Thursday, May 20, 2010

Not All ND Filters Are Created Equal

Recently I was using my Canon 7D fitted with a Canon 100-400mm telephoto to film a Northern Cardinal songbird. I was perplexed why the image on the liveview screen was so soft in focus, no matter how much I manually adjusted the focus at magnified liveview settings. Realizing that I was using a newly-acquired vario ND filter for the first time to adjust exposure, I removed this filter from the lens and instantly regained the sharp focus I had originally expected.

I had not experienced this soft focus situation with an earlier acquired, but much more expensive, Singh-Ray vario ND filter when using my telephoto zoom lens. I then put together this quick trial comparing the cheaper, EBay-sourced "Nature" -brand ND filter against the pricey ($400+) Singh-Ray counterpart. You'll find my conclusions on this video:

Not All ND Filters Created Equal from David Rilstone on Vimeo.

The making of this video:

1. Cameras used: Canon 5D Mark 2, 7D

2. Lenses used: Canon 17-40mm L f4, Canon, 24-70mm L f4, Canon 100-400mm f4.5-5.6

3. Audio used: Rode Videomic (one each on 5D2 & 7D), Samson Zoom H4N, voiceovers done directly on PC Realtek soundcard

4. Moving shots of filters: Glidetrack Sharpshooter

5. Post processing: Adobe Premiere Pro CS5 (trial version -- disks on order!)

For my personal presentation appearances on this video, I used a two-camera setup. The 5D2 was fitted with the 24-70mm set at 64mm, the 7D had the 17-40 set at 40mm; this gave a similar perspective (full frame vs APS-C) with the cameras both approx 8 feet away from me at roughly 30 degrees to my left and right respectively. I used Philip Bloom's recommendation of a custom Picture Style of full negative sharpness & contrast, and about two notches negative saturation. This rather flat picture style gives the best dynamic range and lends itself to better post processing later. In actuality, I did no further processing in this regard as I liked the video appearance straight from the camera, as it turned out.

I had two Rode Videomics hooked into the cameras, but used this sound only to sync later with the exterior, separate Zoom H4N audiorecorder using its built in stereo microphones.

The panning shots of the two filters were taken inside my living room in front of my picture window which had excellent even lighting. The Glidetrack made for the smooth right-to-left motion, despite Bruiser, our cat, trying to literally stick his nose into the proceedings.

Premiere Pro CS5 (Trial Version) worked extremely well on my PC - an i7 920 platform with 12 Gigs RAM and a Nvidia GTX 285 video card. The new Mercury engine now makes it possible to edit the native 5D2 and 7D H.264 video files natively -- no prior transcoding necessary. This saves huge amounts of disk space, not to mention time. Scrubbing through the timeline was very smooth, plus no having to sip a cup of coffee every time you render after laying in a video effect or two -- it's that fast!

Brought over a few techniques from CS4 (split screen, multiple camera sync'ing, etc.), plus learned a few new ones on this clip -- magnifying effect, dropping an imported vid file onto the "New Item" icon to create a fresh sequence/timeline with the exact required presets.

All in all, this was a fun video to produce. If any information in this clip was useful re ND vario filters.....then great!! :)

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