Recently I opted to buy a camera. I asked my brother a suggestion regarding my purchase, and suddenly he started to ask me number of questions. I was able to answer all the questions, except this one: "What is Nineteen Megapixels minus Sixteen Megapixels?. Does anyone know what this means? I checked most of the camera forums and review sites, but I was not able to find the answer. Actually I may know the answer, but I was not able to understand my brother's question when I asked him to clarify, he said the answer is in the question itself. What could he possibly mean?
The answer is simple: "Not a big deal".
It's obviously technically right to say "three megapixels, give or take", but by itself that overstates the importance. 19 megapixels isn't automatically 18.7% better — in fact, the real resolution may actually be worse in the real world, as there are so many other factors.
It's hard to read minds, but I suspect this is what your "bro" was getting at.
I thought one of two things:
A. The camera has two aspect ratios and has a different pixel count for each' one of the two not using the entire sensor.
B. the sensor size is 19mp but the images made are 16mp due to internal cropping. I had an old Sony mini DV that did this to handle motion, vs. a lens based image stabilization.