Shake it Up!

Shake it Up!

Probably the best way to relegate an image to obscurity is to post it on the Thursday before a long weekend (officially in Canada, and I suspect more than a few will turn it into one below the border)...but what the heck...

One of the most predictable things in the animal world is that when a swimming bear gets to land, it wildly shakes its whole body! So, if you know this and happened to be in a position in FRONT of the bear, you have a good chance at capturing a reasonably interesting shot - assuming you know the shutter speed to select. Which begs at least two questions. First, what shutter speed do you need to freeze action? And, what shutter speed do you need to pull off the tricky old "freeze-blur" combination (as shown here)?

In answering both these questions I could point out a million little things that could affect the answers - things like how big the subject is in the frame, how fast the subject is moving, what resolution the final image will be displayed at, etc. But at the end of day really only one thing has to be considered: how many pixels (or, a little more correctly, photosites) is the moving object going to cross on your image sensor per unit time? Cross MORE pixels per unit time and you need a faster shutter speed to freeze the action. Cross fewer and you can get by with a slower shutter speed (and still freeze the action). So, a distant subject that occupies a tiny portion of your viewfinder can be frozen at a much slower shutter speed than can the same object that is moving at the same speed but is much closer.Why? Because when closer it's crossing more pixels per unit time. There are lots of consequences of this - to freeze the action using a higher resolution camera (like a D800) that has "tiny" photosites on its sensor requires a much higher shutter speed than doing the same on a lower resolution camera (such as a D3). So...given the number of different cameras (with different resolutions) in use and how many different shooting situations exist (particularly in reference to how close the subject is), it's virtually impossible to give an absolute rule of thumb. The best thing I can suggest is keep the "how many pixels crossed per unit time?" concept in mind and get out and shoot some test shots with YOUR camera.

Subject: Adult Grizzly (Urus arctos) shaking off water
Location: Khutzeymateen Inlet, Great Bear Rainforest, BC, Canada
Camera: Nikon D4
Lens: Nikkor 400mm f2.8 VRII lens - hand-held from floating zodiac. VR on and in "Normal" mode.
Exposure: 1/400s @ f5; ISO 320. -0.33 stop compensation from matrix-metered exposure setting.
Crop: This is about 85% of the full-framed image

Additional details about the image (including processing details) available here

http://www.naturalart.ca/galleries/latest/detail_2.html.

Comments and critiques welcomed - probably best to view the larger version prior to doing so!

Cheers...thanks for looking...

Brad