain't all bad. For instance, many high-end cams can take amazing infrared photos where the only light reaching the sensor is in the infrared spectrum. (You use an IR filter to do this.) Plants glow, metal turns black regardless of the painted color, and the resulting photo has an otherworldly look that is at the same time eerily familiar.
Another boundary that when crossed can produce some fantastic effects is long exposures ( keeping the shutter open longer than what's needed given the available light). When you do this any movement leaves a trail, the brighter the object that's moving is, the brighter the trail it produces. This technique is typically called creating light trails, and it is the topic of this installment of iPhoneography 101.
When most people think of creating light trails they think it has to be done in the dark, and it's true that you can get some pretty amazing shots when the lights are low. Take a look at the photo of the train station in Winter Park, Florida below. It was taken around 9PM and I don't think it would look nearly as good if it were taken any other time of day.
Train station in Winter Park, FL (iPhone 5, App: Slow Shutter Cam: Light Trail mode, 4 sec, 3 sec timer) Photo by Vern Seward)
But why limit yourself to the night? Light trails can be created on bright sunny days as well, and that opens up a world of possibilities.
Here's a shot of Lake Eola in downtown Orlando. Note the swan boat in the foreground. Light trails! But how did I get them?
Swan boat on Lake Eola (iPhone 5, App: Slow Shutter Cam: Light Trail mode, 4 sec Photo by Vern Seward)
You'd have a tough time trying to get that shot with a traditional camera. You'd have to find a way to expose the rest of the shot properly while leaving the shutter open long enough to get a trail. That not impossible, a neutral density filter would likely help, then some judicious dodging and burning in post processing.
It's even tougher on your iPhone because the slowest shutter time is a second and you'd need at least 2 seconds to produce something similar to the Lake Eola shot. But you iPhone has a distinct advantage over dedicated cams, it can run a variety of camera apps. The one that produced the Lake Eola shot is called Slow Shutter Cam from Cogitap[ US$0.99, 6.2 MB, all devices capable of running iOS 7.0 or higher] and it is one of, if not the best specialty camera apps around.
I've had Slow Shutter Cam on my iPhones for a long time. A few versions back the app was merely interesting. I used it to get this shot of downtown Orlando on my iPhone 3.
Downtown Orlando (iPhone 3, App: Slow Shutter Cam: Light Trail mode, 6 sec Photo by Vern Seward)
The stream of light in the mid-ground is I-4, the foreground trails are from local traffic under the I-4 overpass. The shot is cool, but hardly worth the bother of posting on Instagram. Back then the best the app could do was to produce a relatively low resolution JPEG.
Today's Slow Shutter Cam spits out TIFFs in a variety of resolutions and aspect ratios. All the more interesting when you think about how Slow Shutter Cam does its magic.
The app takes a series of photos in quick succession then combines them to produce the final photo. This is a technique astrophotographer have long used to get amazing details of celestial objects too faint for the naked eye to see. And because you have a series of photos the app lets you pan through them to find the exact effect you want to achieve.
Slow Shutter Cam also offers three modes of shooting: Motion Blur that can be used anytime to get a blur effect while still getting proper background exposure, Light Trail which emphasizes moving lights like car lights while the rest of the photo is exposed right, and Low Light which takes in all light regardless of exposure, and lets you adjust after the shot is taken.
There's a bunch of other nice features in Slow Shutter Cam, but what I'm most interested in is what it can produce. This photo of a neon gelato sign was done by setting the app to Light Trail mode, the shutter speed to 4 seconds then moving the camera while the shutter was open.
Gelato sign (iPhone 5, App: Slow Shutter Cam: Light Trail mode, 4 sec Photo by Vern Seward)
That's the thing about this app, it lets you adjust to your heart's content before and after you've taken a shot. To really get the most out of Slow Shutter Cam, as with any serious app or device, you should play with it. Get to know the features and what the limitations are before you go out to capture that 'Money Shot'.
You should also know that every shot I've taken with Slow Shutter Cam was done on a tripod. The train station shot was done with a remote shutter release as well. (Moral: get and use a tripod)
There are other shutter focused apps worth mentioning. Slow Shutter! [US$1.99, 1.5 MB, iOS 7.0 or higher), for instance, works similar to Slow Shutter Cam and has similar features. The interface is different enough to set the two apps apart. Another app, Top Camera [US$2.99, 14MB, devices capable of running iOS 6.0 or higher], offers a slow shutter mode along with an HDR, traditional camera and video mode. All worth trying out.
So, light trails, fun and easy to create with the right app. Grab your iPhone, tripod, and download an app and see what you can come up with.
That's a wrap. In the next iPhoneography 101 session I'll discuss black and white photography.m Stay tuned.