Every month, National Geographic staff photographer Mark Thiessen answers your photography questions—and spills the secrets behind the shots.
Widely published in books and magazines, Thiessen has been on staff at National Geographic since 1997. He's covered subjects from the discovery of the U.S.S. Yorktown to the search for other Earths. He is also a certified wildland firefighter.
July 2008
- What are your tips for a newbie wildlife photographer, and what equipment (lens, film, etc.) do you recommend?
- How do you photograph water with that soft motion?
- My digital camera often puts a red AF sign in the window and the picture goes blurry. I have tried loads of different settings when it does this and it just won't focus correctly. Also, I love taking close-ups of plants and insects. What is the best setting for this type of shot?
- With outside and landscape photos I always seem to get the picture too dark. On the camera, after I take the picture, the lighting looks great, but when I download it to my computer it is way too dark. I have ruined a lot of what I thought were good photos.
- Do you always use manual exposure mode? Or do you prefer aperture/shutter priority mode?
- How do you achieve the correct light exposure, what technique do you use in digital photography, and what kind of in-camera exposure meters do you usually use?
- I have had the incredible luck of stumbling on a very rare photo opportunity. How do I copyright a photo to sell and/or publish?
- How does spot metering work, in what conditions is it used, and how useful is it?
- Do you have any tips for action photography? I’m learning with a new digital SLR and am a little confused with the f-stops, ISO, and shutter speeds, and all my photos turn out blurry.
- What is the most versatile set of lenses and camera filters for 35mm DSLR photography?
- Do we need specific lenses or flashes to take pictures at night (for digital or manual cameras)?
Q: What are your tips for a newbie wildlife photographer, and what equipment (lens, film, etc.) do you recommend?
A: Animals can spook easily, so you will need a telephoto lens to get close. Something in the 300-400mm range should work. Some wildlife photographers shoot from a camouflaged blind to get even closer shots. Another technique is to position a camera close to a den or nest, using a shorter lens, and fire it remotely with a wireless transmitter. Then there is the "set it and forget it" approach—using motion triggers to trip your camera when the animal's motion triggers the camera. As for technique, get close enough so you don’t need to include the entire animal in the frame. Shoot in early morning or late afternoon when the light is best and when animals might be feeding. This means arriving or leaving in the dark and being very quiet. A tripod is best to keep camera shake to a minimum when using a long lens. Don’t be afraid to increase the ISO on your digital camera if the light is low and you need a higher shutter speed. These newer digital cameras perform wonderfully at higher ISOs.
Question submitted by Prakash in Kolkata, India
Q: How do you photograph water with that soft motion?
A: The "silky water" effect is achieved by taking a time exposure of moving water. First set your camera on a tripod so it won’t shake during the long exposure. Set your ISO to the lowest number. Next, reduce your aperture all the way. This will allow you to use the slowest shutter speed possible. If the shutter speed is still too fast, attach a neutral-density filter to your lens. This will knock down the light further without adding a color cast. In bright sunlight I find long exposures of water difficult because it’s so bright and the water turns out too contrasty. It’s best to try this in open shade or at dusk or dawn when the light is softer. Whenever I’m doing time exposures there is the chance I might shake the camera while pressing the shutter release button, so I always use a cable release to trip the shutter.
Question submitted by Heather in Sutton, West Virginia
Q: My digital camera often puts a red AF sign in the window and the picture goes blurry. I have tried loads of different settings when it does this and it just won't focus correctly. Also, I love taking close-ups of plants and insects. What is the best setting for this type of shot?
A: It difficult to tell exactly what the problem is without more information. But here are a few possibilities. Your camera’s autofocus mechanism works by detecting the sharpness of contrasting tones in your subject. It doesn’t focus on the entire scene, only the portion of the scene in the autofocus box. If the box is over an area of the scene with no contrast, like a clear blue sky, or a black shirt, then your camera might have trouble finding focus. You can tell this is happening when your camera is continuously changing focus as it seeks to find sharpness. The red AF sign could be a warning telling you the camera can’t determine if the image is sharp or not. Since you mention close-up photography of plants and insects, the problem could be that you are trying to take a picture of something too close for your camera to focus on. It tries its best but can’t find focus, so it throws up the red AF sign as a warning. Most digital cameras have a macro mode that allows it to focus very close. This button is often represented by a flower icon.
Question submitted by Amanda in Isle of Wight, United Kingdom
Q: With outside and landscape photos I always seem to get the picture too dark. On the camera, after I take the picture, the lighting looks great, but when I download it to my computer it is way too dark. I have ruined a lot of what I thought were good photos.
A: There could be several reasons why your landscapes are turning out dark. One reason might simply be that your computer monitor is not calibrated properly and is displaying perfectly exposed landscapes as too dark. There are several monitor calibration software packages on the market that can help with this. One way to check this is to look at the histogram for the image on your computer. A histogram is a graph of the different tones in the image from black to white and everything in between. (You can view the histogram for your image in most photo-editing software.) See if the histogram roughly matches the image on the screen. Another reason might be that your camera meter is being fooled by the bright subject matter in the scene. Generally speaking, a camera’s meter wants to make the scene a neutral gray. If you are shooting bright snow or sand dunes, there is a good chance your meter is underexposing the scene. Take a range of exposures, some lighter, some darker, to try and troubleshoot the problem. If you are using an autoexposure mode, try adjusting the exposure compensation to the plus (+) side to overexpose your landscape to compensate for how the scene is fooling your meter.
Question submitted by Andrew in Caldwell, Idaho
Q: Do you always use manual exposure mode? Or do you prefer aperture/shutter priority mode?
A: Autoexposure allows me to pay more attention to my subject than to the changing light conditions. I use aperture priority most of the time. This automatic mode allows me to select the aperture while the shutter speed is automatically adjusted to match. If the scene changes brightness, the shutter speed will automatically change as well. Although you might be surprised that I use autoexposure nearly always, I often use it in combination with exposure compensation. Camera meters try to adjust the exposure of the scene so it is a middle-gray. For example, if I’m shooting a snow scene, the camera’s autoexposure will underexpose, making the white snow gray. By using exposure compensation, I can set the camera to slightly overexpose everything.
Question submitted by Maciek in Poland
Q: How do you achieve the correct light exposure, what technique do you use in digital photography, and what kind of in-camera exposure meters do you usually use?
A: I usually use evaluative metering to achieve the best exposure. In evaluative metering, the camera divides the scene into several zones and does calculations to come up with what it thinks is the right exposure. It is well suited for most subjects, including those that are backlit. It is basically just what your eyes do when looking at something. Because it is often too bright outside to accurately view the image in the LCD monitor, I use the histogram on the camera to help judge if the meter correctly exposed the scene. The histogram is a simple graph that displays where all of the brightness levels contained in the scene are found, from the darkest to the brightest. These values are arranged across the bottom of the graph from left (darkest) to right (brightest). If I think the meter isn’t accurate, then I will use the exposure compensation setting on my camera to over- or underexpose the scene.
Question submitted by Pedro in Temuco, Chile
Q: I have had the incredible luck of stumbling on a very rare photo opportunity. How do I copyright a photo to sell and/or publish?
A: You don't have to copyright your photo. It's already copyrighted, and you own the copyright. You don't need to submit a form, and you don't have to use that "©" symbol or a digital watermark—those are just customary ways of identifying the copyright owner. At the moment of creation, when the artwork is "fixed" in some tangible form, copyright applies automatically. For a photographer, when you press the shutter release you are making a photo and gaining copyright to that photo at the same time. You don't have to declare copyright or file any paperwork. Copyright applies to most artistic works, such as paintings, murals, statues, TV shows, music, and for us, photography. It gives you as the photographer the exclusive right to make and sell copies of the photo. As for selling your photo there are several online stock agencies that have cropped up, such as istockphoto.com or fotolia.com. These sites allow anyone to upload their photos to sell, but the sale price is very low, ranging from $1 to $10.
Question submitted by Debbie in Rexburg, Idaho
Q: How does spot metering work, in what conditions is it used, and how useful is it?
A: Spot metering tells the camera to do its metering from a very small area in the scene. It gives the photographer far more control over the exposure than any of the other settings, but this also means that it is more difficult to use, at least initially. It is useful when there is a relatively small object within your scene that you either need to be perfectly exposed or know that it will provide the closest match to middle-gray. One of the most common applications of partial metering is a portrait of someone who is backlit. Metering off of their face can help avoid making the subject look like an under-exposed silhouette against the bright background. Spot metering gives you very exact control when there is a very specific (and small) part of the scene that you want to get right.
Question submitted by Ritin in Bangalore, India
Q: Do you have any tips for action photography? I’m learning with a new digital SLR and am a little confused with the f-stops, ISO, and shutter speeds, and all my photos turn out blurry.
A: To capture fast-moving action, you need to use a high shutter speed somewhere around 1/500th or 1/1000th. The shutter speed is represented as a fraction. For example, a shutter speed on your camera of 500 really means 1/500th of a second, which is a higher shutter speed than 1/250th of a second. Since the shutter is open for a shorter time, less light reaches the sensor. Set the f-stop (aperture) of your lens to the widest setting (the lowest number). If that still doesn’t get you an action-stopping shutter speed, then increase your ISO. The ISO is how sensitive the sensor is to light. Increase the ISO until the shutter speed is fast enough to stop the action.
Question submitted by Eva in West Jordan, Utah
Q: What is the most versatile set of lenses and camera filters for 35mm DSLR photography?
A: I use a Canon 5D, which has a sensor the same size as a frame of 35mm film. My kit has three zoom lenses: 16-35mm, 24-70mm, and 70-200mm. With this set of lenses there isn’t much I can’t do, and they don’t take up much room. The widest aperture of these lenses is 2.8, which means they let in a lot of light so I can shoot in low-light conditions. If your digital camera uses a smaller chip, look for lenses of a comparable focal length. As far as filters go, I suggest using a UV filter to protect the front element of your lens. It is basically clear and won’t influence your image. If you are constantly cleaning your lens like I am, there is a chance it may get scratched. It’s much easier to replace a scratched filter than a scratched front lens element. I also suggest a polarizing filter. This filter can help remove reflections and give you deeper, richer color. It comes at a price, though, as it will knock down the light by two f-stops.
Question submitted by Mohit in Himachal, India
Q: Do we need specific lenses or flashes to take pictures at night (for digital or manual cameras)?
A: To take pictures at night you don’t need special lenses, but you do need something to steady your camera, such as a tripod. Because it’s so dark you will need a long exposure to capture the scene. Some cameras have a “night” autoexposure setting that allows long shutter times. If yours doesn’t, set your camera on something steady like a park bench or tripod, then try different long exposures until you get a pleasing image. We are talking exposures that are in the seconds. I prefer to shoot several exposures, some lighter, some darker, then review them later on the computer. I find it difficult to judge exposure while looking at the camera’s LCD at night.
Question submitted by Vanessa in San Jose, Costa Rica
