Filters
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I promised this a little while back and an finally getting around to it. Filters, and their place in whitewater kayaking photography. I’ll brush on some other aspects of photography too.
I’m just going to cover a few of the most commonly used filters here.
UV aka Skylight filter.
In the old days these were used to block UV rays. They can make a big difference on film, and almost none on digital, because the glass now used in lenses, combined with digital sensors, will filter UV rays on their own. They still remain popular as a layer of protection for the front element. I personally don’t use these, at all. As a rule of thumb (and of course there are exceptions) there more elements (pieces of glass) in a lens, the more prone the lens is to flare and ghosting. What’s flare and ghosting? That’s when stay light hits the front element and leaves a flare, or ghost in the image. The glass in all lenses since the late 60’s have coatings that help reduce flare and ghosting, but cheap UV or skylight filters are often not coated. So adding in this extra, often sub-par element into the equation makes flare worse, and if it’s a cheap filter, degrades the overall image quality. Want protection for the front element? I recommend the appropriate lens hood, it will reduce the chance of stay light hitting the lens and causing flare, and help increase contrast for the same reason.
Will a UV or Skylight filter help improve your whitewater (or any photos)? Nope. It will also not hinder your whitewater shooting because you should be shooting with the sun, so flare and ghosting wont be a problem, unless you go for back lit images, in which case it will cause problems. I’d rather be careful with my lens and spend that same money on the appropriate lens hood.
Light from the flash hit the front of the lens, so there is some flare.
Circular Polarizer.
A polarizing filter sounds just fabulous for shooting whitewater. Circular vs linear polarizer? Both do the same thing in different ways, but with a linear polarizer you can’t use the AF or metering in a modern TTL (through the lens) camera. All dSLRs are TTL. No problems with a more expensive circular polarizer, all functions still work as normal. A polarizer filter helps remove the glare from water (and glass) among other things. The good: They do reduce glare. The bad: To effectively reduce flare, the lighting has to be pretty bad, they work best at 90 degree angles to the sun rays. Using one may help bad lighting look a little better, but it’s still bad lighting, see example below. The other major downside to a circular polarizer is that they reduce the amount of light entering the lens by roughly two stops. If you stop and think about it, that’s a lot! We’re talking about F8 down to F4, and if you have a consumer zoom with a maximum aperture of 5.6, you’ll be forcing your shutter speed down or ISO up, even in broad daylight.
I don’t think it’s much of an addition to shooting whitewater due to it’s drawbacks, and a few years ago when I left mine on a river by accident I’ve never replaced it. More useful for landscapes where you can use a tripod and ignore the two stops loss of light.
I used a polarizer on this shot to reduce glare from the water, but the lighting is still too bad to do much with it, I should have chosen my angle based on the light not the drop.
Dustin Knapp, West Cherry.
Nikon D200, Nikkor 50mm 1.8 @ 1/1000 F5 ISO 250 with a B&W Circular Polarizer
Graduated Neutral Density.
The Grad ND for short. Not too common for action sports shooters, wildly (and rightfully so) popular for landscape. Grad ND filters reduce light on one side, and then fade to normal on the other. Useful for shooting scenes with a large dynamic range between the foreground and background, typically mountains and sky together.
Stand Up Paddle in downtown Sacramento, no Grad ND.
Nikon D700, Nikkor 50mm 2.8 @ 1/800 F8 ISO 200
Stand Up Paddle in Sacramento again, two stop Grad ND.
Nikon D700, Nikkor 50mm 2.8 @ 1/800 F8 ISO 250 and 0.6 Grad ND.
Useful in whitewater? Maybe more often than you would expect. Often the whitewater is so bright, the landscape also included is too dark. Here I used the same 2 stop (0.6) Grad ND filter, dark side on the bottom to reduce how bright the water is, so the hillside shows up too.
Lots of people, Burnt Ranch Race 2009.
Nikon D700, Nikkor 20mm 2.8 @ 1/1000 F7 ISO 200 + Grad ND 0.6
On the whole, I personally rarely use filters while shooting whitewater. They can be priceless for landscapes, but have just too many compromises while shooting sports, other than the very occasional use of the last one people would expect, a Graduated Neutral Density filter. Spend that money on the right lens hood!
