Converting Megapixels

Digital Imaging: Here’s a question one of our readers had:

I have a 2.1 megapixel digital camera and I just got a new 5 megapixel camera. I know that the more megapixels, the better. Is there any way to convert my 2.1 megapixel images to 5?

Actually, it’s really easy – Just use your new 5MP camera to re-take the photos you shot with your 2.1MP camera πŸ™‚

However, anything beyond that is probably not going to give you the results you want. Let me explain.

When you shoot a digital photo, you capture an image made up of thousands of little pixels. The more of these buggers, the bigger you can reproduce the image. Keep in mind that these pixels are created when you snap the shutter on your digital camera; it’s going to be important in a few paragraphs.

A 2.1 megapixel camera will generally produce an image around 1600 x 1200 pixels in size. A 5 megapixel camera will give you an image size in the neighborhood of 2560 x 1920 pixels (nice neighborhood πŸ™‚

Now, you can twist the virtual arm of most imaging software and force it to turn a 1600 x 1200 image into a 2560 x 1920 image – but there’s a problem. Where do all those extra pixels come from? The software makes ’em up. Just yanks ’em out of the air.

Since the software wasn’t there when you took the photo, it’s forced to “guess” at where all these new pixels should go and what they should look like. The end result is that although it can be done, the image quality isn’t going to be on par with the same image taken with a 5MP camera. Better off sticking with your original 2.1 megapixel images.

Here are some samples:

Let’s take this lighthouse…

Here’s what it looks like cropped in with a real 5 megapixel camera:

Here it is from a 2.1MP converted to 5MP

Pay close attention to the sharpness you lose with the transfer (esp. the bricks). Also, keep in mind that these images have been compressed so they load fast. The difference between the two was even more pronounced before the jpeg compression.

Some other things to consider…

1. It’s only a lighthouse – it should be pretty easy to create “extra” pixels where there were none before, yet there is a noticeable difference in clarity.

2. This was converted with the newest version of Photoshop. Chances are, if a $650 program can’t make it happen, other software won’t either.

Conclusion? Although you can make your software create something out of nothing, you still aren’t getting 5 megapixel image quality. If the details aren’t captured in the first place, no amount of software wizardry is going to be able to make ’em up.

One more note – A 2.1 megapixel camera can generally print a good quality 5×7. In fact, a 2.1 megapixel camera’s 5×7 will be nearly impossible to distinguish from a 5×7 from a 5 megapixel camera. Better resolution = bigger picts, that’s all. It won’t make your smaller ones look any better. So, maybe those 2.1MP photos weren’t so bad after all…

~ Steve

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