rsp@odyssey.net
Very nice Steve. I really liked the shot of the berry. I'm getting into macro stuff myself now. What's the benefit of the extension?
Randy
Thanks mate
The extension tubes are just a device to move the lens further away from the film plane.
With the lens further away from the camera than normal, it doesn't have to refract the incoming light to such a degree, which basically means it can focus on objects much closer than without the tubes, hence the apparent 'magnifying' effect. On the really close pics of Gary, the front element of my lens was less than an inch away from him; the
normal closest focussing range of the lens I used is around 18 inches.
A big plus is that they contain no lens elements (they are basically just a set of hollow tubes of different length) so they (near enough) maintain the optical quality of the lens itself. Plus, the Polaroid set I bought each have Canon electrical contacts which lets the lens communicate as normal with the body, and hence allow autofocus and auto-exposure options to be selected.
Randy, Polaroid also make a set for Nikons, and I reckon they're a real bargain for just 75 of your American Dollars on
AMAZON. I can't recommend them highly enough. From my experience, the only proviso is that although the auto-exposure works perfectly (and incidentally also maintains full TTL flash exposure), sometimes the autofocus does tend to hunt around a lot and often fails to find focus (although that's a limit of my camera, not the tubes) so I normally switch over to manual focus.