Buying a new camera & The Megapixel Myth
In this entry I will explain why you shouldn't listen to manufacturers & over-eager reps when they try to use megapixels as a major selling point.
So, your camera just broke - you dropped it in a nightclub & now the lens is warped, or you dropped it on the beach & the lens motor is grinding from the sand invasion.. You are not alone. These were common situations I came across when I was working at Jessops (photography store). The good news is you get to buy a new camera. The bad news is the market is diluted with too much to choose from. I shall help.
The Megapixel Myth..So, perhaps the first thing that comes to mind is megapixel count. But I want you to forget about megapixels. Unfortunately, vendors use megapixels as a shiny selling point for consumers because they know it's something people already associate with 'better photos' & a quality product. They oversell & misguide people by doing this - & now camera phones are commonplace it's not just cameras. Anyone seen the 41 megapixel Nokia advert? Classic megapixel misdirection.
Today it is easy for manufacturers to stick a sensor with a decent megapixel count in their cameras and use it as a selling point. So, megapixel count is often mistaken as the single most important factor affecting the quality of the final image.
Historically (8-10 years ago) megapixels would have been a valid or even an important consideration in choosing a camera, as the technology was new & the megapixel count was small enough to consider upgrading (it was around 2-4 megapixels, 4 on high-end compacts. Now, every camera has more than enough resolution for your needs. Even the cheap compacts.. So, it's not even an aspect you should be considering any more. I will explain why below.
The truth is that megapixels are not important. Don't get me wrong, it's true that megapixels play a part in image quality, but other factors such as lens quality, the image sensor (the component that captures & records the image data) - particularly the sensor size & post-processing (built into the camera) are FAR more important.
Some Points to Consider..
1. Take HD. Society today states that HD is effectively just a name for certain resolutions - 1280x720 (or 720p ('p' meaning progressive scan, which is the same way images are drawn on computers - top left to right then a zig-zag down the screen) which is also known as 'HD Ready'. Then there is full HD, 1920x1080. Now, HD looks great, right? Lovely & crisp compared to DVDs (720x576) & especially VHS (~352x240 lines of resolution)!
Now, full HD equates to about 2 megapixels.
Let that sink in. Those Hollywood movies that look so good on your TV are 2 megapixels. I know that the images used for Hollywood movies are produced by amazing pieces of kit - which are uncomparable to consumer goods - but the point is that's a far as megapixels go towards 'importance'. I know some of you may be saying "well why do my images look much lower quality than HD movies & I have a larger megapixel count?!" Well that's to do with the ability of your camera & how you use it - including the factors I mentioned above.
2. Another point to consider is the fact that we don't get to see our photos in the native, full resolution anyway! Even top spec displays for computers nowadays - 2880x1800 on the Macbook Pro Retina - don't match up to my Nikon D300s at the full, true resolution of 4288x2848.
3. Without going into too much detail here, another consideration is sensor size & crop. Full frame digital cameras - almost exclusively expensive professional DSLRs - are referred to as this due to their sensor relecting the size of 35mm film frames. Now, many DSLRs have a crop factors, most commonly ~1.5, meaning that 18mm in focal length is 18mm on a full frame camera, whereas on a 1.5 crop sensor camera it is in fact 27mm. The larger the sensor, the better performance due to the capacity the sensor has for capturing light. Bear with me here. Now, a tiny consumer compact will have a MUCH smaller sensor than this. The manufacturers boast 8mm or whatever focal lengths on these type of cameras - but think about it - they need it! Whatever the crop factor is, this will be times by the focal length, so say if it was 2.7 (crop factor of the Nikon J1s), then the true focal length is in fact 21.6mm.
It's worthy of noting that with some cameras the higher the megapixel count, the higher the intensity on the camera's processor because it has to process higher quantities of information - from capturing the raw data to higher bandwidths to cope with interpolating it, then compression. So, high megapixel counts can actually decrease performance. This is partly why DSLRs generally have a low count, especially models that boast high frame rates for applications such as sport, alongside the fact that we just don't need the resolution. And pros know this.
Ok, there is one solution I would recommend high megapixel cameras for - studio work, or work which constitutes heavy cropping in on an image for which a high megapixel count is a big benefit. One digital SLR which fits this category exactly is the D3200, which is exactly the same camera as the D3100 except that is has a 24mp sensor not a 12.