Finally, I zoomed to 65mm, providing a wider field of view to retain the line of mountains leading from the left to the rainbow. As well, I could incorporate the small area of meadow in the bottom left to invite the viewer into the scene, creating a greater feeling of three-dimensionality than the narrower view at 100mm.
FIELD: Technical Controls
Once the composition is set, it's time to (a) put the camera on a tripod or (b) handhold and hope for the best. Choosing (a) or (b), along with any movement caused by wind, determines your shutter speed in tandem with the aperture.
In this case aperture was pretty straightforward. In fact, most landscapes are fairly straightforward—a small enough aperture to provide enough depth-of-field to cover foreground to background at a high enough shutter speed to freeze whatever motion is happening.
Regarding ISO, for landscapes I do not, absolutely do not use auto ISO. I working with only the optimal ISO for the camera being used, which, in this case was ISO 100. Optimal ISO provides the greatest dynamic range and the least amount of noise. With higher ISOs, noise can be reduced in post-processing, but you can never recover dynamic range.
An aperture of ƒ8 covered the depth-of-field needed and happens to be the sharpest aperture for lens I used. NOTE: Given the same perspective, ƒ8 in Micro Four Thirds provides equivalent depth-of-field to ƒ16 in full frame. ƒ8 gave a shutter speed of 1/250.
From here, I check for 'blinking highlights' which indicate if the highlights are too bright. Overexposed highlights mean they will be pure white without any detail—not at all what I want! In this case, the highlights were underexposed and could be raised slightly, in fact by ⅔ of a stop, so I dialled in +⅔ exposure compensation. Choosing +1 caused blinking highlights’, so +⅔ was ideal and only reduced the shutter speed to 1/160.
The whole goal of proper Field Techniques is threefold: to nail down a well-composed image that fills the frame and is correctly exposed, especially for the highlights. ƒ8 at 1/160 allowed me to hand-hold the camera while maintaining an optimal ISO of 100. If I had been using full frame at an aperture of ƒ16, the shutter speed would drop to 1/40, jeopardizing the crispness of the image due to movement of the trees by the wind or handholding. Modern stabilisation is often good enough to cover that, but 1/40 may still warrant a tripod.