Cell Phone Cameras / by Mark Van Noy

I am going to give the classic I.T. answer to the question of whether a cell phone camera or a DSLR is better: it depends.  What cameras can do is controlled by physics; though software can fake some effects and is getting better all the time.  The catch to software solutions is that the laws of physics refuse to be broken.  What that means is that the size of things will always matter.

Since the cameras in phones and tablets are inherently as small as possible, their sensors and lenses must also be as small as possible.  So if we had two equal quality sensors with the exact same number of megapixels with one sized for a phone and the other sized for the DSLR the DSLR image quality will always be higher quality with less noise because noise increases with pixel density.  Essentially, the smaller lens and the smaller sensor will gather fewer photons and the ones they do receive will strike a smaller surface area so each pixel is going to have less information about what is being photographed than a larger pixel receiving more photons.  There is also the problem of electrical noise in sensors which looks to be less impactful with each new generation as engineers find amazing new ways of dealing with the physics of electricity.  I am also intentionally skipping past how sensors work in order to keep this simple.  There is otherwise a lot of math and surprisingly complex physics involved.

Because everything is so compact in a phone that also means that more of an image will be in focus than a DSLR at the same equivalent field of view.  It is fairly rare to see a cell phone camera take an out of focus picture in good lighting.  This is a fantastic feature in many cases such as group photos of people, landscapes, and close-up photos.  It generally guarantees that whatever the subject of the photo it will be completely in focus.  However, the converse is also true: parts of a photo that are not important will also be in focus.  A DSLR has a more limited range of what is in focus which can be helpful for doing things like blurring out distracting backgrounds.  The latest iPhones can simulate the effect of blurring the background using software and the effect is awfully convincing.  To get more of an image in focus with a DSLR you have to take multiple pictures then use software to combine the pictures keeping only the parts of each picture that are in focus.

The last technical detail I want to talk about is the ability to zoom.  No current camera phone can zoom.  The closest to an actual zoom would be the phone designs that include two cameras with different focal lengths. Two be fair, two cameras effectively give zoom functionality comparable to owning two prime lenses on a DSLR.  What I really mean is that camera phones do not zoom; they crop.  They throw away all of the pixel data outside the area that would be zoomed which trades resolution for field of view.  A zoom lens or changing to a different length prime lens is also essentially a physical crop of the picture.  The difference is that changing the lens focal length maintains all of the resolution of the image sensor while the camera phone crop drops the resolution.  As long as the resolution stays at or above the intended presentation medium, like posting to Facebook or printing a photo, then the distinction of zooming vs. a digital crop is purely academic with no practical impact.

Which brings me back to the question of which is better.  In specific situations either type of camera can be better than the other because, physics.  If the goal is to take pictures in good light that will be used on Instagram, Facebook, or similar services then a cell phone camera is probably the best camera out there because it will be easy to use, give high quality repeatable results, and is virtually guaranteed to be carried with you.  For pictures that may one day be printed or for which more control over the aspects of capture of the image are desired, then the DSLR is going to be a better fit.


Note:  This got more complex than I had intended very fast.  I have intentionally left out any mention of mirrorless cameras, medium format cameras, range finders, sports/action photography, and low light photography among the many details I likely forgot to mention that I otherwise would have liked to talk about.  Different types of cameras have different physical properties that will always make them behave differently which makes the whole attempt at comparing the systems in terms of better or worse, with the idea that there is a single superior technology, rather futile.