High megapixel cameras preferred by lousy photographers

Photography equipments are full of trade-offs, and amongst them, cost, optical quality, speed (aperture). When camera companies pack many megapixel in a little sensor, the sensor will gain an undesirable trait: noise.


Megapixel race:

A lot of beginners think megapixel is a desirable attribute. There's a brand that starts with "C" that is very good at marketing to consumers; they tend to produce plastic cameras with high megapixels bundled with cheap plastic zooms (e.g. 55-250mm IS). Don't get me wrong, I use this brand, and I love the 55-250mm IS as a lightweight substitute for the 70-200mm f/2.8 monster. But I digress...

High megapixels are great if you need to print big sized pictures (16x20"), or if you tend to crop frequently. For most people, this is irrelevant because they only print up to 4x6, or upload to the internet at 1600x1200 (only 2 megapixel). A 12 megapixel APS-C (cropped sensor DSLR) is way more than enough to print a nice 12x16 wedding album. Heck even a 8 megapixel APS-C is more than adequate.

Thanks to marketing, common people now want lots and lots of megapixels (kind of how the layman cares about a CPU megahertz but doesn't care about cache+RAM). Company "C" loves to pack lots and lots of megapixels to consumers. But here's a catch. Noise. The moment you pack a lot of megapixels (and given the same sensor and processing technology), more noise occurs. The noise becomes much more apparent at high ISO, which makes it difficult to use at night. Technology is about trade-offs; nothing is free.

Let me ask you this. Given the following two choices (without using flash), what would you buy?

1. 15 megapixel that looks great when shot during the day and you can print up to 16x20. Good grains up to ISO 800.
   
2. 8 megapixel that looks great when shot during the day but you can only print up to 8x10. Good grains up to ISO 3200.
   

It really depends on your style. For me personally I shoot at night-time frequently. I love shooting at night not because it's easy, but because it's extremely difficult as it is very demanding on the capabilities of the camera sensors and the lens, and the skill of the person behind. Despite years of experience I still make crappy pictures at night, and occasionally good ones; I do it because it's tough, and because it's always an educational and fun learning process. Most people can take technically good pictures (proper exposure) during bright day time using full auto-mode, but very few can shoot well at night. Personally I go for the second option. In fact, since I never print 16x20 and almost all of my pictures are internet sized (1600x1200 or less, or 2 megapixels), choice 2 is more than enough for me. In fact, if I can pick 5 megapixel with super high ISO (3200-256000 ISO) for night time, I'll take it over a 15 megapixel sensor with only 800 usable ISO.



Newest low-end Brand A vs. Brand B at 100 ISO. The two classes are quite equivalent, and look great at ISO 100.



Top Brand X 15MP vs. Bottom Brand Y 12MP, ISO 3200. Pictures saved as GIF instead of JPG since JPG has a way of "smudging" over noise. Note the blue "chroma" noise for Brand X, despite having more megapixel.

Wasted megapixels:

The other interesting thing about camera companies these days is they pair up a high megapixel camera with a cheap kit lens. What consumer end up is having a sensor with resolving power much higher than that of the lens, so the extra megapixels end up being wasted. Pairing up a high megapixel camera with a kit lens is an engineering mismatch, but apparently, it is brilliant from the marketing perspective.

For example if the lens can barely project 15lpmm (lines per milimeter) but the sensor can record up to 30lpmm, then the sensor will still only record 15lpmm from the lens. With this combination, it is no different than buying a sensor that has 1/2 the megapixels, then upsizing it. By doing so, no extra details will be recorded, and the only thing a consumer will end up is having a bigger image and a bigger file, and an underutilized camera.

One similar analogy I can think of is a car company that pairs up a super expensive Y-rated sports tire with a car that barely has 50 horsepower. The Y-rated tire can go up to 186mph. But seriously, I don't know any sportscar with 50 horsepower that can go up to even 100mph. It's wasteful and a plain mismatch to put such a high quality tire on a slow car. However, marketing knows better, and marketing knows that consumers will buy based on meaningless numbers and slogans alone (megahertz? megapixels? 16X CDROM speed? MMX! IT'S A PENTIUM INSIDE!)


Moral of the story:

Camera engineering is all about trade-offs. A camera with high megapixel is sacrificing the ability to shoot well at night. Nothing is free. Don't fall for the megapixel numbers. They mean very little by themselves. One needs to evaluate a camera system as a whole.


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High ISO shoot-out comparisons:

Nikon D5000 (12.1MP) vs. Canon T1i (15 MP)
http://www.cameralabs.com/reviews/Nikon_D5000/noise.shtml

Nikon D700 (12 MP) vs. Canon 5d mk 2 (21MP)
http://www.xtremephotography.ca/Canon-5D2-Vs-Nikon-D700/