ND Filters - Vari and non Vari

W

Winston2012

New member
Hello all,



I'm brand new to DSLR video and have been doing some reading/video watching online. I'm thinking about buying the Tiffen 77mm filter set (.6.9 1.2) they sell at BH rather than the Vari-ND filter. Why not just get the Vari for ease in the field ? I've read/heard that Vari-filters have problems with color shifts (not talking about cross hatch pattern or wide angle issues) and sky shots can be a problem. The purest in me says - well just get the a set of regular filters and deal with extra little bit of hassle in the name of better IQ.

Question - Is this a reasonable way to employ ND filters for in-field video on a DSLR ?

Question - Is there anyone here who has done both methods on a DSLR and can comment about the differences - if any?


I don't mind shifting one stop or so to get the exposure correct.

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Using a D5100

Thanks in advance and its great to be aboard here at DVX:D
 
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changing screw-in filters is a pain, but I tried every other route (except a matte box, that's beyond my budget right now) and ended up going back to screw-in
variable ND filters may be better today than when I ran these tests, but screw-in won't let you down, even the cheapest Tiffen ones (which are the ones I use) have basically no effect on sharpness (even in D800 36 Mpix stills), the only downside is a color cast that can be mostly corrected by changing your WB
http://www.similaar.com/foto/lenstests/lenstestsn.html
 
Screw-in is entirely a pain, but variable NDs are based on polarizers, and thus may have unintended results.
 
it really depends on your uses, expectations and budget. im like the other guys, i find screw on filters a pain. but if youre just doing some quick hand held shots it's kinda unrealistic to carry around a rig with a proper mattebox. and if youre in a situation with rapidly changing sunlight, its going to be nearly impossible to keep screwing and unscrewing a collection of filters.

so you have to ask yourself whats more important. absolute image perfection or not being ready for the shot?

from what ive seen there is detectable chromatic aberration / softening in most of the variND. whether that is going to make or break your shot is up to you. most of my clients wouldnt ever notice it unless i pointed it out to them.
 
Thanks for all the input guys...

Samuel H - Fantastic examples - thanks a ton.

I guess it's a tug-of-war between absolute performance and getting the shot as wgzn said. A lens combination that has to be screwed on and then white balanced - ugh. Screwing on the lenses would be okay but with my camera, custom white balancing is slow and painful.

Things to think about.
 
When I have to run-and-gun in changing light conditions (for example for something like this, which I shot last Saturday) what I do is that I go to the brightest spot where I expect to find myself shooting, set my desired aperture (in this case, on my APS-C camera, that was f/2.0, knowing that I will use anything from f/1.4 to f/2.8, and maybe a couple of shots at f/4), put enough ND so that I can shoot there at ISO 100, and set my WB with a white or gray card. Then I go along changing aperture to get my DoF and ISO to get my exposure. In that example I shot everything between ISO 100 and ISO 800. For the most part, I don't think I'd be able to tell which is which.

Another example is the video from Sunday, here. This one was indoor, so lighting was mostly constant. I set my ND (and WB) for f/2.0 and ISO 200, so I could shoot at anything from f/1.4 to f/4.0 by changing ISO from 100 to 800. (well, this one was actually trivial, since the required ND level was "exactly no ND", but you get the idea)

A variable ND is even more convenient, and with a 50mm the sharpness loss is not huge, but you can get around the screw-in issue even in run-and-gun if you don't mind playing with the ISO.

And yes, this was a fun weekend :)
 
A Marumi Super DHG CPL + B&W Linear MRC Polarizer (in front) works great as a variable ND 2-8 stops :)

tape down the CPL, and turn the Linear one to get the right exposure.
Then turn both together to get the right polarization
 
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