Monday, July 12, 2010

Rack 'em and Stack 'em!

Wildlife video making presents its own set of challenges. Frequently the shooting is done in low light conditions at dawn and/or dusk. The subjects are often very small and timid, requiring powerful lenses to give decent image presence from a fair standoff distance away. The very nature of wildlife subjects means that they are likely to be very unpredictable in behaviour and movements. Finally, they are usually well-camouflaged against their background, requiring adept use of Depth of Field to visually isolate and separate them from their surroundings.

My still photography background dictates that the optimal photo equipment would be a high quality dslr coupled with a powerful prime telephoto with as wide an aperture as possible. Flash is not always practical due to the spooky nature of the subjects, the excessive distances involved (Better Beamers notwithstanding), plus the desire to use natural existing light where possible. Continual lighting with video shooting is completely out of the question for most wildlife settings.

Unfortunately, the prime telephoto lenses with large f/2.8 or f/4.0 apertures with long focal lengths (minimum 400 mm) are, for many of us, prohibitively expensive! In the past year and a half, I've acquired two dslr cameras, the Canon 5D Mark 2 and 7D that both offer superb low-noise photo & video capabilities at previously unheard-of high ISO's. This greatly assists shooting in low light with the smaller-apertured (but still high quality) 400mm telephoto lenses by Canon. Many wildlife photographers prefer Canon's prime f/5.6 400mm, which has a reputation for sharp capture and, in the case of still photos, fast auto-focusing ability. Personally, I opted for Canon's popular f/4.5 - f/5.6 zoom telephoto due to the flexibilty of the 100-400mm feature. (Zooming out to 100mm to actually acquire a small subject, then zooming in to 400mm is a real advantage -- saves a LOT of "hunting around" for an elusive target). Sharpness has always been good with this lens for me, and it does an admirable job of locking focus on fast-moving birds in flight when taking photos.

That said, everything changes when you try bumping up the focal length with teleconverters. With the prosumer Canon cameras you automatically lose autofocus, even with the addition of the 1.4x TC to a 400mm f/5.6 lens. Image quality does soften somewhat, and many photographers feel unacceptably so with the 2.0x TC. Does this apply to the Canon 7D's video side? Let's see:

Songbirds in the Backyard from David Rilstone on Vimeo.



Unfortunately, this downsized imbed from Vimeo doesn't have the sharpness that the full 1080p h.264 .MP4 export demonstrates. However, it certainly is sharp enough to see the fine feather detailing on the birds, as well as showing some good blurring in the background which places more focus (pun intended) on the subject itself. The cost of a 100-400m plus the two teleconverters --all combined-- is approx 1/3 to 1/4 the price of a single f/2.8 400mm prime (or a f/4.0 500mm or 600mm lens for that matter). No arguing that the bigger glass would give a better image than the zoom 100-400 + teleconverters, but are the stacked lenses a viable cheaper alternative? It depends on your circumstances and destination of your efforts. For professional National Geographic or Discovery/Life Channel work.....likely not. For casual enthusiast work or even some low end video stock submissions, I'd venture to say yes.

Some production notes:

Songbirds such as sparrows and robins are quite tiny in size and, in my neck of the woods, very timid in nature. This is problematic when trying to fill a video frame with the bird itself. Perhaps going a little overboard, I stacked two Canon teleconverters (1.4x and 2.0x) onto my 100-400mm lens and hooked all this onto my Canon 7D -- with battery grip. My small Manfrotto 501 spring head was almost overwhelmed with all this weight, especially when I slid a Marshall 7" HDMI monitor into the 7D's hotshoe mount to help me with focus and exposure.

The final focal length in terms of a "standard" 35mm full frame dslr worked out to be quite impressive:

400mm (lens) X 1.4x (TC) X 2.0 (TC) X 1.6 (Canon APS-C crop factor) = 1,792mm!!!

I had a real problem with vibration and shaking -- I was on a wooden deck (mistake) and it was a windy day. Definitely a heavy duty Miller tripod + head will be in my future. As it is, the inexpensive remote on/off switch available from Canon is a huge advantage in avoiding physically touching the camera -- any and all vibrations are picked up as camera movement with such a huge magnification factor.

I just picked up a Marshall 7" HDMI monitor at the recent Profusion Expo 2010 in Toronto. As Mr. Philip Bloom would say, "It works a treat". It made everything so much easier - focusing with a bigger screen is in itself very helpful, the inclusion of a peaking filter to verify focus is a bonus. Even checking exposure was easier with the false colour filter on this monitor. Finally, by its flexible hotshoe attachment it's easy to twist the monitor to face any direction, including up and down -- a real boon to anyone with an aching back from hunching behind a camera all day peering into a tiny 3" LCD.

I'm using the fabulous Adobe Premiere Pro CS5 with its new Mercury Playback engine on my i7 920 quad core PC. With its Nvidia GT285 vid card, this version of Premiere Pro can edit & scrub the 7D's h.264 .MOV files effortlessly, with only occasional rendering needed after some visual effects (highlights, USM) were added, along with a lowpass filter to knock out the persistant AGC hiss in the background. I'm holding on to my Cineform Neoscene, but find I'm using it less and less now that CS5 edits in floating 32-bit.

I've gone with Phil Bloom's recommended 7D custom picture style setting of completely knocking down sharpness and contrast (-4 notches each), and reducing saturation within the camera by 2 notches. This yields a fairly flat image which is easy to work on later in post.

I wanted to work at the maximum f/11 aperture to reduce DOF as much as possible to better isolate the subjects from the background. I eschew even the Singh Ray Variable Density Filter for telephoto work, preferring to use ISO as an exposure control (in this case generally ISO 320 worked well). Frame rate was set to 23.97 fps and shutter speed as close to 180 degrees as the camera would allow -- 1/50 second.

Hope the above provides useful information and I welcome any comments, questions, debate, thoughts, etc.

2 comments:

  1. Great shot of the birds!

    Francis

    ReplyDelete
  2. Thanks, Francis! I do a lot of backyard shooting to develop/practice technique, plus work out any possible equipment glitches under "controlled" conditions.

    ReplyDelete