Getting Your Pictures Really Sharp
If you are at all like me, you will many times have been frustrated with your pictures coming out un-sharp! This problem can have many sources, and I will try to cover the most common ones in this article.
1. Too Long Exposure Time
When shooting in low light, like in deep shade or near sunset, the light may be so low that the camera needs to use a long exposure time, ie. a slow shutter speed, to pass enough light into the camera to create a clear image.
The result may be that you, or the subject, or both, move slightly during the exposure - creating some blurriness. If everything is unsharp, it was likely you that moved, and if the background is sharp while the subject is kind of hazy - assuming it is something likely to move, like a person or an animal - it was they that moved.
What to do? Make sure you use a shorter exposure. If possible, you can compensate for the shorter exposure time by simply using a larger aperture (which creates a larger opening into the camera to let more light in).
One other thing you can easily do, besides using a larger aperture setting if possible (larger aperture openings have lower numbers on the scale) - is changing the ISO setting on the camera. If you change that setting to a higher number, for instance from “100″ to “400″, it means you increase the sensitivity of the camera sensor to incoming light.
The drawback is that the quality of the picture will be somewhat impaired - there will be more “noise” in the image, which is increasingly evident the larger you make the final picture. However, in some situations you may live with that in order to get a shorter exposure time.
The simple operation of increasing the ISO setting is the modern equivalent of changing to a film with higher sensitivity (a “faster” film) in the old roll film cameras. In these silver-based films, a higher sensitivity meant a film with coarser grain.
Another obvious remedy is to use flash. Now, there are problems with using flash: it tends to destroy the “mood” of the scene and also it only works at short distances (I have seen ridiculous things like people making snapshots of fireworks with the flash unit turned on!). Besides, in some situations you are not even allowed to use flash. Still, it is unfortunately the typical way most people deal with any low-light situation.
Digital cameras may even be pre-set to automatically fire off the built-in flash unit as soon as the light gets low, by default. And the result tends to be a sharp, but very ugly, image. Professional photographers use flash all the time, but in a very sophisticated manner; and I guess if you are one of those you are not reading this anyway - so I won’t try to get into that subject here.
Conclusion: simply firing off the built-in flash unit that comes with every camera is usually not a good solution to the problem of blurriness caused by too long exposure time in low light, in my humble opinion. Instead, try to gain a shorter exposure time by using a larger aperture and/or change to a higher ISO setting.
If all else fails, you can of course stick with a long exposure time, AND use a tripod. This works if your subject doesn’t move and you have the time to get your tripod set up in the position you want. Actually, I have seen very interesting pictures made in low light, by simply placing the camera on the ground or some other solid surface; so don’t despair if you don’t have a tripod or you left it at home because it was so clumsy!
If you snap a picture of something that moves very fast, like a speeding car or a speeding fish, you need to either use a VERY short exposure (like 1/500 of a second), or you pan with the subject - meaning you follow it in the viewfinder and make sure you keep it there while pressing the shutter. Using this method with some skill, you can make very interesting pictures where the subject is rendered sharp but the background is blurred.
2. Incorrect Focus
A different cause of unwanted blurriness in your photos is when there is focus - but in the wrong place! For instance, you take a close-up of a friend standing in front of a building and it then turns out the building is nice and sharp but your friend is blurry.
Usually, this is because the automatic focus mechanism in modern cameras assumes that whatever is at the center of the image in the viewfinder is the most important part of the scene. And if you placed your friend off-center to make the composition more interesting (as discussed in the Rule of Thirds article), then the building ends up in the center of the picture and of course the camera then puts the focus there also!
Remedy: you must anticipate this problem and avoid it by pre-focusing. What that means is: you first place your friend in the center of the viewfinder, and let the camera focus on him/her. Next, you lock the focus before switching to the placement you actually want, with your friend off-center.
So how do you lock the focus? Well, in my experience it is usually done by pressing the shutter half-way down - not enough to snap the picture but enough to engage the focus lock. Please read the manual that came with your camera to make sure how it works in your case. (Reading the manual is ALWAYS a good idea!)
A different variety of this problem is when you try to focus at a shorter distance than the camera can actually handle. On most digicams, there is a special setting you can use when trying to get nice snapshots of snails, butterflies and such critters. Or flowers - the closeup setting is usually indicated with a tulip-like symbol.
3. Other Causes of Poor Sharpness
There are of course other ways you can end up with blurriness in your digicam pictures. For instance, there may simply be dirt on the front lens. Be very careful when wiping off such dirt, or you may scratch the delicate surface of the lens.
And, there may be some technical problem with the camera. For instance, my old Canon digicam seems to have contracted a case of nearsightedness nowadays. Pictures taken at short distances are quite sharp, but everything at a longer distance is rendered slightly out of focus. It gets better if I use the smallest aperture (since the depth of focus increases at small apertures), but by and large I just have to live with this until I can afford to replace the camera.
Photo credits: flower picture by *Micky; ray picture by jurvetson
