DSLR guide

Do I need a Full Frame DSLR?

The Canon section mentions that one of the advantages of going with Canon is that you have the option of upgrading to a full frame body in the future. But will you ever need to?

A full frame DSLR is one that has a sensor that is that same size as a 35mm film frame. Most DSLRs have what is referred to as a 'cropped' sensor - one that is smaller than 35mm film. Different cameras and manufactures have different crop factors, the most common being 1.5x and 1.6x. That is, the sensor is 1.5 times smaller than full frame (or 2/3rds as large).

A lens will not change how it delivers light based on the size of the sensor, so in effect the only difference between FF and cropped sensors is that the cropped sensor picks up less of the area of light delivered by the lens. This gives the impression that cropped bodies are zoomed in compared to FF, however this is not the case - they simply have a smaller Field of View (FoV). Changing focal length (ie zooming) not only affects the FoV, but it also the Depth of Field and perspective.

There's a discussion in this thread about why people have, or would, choose to buy a full frame DSLR. In summary:

• FF cameras are high-end, and hence come with many features unrelated to the sensor that are useful, such as in-built portrait grips, weather seals, better viewfinders etc.
• At a given megapixel rating, a larger sensor should produce less noise. People certainly claim this as an advantage, however some tests seem to disagree.
• Many people noted that FF allows you to get closer to your subject at a given focal length, and hence allows you to produce a shallower DoF. This is particularly desirable for portraits.
• Most FF sensors have a higher resolution than most crop sensors, so there are advantages if you plan to print very large images. This is not always the case though, for example the Nikon D2X (1.5x crop) has a very similar resolution to the FF Canon 5D.
• Many people bought FF cameras because, basically, they could. They have the money and like to buy nice things - no technical reasoning behind it.

The major downside to FF is cost. The cheapest FF body on the market currently is the Canon 5D, which is around $4,000. For that price you could buy a mid range body and some very nice glass. FF bodies also require more expensive lenses in order for the image to maintain quality at the edge of the frame.

Unless you are a professional photographer with specific requirements (and if so, I doubt you'd need this guide!) its fairly unlikely that you will need a FF DSLR. Of course if money's not an option, there's no real downside.

If you think it's likely that on day you'll need or want full frame, Canon is currently your only option. If you buy a cropped Canon body and plan to upgrade to FF, keep in mind that only EF, not EF-S, lenses will work on your FF Canon.