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Wednesday, September 9, 2015
Mostly It's a Shutter Thing
With many years of photography under my belt now, and several years as a wildlife photographer, I can honestly say that shutter speed will make you or break you in this genre. In this post I will examine why the shutter is so crucial in wildlife as well as other action photography disciplines.
The shutter in your camera is quite a powerful and useful tool. From a technical perspective, the shutter mechanism is simply a set curtains that open and close for a certain period of time. This action allows light to hit the film or sensor for a measurement we call shutter speed. For example, a shutter speed of 1/500 causes the shutter to open for 1/500th of a second exposing the sensor. Essentially the shutter controls the time of exposure and the aperture controls what is in focus in the scene. OK, so that is the technical, but why is the shutter operation so vital to understand?
Stopping the Action
First, let's talk about high shutter speeds and what they can do for us. A high shutter speed, in my book, is any speed set at 1/500th or higher. Using a high shutter speed is vital for capturing fast action shots and freezing the subject, but how can you know how fast is fast enough? My answer to this is quite simple. Use as fast a shutter speed as you possibly can. Generally, I keep my camera set on manual at 1/1000th of a second, aperture wide open and an ISO of 400( when it is stowed in the camera bag). This gives me a good starting point in case I need to use my camera suddenly. If I know before hand that I am going out to shoot birds in flight, or running deer, I will set my camera to shutter priority and start at about 1/1600 and auto ISO. In order to stop the bird's wings, I will need at least 1/1000th, but I prefer to get as close to 1/2000th as possible. Once I am there and shooting, I usually switch over to manual so I can fine tune the exposure better. With my 7D, I also set the auto-ISO threshold to 1600 speed because the APS-C sensor is slightly more prone to noise problems.
Why are my Animal Pictures so Blurry!
This is a question I get from beginning photographers, and primarily, what they are seeing is not a focus issue ,but rather it is a problem called camera shake. Camera shake is caused by having a shutter speed which is long enough to capture the movement caused by hand holding the camera and lens. Humans do not do very well holding something in front of them for any period of time and their muscles weaken causing the camera to move while exposing the shot. Even tripod mounted, micro-vibrations can cause camera shake with long lenses. Camera shake is truly the enemy all all photographers, and wildlife photographers are no exception. In order to fully discuss this evil foe, I want to break down two scenarios to help you understand the problem.
Low Light and Long Lens - in this scenario, we have a subject which is in low light such as early morning and we are using a lens in the 400-600mm range. First, I highly recommend you have your camera and lens mounted on a tripod when shooting with long lenses in general. The tripod will help to reduce shake caused by hand holding. Next, rest your left hand on the lens barrel between the tripod collar and the camera body. This will keep micro-vibrations from causing camera shake. Do not press the left hand down hard on the lens as this could damage the lens or lens mount. Just rest it gently. Finally, rest your finger on the shutter release button breath in, slowly exhale and hold your breath while firing the shutter. The bear picture below was shot using the above technique. I had a shutter speed of only 1/100 and was mounted on a tripod. That is a very low shutter speed and should not be attempted hand held or with a moving subject.
Mid-morning Daylight and a Long Lens - in this scenario we have good mid-morning light and are shooting with a lens in the 400-600 range. This is the conditions I was in when shooting the osprey above. At At this point, we have stronger light which means you can shoot at higher shutter speeds, but now you have a choice. Do you shoot on a tripod or not? For me, I am going to shoot handheld whenever possible. Shooting handheld allows me to be faster and to frame my subject better, but it is not always the right choice. There are variables to consider such as the weight of the camera and lens, the predictability of the subject, and what are acceptable noise levels. To help answer the tripod question ask yourself this: Can I get a shutter speed high enough to keep camera shake at bay and freeze the action? If you can achieve 1/1000 of a second or higher than you may be able to hand hold the lens correctly. Remember that we are talking about big lenses here. My 600mm becomes effectively a 960mm when used on my 7D and weights about 6 pounds when the camera is attached. That is the weight of a new born baby! That focal length will be a huge increase in magnification over your typical 200mm telephoto. Remember, magnification increases the movement of the camera and causes camera shake. Honestly, to shoot handheld even in these conditions, I am going to need at least 1/1600 for me to feel comfortable. I am not saying you couldn't pull off shooting a bit slower, but my goal is to go home with the shot, not a bunch of blurry images.
This blog post gives you a quick view of how to improve your wildlife image quality and keeper rate. As time goes on and you improve your photography, you will find your own combinations and scenarios which work best for you. Here is a summary of my best practices....
Keep your shutter speed high(1/500 to 1/2000) to reduce camera shake with long lenses.
When tripod mounted, rest your left hand on the lens barrel between the tripod ring and the camera body to reduce micro-vibrations.
Do not shoot handheld birds in flight at less than 1/1000th of a second (unless going for artistic blur, but that's another blog post).
Big lenses magnify any type of movement more than smaller lenses so keep the shutter speed high.
Don't be afraid to use higher ISO to get higher shutter speeds. Of course this is within reason. I recommend capping the ISO at 1600.