RootsTech 2014

Some people eat, sleep and chew gum, I do genealogy and write...

Monday, August 12, 2013

How good are the photos from your smartphone?

Extravagant claims of huge numbers of megapixels are starting to emerge for smartphone cameras. For example, the new Nokia Lumia 1020 claims to have a 41 Megapixel camera. The promotion for the new phone claims the following:
Take photos like a pro. 
Capturing stunning images is easier than ever with Nokia Pro Camera. Take your photos to a new level by adjusting focus, shutter speed, white balance and more with easy and intuitive controls.
Does increasing the number of pixels in the camera's sensor automatically infer that the quality of the images increases? Does increasing the pixel count and adding some controls enable you to take photos like a pro? The answers to these questions are not simple.

These advertising claims prey upon the ignorance of the public concerning the relationship between pixel count and quality. There is definitely an advantage to increasing the number of pixels on a sensor, but to infer that you automatically get a higher quality image from an increased pixel count begs reality. Additionally, to claim that increasing the resolution of the camera sensor will improve your photographic ability is ludicrous. I am of course talking about the ability to shoot professional level photos. A skilled photographer can take great pictures with a mediocre camera. But someone who has no feel for photography cannot improve the photos by purchasing professional level equipment. The camera does not take the picture, it merely records what the photographer has selected.

It is probably important to start with some basics. A camera is nothing more than a light-tight box with a hole in one side. In fact, you can take recognizable photos with a pin-hole camera. Other than the requirements of the box itself, the next most important element in a camera is the lens. The purpose of the lens is to gather and focus the light from the subject on the image producing part of the camera. Historically, this was some type of light sensitive film, but most recently, the task of recording the image focused by the lens has transitioned to an electronic sensor. The camera also has a way to open and shut the shutter of the cameral and control the amount of light that makes it to the sensor either by an adjustable diaphragm or by adjusting the length of time the shutter is open.

Smartphone camera manufacturers have focused on only one aspect of this system; the number of discrete imaging elements on the sensor. As explained on the HTC Blog by Symon Whitehorn entitled "Breaking the Megapixel Myth:"
The megapixel speaks to the number of pixels a camera’s sensor can capture when it’s exposed to light, so in theory the more megapixels the better. However that’s really only half the equation. The other half is the size of the sensor, which determines how much light the camera can bring in. The dimensions of the smartphone dictate a finite size for the camera lens, the only way to increase the number of megapixels on this sensor is to decrease the size of the pixels, which can be extremely detrimental to image quality.
So no matter how hard you try to explain away this physical limitation, a smartphone with an extremely small sensor will never have the quality of a full-size DSLR camera with full-sized 35mm equivalent sensor. This is even assuming that the lens and shutter system of the smartphone were even vaguely comparable to the more expensive professional level camera. For a complete explanation of this issue see "The Megapixel Myth" by Ken Rockwell. Even though this article is now dated, it accurately explains why increasing the number of pixels does not necessarily increase image quality.

But the real question for a genealogist is not whether the smartphone camera is professional level (whatever that means) but whether or not the images produced are good enough for the purpose of recording documents and copies of other photographs? In most cases, the images will be good enough. But likely, if you have a smartphone with a camera, you likely already have the necessary tools to do an adequate job of taking digital notes in a library or other repository (assuming the repository allows photographs).

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