Architect1776 Loc: In my mind

Most every camera made has very good DR now. virtually no difference between models and makers.
So as you say it is a matter of looking at the subject and from playing around and learning you learn to guess pretty good how to adjust and with digital and immediate feedback keep adjusting as needed. If fast action that is where previous playing around helps get close enough where ALL cameras can recover from a bit of exposure error as they all have good DR now.

amfoto1 Loc: San Jose, Calif. USA

Exposure Compensation is a tool for use with a camera's auto exposure modes.

If you are shooting fully manual exposure, it's not needed. But with auto exposure if you change any setting, the camera will counteract it by changing another setting. Say you have aperture priority AE set up, have selected selected f/5.6 and set ISO 100... then based upon its metering system the camera chooses 1/500 shutter speed to make what it thinks is a "correct" exposure. Now you decide to tweak the aperture to f/8... what happens? The camera drops the shutter speed to 1/250 so the exposure remains the same. Or, perhaps you go the other way and open the aperture to f/4... and the camera doubles the exposure to 1/1000.

This will happen with any of the auto exposure modes. Whatever change you make, the camera will counteract to maintain the same exposure!

However let's say you are shooting a lighter than usual subject... maybe something like a bride in a white gown in a snow scene. In any of the auto exposure modes, the camera is going to want to under-expose badly... maybe as much as 1.5 or even 2 stops! That's because camera meters read the light reflecting off of the subject and they "assume all subjects are 18% gray" tonality. Here the subject is much lighter than that, but the camera has no idea what it's being pointed at, so it does what it always does and will under-expose a lot.

The solution is to quickly dial in some + Exposure Compensation.

The opposite happens when subjects are unusually dark... how about a black bear in a coal mine. The camera will read it, think it's supposed to be 18% gray and want to over-expose the scene a lot.

The solution is to dial in some - Exposure Compensation.

A photographer who's learned to use it and is on their toes will recognize scenes where some E.C. is needed.

Some other situations where E.C. comes in handy include when wanting to make a "high key" exposure.... a deliberate over-exposure. At the other extreme are silhouettes where under-exposure is often needed.

All this is handled differently if you are using fully manual exposure.... shutter, aperture AND ISO all set by you. No auto exposure at all.

Along with fully manual exposure, there are other methods of metering. An "incidence" meter measures the light falling onto a subject, rather than what's being reflected off of it. As a result, an incidence meter isn't influenced at all by subject tonality. When done correctly, there's no need for compensation with incidence metering. (But it is not possible to build an incidence meter into a camera. To meter "through the lens", they have to use a reflective meter that's effected by subject tonality.)

Even with fully manual exposure and incidence metering, sometimes you still may want to skew an image lighter or darker. But in fully manual mode it's done by you and the settings you make, not by overriding auto exposure with E.C.

Sounds like everything can be solved simply by shooting manual exposures, doesn't it. However that's not always possible. Sometimes auto exposure is necessary. For example, let's say you are photographing cars orwildlife ad as they are moving in and out of shadows or following an athlete around an arena where there is variable lighting. Then auto exposure is very necessary. And when that's the case, E.C. also may be necessary.

Another consideration.... Camera meters using 18% gray works out pretty well most of the time. Even when a scene has a broad range of tonalities, they often average out pretty close to that assumed tonality. However, the more narrowly the scene is metered, the greater the chance some E.C. will be needed. Very narrow "Spot" metering only reads a small area and the tonality of it will dictate how auto exposure is set, effecting the entire image. If you are metering the side of a building painted white or a only the dark face of that black bear, it very likely will cause your camera to skew the exposure more than if a broader portion of the entire scene were being measures.

Back in the days of film some of us used a Zone System and a 1 degree spot meter to very precisely determine exposure, film development and printing processes that will place various tonalities in a scene exactly where we want them in the final print. That was a slow, painstaking process! Today with digital, Exposure Compensation and post-processing it is sooooooo much easier!

Exposure Compensation is a tool for your use, any time you are using an auto exposure mode. Some people may never need it. A landscape or still life or portrait studio photographer might always use fully manual exposures. But anyone shooting moving subjects and using auto exposure has potential to improve their images by learning when and how to use E.C.

Of course, you have to remember to reset any E.C. you use to 0 when done using it. That's no different from a variety of other settings the photographer chooses, for any particular shooting situation.... Exposure mode, metering pattern, autofocus set up, frame rate, JPEG or RAW, yada, yada.... all stuff you need to check before you start shooting, then reset later.

Architect1776 Loc: In my mind

DavePDX

This is exactly how I use it. I shoot mostly wildlife, and in most cases want my exposure to best isolate and display the subject. I shoot with manual shutter speed and aperture, but with auto ISO, since my subjects are rarely still. With Exposure Compensation, I can dynamically alter my ISO. Why not just use the ISO control in the same manner? Because the changes are often large, and the auto function keeps me in the ballpark, allowing me to quickly fine tune it with EC.

PlymouthWoodworker Loc: Plymouth, MA

I haven't read all 7 pages of this thread, so I may be duplicating what someone else has said, but here goes:

The camera meter will always adjust exposure for an "average" scene. If you are photographing mostly snow or sand on a beach, the cameral will adjust to make that subject "average" and the snow/sand will look too dark. Conversely, dark subjects that you intend to be dark will appear too light. If you are in manual mode, you don't need exposure compensation because you control the exposure. However, it you are in, for example, aperture priority mode, then the camera will adjust for an "average" scene by changing the ISO and/or the shutter speed. In this case, if you want a snow scene to be lighter, you can use exposure compensation. How much compensation depends on the scene. It's kind of like the Zone System where you take the snow that initially is on Zone 5 and open up 3 f/stops to put it on Zone 8. Also, as some others have commented, my particular camera takes a better image if I over expose slightly. So I keep my exposure compensation set to +0.3 most of the time. Hope this helps. Sorry if I repeated comments from others.

PHRubin Loc: Nashville TN USA

While EC is for other than Manual Modes, there is also a flash EC which is for ALL TTL modes, INCLUDING Manual.

jack schade Loc: La Pine Oregon

There are occasions when I need a certain shutter speed and sometimes for depth of field issues I also need my aperture to not be too low (sports and wildlife photography). In those cases I can make minor exposure adjustments without affecting shutter speed or aperture.

Jack

BebuLamar

You mean you adjust your ISO? Because you can't change the exposure without changing at least 1 of the 3 parameters.

Sinewsworn Loc: Port Orchard, WA

Why are we tying ISO to exposure?

Architect1776 Loc: In my mind

Because it is a part of it.

Maxpixel

When shooting wildlife, I use manual exposure with auto ISO. For wildlife I need a certain shutter speed and dof, but ISO noise I can deal with in processing. I need EC to do rapid exposure changes while following the action, faster than I can move camera dials. The new Canon RF 600mm f4 lens is the only Canon RF lens that lacks an EC ring, and for that reason I have the EF version with the EF to RF adapter which has the EC ring built into it. I would not consider buying a wildlife lens without EC capability. Actually, the RF 600 f4 has a ring that can be switched to EC or manual focus, but you can’t have both with that lens.

tkphelps

I am basically lazy and do most of my shooting in programmed mode with auto ISO starting at 400 as my base. When I see that I really need more or less exposure the compensation dial is the easiest change. Any thing else requires full manual mode and thinking about what I want to do. Consider: You can't just change aperture or time or ISO - the camera simply corrects the other exposure parameters to fit its own version of perfect. Only the exposure compensation directs the camera's idea of perfection.

Sinewsworn Loc: Port Orchard, WA

Part of exposure?

Architect1776 Loc: In my mind

yes, part of the triangle. Shutter, aperture and ISO.
Here is a beginner's guide to help you understand.
https://petapixel.com/exposure-triangle/

wdross Loc: Castle Rock, Colorado

Exposure is shutter speed (timing of light), aperture opening (amount/strength of light), and ISO (sensitivity to light). Without the three, there is no photography.