I'm not going to beat around the bush. In my humble opinion, THE most useful function to be added to a digital camera for landscape, close-up and, to a far lesser degree, bird and mammal photography, is Live View! Before LV, pin-point accuracy on small areas was troublesome to say the least. AF is wonderful for action but when shooting close-up where the focus has to be bang-on, I would never rely, purely, on AF. Why? Well, take this scenario, illustrated with the image below of a dew laden wood anemone photographed at sunrise. I wanted to shoot it with the lens wide-open (f/2.8) to limit the depth of field and create something a little different to the norm. It was imperative that the very front lip of the petal was to be sharp and no-where else. Not halfway up the flower but right at the front. With the lens on AF, it may get me close but I couldn't be sure. With LV, I can magnify the image on the monitor and focus with confidence. Needless to say, this technique requires the use of a tripod.
And here's how I did it while photographing this chalkhill blue butterfly. There were numerous factors which forced me to use a relatively wide aperture. The proximity of the background and the nagging breeze. Chalkhill blues are tiny so, once again, it was essential that the focus was bang-on! Unlike the shot of the anemone where, due to the depth of the image, the camera didn't have to be parallel to the flower, in this instance it was essential to get the camera back completely square on both the vertical and horizontal axis if I was to be certain of edge to edge sharpness.
After much jigging around of the tripod, I composed the image and got the camera as parallel as I could. I then activated LV.
Using the + (magnify function), as if you were magnifying the image when reviewing, I zoomed all the way as far as it would go and then, using the scroll wheel, moved the magnified area to the head of the butterfly. With the lens on MF I carefully focused on the eye. When this was done, I scrolled to the tip of the wing.
If the wing required a focus adjustment, I knew the camera wasn't quite parallel so, depending on whether the wing tip was closer to or further from the plane of focus, I would adjust the tripod accordingly. This exercise was repeated on all parts of the butterfly until I was happy it was pin sharp throughout. Now, if the conditions were perfect - i.e. still and the background several metres away, I could have used a smaller aperture of, say, f/16 and allowed a little for parts of the wing to be fractionally out of alignment since there was every chance the depth of field would have taken care of it. But, with such a wide aperture, you just can't take those kind of risks. Depending on your camera model, once you are done with LV, de-activate it and, if you have it, use mirror-lock. If you take a picture with a slow shutter speed of around 1/8 sec and lower with LV activated, there is every chance your image will have signs of vibration, resulting in a soft image. Many bodies, however, retain the mirror-lock function when the shutter is released with the camera in LV mode so you need not worry about de-activating it first. This is a big advantage since, with the image magnified, you can very easily see when the subject is completely still.
There are few disciplines in photography more technically demanding than close-up. Technique, technique, technique. A photographer with inferior equipment using a solid tripod, utilising LV focus, mirror-lock and a cable release will always produce superior results than a photographer with the most up to date gear using a sloppy technique!
LV for landscape work can be equally useful. For the most part, AF works perfectly well on focusing on a specific spot but, when light levels are low and the subject you want to focus on lacks contrast (AF lenses require contrast or an edge to lock-on), autofocus struggles. So, all you need to do is the same as above. Turn off AF and activate LV, magnify the image, scroll down to the part of the scene you want to focus on and do so manually. Below are a few examples.
European bison. Due to the lack of contrast on the bison's fur, the AF really struggled but since it was standing motionless for quite some time, I was able to use LV to zoom in and focus manually on its eye.
