advice on filters
Posted 12 July 2007 - 09:07 AM
i know its not strictly an SD question but im an SD person (at the moment) and so ill ask it here anyway.
ive just invested in a matte box to use with my camera and 35 mm kit and im trying to shop around for filters. i really didnt fully appreciate how expensive these things actually are, and so im wondering if anyone might know of a manufacturer of 4x4 filters that produces reasonably good glass without the very high cost (im uk based if that makes any difference to anyone).
also, it seems pretty tough to get my hands on these things to check out what certain filters actually do and what their results are, so if anyone has a good suggestion of a starter kit style thing (just a few of the essentials as something to get me to grips with their function and to start the ball rolling) then id be very very appreciative.
Posted 12 July 2007 - 01:51 PM
If you go to these manufacturers websites, they will tell you exactly what all of their filters do, but here are some basics that I recommend for video:
Neutral Density: These bring down exposure without effecting color. They are especially handy for acheiving shallower depth of field with video cameras. They come in a variety of grades -- .1=1/3 stop, .3=1 stop, .6=2 stops, etc. Also come graduated (half the frame will be clear) which is handy in landscapes for getting the exposure of the sky within range without effecting the land.
Polarizer: Reduce reflections on non-metallic surfaces and make the sky darker. You'll need a rotating filter stage in your matte box for these to be of much use.
Some sort of diffusion (pro-mist, soft effects, diffusion, or all): basically they spread some of the highlights into the darker portions of the frame to reduce contrast while also softening details. The three types (and their are even different types of those types) all work a little differently and have their own look so you'll have to look at some example images (tiffen's site has some) and then try them out to see what looks best. These also come in different grades; typically lower grades are used for wider shots and higher for close-ups. You may not even need these if you are using a 35 adapter, as the ground glass seems to add some diffusion (but I there are so many different adapters and I don't have experience with any so I can't say).
I don't think I would recommend any color filters, especially if you are on a tight budget. Maybe graduated colors for enhancing or changing the color of the sky. For the most part, you should be able to get close to the effect you want with simple white balance or color correction in post.
Also, if you really want to get into controlling your image with filters, I recommend the book "Image Control: Motion Picture and Video Camera Filters and Lab Techniques" by Gerald Hirschfeld, ASC.
Edited by Toby Orzano, 12 July 2007 - 01:53 PM.
Posted 15 July 2007 - 04:28 PM
I have several P-series filters and holder which fits most 2/3" broadcast lenses. The size is not compatible with 4x4, but again the holder is so cheap it's worth the investment to learn what different filters do.
About the only thing missing from the Cokin lineup is any kind of subtle diffusion or contrast lowering, I guess because the manufacturing of such isn't practical with resin filters.