Posted 23 August 2005 - 03:13 PM
Posted 27 August 2005 - 11:49 AM
Been looking for some info about shooting extreme closes...
Not sure I understand your question, but here goes:
1. Ordinary lenses become poor in resolution when shooting near 1:1 with extension tubes alone (when the subject is the same size as its image on the film) because all of the optical corrections fail. Stopping down helps. Diopters help maybe but these are not always very good quality either.
The best thing is to use a lens that is specially corrected for 1:1 such as a macro lens with floating elements. This can be faked by using two similar lenses mounted front-to-front with a macro coupling ring.
Good macro lenses are made for Nikon, Pentax etc. still cameras and if you adapt one to your movie camera this should be a good cheap solution. Be wary of Canon and other newer autofocus lenses as you may not be able to change the aperture.
2. When shooting 1:1 the usual rules do not apply. Moving the lens in and out changes the image size and not the focus. Moving the camera only, or the subject only, changes the focus.
3. At 1:1 the effective F number doubles. So your f/4 lens only lets through as much light as an f/8 lens. So you need to correct exposure by two stops accordingly, unless you are metering through the lens.
Posted 27 August 2005 - 04:42 PM
At the moment shooting with dioperts as could only get a maco lens with a PL mount and shooting with an Arri 3 with an unmodified hard mount. Will have to try and figure out the macro's the next time i can get my hands one one. But it does seem like the best way to go. there is a locally available Zeiss 100mm macro 1:1 - the lens cuts off at a higher stop when on macro right ? Wasnt clear if that was a new 'lens speed' or if it worked out the compensation.
Also was wondering of there were any books or sites where one could learn more about macro lenses and macro cinematography.
Thanks a ton.