Help me understand zoom magnification.

[Bonhomme Richard]

Will a sigma 70-300 at 300mm zoom magnify subjects the same size as a nikon 70-300 at 300mm? Reading specs I am getting confused. The sigma (it is a macro zoom) show 1:2 max magnification while the nikon (no macro) show 1:3.9 magnification.
I need to get as close to my subject as possible ( I can't afford a 500mm lens) and if the macro feature is costing me magnification then I can do without it.

[Boo_Radley]

1. Different measures

1:3.9 is your speed, or maximum aperature. Then, there's the size of the film/sensor. If your sensor is smaller, then your zoom equivalent is longer. The sigma and the nikkor should magnify the same ammount on the same camera. If you put the lense on a digital camera, and then put it on a 35mm film camera, it would be different, because the media is a different size.


What you posted above suggests that they're equal, except that the nikkor is slower, but probably not enough for you to really care. Not unless you're photographing NASCAR or trying to get a stop motion on the ball being pitched in a professional baseball game or something. (And even then, it may not matter).

1:2 = f.2 max aperature, meaning a large aperature. 1:3.9 means f.4 maximum aperature, meaning not quite as large.

[Bonhomme Richard]

2. Thanks

So when they give the description as magnafication then it really isn't. I use a nikon n80 so at 300mm they are equal, as far as magnification is concerned?

[F.Gordon]

3. Those are "macro" specs. Ignore them

Unless you want to do "macro"/closeup stuff. Doesn't have anything to do with the "reach" of the lens. My Canon 24-70 has a "macro" setting (1:2.??) but it really isn't a true macro.

300mm is 300mm is 300mm.
:hi:

Edit? Too many M&M's
:crazy: