September 212009
Digital Cameras - how much is enough?
The digital camera world has gone through a couple of development stages. At first, it was all a battle get more mega-pixels. But at about 3 megapixels, this increase flattened out, and the emphasis was on features. Since then we have had another leap to the 10 - 12 megapixel bracket and again, this seems to be holding for a while. Now we are seeing an increase in digital SLRs with their wider range of features and changeable lenses.
So what do we really need?
Before buying a new camera, I stopped to think about how I use the photos produced by a digital camera. With a film camera, you get the packet of prints or the box of slides back from the developer, and everyone has a look, then they all go back in the packet. With digital photos, they go onto the computer. They get made into screen savers, slide shows, emails and web pages. So we use our photos far more, but in a very different way.
Most usage of digital photos is on the computer screen, so any resolution that looks good on the screen is high enough. If you really need to print high quality photos, then that is when you need the extra megapixels.
I calculate my printing like this:
If I want a standard photo print, it measures 6 inches x 4 inches.
300 dpi gives me a good quality print out, so for 6 inches, at 300 dpi, I need 1800 pixels (6 x 300). The overall image needs to be 1800 x 1200 pixels which is just over 2 megapixels.
Applying the same calculations to a standard sheet of paper (US Letter or A4), I find I need 8 - 9 megapixels. Any resolution greater than that is more than I need for what I do.
In fact, my most frequent editing of photos is to shrink them to fit on to web pages or into emails. Luckily Apple Mail does this automatically for emails, but I have to do it myself for web pages.
The other major factor in using a digital camera is convenience. How many more photos will you take if you have a camera with you all the time? You have to make a decision to carry around an SLR, but the camera in your phone goes with you. Apparently 40% of new photos published on Flickr are taken on an iPhone. It's only 3 megapixels, but for sharing photos on a web site, this is good enough.
So I have my iPhone for spur-of-the moment pictures, and a compact 7.1 megapixel camera which is easy to carry around and goes with me when I expect to take photos.
So what do we really need?
Before buying a new camera, I stopped to think about how I use the photos produced by a digital camera. With a film camera, you get the packet of prints or the box of slides back from the developer, and everyone has a look, then they all go back in the packet. With digital photos, they go onto the computer. They get made into screen savers, slide shows, emails and web pages. So we use our photos far more, but in a very different way.
Most usage of digital photos is on the computer screen, so any resolution that looks good on the screen is high enough. If you really need to print high quality photos, then that is when you need the extra megapixels.
I calculate my printing like this:
If I want a standard photo print, it measures 6 inches x 4 inches.
300 dpi gives me a good quality print out, so for 6 inches, at 300 dpi, I need 1800 pixels (6 x 300). The overall image needs to be 1800 x 1200 pixels which is just over 2 megapixels.
Applying the same calculations to a standard sheet of paper (US Letter or A4), I find I need 8 - 9 megapixels. Any resolution greater than that is more than I need for what I do.
In fact, my most frequent editing of photos is to shrink them to fit on to web pages or into emails. Luckily Apple Mail does this automatically for emails, but I have to do it myself for web pages.
The other major factor in using a digital camera is convenience. How many more photos will you take if you have a camera with you all the time? You have to make a decision to carry around an SLR, but the camera in your phone goes with you. Apparently 40% of new photos published on Flickr are taken on an iPhone. It's only 3 megapixels, but for sharing photos on a web site, this is good enough.
So I have my iPhone for spur-of-the moment pictures, and a compact 7.1 megapixel camera which is easy to carry around and goes with me when I expect to take photos.
