Focal length problems
There are some specific issues to be aware of when you use wide-angle or telephoto lenses
Wide-angle lenses 1. Composition: check the edge!
It’s easy for branches, lampposts and other unwanted guests to sneak into the edge of a wide-angle picture while you frame up.
Try running your eye around the viewfinder before you take the shot. Zooming out slightly can help you spot visual intruders too.
2. Filters: watch out for vignetting!
Some ultra wide-angle lenses have such a wide angle of view that they can actually capture the edges of a filter attached to the lens.
There are a few options here: choose a slimmer filter, remove the filter, zoom in a little, or clone out the dark corners with your editing software.
3. Dealing with lens flare and glare
Lens hoods for wide-angle lenses tend to perform poorly: they can’t be too deep, otherwise they’d be in the shot, but that means they’re less effective. To prevent glare, make sure the front element is spotless, and hold your hand just out of shot in order to shield it from indirect light.
Telephoto lenses 1. Shallow depth of field and focusing
Get close with a long lens, and the depth of field will be wafer-thin when a large aperture is used. It may help a subject pop, but it’ll show up any focusing errors without mercy.
The answer is to manually select a single autofocus point and use this to focus on the most important detail.
2. Slow shutter speed shakes
Telephoto lenses tend to be big and bulky, making them hard to hold steady. Any vibration will be magnified by the narrow angle of view.
Activating image stabilisation helps, but you may also need to boost the ISO or pick a larger aperture. Alternatively, use a tripod.
3. Haze: keep an eye on the weather!
A long focal length will magnify the effect of shimmering heat haze in warm weather, which can affect AF performance and lead to pictures that look soft and low-res.
You can boost contrast using a digital ‘dehaze’ filter, but you can’t restore sharpness. So, if you can, get closer to your subject.