Some lens basics

Recently I learnt a little about lenses, and here it is…

  1. A “Normal” or “Standard” lens is one that is about 50mm. It gives the most natural looking image, very close to what you see with the human eye.
  2. “Wide Angle” lenses are those that are smaller then 50mm (15mm, 24mm etc). They produce a smaller image for the same lens to subject distance as a standard lens. This means it includes more subject matter and so the subject looks smaller in the photo. More of the surrounding matter gets into the photo with your subject. Good for group shots.
  3.  “Telephoto” lenses are larger then the 50mm standard lens. 85-135mm are moderate telephoto lenses, 135-300mm are medium and then you get into the 300-500+mm range. This does the reverse of the Wide Angle, making the image larger and loosing lots of the surrounding matter. Good for get closer to a subject while being far far away.
  4. Fixed Focal or Prime Lens is a lens that doesn’t have any zooming abilities. It’s fixed at a particular size and that’s it.
  5. Lens Speed refers to the size of the aperture. A bigger aperture (lower f stop number) the “faster” the lens.

If your interested in portrait photography, take note:

  • The human eye sees at about 50mm range, photos at this focal length appear normal
  • For close up headshot work, stick with a focal length of around 85-105mm and fill your frame (this means you might need to move forward or back, not your subject).
  • Why 85-105mm? Because at these lengths you keep everything in perspective, it gives the subjects body the correct proportion sizes.

Ok last thing, and this is important. If you use a digital SLR then the focal length of lenses is actually slightly different then what the lenses say they are.

  • Nikon & Sony camera owners need to times by 1.5
  • Canon camera owners by 1.6 (I think, check that one)
  • Olympus camera owners times by 2

What do I mean by this? Well, if you own a digital Nikon body and you slap on an 18-200mm lens, what you actually end up with is a 27-300mm lens (18 x 1.5 =27  and 200 x 1.5 =300).

So with a digital body, you gain extra magnification but you loose minification. So if I wanted to be shooting at 50mm on my Nikon D70 I need to use a 33mm lens. For portrait work I need a lens that is in the 55-70mm range (to get the 85-105mm equivalent).

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