Getting slow shutter speeds with cell phone cameras

Android (top), DSLR (middle), and iPhone (bottom) cameras varying shutter speeds.

Shutter speed, aperture, and ISO are the three core parameters controlling light.  Traditional cameras have a means to vary all three of those parameters while cell phones can only alter two.  Apertures are fixed in most cell phone cameras, usually around f/2 give or take a bit.  This poses a rather large problem when it comes to controlling shutter speed.

Since traditional cameras have the ability to control aperture, they can vary shutter speeds by a wide margin.  In the center images above, I photographed a scene using a DSLR camera with a wide open aperture (left) and a small aperture (right).  This resulted in shutter speeds of 1/80th and o.4 seconds respectively.  The blurring effect that a slow shutter speed has on moving water is often striking, no less so in this case.  It is a technique I often use when photographing fast-moving water.

Reproducing this effect is more complicated in cell phone cameras.  Since apertures cannot be altered, one is left with altering ISO as the only viable means of controlling shutter speed.  Even when ISO values are set to minimum values, shutter speeds remain unreasonably high in normal conditions.  In order to get a slower shutter speed for my Android phone, I had to photograph the scene at dusk when the low light allowed the values I was looking for.  It just wasn't going to happen during normal daylight hours.

The iPhone has an interesting solution.  You can set the camera to record a short video using the live-action mode.  Then, in playback, you can alter the photo by converting it to a time-lapse image.  This takes the individual video frames and stacks them together to form a single image.  The problem I had was in trying to save the emulated slow shutter speed image and export it to my computer.  That took a fair amount of effort to achieve, but it was eventually done.  Not a convenient process at all.

It turns out that there is another solution to the problem.  You can buy cell phone clip-on filters for your device.  Called neutral density filters, they restrict the amount of light entering through your camera's lens and makes lower shutter speeds possible.  They are not very expensive, less than $20 on Amazon in general, and provide a new means of controlling light for your device.  Variable neutral density filters allows you to alter the degree of shading and thus giving you more control over shutter speed than single-density filters.

Keep in mind that slow shutter speeds benefit from the use of a tripod.  In-camera stabilization does help with the process, but the technology is not foolproof, especially at shutter speeds approaching or surpassing one second.  However, as with all photography, it is better to try and not succeed rather than not try at all.  You may be quite pleased with the results.

Thanks for reading.

Eric Svendsen     www.ericspix.com