Image sharpness

image sharpness

There s no point spending a small fortune on a high-resolution DSLR andtop-quality lenses if you don t make the effort to get the very best from them. An obvious place to start is with cleanliness - dirty/dusty/ smeared lens elements and filters are going to knock the edge off image sharpness, so check optical surfaces regularly and keep them sparkling. Scratched filters are another no-no. Okay, so you may have spent £50 on an NDgrad, but the lens probably set you back £500, so if the filter s scratched, bin it and buy another one.

Technically, there are also steps you can take to maximise sharpness. Landscape photography is a slow process, so you have the time to set up a tripod and use it to keep your camera rock-steady. By doing so, slow shutter speeds are not an issue, which means you can also keep the ISO rating low to maximise image quality.

It s tempting to always stop your lenses down to f/16 or f/22 when shooting landscapes to maximise depth-of-field and achieve front-to-back sharpness. However, if you do

therea strong chance your shots will suffer from diffraction, which causes a reduction in image sharpness (see left). It s a common fact that lenses give their sharpest results in the middle of the aperture range -f/8 and f/11 are usually the optimum f/stops, and you should only stop down beyond f/16 when you really need to.

 shooting landscapesHyperfocal focusing is a great technique to use for landscapes because it allows you to achieve the depth-of-field you need so the image is sharply focused from front to back, without stopping the lens down any further than you have to. Speaking of focusing, though you can use AF when shooting landscapes, itfar less fiddly if you switch to manual focus. Not only can you control exactly how far into the scene the lens is focused - which is crucial when using hyperfocal focusing - but once you ve focused the lens you can leave it and focus won t shift, which is handy if you ve set up a shot and need to wait for the light. Many experienced photographers focus a third of the way into a scene and find this provides enough sharpness for foreground to background.

Comments are closed.