Every photographer wants crisp and sharp images, yet quite frequently the results can be disappointing. Here are some quick tips to achieving the sharpest images possible with your existing gear.
(Nikon Df with Nikkor 200mm AI-s lens at f/8, 1/100 sec)
Keep your equipment clean. This is the basic pre-requisite for sharp images. Dirt on the front of the lens does not interfere in photographs however it does soften the images. So do finger-prints, mist, spray from sea-breeze or even clumsy cleaning marks. The front surface of the lens is most prone to getting dirty. Don’t wait for it to get really greasy before cleaning. For getting sharp images clean your lens as soon as you notice any dirt on it. Apart from dust, another culprit in old lenses is fungus. Store your lenses in dry places and use them frequently to prevent lens-fungus from developing.
Remove all the filters. Every piece of glass in front of the lens reduces the image quality. Even the most expensive filter that you can afford will also be an added material for the light to pass through. Remove all the filters if possible and then capture your photograph.
Use a lens hood. This prevents stray light from entering into the lens and retains the contrast in the scene. Contrasty photographs appear sharp. Use a lens hood even if there is no obvious source of light directed towards the lens. (Hoods & Lens Flare)
Set the sharpest aperture. The widest open aperture should ideally be the sharpest theoretically. However in real world, various aberrations and flaws in optical design prevent this from happening. As the aperture is closed a little, lenses start giving their best performance. When the aperture is further closed down, the diffraction of the light from the edges of the aperture blades becomes significant in comparison to the total area and the image starts to soften. I have found the sharpest aperture setting on most of my lenses on closing down around 3 stops from the widest. For most primes this is around f/5.6 and most consumer normal zooms this is somewhere around f/8.
Set Vibration Reduction to Off. While vibration reduction or optical stabilization may help use lower shutter speeds but in the presence of good amount of light (where the shutter speed is sufficiently high) or while using a tripod, this can be counter-productive. Go old school and forget about this mode if your aim is to achieve razor sharp images. This mode does help when the light is low or you have to shoot hand-held at slow shutter speeds. In such cases, do switch it on but always remember to capture some photographs even in such conditions with vibration reduction switched off.
Reduce the camera noise but add grains later on. Use the lowest ISO possible. Camera noise robs an image of its sharpness. However some amount of grains added during post-processing gives a false perception of increased sharpness. (Remove Noise, Add Grain)
Stabilize the camera. Use a sturdy tripod. Follow the tips from this article to get the best out of your tripod – Buying a Tripod. If you can’t use the tripod and the shutter speed is also going to be slow, then use the tips from this article – Flash and Tripod – Not allowed !. Camera movement appears as a blurred photograph but very few photographers know that slight movement of camera can make the photograph appear soft though not blurred. Yes, even soft or unsharp images can result due to camera movement even though the overall photograph may not show signs of this camera movement.
Mirror lock and remote release. Mirror slap (what a strong word for this movement of mirror!) which happens when the mirror in the DSLRs moves up is a source of vibration, that unfortunately occurs just an instant before the image is captured. By locking up the mirror before exposure, this vibration is allowed to die down before capturing the image. Most DSLRs have an option to lock up the mirror before exposure. Another work around for cameras that don’t have this feature is to use a timer. As soon as the timer is engaged, the mirror locks up in most cameras.
Similarly press of the shutter release button is another source of vibration. Using a remote release helps by removing this vibration. Use both of these methods when your camera is mounted on a sturdy tripod.
Focus well. Even slight error in focusing will make the subject appear soft. When in doubt, either zoom in on the subject in liveview and then click or use a slightly smaller aperture than required to increase the depth of field. Some amount of focusing error can be hidden away when the depth of field is sufficiently deep. However remember that regardless of the depth of field, the sharpest image is always formed at the plane of focus. So, work meticulously to focus well. I recommend using manual focus. (Staying Focused) or single point AF using the central focus point with the help of back-button for AF.
Stay away from extremes of focal lengths on your zoom. If you are using a zoom, do not use the extreme ends of the zoom range. Most zoom lenses are soft on their extreme ends. For a 18-55 mm lens that comes as a kit lens with many cameras, I recommend using the lens within about 24-45 mm focal length range. This method also has the added advantage of avoiding extremes of pin-cushion and barrel distortions. Use prime lenses if you have them. Though this article is about getting the sharpest images from your existing gear, it does help to have sharp lenses to begin with.
Click raw and post-process. Whatever techniques you use, the photographs will still turn out to be softer than required. This is where post-processing steps in. Click raw and post-process all your images. While post-processing, use sharpening (unsharp mask) to neutralize the softening nature of digital photography. (Sharpening)
Expose to the right of the histogram. Overexpose a little but take care that the highlights don’t get blown out. This is where the histograms come of use. Review the histogram after capturing the image and check that there is no clipping of highlights. Even if you need a low key photograph, adjust the exposure in post-processing.
Keep the subject stable. Similar to camera movement, subject movement also softens the image. This is especially true when trying to photograph landscapes on a windy day. Nearby leaves to get slightly blurred but what most people don’t understand is that even the distant trees exhibit some amount of softness. So if you want to capture a razor sharp landscape, going out on a windy day is a bad idea.
(Opera House – Odessa, Ukraine. Nikon D200 with Nikkor 18-35 mm lens. More on using wide-angle lenses : Using Wide-Angle Lenses)