Long exposures on cell phones

Man-made waterfalls photographed on Kona in Hawaii

The way the world takes photos has evolved over the last two centuries, but it has never been so easy for someone to take a picture as it is today.  Cell phones, with their convenient size and respectable shooting abilities, have changed the way the average person snaps an image.  The statistics don't lie.  

World-wide, there are some five billion images taken each day, 94% of them are taken with smart phones.  It is estimated that we will be capturing two trillion photos annually in the next coming years.  Yet, for all the advantages, there are certain significant limitations.  One of them has to do with a fixed aperture set at a very low value.

Apertures control the amount of light coming into the camera and depth of field as well.  Traditional cameras have a variable aperture in the lens that allow you to control both these attributes. Most cell phones have apertures that cannot be changed, and they typically are set to an f/value of around 2.0.  Depth of field is not usually an issue because of the low focal lengths involved (~5 mm), but the low aperture values mean that shutter speeds are often high.

This is not an issue in most circumstances as we like to freeze action and prevent blur.  But when a low-shutter speed is desired, it can be difficult to achieve.  Fortunately, there are a few options.

Android:  Android users can go to the PRO mode in their cameras and select the lowest possible ISO.  This typically means that the shutter speed will become less, but I find that it usually isn't low enough.  You can choose to shoot when near dawn or dusk to facilitate even lower speeds, but this is often not convenient.  One of the best things you can do is to buy a Variable Neutral Density (VND) filter as a cellphone accessory.  These are relatively inexpensive and will give you all the light control you need.

iPhone:  Turn on the live-view feature and take a photo.  Then go to the editor and tap the Live Photo button.  A drop-down menu will appear and one of the choices will be Long Exposure.  Select that and your short video-like image will now look like it was taken with a low shutter speed.  The effect is simulated, but it tends to be somewhat convincing.  VND filters won't be much help as the camera will automatically increase the ISO to keep the shutter speed high.  Your only choice here is to buy a third-party camera app that gives you Android-like control.

Thanks for reading.

Eric Svendsen     www.ericspix.com