In manual mode, what is the best way to check if you have the best exposure? exposure indicator or ... ?
There are two general usages for Manual mode:
- You want to control and choose your own exposure.
- You want to take a series of images with exactly the same exposure.
Case 1, the exposure indicator should just be a vague hint. You can look at it and see if you chose an exposure a little lighter, much lighter, darker, etc from the camera metering system. That will help but you really won't know if that is exactly what you want until you take the shot. You can use the flashing highlight or zebra feature to see if you have under-exposed or over-exposed anything which you want to have details in it. A histogram can help too but if you were exposure to get deep blacks or white-out in parts of the image, it won't be as useful.
Case 2, the exposure meter is what you aim for. You line it up and then will get the same metering as the camera. Still, in this case it is best to take a test shot and look at the histogram in case of camera is in error.
Otherwise, if you simply always line up the exposure metering, you don't need Manual mode.
The histogram gives you a lot more information. You can see if you are clipping highlights or perhaps under exposing the shadows.
The exposure indicator only gives you a single "average" to use.
It however depends on your use case and how much time you have to review in-camera.
Both are useful.
Exposure: There are choices.
The camera exposure meter gives an average value, but it is dependent on the scenes colors. So white or light colors will read too high, and the meter will underexpose it. Black or dark colors will read too low, and the meter will overexpose it. Because, reflected meters simply try to put everything in the middle. But Not everything should come out in the middle. ( See How Camera Meters Work at http://www.scantips.com/lights/metering.html ). Incident meters are more awkward to use, but give better readings, which are NOT dependent on the scenes colors. But when we first walk up to the scene, we use our eyes and brain to first evaluate the scene to choose a "correct" expected compensation. We learn this pretty easily if we think about it.
The histogram shows how the tones are distributed. It is primarily used to prevent clipping. Because a histogram is NOT a light meter. A black cat in a coal mine should be a dark picture. A polar bear in the sun on the snow should be a bright picture. Reflected meters put both in the middle, neither will be "correct". Histogram shows how it came out, but does NOT know what is correct. Again, our eyes and brain can immediately evaluate the scene to know how it should come out. Again, the histogram result is dependent on scene colors. Not everything ought to be fully bright.
The picture on the rear LCD shows what we actually got. Then our eyes and brain can decide if it needs less or more exposure, and we can try again. But the LCD image is pretty much "what you see is what you get".
Again, the good tool is our eye and brain. Novices don't always realize they should use their eyes and brain, and actually think about what they're doing.
Then just make the picture look like you want it to look. Just a little experience trying makes this be pretty easy and automatic.