Today’s Question: I appreciate that you include the camera settings with your photos when you share them, as I find that information informative. However, I’m confused about the settings for one of the images you shared on 500px:
Your metadata shows that the shutter speed was 1/8,000th of a second. Why would you use such a fast shutter speed for a subject that wasn’t moving?
Tim’s Quick Answer: This was essentially a case of “insurance speed”. I was on a moving ship (though moving slowly), was using a long telephoto lens (600mm focal length for the photo in question), and I was shooting hand-held. Thus, I wanted the fastest shutter speed I could reasonably achieve to help ensure a sharp photo under the circumstances.
More Detail: The photo shown on my 500px page at the link above was captured near Hubbard Glacier in Alaska. We had started to depart the Russell Fjord when I spotted the snow-covered peaks. The ship had already been moving, and I was using a Tamron 150-600mm lens (http://timgrey.me/1WyqJ4n), frequently zooming all the way to 600mm.
I was not using a tripod at this point, in large part because the ship was already moving. The vibration of the engines can be transmitted through the ship itself, through the tripod, to the camera, causing blurring. In addition, maneuvering on the deck of the ship can be a challenge with a tripod. Although the sky was overcast, the layer of clouds was relatively thin and so I was able to achieve fast shutter speeds. So I opted to work without a tripod.
When shooting hand-held, the general rule of thumb is that you want the reciprocal of your shutter speed to match (or exceed) the focal length of the lens. So at 100mm I would want about a 1/100th of a second shutter speed, and thus at 600mm I would want about a 1/600th of a second shutter speed. However, with super telephoto lenses (even a lens that has image stabilization technology built-in, such as the lens I was using) I prefer to be far more conservative.
Because there was relatively good lighting even with the overcast sky, getting a fast shutter speed didn’t require much compromise. I was using an aperture of f/8 in an effort to ensure the sharpest images possible. I wanted the fastest shutter speed I could get, and by boosting the ISO setting up to only 400 I could achieve the maximum shutter speed (1/8000th of a second) for my camera.
I am perfectly comfortable with the degree of noise produced by the camera I was using (a Canon EOS 7D Mk II, http://timgrey.me/tgtv7d2) at an ISO setting of 400. So in this case the decision was easy. I could shoot at f/8 with an ISO setting of 400 and achieve a fast 1/8000th of a second shutter speed. That worked out well, and more importantly the scene was very nice, with snow-covered peaks seeming to blend in to the overcast sky above.