2 lens questions...

[Wiggly]

So these have both been on my mind for a while...

1 - If I have a 70-300 MACRO lens and a regular 70-300 lens... the one thats macro wont be any less productive at non macro shots would it?

2 - I'm pretty sure I already know the answer to this one but I'll ask anyway... if I have a 10mm Fisheye and a 10mm... the reg wont be all fisheye distorted would it?

 

[Dao]

1. I believe the MACRO you mentioned is not a true MACRO lens like those that has 1:1 magnification. And usually those zoom lens that has the MACRO function is made to be able to do close focusing. So the non MACRO one may not be able to focus closer than the one with MACRO.

2. For those ultra wide angle lens such as 10-20mm Sigma lens, they do have distortion at 10mm, but that much when compared with the fish eye lens.

 

[Big Mike]

1 - If I have a 70-300 MACRO lens and a regular 70-300 lens... the one thats macro wont be any less productive at non macro shots would it?

Firstly, I don't know of any 70-300mm lens that is actually capable of 1:1 macro. But they put 'Macro' on the lens because it sells. :roll:
Compare the two lenses and look at the minimum focus distance. The feature that distinguishes a lens's macro ability, is how close it can focus. This (along with the focal length) will determine the reproduction ratio. 1:1 means that the actual size of the subject is the size of the image on the film (or at the sensor). One of these pretend macro lenses might have a ratio of 4:1 or something like that.

if I have a 10mm Fisheye and a 10mm... the reg wont be all fisheye distorted would it?

Most wide angle lenses are made to correct for the distortion that is inherent with wide angle lenses. I believe they call those rectilinear lenses. They usually can't eliminate all of the distortion though.