Why Megapixels don't matter and other consumer myths debunked

I got some great feedback on my post last week about the shady business model of inkjet printers (they give-away the printer then markup the ink), so I thought I could post this week about some other consumer "myths".    

As consumers, we're always looking for "figures of merit" to make it easy to tell if one product is better than the other product.  Sometimes these figures of merit are easy to understand and thus make clear sense like the size of a TV (wow you got a 72" plasma, mine is only 52").

Many times with technology products the figures of merit are harder to understand and thus can be misleading about what is really better.  Here are three areas where people commonly get duped by the figure of merit.

1. Computers.  It used to be that you could pretty much judge how fast a computer was by it's processor speed.  A 750 MHz processor was better than a 500 MHz processor.  This is simply not true anymore.  The true "speed" of a computer is determined by complicated things like the "processor architecture, size and speed of RAM, and graphics hardware.   Manufacturers are mostly to blame - instead of labeling processors according to their true power, they complex pseudo names like "core 2 duo" or "core i5".    

Bottom line: When buying a computer "Gigahertz" doesn't matter, look at other things like processor type, RAM, and graphics support (dedicated is better than integrated).

2.  Internet Speed.  A 20 Mbps DSL line is going to be "faster" than 7 Mbps Cable, right?  Mbps stands for "Mega-bits-per second" and is a measure of how fast information flows, but it is not the dominant factor in determining how fast an internet experience you are going to have.  When you are surfing the internet, the web sites you visit usually can't send information faster than 3 Mbps.  So even if you could theoretically download at 20 Mbps, websites are never going to send information faster than 3 Mbps.  The last thing to consider is "latency".  This is how fast the internet responds before it starts sending information.  Many times this latency can have a much bigger impact on internet speed than the download speed.  In other words, a 100 Mbps connection with a high latency could be slower than a 5 Mbps connection.

Bottom line: Anything faster than 5 Mbps is probably overkill - ask your provider about latency.

3.  Compact Digital Cameras  
This one is my favorite because I used to design imaging systems for satellites.  Cameras are complicated, so the figure pushed by manufacturers is the "Megapixels".  A 10 Megapixel camera takes better pictures than a 3 Megapixel camera.  Not true.

A pixel is a tiny dot that can represent a color.  Your computer monitor is made up of pixels.  My laptop has a resolution of 1280 X 800 which means it has 1280 pixels in each row and 800 rows for a total of about 1 Million pixels or 1 Megapixel.  It works the same way with cameras and you can start to see the problem.  If I take a 10 Megapixel picture, how do I even look at it on a 1 Megapixel screen?

Furthermore, point-and-shoot digital cameras are limited by something called Modulation Transfer Function or MTF.  This means that the lenses in point-and-shoots are so small and cheap, that they blur the scene across multiple pixels anyway.  So a 10 Megapixel point and shoot camera takes just as good of pictures as a 3 Megapixel.  So why do they make 10 Megapixel point-and-shoots?  Because you will buy them over the 3 Megapixel camera.  If fact, you can't even buy a 3 Megapixel camera anymore.  Notice that this is untrue for SLR's (the big cameras) because they have big lenses with a much better MTF, so they can actually use all the pixels.

Bottom line: Anything over 3 Megapixels in a compact camera is a waste

That's it!  I hope you enjoyed this weeks consumer myths debunked!