Today I attended the second lecture on the photography workshop by Dr. Anupam Pal. I'm putting down some of the things I learnt for future reference.

Buying Guide:

1) Fix your budget
2) If going for DSLR make sure you're getting a lens with the body!
3) Keep some money for a UV filter
4) Keep some money for memory card and a battery charger too (if Eveready type pencils cells are used)
5) Keep some money aside for Memory card reader and camera bag too.

1) 5 mega pixels resolution is sufficient.
2) For point and shoot camera, go for the best OPTICAL zoom. Digital zoom is of no use.
3) Look for exposure control. (A, T, M etc.)
4) look for anti-shake technology.
5) Go for the largest aperture (i.e. smallest f-number)
6) Look for minimum lag time
7) Look for swivel and largest LCD. (swivel means one can change the orientation of the LCD if, for example, the sun is shining directly on to it.)
8) Multimedia capability (just an extra)
9) Go for camera manufacturing companies like Canon, Nikon, Olympus, Pentax, Sony, etc.)
Avoid electronics companies like HP, Panasonic, Epson etc.

Features

Lens types:

1) Prime lenses: have fixed focal length.
2) Lenses with variable focal lengths: zoom lens and varifocal lens.

Lens with focal length of 50 mm is a normal lens (I don't know if that is the technical name). The image looks nearly as you see it.

Lens with focal length < 50 mm is called wide angle lens. Allows more elements to be captured in the frame.
While buying a lens, go for the one which has a smaller lower limit on the focal length (i.e. more wide-angle). The upper limit probably does not matter so much (I'll have to confirm this part)

focal length > 50 mm: telephoto lens.

Macro lenses are used for close-ups. There are something called tilt-shift lenses.

Filters

UV filter for protection (to camera sensor or the eye?)
Circular polarizer (removes reflection and saturates color)
Graduated neutral density filter (can be used for sunsets when the sky is too bright and the earth is too dark)
Neutral density filter.

Flash

Built-in flash: good for fill flash (what's that?) but bad if used as a primary source of light. Creates red eye.


Accessory flash.


Using flash in the sun can be useful. For eg. , if the sun is overhead and illuminating the head or hat of some person, but leaving the face in darkness or the eyes as black spots because of the shadow, then flash can be used to reveal these features.

Using flash at slow shutter speeds can create interesting effects while capturing movement. There will be a general blur with a sharp image at the instant the flash was on.


Light metering: amount of light entering the camera.
1) Auto: camera decides everything.
2) Aperture priority: You set the aperture, camera sets the shutter speed- this is MOST USEFUL.
3) Shutter priority: other way round as above.

Gray scale: camera tends to make images gray by 18%. So a black object will try to be whiter and a white object will try to be darker. For this it may be necessary to do full manual light metering. for eg. it may be necessary to underexpose a dark object and over expose a bright object.

Calculation for mega pixels: if you need a 8" by 12" print, you need 8 * 12 * 300 * 300 number of pixels.


There are two minor problems with DSLRs:
1) small sensor size compared to 35 mm film. There's a 1.5 or 1.6 multiplication factor which makes wide angle lens not so wide but a tele photo lens super-tele.
Sensor in DSLR has to be small because large sensor size makes the image quality at the edges bad. (But why does this problem not exist in 35 mm film?)

2) Dust accumulation on sensor. But Nikon has come up with ways to deal with this.