The Amazing 1.6x "Zoom"

Canon has made a brilliant marketing decision to sell cameras with APS-C sized image sensors. These amazing sensors take your existing lenses and make them zoom in 1.6x closer! Imagine you own a $1140 Canon EF 300mm f/4 L IS USM Super Telephoto lens. Believe it or not, it effectively makes it a $5500 Canon EF 500mm f/4.0 L IS USM Super Telephoto Lens. Wow!

 

Well, you shouldn't believe it. It's only partially true. If you were to compare a full frame camera to a APS-C camera you'd see that the image is identical to taking the large image and cropping it. You could easily do this operation in Photoshop. So 1.6x zoom is more appropriately called a 1.6x crop factor. Even so, there are some practical reasons why this is better. In reality, you're not planning on cropping an image from the start. You look through the view finder and that is the image you want. It can be hard to visualize the crop when you are in the heat of the creative moment. In this case you actually want the image zoomed in more and that would be better.

 

You can actually do this. It's called Digital Zoom on most consumer digicams. I'm not sure why they don't put it on DSLR's. It would only be a software change. Although the technical size of me thinks this is stupid because all you are doing is throwing away information, the creative side of me sometimes is happier with the image being closer. And, ah, hey technical size of me, the image written to the flash is smaller with the crop so you aren't wasting flash space with pixels that you are just going to throw away.

 

If you were in a store and had to pick between a APS-C camera and a full frame camera which would you choose? The full frame. No question unless the price or some other decision changed your mind. And recently, the price changed my mind. I couldn't justify 5x the price for the full frame Canon EOS 1Ds Mark II so I went with the Canon EOS 20D.

 

The cost of semiconductors follows Moore's Law which states that every 18 months the performance will double. Since sensors are semiconductors made on silicon wafers just like Pentiums this law holds for them too. Let's look at why this is a little misleading. If you make a 8 megapixel sensor today in 18 months you'll be able to make it for half the price. This cheaper sensor will be smaller. Hold a sec. You don't want smaller. You want a full frame sensor. So what you get instead in 18 months is a sensor for the same price, but with 16 megapixels. This is nice, but the price of the sensor isn't going down. So if you're trying to make a $800 camera, you are still going to have to put a smaller sensor in it. Non-profession DSLR cameras are going to have these smaller sensors for a while.