Lens Testing for sweet spot
Posted 12 July 2008 - 02:51 PM
What I am trying to determine is how to do this most effectively. Are there specific lens charts I should use, or should I light a relatively flat scene, or how would any of you more experienced folks set this up? Or is there another way, say with using a collimator or something, that I should use to determine where the lens has it's sharpest and best characteristics.
Thanks in advance for any and all assistance.
Posted 12 July 2008 - 04:02 PM
same with just a siemens star with nice result.
Not shure about it but i belive it´s a good idea to do the test at different distace aswell,
like 1, 5, and 15meter.
Posted 12 July 2008 - 06:30 PM
Posted 13 July 2008 - 02:34 AM
Or is there another way, say with using a collimator or something, that I should use to determine where the lens has it's sharpest and best characteristics.
Tim, the best way to this by far is t project the lenses on a lens projector. This will show up many of the common issues and is far easier to pick than using a lens collimator, which is really only designed to check a target set to infinity. The small scale of the collimator will make it harder to judge compared with a lens projector, not to mention what's happening at the edges compared with the centre of the lens.
You will see all of this and more when the lens is projected. It's a revelation....
Posted 14 July 2008 - 03:54 PM
I would love to have access to a lens projector. I have a collimator, but not a lens projector. In fact, I have never seen a lens projector and everyone I have asked about them has been pretty fuzzy. I can't even find info online about them.
I am going to start a new thread specifically about lens projectors. If I can find one to use, that is the way I will test the lenses, if not, the Panavision chart from Australia will be a good start, and then shooting some screen tests with the actors.
Thanks again to everyone,