Introduction to photography

Maybe half of everything one needs to know about photogrpahy!

Anatomy of a digital camera

From a top-end large format Hasselblad camera (doing a professional model shoot) to the tiny camera on an inexpensive smartphone, both have the identical basic anatomy: a lens, aperture ring, shutter, and a digital image capture. The same applies to a movie camera.

Elements of a digital camera

Focal length

  • Focal length is typically stated for the “35 mm equivalent”:
    — 35mm or less is a wide ange lens
    — 50mm is “pretty normal”
    — 85mm to 135mm is typical for portraits
    — 200mm is telephoto
  • Optical zooming and digital zooming (crop zooming)

Focal length example

Exposure

  • under and over exposed
  • shadows and highlights
  • contrast
  • clipping

Example of exposure error


Three parameters of exposure, with trade-offs…

1. Aperture

and depth of field

f-stops:

  • f/1.4 for letting in much light and a paper-thin depth of field; f/22 for a tiny “aperture hole”, and a very large depth of field
  • full-stop increments (each halves the amount of light): f/1.4, f/2, f/2.8,f/ 4, f/5.6, f/8, f/11, f/16, f/22…

2. ISO

the “capture sensitivity”

  • An ISO of 100 requires a lot of light for image capture and produces a crisp image; as ISO needs 12800 needs little light but produces a noisy image
  • full-stop increments (each doubling of the value halves the amount of light): 100, 200, 400, 800, 1600, 3200, 6400, 12800…

noise, and post-production (or in-camera) noise reduction, and sharpening

Aperture and ISO examples

3. Shutter speed

“long exposure”, 1/15, 1/30, 1/60, 1/125 … 1/4000, 1/8000
(“1/30” means one-thirtieth of a second)

  • motion blur
  • freeze or show movement (drops in a waterfall; helicopter propellers; panning when tracking moving object like a cyclist…)
  • “1/focal length” is a rule-of-thumb for smallish photos (hand-held camera; not much movement of the subject), so a 60mm lens requires a shutter speed of 1/60 — this can be improved somewhat with modern image stabilisation; this can be improved massively if you use a tripod!

The exposure triangle, illustrating the tradeoffs

White balance (colour temperature)

Almost everything one sees is the result of reflected light!

Sensor size

Digital photos are made up of individual pixels. Open a photo in Photoshop and go ⌘+ repeatedly until you see the individual pixels. A bigger sensor size means more pixels (sort of) and, generally, better image quality.

Composition

  • Composition is a big subject!
  • Aspect ratio, etc.

The most common error that amateurs make is placing the main feature (like the face) right in the centre of the picture. Need to consider the whole.

Formats, compression, and RAW

For example…

  • TIFF
  • JPG, and JPG compression
  • PSD
  • (PNG / GIF)
  • RAW

The RAW advantage…