For any genre of photography, it is important to be precise with attaining a focal point with the desired depth of field. For today’s discussion, I will concentrate on the genre of landscape photography, particularly when using filters.
Use Back Button Focus
This is a general tip but applies to landscape photography too. It dissociates the shutter button from any focussing activity therefore will avoid any inadvertent refocussing on unwanted areas after you have already achieved the focal point you desire. Camera brands have different ways to set this up but the principle is to set a focus button to one of the lesser used buttons at the back of the camera and leave the shutter purely for releasing the shutter.
Situations where autofocus can be useful
If you are using a circular filter such as a CPL and shooting handheld images, I would recommend using auto-focus. Remember to utilise the different focus zones that your camera offers so that you can maintain a composition without having to focus on an area and then recompose.
For landscapes shot at F8 or higher on a wide angled lens, an easy rule of thumb to remember would be to focus 1/3 of the way into the depth of the scene. This will achieve focus from front to back in most cases unless you have extremely close foreground elements.
Situations where manual focus is preferred
- Using prime lenses
Many prime lenses to not have an autofocus option! In this situation, learn to utilise the focus zones for your given aperture. This will be marked on the lens’s focus ring. For example, when shooting handheld, I would set a manual lens for a focus zone of infinity to 0.5m when at F11. Once set, all I need to do is remember to photograph scenes without objects closer than 0.5m to the lens. In many ways, this can be an advantage since you can shoot without worrying about anything except composition and your distance from the subject.
- Long exposures using ND filters
The danger with leaving autofocus on while shooting long exposures with ND filters is that the camera may ‘hunt’ for a focal point and end up focussing on nothing due its inability to find one. This will result in an out of focus and unusable image. Using back button focus or shooting in manual focus mode avoids this problem. I recommend finding the focal point and optimising composition without the ND filter on first. Then place the ND filter on and shoot the long exposure with an appropriate shutter speed to achieve optimal results.
Filters for Long Exposure Seascape Photography
by Dylan Toh
