Photo Quickies

PhotoQuickie has often wondered why digital SLRs have much lower focal lengths than film SLRs. First though to be sure PhotoQuickie and our friends are on the same page; the focal length is the distance needed for a lens to focus the image onto the photo sensor.

For film cameras, PhotoQuickie sees lenses with focal lengths of say 35mm - 80mm while lenses made specially for digital SLRs have focal lengths in the 18mm - 55mm range. PhotoQuickie muses that the result should be similar and of that we are correct.

The reason is that on dSLRs, the photo sensor is smaller than a frame of 35mm film so the focal length of a dSLR lens must be multipied by a focal length multiplier to find out the equivalent 35mm focal length. For most Canon dSLRs this is 1.6, while for Nikon dSLRs this is 1.5. Which means that PhotoQuickie’s hypothetical 18-55mm digital lens is like a 28-80mm film lens in fact.

Read more about: Focal Length, Digital camera backs (bodies),

This entry was posted on Tuesday, December 27th, 2005 at 11:49 am and is filed under Terminology. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.