Wide angle lense

[aussben]

Hi All,

I am sure this horse has been flogged to death, but I new to the photography seen I have been doing a lot of reading, I am trying to head my head around different terminology around wide angle, telephoto etc.

I know the definition of wide angle, telephoto etc, but I am trying to understanding what is the difference between a lens classified zoom and one classified wide angle with in similar focal ranges?

This part I don't really understand, I thought the wide angle part is basically how low the focal length is eg 14mm

My example is the sigma lens "Sigma Zoom Super Wide Angle 18-50mm f/3.5-5.6" compared to the lens that comes with the E-510 kit which is advertised as "Olympus 14-42mm f/3.5-5.6 Zuiko ED Zoom Lens"

One is classified wide angle and the other is classified zoom but will similar focal lengths both lenses are for the Olympus four thirds.

Maybe someone can help me understand the difference.

Thanks

Ben

[jdepould]

Some of it just depends on what the manufacturer calls it. Basically, anything wider than 28mm is considered wide angle, if it's significantly wider, some people might call it ultra-wide, but that's really irrelevant.

Zoom is completely separate from focal length. A 70-200 telephoto and a 12-24 wide angle are both zoom lenses. The opposite of a zoom is called a prime, or fixed-focal lens. The most common example is the 50mm lens. It has one focal length. Zoom lenses can zoom through a range of focal lengths, hence the name.

The two are really apples and oranges, hope this clears it up.

[aussben]

Thanks very much for you answer very clear.

Now I under stand you can have a wide angle zoom lense and also a telephoto zoom lense both been zoom just at different focal ranges, wide at the lower end and the telephoto at the higher end.

I have also noticed that you can have two wide angles being both 18-50 but one has a lower f stop I think that is right one being f3.5 min and the other being f2.8 min. The lower f stop is about 75% more expensive both sigma's, is the f rating the aperture? I hear some people also referring to the lower the number the faster it is, I guess this is what you are paying for.

[jdepould]

That's correct, the lower f/number corresponds to a wider maximum aperture. This allows you to use faster shutter speeds in low light, but they do cost more.

[aussben]

Ah I understand why people say it is faster lense now, they are referring to the shutter speed you can use.

Thanks very much for your answers you have cleared up a lot.

[marxz]

though it's not so important for photographers (but critical for film/video folk) there is a stricter definition on what is a "zoom" lens. in that a zoom lens has to remain focused on the same focus point when moved through it's focal range - this allows a subject to remain in focus during a single shot as the cameraman zooms in or out. If the lens requires refocusing between changes to the focal length then it's technically a "variable focal length lens".


as I said not so important for photographers as we generally change the focal length, re composition the shot then focus (manually or automatically) so maybe I'm being a bit pedantic to bring it up but meh that's me. Most high end camera lenses are true Zooms and indeed Canon's L series photographic lenses can be fitted to their high end video "XL" series video camera (via an adaptor)

[matonanjin]

That's correct, the lower f/number corresponds to a wider maximum aperture. This allows you to use faster shutter speeds in low light, but they do cost more.

It will allow you to use a comparibly faster shutter speed as he stated. The other thing it gets you is brighter light in your viewfinder which: 1) Allows your autofocus to respond more quickly, and 2) Allow you to see better to compose.

Also, the faster lenses are generally of better build qulity as well for better sharpness and contrast. Usually!