Low light photography needs a careful balance of settings to ensure a sharp shot and avoid hand-shake blur.
Hand-shake blur and sharp results.
Hand held shots often return blurred results. While using auto-settings the problem does not seem to arise. What is going on and how do you overcome hand-shake blur?
Manual settings and auto
Your digital camera is a sophisticated computer. It has access to a range of powerful programs that make decisions about each shot. When you use auto settings you are handing the camera over to the control of its programming. The auto setting is selected with the green square on the program dial. It makes all the decisions and you just point and shoot. This ‘auto’ strategy is limited. It leaves you unable to make creative decisions about your shot. Depth of field, movement blur and the light or dark emphasis in a scene is beyond your control.
With any of the manual settings on the program dial things are different. Shutter speed (S or Tv), Aperture (A or Av) and ISO settings allow you to get control of the exposure. Once you control these settings you are able to make creative decisions about your shot. But if you get it wrong you might allow hand-shake blur to creep in. Equally, with the right strategy, you can also set up to prevent the effects of hand-shake blur.
What causes hand-shake blur
Low light, long shutter opening or low ISO can all contribute. Hand shake-blur is caused by hand movement while the shutter is open. To prevent it you shorten the time the shutter is open. With a shorter shutter opening any hand movement is not given time to impact on the shot. Very fast shutter opening, say 1000th of a second, freezes the shot. The hand has almost no time to move in that short period. So, no hand-shake blur.
However, short shutter opening time means less light reaches the sensor. A good exposure requires sufficient light. A shutter speed of 1000th of a second would leave the picture under exposed in low light conditions. On the other hand, if you select a 15th of a second, the shutter is open for a long time. Hey presto! Enough light. But, (boo!) hand-shake blur. The shutter is open too long. Your hands have plenty of time to move.
Over coming hand-shake blur is about balance
If you raise the ISO setting, the sensor becomes more sensitive to light. So, raise the ISO until you can set the shutter to around 200th of a second. At that speed it is easier to hold the camera steady.
Of course, if you have to raise the ISO a lot to allow 200ths sec. you will get a grainy picture. Raising the ISO reduces the quality of the shot. Ideally an ISO setting of 100 will give you the best quality photographic result. On an average day you may have to set your ISO at around 200 or 400 to get a 200ths of a second shutter speed. Up to about ISO 800 the quality from most good DSLRs will be fine. After that, the quality of the image will be affected more and more by grain or “Digital Noise”.
Pictures taken in a dark church, or at an evening dance will have very low light. So, as an example, an ISO of 1600 would possibly give you enough sensitivity to work with a shutter speed of, say, 160th of a second. That would allow you to get a hand-held shot without hand-shake blur, if you have a steady hand. But you might also get a little digital noise in the final image.
Getting the right settings between the ISO and shutter speed is a fine balance. You need to raise the ISO the right amount to give you the shutter speed you need. Too much ISO and you get bad quality in the picture. Too little ISO and you will be forced to use a shutter speed that’s too low. Hand holding under these low light conditions may cause hand-shake blur.
Hand-shake blur and aperture
With ‘auto’ shots the camera program takes account of the light conditions. The program sets the ISO, aperture and shutter speed to values that allow shorter shutter opening. So far we have only discussed shutter speed and ISO. But aperture has a part to play too.
If you open the aperture wider it lets in more light. So, you don’t need to raise your ISO so high if you also open your aperture. In our church example above, an ISO of 800 (not 1600), shutter speed of 200th sec. and an aperture of f4 (wide) could create a good exposure.
If your aperture is set at say f11 (small) less light will get through. So, again you are going to need to have higher ISO or long shutter opening (or both), depending on your light conditions. A small aperture, like f11, will give you a sharp picture to infinity. But, you may have to sacrifice picture quality (high ISO) or suffer hand-shake blur (from longer shutter opening).
The wide aperture does have a penalty too. As the aperture gets wider the depth of field gets shallower. So once again we are back to a balance. To hand-hold a camera we must make decisions about all three basic settings – Shutter speed, aperture and ISO.
Other strategies for avoiding hand-shake blur
Camera movement or hand-shake blur can be avoided in a lot of different ways. Sometimes you must work in situations where hand-shake blur is inevitable without more radical solutions. Then there are other things you can do to reduce hand-shake blur. Here are some of them…
- Lens anti-vibration: Many quality lenses have anti-vibration systems. These sophisticated systems detect hand-shake blur as it happens and counteract it. This might extend your safe shutter speed down to quite slow shutter speeds (say a 60th of a second). While this many not solve all your problems it can help in less extreme light conditions.
- Tripod: A steady platform will prevent camera movement. If you need a long shutter opening then work from a tripod to eliminate hand-shake blur.
- Flash: If you are working in a low light situation you may need to raise light levels. A flash unit, on or off the camera, is one answer. An intense flash of light can raise the light high enough for you to work with settings that prevent hand-shake blur.
- Studio lights: More controllable, but more expensive, these lights can accurately raise light levels to enable you to reliably avoid hand-shake blur and get a good exposure.
- Reflectors: You can use these to bring more light to where you are working by, say, reflecting from another artificial light or natural light source. Reflectors are particularly useful in reducing the darker areas of a shot. You can reflect the light to just raise light levels in some areas bringing the over all light level up. As the light level across the shot is raised the hand-shake blur can be reduced since shutter speed can be faster.
- Improve your stance: A better stance is a great way to improve your steadiness.
- Go to the gym: “What? This is about photography not fitness”, I hear you say. Well, here is a revelation. If your arms are stronger you can hold the camera steadier. A DSLR is a heavy object. Especially after a long session your arms will not hold the camera steady. If your camera is too heavy for you – well, strengthen up. Actually, more strength gives you much better motor control of your hands in any case. You will be able to hold even a point and shoot camera or phone with a steadier hand after regular exercise. Photography, like all other pursuits benefits from a fit body. Improved fitness will reduce hand-shake blur.
The answer to avoiding hand-shake blur
The auto program in your camera may give good results and reduce hand-shake blur. However, it will only do so in average conditions. In more extreme conditions, or where you want to exert some creative control over your shot you need to go manual.
The use of manual settings gives you control. You can control depth of field, subject movement-blur and light vs. dark emphasis in your shots. But, to get the best out of your camera you will need to set it up to avoid hand-shake blur. In this article I have tried to help you understand that the settings you pick can help you control hand-shake blur. Overall, the answer lies in creating a balance between the basic settings of aperture, shutter speed and ISO so that your hand held shutter speed is around 200ths of a second or higher. Lower than 200ths of a second and hand-shake blur is liable to creep into your shots.
Of course there are other things you can do to help raise your shutter speed. I have mentioned some of them. But they all have the same effect. They either stabilise the camera (tripod) or allow you to get the shutter speed high enough so you can steady the camera. So, now you know. Get out there and try to get your settings so you have around a 200th of a second when you take the shot.
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Damon Guy (Netkonnexion)
Damon is a writer-photographer and editor of this site. He has run some major websites, a computing department and a digital image library. He started out as a trained teacher and now runs training for digital photogs.
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