A long, long time ago I had written two on-line calculators to help photographers answer the following questions:
- How far away from my photographic subject can I be and still fill up the frame of the photo with that subject?
This question gets at how large a focal length your lens needs to be in order to photograph a distant object without it appearing the size of a pin-prick in the resulting image. If you find yourself wondering whether you need that 300mm lens in order to capture a water buffalo at 500 meters, this calculator will be very useful to you. - When doing macro photography, how much of my camera sensor area will be covered by the subject at a given distance?
This is for photographers working on extreme close-ups who want to fill the entire area of the camera's image sensor with the subject of their photograph (a flower, an insect, etc.). This calculation will tell you whether or not you have to have a 'true macro' lens (one that has a macro ratio of 1:1) in order to pull it off.
The calculators are available here. Enjoy!
PS This would not have been possible (or at least as easy as it was) were it not for the Internet Archives. The old version of my calculator page had been lost when I migrated to TypePad as my new weblog platform of choice, but luckily a snapshot of my website from April of 2005 was available, allowing me to pull the original formulas out of the digital dust bin.
