Quick question

timputtick · Oct 4, 2012

Hello,
I'm looking to buy this lens:
[FONT=Trebuchet, Trebuchet MS]Tokina AF AT-X 124 AF PRO DX II 12-24mm f/4.0 [/FONT]
[FONT=Trebuchet, Trebuchet MS]I'm stuck as to whether it would be 12-24 on a crop sensor dslr, Although it says DX which I believe is meant for crop sensor cameras it says it has a x2 magnification factor, a quick reply would be greatly appreciated. I've tried googling this but stuck for a solid answer.
Thanks for any help in advance[/FONT]

480sparky · Oct 4, 2012

Focal length is focal length. It will be 12-24m whether it's on a crop sensor, full-frame sensor, a cell phone or a 20x24" view camera.

Being a DX lens, I'd say it's designed for Nikons crop sensors. You can still use it on an FX body, either in DX crop mode or FX, but the latter will record a less-than-full-frame image.

SCraig · Oct 4, 2012

A 2X magnification simply means that from minimum zoom to maximum zoom is 2X (12mm x 2 = 24mm). That, in and of itself, has nothing to do with whether it's a DX or FX lens.

Patrice · Oct 4, 2012

Sparky is correct, however, if you have a 1.5 crop sensor (as in Nikon) that lens will have a field of view equivalent to a 18-36 mm lens on a full frame body. What is meant by the 2x magnification factor is that the longest focal length is twice the shortest focal length: 12 mm to 24 mm. Similarly, nikons 24 to 120 lens can be said to have a 5x magnification factor, the 14-24 a 1.7 magnification factor and the 70-200 a 2.85 magnification factor. It just indicates how much the lens 'zooms' from its shortest to longest focal lengths. You can't use this number to compare one lens to any other since it has no relevance to anything other than itself.

PS: Scott types a bit faster than me!

Scott, I didn't mean to parrot your response. Sorry.