http://www.adammillerrealtor.com/digital-cameras-jargon-buster/
I need help in understanding focal lengths?
Oh well, I’m really awful at reading all those ‘mm’ readings that you find on lenses and stuff. Can anyone explain the following questions, in complete idiot’s terms please?
i) What are all those ‘mm’ readings and how do they correspond to wide angle or telephoto lenses?
ii) What on earth is a 35mm SLR camera, and how are the focal lengths on fixed lens digital cameras ‘equivalent to’ the focal lengths on the 35mm camera?
iii) Oh wait, what are focal lengths?
Thanks for your help, I need some jargon-busters out there to help me understand this. =)
In question ii) I’m not really comparing digital and film, just take the ‘SLR’ term as a general one, could mean both film and DSLRs.
Thanks for all the very helpful answers indeed. One more thing though, does the same thing work for aperture readings e.g. a f/4 on my fixed lens digital camera is ‘equivalent to’ f/__ on a 35mm SLR camera?
The lower the mm number the wider the angle of view will be. Generally anything 35mm and under is a “Wide Angle Lens”
The higher the number, the further out you can “reach” to subjects that are far away from you. Anything over about 75mm is considered a telephoto lens.
SLR refers to “SIngle Lens Reflex” this just refers to a camera with interchangeable lenses in which the user sees through the viewfinder the actual view through the lens of what they are about to capture on film or digitally.
For this last part I’m going to have to throw one small bit of technical stuff at you! Sorry!
If the camera has a “full frame sensor” you don’t need to know anything else. The camera will function exactly like the film cameras and the view is the same through the lens.
If it is a “cropped sensor” camera the field of view changes. Most of these cameras have about a 1.5 crop ratio. That means that looking through a 50mm lens on a “crop sensor” camera will give you the same field of view as a 75mm on a film or “full frame” digital camera. If you are using telephoto lenses a lot, that is great because it makes your 70-300mm lens a 105-450mm lens. But it also makes your nice 24mm wide angle lens now become only a 36mm barely wide angle lens. There is a lot more technical differences between these two formats, but for the layperson who just wants to go out and take some pictures and have fun, that’s really all you need to know!
EDIT: Aperatures remain the same regardless of which camera type you mount them on…
Good Luck!