Rule of Thumb
From Antalya
Some simple rules
- The Sunny f/16 rule says:
- On a sunny day, with ISO 100, you expose at 1/100s with aperture f/16
- The minimum exposure time for a lens with focal length N mm is 1/N s. So minimum exposure time for a 50mm lens is 1/50s
- For every doubling of the aperture, you need to quadruple the exposure time for the same light condition. So if you are exposing 1/200s with f/2.8, you need 1/50s with f/5.6 to get an image that is similarly bright.
- The minimum focus distance of a regular lens is around 10x its focal length. So a 200mm lens focuses starting at 2meters. Macro lenses are obviously not like that.
These pages are for Amateur Photographers and not really for seasoned photographers and professionals. I have no affiliation or commercial interest with any brand/make. I write from my own experience. I ended up using mainly Nikon, so I am more familiar with this brand than others. See price for notes on pricing as well as photography related links.