Free Photography Tutorials, Beginners to Advanced

Choosing a Camera - Page 4

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How Many Pixels & is it the Most Important Measure of Quality?

Until recently, the quality of a digital camera was measured by how many pixels it boasted. Now we have cameras with tens of millions of them (we even have phones with many millions) and it has ceased to be the most important test of quality. In the real world the number of pixels you need depends on how big you want to print your pictures. If you mainly want postcard size or A5 then I would consider 6 to 10 million pixels to be perfectly adequate. Even at A4 size I would be hard pushed to tell the difference between my old 10 million pixel camera and my 18 million pixel camera. Don’t forget though that your framing in the camera may not always be perfect so you may be enlarging only a portion of the image (see cropping). Top of the range camera sensors seem to have settled down now at around the 16 to 20 million pixel mark, and maybe we finally have enough of them (the Hasselblad pictured on the previous page has 60 million, so maybe not :-)).

The Physical Size of the Camera's Sensor Matters

The main difference between a pro camera and an amateur camera is that the sensor is physically bigger and, therefore, although there are roughly the same number of them, each pixel is bigger. The bigger pixels certainly do seem to produce better quality, smoother pictures.

As you can see from the diagram on the right, the 'full frame' sensor of the pro cameras is significantly bigger than the APS-C chip used in most 'pro-sumer' models. On the down side the larger chip bumps up the price of the camera considerably.

I find the main advantage of having more pixels is being able to shoot at faster ISO settings and still get decent quality. This really helps to freeze the action in sports photography and other kinds of fast moving subjects. You get better definition at all ISO settings of course but, be warned, you need a good quality lens to really see the difference.

However, I must say, we do sometimes seem to get a bit too hung up on image quality, a fellow photographer once observed that photographers tend to smell pictures rather than look at them, by which he meant that they were more interested in the graininess and sharpness of the picture than the actual content of the image itself.

The Quality of the Camera's Sensor

As well as the size of the sensor, which is important, the bigger the better, they do vary in quality from brand to brand. The better chips will have better color saturation and less 'bleed' between pixels, which in turn gives you better definition. There is a lot to be said for sticking with the main brands in this regard. If you are reading camera reviews, have a look at the color quality details. You don't necessarily want the chip with the most color saturation (sometimes this will be too much) or the one with the most realistic color (too dull). You want the one with the most pleasing balance of both. On good cameras like my Canon EOS 7D this is actually adjustable.

Conclusion - Choose the Camera that's Best for You

I have tried over these few pages to lay out the pros and cons of the different types of cameras and highlight what is really important as far as 'features' are concerned. As I said in 'which brand?' there is no such thing as 'the best camera' so don't get too hung up on making the best choice, sometimes the best choice is the one that is on special offer this month. If you are going for a DSLR, which you should if you are going to get serious about photography, I would say buy a recognized brand (my choice would be Canon or Nikon) so that you have the widest choice of accessories.

Whatever you buy, get a decent amount of pixels, a good quality sensor and the best lens you can afford.

Other tutorials in this section


A short introduction to the types of cameras available and a discussion on what you need to look out for when buying a camera.

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What you need to know when choosing a new lens.

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Lens Conversion Factor

Confused comparing 35mm lens focal lengths to the new DSLRs? This will make it all clear.

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What you need to know before you go shopping.

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More of a 'why you need a tripod' than a buyers guide, but it does include some tips on buying and using a tripod.

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