TechRadar: All latest feeds Take pin-sharp landscape shots with these advanced depth of field tips
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Getting your landscapes sharp from front to back is tricky, but exploiting a phenomenon of depth of field can help you get a tack-sharp scene every time.
Depth of field is the distance either side of the focal point that is 'acceptably sharp'; it's determined by aperture, focus distance and focal length, and – crucially – it extends twice as far beyond the focus point as it does in front.
The point of using hyperfocal distance focusing is to focus at the point at which the depth of field stretches to 'infinity' so that the maximum possible amount of the scene appears sharp.
You get a greater depth of field at shorter focal lengths and narrower apertures, so if you shoot at an aperture of f/16 on a 16mm wide-angle lens with a full-frame DSLR, the hyperfocal distance is 50cm. Focusing at this point will make everything from roughly half this distance (25cm) to infinity appear sharp.
Before dialing in your lens's smallest aperture, though, you need to take 'diffraction' into account, as images actually become progressively softer at narrow apertures due to light being diffracted by the aperture blades.
This becomes noticeable beyond around f/16 on an APS-C (DX) format sensor, or f/22 on a full-frame (FX) one.
Maximise depth of field in your landscapes
1. Keep it steady
Shooting with a tripod doesn't just keep the camera rock-steady for long exposures, it also gives you more time to perfect your composition and focus precisely.
Putting your camera on a tripod enables you to set the hyperfocal distance with care.
2. Stay in control
Swapping to Manual mode gives you complete control over your exposure, not just your aperture. Set the focal length to fit your scene – we shot at 35mm – and bear in mind that the wider the angle, the greater your depth of field will be.
3. Work it out
Use a hyperfocal distance app or our tables (see the next page for more on both) to look up your focal length (35mm in our case) and desired aperture. Shooting at f/8 on our full-frame DSLR gives us a hyperfocal distance of 8.122 metres.
4. Measure it out
Everything from around half the hyperfocal distance (in our case, the hyperfocal distance is 8.122 metres, so that's 4.577 metres) to the horizon will be sharp. Unless you're carrying measuring tape, you'll need to judge the hyperfocal distance by eye, or roughly pace it out.
5. Focus with care
Use autofocus to focus on a point at the hyperfocal distance, then switch to manual focus to lock the focus. If there's nothing at the appropriate distance for your Nikon's autofocus to pick up on, try focusing on yourself with a remote release.
6. Beat the shakes
You'll need to avoid touching the camera in order to prevent camera shake, so use a remote release (or your Nikon's two-second selftimer). Disable image stabilisation, too, as this can cause shake when shooting on a tripod, and set mirror-up.
Hyperfocal distance charts
Using our hyperfocal charts (or a smartphone app) gives the distance to focus at from the focal plane of the camera, so that everything between it and 'infinity' will appear sharp.
However, because depth of field stretches in front of the hyperfocal distance point, as well as beyond it, objects up to around half this distance will appear acceptably sharp, too.
So if you were to use a 50mm focal length focused at 14 metres away at f/5.6 on a full-frame camera, a subject between roughly seven and 14 metres away would also appear acceptably sharp – enabling you to get more benefit from the depth of field.
Software hyperfocal distance calculators
There are plenty of smartphone apps that will calculate the hyperfocal distance for you on both iOS and Android – we used free app HyperFocalPro on Android, downloaded from Google Play, which we found simple and straightforward to use.
You can input your camera model, focal length, aperture and the subject distance. With all of this information, the app generates a 2D diagram, showing the depth of field and the hyperfocal distance, for you to better understand the information.
There is also a table view for the selected camera, and this can be simpler to use if you do not know the exact subject distance but want to estimate. The best thing about this app is that, once installed, it does not need an internet connection when out and about, making it useful for use in the field without racking up excessive data charges.
SetMyCamera is a good alternative app for people with iOS devices, and can be downloaded for free from Apple's App Store.
Reading hyperfocal charts
Here are tables for both fullframe and APS-C sensors. Select your focal length along the top, and your aperture down the side, to see how far from the camera you should focus, in metres, for maximum sharpness all the way to the horizon.
You'll notice that at very wide angles and narrow apertures, hyperfocal distance is much less than metre.
http://www.techradar.com/us/how-to/photography-video-capture/take-pin-sharp-landscape-shots-with-these-advanced-depth-of-field-tips-1324118?src=rss&attr=all
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