cameras as we know them get their name from the camera obscura (Latin for dark room) this was an early way of projecting images across a room. A basic camera generally is box with an opening (aperture) at one end for light rays to pass through. This opening can be a pinhole or an iris or as in most cases that interest us a lens with an iris inside it.
Thanks Arisotle 1/2mm Pinhole
Now enough of that lets get down to the nitty gritty. There is an enormous range and types different cameras on the market we have to be realistic and limit ourselves a little.
Specialised cameras; Digital, film, Architectural, panoramic split into two types static and revolving, underwater, large format e.g. 10x8 “ or 5x4”, medium format normally 6x6
(2 ¼ x 2 ¼ inch), and many more. Will be added as time goes on
Viewfinder cameras normally and I mean normally in this day and age, would be in the cheaper range, not a golden rule as some are the most expensive Leica for example (before I get my head bitten off)
They do have one great advantage they are very quiet.
The standard DSLR means digital single lens reflex. The D is obviously for digital. The SLR part means that you look through the same lens as the photo is taken achieved by a pentaprism and a front silvered mirror, this flips up at the moment of exposure and drops down again immediately after, most of the noise made by a DSLR or a SLR is from this action.
The advantage of this system is that it solves all the parallax problems encountered with a viewfinder camera And makes changing lenses possible. (yes I know that some viewfinder cameras Leica for example,have the possibility to change lenses)
Most DSLR / SLR makes have a wide range of interchangeable lenses but each make will have it's own fitting therefore will only fit that particular make
Most independent lens manufacturers will however offer in their range a choice of lenses adapted for each camera make.
It must be remembered that the pre digital SLR had a film size of 24x36 mm and strangely enough was always called a 35mm camera. Whereas the DSLR has a sensor to replace the film that may be of different sizes depending on the make, model etc. These sensors are gradually increasing in size and some now are available with a 24x36 sensor.
Medium sized cameras are normally 6x6cm or 6x7 cm Hasselblad has a digital back for it’s 6x6 camera with a sensor size of 36x49mm and 33mp Mamiya also have a 33mp camera, and Leaf have the afi-II with a massive 56 mp. These would be used mainly by professional’s for fashion etc.
An up to the moment digital SLR.