Focal lengths

[UKBob]

Does anyone know of any websites which show a series of photos of the same subject taken from very wide angle through to telephoto?

[simpo two]

A more realistic exercise would be to go to a camera shop and try some lenses.

Another way to get your head round focal lengths is to express each as in degrees: 'angle of view'. All a lens does is chop a piece out of what you see before you; it's either a big piece (wide angle) or a little piece (telephoto), and make it fill the screen.

[touchingcloth]

www.warehouseexpress.com/photo/lenstech/tamfocal.html

Not very wide angle but a reasonable example of differing lenses.

[UKBob]

simpo two said:

A more realistic exercise would be to go to a camera shop and try some lenses.

I know, but I dont want to make them feel Im just wasting their time until Ive bought an SLR and am ready to shell out for the glass.

touchingcloth said:

www.warehouseexpress.com/photo/lenstech/tamfocal.html Not very wide angle but a reasonable example of differing lenses.

Excellent, thanks

[HankScorpio]

By my own fair hand
www.hankscorpio.net/misc/zoomtest

[UKBob]

HankScorpio said:

By my own fair hand www.hankscorpio.net/misc/zoomtest

Thanks for that!

The bushes in the forground of the 280mm (1.4x) shot are so much clearer than the same bushes in the 270 (2.0x) photo.

I know a 2.x TC wont give you as good a picture as a 1.4 will - does anyone know if the canon 2.x TC looses as much as the sigma seems to (ie a lot!)

Its put the right off the idea of the 2.0

[_dobbo_]

Bob, the 2x will be lower quality than the 1.4x all else being equal, this is unavoidable.

I wouldn't let one pic put you off though.

That said, a 200mm (which is effectively 300mm) on a digital SLR, with a 2x teleconverter would be pretty much useless at 400mm (which would be 600mm), so I wouldn't bother with a 2x anyway.

Better to get a decent shot and crop it afterwards than not get the shot at all cos the teleconverter stole your maximum aperture.

>> Edited by _dobbo_ on Saturday 11th February 23:55

[HankScorpio]

It is a bit soft but there's also a bit of shake there.

Here's another one at 400 but with a VR lens (400px unresized from the original image):




Measured using Google Earth, those railing posts are 2106 yards away (allow a little more for triangulation), the fact that they can be resolved so clearly just blows me away.