Megapixels are a measure of how *LARGE* an image you can create. A 4MP camera displays all the resolution an ios device can display. Meaning if you take a photo and view it full size on your iphone or ipad without zooming, anything larger than 4MP will look no better than the 4MP image will (often it can look worse, as discussed below). An ipad retina screen is 2048 x 1536. A 4MP camera can capture 2,289x1712.
Now, if you have a larger than 4MP sensor, it can do things like have clearer zoomed images. So if you have an 8MP sensor, you can zoom in 200% and the image looks as clear as if you shot it that way at 4MP (this is called digital zoom-basically you are capturing extra data that is only visible when you zoom in). Therefore an argument can be made that slightly more than 4MP has a use, but it always comes with tradeoffs. Remember the awful, grainly, terrible photos your old ipod touch or iphone 3 would give you? That's because of poor light sensitivity. The higher the MP, the poorer the light sensitivity (sensors have improved over the years, so you have to compare sensors of the same time period). And of course one of the drawbacks is storage space. Pictures take up more space than anything else on my ios devices, and doubling sensor size quadruples storage space requirements.
In fact, super pro cameras often have low megapixels, because the picture *quality* is higher, you just can't have as large an image (ie it won't look as good zoomed in or printed on a huge poster).
Case in point:
Nikon D3300 is $499 for 24 MP
Nikon D4s is $6,000 for 16MP (their top of the line camera, even though it has "less megapixels! OMG!"
http://www.kenrockwell.com/tech/mpmyth.htm
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^^ Gets it.
The biggest drawback to using my phone as a camera vs my DSLR is its low light performance, which will only be worse with 12MP.
Now, if you have a larger than 4MP sensor, it can do things like have clearer zoomed images. So if you have an 8MP sensor, you can zoom in 200% and the image looks as clear as if you shot it that way at 4MP (this is called digital zoom-basically you are capturing extra data that is only visible when you zoom in). Therefore an argument can be made that slightly more than 4MP has a use, but it always comes with tradeoffs. Remember the awful, grainly, terrible photos your old ipod touch or iphone 3 would give you? That's because of poor light sensitivity. The higher the MP, the poorer the light sensitivity (sensors have improved over the years, so you have to compare sensors of the same time period). And of course one of the drawbacks is storage space. Pictures take up more space than anything else on my ios devices, and doubling sensor size quadruples storage space requirements.
In fact, super pro cameras often have low megapixels, because the picture *quality* is higher, you just can't have as large an image (ie it won't look as good zoomed in or printed on a huge poster).
Case in point:
Nikon D3300 is $499 for 24 MP
Nikon D4s is $6,000 for 16MP (their top of the line camera, even though it has "less megapixels! OMG!"
http://www.kenrockwell.com/tech/mpmyth.htm
----------
^^ Gets it.
The biggest drawback to using my phone as a camera vs my DSLR is its low light performance, which will only be worse with 12MP.
