For landscapes...
#1 Use a tripod ... even if you think you don't need one and this is because...
#2 You'll want to keep the ISO value extremely low (e.g. ISO 100 ideally). Contrary to popular misconception... ISO is _not_ part of "exposure". Aperture is. Shutter speed is. ISO is not. ISO is an amplification which is only applied to the image AFTER the shutter has closed and the exposure is complete.
To reduce "noise" in an image, you want good "exposure" (speciifically it's the signal to noise ratio of the image but I'd rather not get into that here). ISO is boosted BECAUSE the signal wasn't adequate (exposure was too low) and this results in an amplification of both whatever signal the camera sensor collected PLUS whatever noise managed to build up on the sensor. That's why high ISO images have more noise (the noise was always there... it just wasn't being amplified until you cranked up the ISO dial.)
#3 There's rarely a single set subject distance for a landscape because the whole "scene" is the subject. This means you want a very broad depth of field. You can get that by using a high aperture value (e.g. f/16 or even f/22). There's a problem in that light "bends" around edges due to it's wave-like nature and if you use a tiny aperture value (high f-stop) the problem is increased. This means you can get very slightly soft images due to the diffraction nature of light at very high f-stops and you don't notice this as much at low f-stops.
In other words... at say... f/4, you'd probably get extremely low diffraction and the focused part of your subjects would look very sharp... but the depth of field is shallow so much of the image wont be in focus. If you increase the aperture to make everything in focus (e.g. f/22, f/32) now you have a broad depth of field, but you also have stronger diffraction meaning that even the sharpest stuff isn't as sharp as it was down at f/4. So we work to find a trade-off we can live with. Of that's arounf f/16... if you can get away with it... f/11 (but you'll start to lose more depth of field at f/11).
When you use this smaller apertures, you'll need to take LONGER exposures (which is why you need the tripod and make sure nothing bumps it). If the tripod isn't rock solid, then use a remote shutter trigger to take the shot (beucase the act of you simply pressing the shutter button can vibrate the tripod enough to soften the shot). If you don't have a remote release, use the 2-second delay timer option so the tripod has a chants to damp the vibrations before it takes the shot.
#4 Dynamic range during daytime landscapes can be a challenge. Especially in very early morning or late evening during the "golden hour" when the sun is low, shadows are long, and the lighting is at it's best. But... a shot that nicely exposes the foreground can end up leaving you with an over-exposed sky. A shot that nicely exposes the sky can leave you with a very dark foreground. What to do?
There are two solutions...
one is to use a "gradient neutral density" filter (e.g. Lee filters makes excellent ones and loads of tutorial videos on how to properly use them). They darken the sky without darkenging the foreground because half the filter is clear and half is tinted.
Another solution is to use High Dynamic Range photography (HDR). This is where you take a series of bracketed images. You set the camera to spot metering mode and you manually meter the darkest areas of the foreground and then manually meter the brightest parts of your sky (a white puffy cloud for example). This is the range you need. Now you take several shots where you shift the exposure from the darkest through the lightest (you can shift about 2 stops at a time... you don't need every 1 stop). Those shots are imported into HDR software (lots of choices) and merged together.
Tim Campbell
5D III, 5D IV, 60Da
