Leaving Durban Harbour, South Africa on the MSC Sinfonia
Today's shot was taken from the deck of the cruise ship MSC Sinfonia, as we departed the Port of Durban en route to Portuguese Island and Inhambane, Mozambique. The weather looked a bit threatening, though it was very warm and humid, and the keenest tourists were already lying by the ship pool with cocktails in hand by this point. More technical details on the shot below, but first the tutorial, because it's been a while since the last one!
In the last HDR Tutorial, we looked at how to use a tripod for HDR shooting. Now, suppose for a minute that you have decided to take some HDR photos but you are too lazy to carry a tripod, or too cool to carry a tripod, or are being threatened by a burly but well-cologned museum security guard who confiscates your tripod.
This leaves you with a problem. Not a major one, granted, but a problem nonetheless. You can use handheld shots for HDR, but shooting without a tripod is not advised. Here's why:
- Camera shake. Remember with HDR how you take at least three bracketed shots, varying the shutter speed with each one? Well, your slowest shot is likely to be at quite a slow shutter speed, and possibly hard to handhold without getting camera shake and blurry images. You won't be able to use a blurry image in your HDR set.
- Poor alignment. While your camera is busy shaking and making your image all blurry, it's also ensuring that your three images won't line up at all well when it gets to HDR processing time. You can try and line them up later in software with Photoshop or Photmatix, but if you get them poorly enough aligned when shooting, your software is not going to work.
I do often shoot handheld HDR though, and it works surprisingly well. Here's what to do to make sure things (mostly) turn out ok:
- Auto-bracketing. Use auto-bracketing if your camera supports it. On my Nikon D7000, I can shoot shoot a three shot bracket set on auto, so I can just hold down my shutter button once, and the camera takes three shots for me. I never have to take the viewfinder away from my eye to change settings, so I have very small risk of things not aligning.
- Rapid fire mode. On my Nikon this is called Continuous High (CH) and it allows me to shoot the bracket set very fast. Combine this with auto-bracketing, and you can shoot off your three shots in a second. Again, this makes your alignment much easier later.
- Bigger bracket sets. If you're going to do bigger bracket sets than your camera can auto-bracket, you need to know your camera very well, and your odds of success will be rapidly reducing. You will either need to change all settings by feel without moving your camera from your eye, or you will need to remember exactly how the previous shot was framed. Good luck with that!
- Favour brighter scenes. With brighter scenes you are less likely to run into low shutter speed problems. Unfortunately, the best time to photograph is usually when the light is lower. Murphy's Law right there.
- Watch your shutter speed. Here's a simple calculation you can run in your head to see if you can handhold the shot. This assumes you are shooting a set of -2, 0, +2 and in that order. Your first shot will have the fastest shutter speed, let's say 1/2000 sec, as worked out by your camera exposure meter. To work out the shutter speed of your 0 shot (which has two stops less light), you halve your shutter speed twice. That means your 0 shot will be at 1/500 sec. To work out your +2 shot, do the same thing. It will be at 1/125 sec. You can see that the shutter speed decreases fast, and handholding can quickly become a problem.
- The Reciprocal Rule. This is not about being nice to people and stuff. Rather, there's a rule of thumb from back in the day that helps tell you when you can safely handhold a camera. Take the focal length of your lens. Let's say you are shooting with a 100 mm lens, so take 100 as your value. The reciprocal value of 100 is 1/100, and therefore 1/100 sec is the slowest shutter speed at which you would be able to handhold this camera. If you don't have a full frame DSLR, correct the focal length to full frame first, before you do this calculation. For example, a 100 mm lens on my Nikon D7000 is equivalent to a 150 mm lens on a full frame camera, so I can't handhold below 1/150 sec. Image stabilization cameras and lenses can help you set the shutter speed even lower than this. So can hands of steel.
- Open wide. Opening up your aperture has the effect of allowing you use a faster shutter speed, so if you risk camera shake with a slow shutter speed, make sure you are using your biggest aperture. This is when it's especially sweet to have a fast lens like an f2.8.
- Underexpose. You may want to consider deliberately underexposing your whole bracket set by a stop, to allow a faster shutter speed. So you could shoot a -3, -1, +1 set instead of the usual -2, 0, +2. Watch out for increased noise though, as underexposing will tend to emphasize this.
- Increase your ISO. This is a last resort, as increasing ISO will increase noise on your images, and HDR amplifies the heck out of noise. Still, if it means getting the shot, consider increasing your ISO by a few clicks. How much you can get away with will depend on your camera sensor, and how it handles noise, but I wouldn't push it beyond ISO 400.
- Be the tripod! Be the envy of photographers everywhere. Try and cultivate a sturdy and well-braced posture, and not only will people find you more desirable and assertive, but you could train yourself to handhold another shutter speed setting or two slower.
Today's shot was a bit of a handholding test to illustrate the tutorial. The day was bright, so shutter speed wasn't a problem. I shot the three shots at 1/2000 sec, 1/500 sec and 1/125 sec , which was a -2, 0 and +2 set. The focal length was the equivalent of 30 mm, so the Reciprocal Rule says I can handhold at 1/30 sec. The kicker though is that not only was this shot handheld, but it was handheld while on a moving ship.
As a consequence, the three shots were very misaligned, about as bad as you are likely to get without trying to misalign. I threw them at Photoshop with thumbs held tight, and it did a very impressive job of aligning the images. There were a few slight errors, especially on the crane, and various towers on the skyline, but I was able to remove them with the Photomatix ghosting tool.
That's it! We've come to the end of the tutorials about capturing your bracketed shots on camera. From next week, I will start looking at processing your first HDR image in Photomatix Pro.