EC - Why?

[Ceyber]

Someone needs to correct me, because I think I'm wrong, or missing the point :)

Why would I use EC on my camera? From my understanding, it is an after-picture effect added to the JPEG, and if I'm shooting RAW, I can add it myself later. Is it only for workflow speed, or is this an actual added benefit to doing it in-camera as opposed to afterward?

Honestly, I'm not the type of person to say "I'll fix it later", but in this case, since I tend to PP all my shots quickly anyway, why wouldn't I lighten/darken afterward?

[Grimes]

Do you mean exposure compensation? It's just a way to adjust the camera's light meter; it's not an effect applied to the image.

One example of where you would use this: If you are shooting a scene that is mostly white, and you want it to be white in the picture (like snow) then you will have to dial in some EC. Otherwise the camera's meter will try to adjust exposure so that the snow will be some shade of gray.

It's always better to get the exposure right in camera, even if you are shooting in RAW. Your RAW file will have the best "flexibility" this way.

[Ceyber]

Interesting - I read somewhere (I suppose incorrectly) that white balance was also set in JPEG format, and the RAW file really didn't take it into consideration. Incorrect?

[jklewer]

I use EC most often when Im shooting in dim areas on Av. I will set EC to -1/2 in the evening and -1 at night typically. I usually dont want a night photo to look as if it were daytime, you know what I mean? John

[Grimes]

Interesting - I read somewhere (I suppose incorrectly) that white balance was also set in JPEG format, and the RAW file really didn't take it into consideration. Incorrect?

That's a correct statement.

However white balance is different from exposure, your original question. If you do some searches on this site, you will find some pretty good info on white balance. In a nutshell, for example: a white piece of paper to human eyes "looks white" outside in the sunlight, and "looks white" to human eyes indoors under, say, fluorescent lights. However, this is because our brains compensate, and we never really notice any change.

A camera needs to be set to the proper white balance (ex. sunlight, fluorescent, tungsten lights). Otherwise the paper will not turn out white in your final picture.

[tzalman]

EC is a physical change in the hardware (the camera), altering either aperture or shutter speed. You use it when you know the metering system is making a mistake.
WB is a software alteration of the digital image data done during the transition from RAW data to RGB image, either by the camera's processor or a RAW converter.

[egordon99]

EC is NOT just an effect added to the JPG :(

It affects the actual exposure the camera takes, so although some RAW editors have an "exposure" slider, all that really does is bump up the brightness digitally.

Here's how "real" EC works....Let's say you're shooting in Av mode (which you should be, unless you shoot in M, and if that's the case, then EC does not apply) You are at f/2.8, ISO200, you meter the scene with your camera and you get a shutter speed of 1/500s. You disagree with the camera (when to "disagree" comes with experience, and that's another thread), so you set EC to +1. The camera will now use 1/250s. So you'll end up with a ISO100, f/2.8, 1/250s shot. Likewise, you set EC to -1, the camera will then use a shutter speed of 1/1000s.

So no, it's not just a "JPG Settings"

[egordon99]

Shalom Elie! How's the weather over there in Israel? ;)

[tonydee]

I think it helps to be aware that a scene has a range of brightness levels reaching the different areas of the sensor. Your camera can only capture a particular range too: this varies with camera model and conditions, but let's say for argument's sake it's 11 stops, which is a 2048:1 contrast ratio. Real life scenes may easily exceed that, hitting maybe 100,000:1 or 20 stops if you've got the sun in the shot as well as heavy shadows - in which case you typically want to make sure that the most noticable parts are recorded properly. The bright parts are most noticable - issues with them are perceived much more strongly - so you want the camera's sensor range to overlap the brightest part of the scene's range. EC effectively lets you line them up like this. Being extremely casual with the terminology here, which will help me explain other things later, you can think of this as recording stops 9 to 20 :-). Lining up like that is known as Exposuring to the Right (ETTR).

If the EC value is too high, then your highlights will be blown and the texture and colours therein compromised or lost. Think of this as recording stops 7 to 18: everything over 18 is blown and a mess.

If it's too low - you'll try to record say stops 11 to 22, but no areas have values in the bright 20-22 range anyway so you've wasted that capability, and you've failed to record as much of the shadow detail down at stops 9 to 11, so they will appear totally black whereas lining up the exposure ala ETTR would have recorded subtle greys. Throughout the image you'll have a worse signal-to-noise ratio. You probably won't notice noise issues anyway unless you post-process the image to make it brighter or add contrast, or are using a high ISO setting, but it's generally better to be on the safe side and record better information to begin with.

If you're lucky and the scene has less than 11 stops of range, then it's less critical how you expose it as long as you get it all in, but exposing to the right will record the best possible quality.

The problem is really that our cameras are usually too stupid to know how much light is going through them until after they've tried to capture the shot, so they have to make a guess, and using our experience we can second-guess them by dialing in an EC correction, but it may still be out a bit. We then check the histogram, or look for flashing overexposed regions when reviewing the shot, in order to see if the guess + any EC correction worked out optimally. Shoot again if we have to until it's all good. With live view the cameras are getting smarter at this and may one day automate this process, though who wants to shoot looking at an LCD?

When you save in RAW, you're capturing the unaltered values the digital sensor recorded. These are independent at each point in the scene. The camera has to look for the brightest points across all the pixels to get an idea of what "white" things might have looked like in the available light, and it records that information as a colour temperature. But, if it was wrong the RAW image has all the unaltered local readings so some other temperature adjustment can be applied in post-processing. For JPEG, the camera's adjustment is applied destructively - changing the colours of each pixel in the image - and it can't be reversed without a loss of quality, so changing white balance after the fact becomes less desirable, especially as the JPEG colours are rounded off to a much lower precision (256 levels) than that used in RAW images (4096 or more levels).

Cheers, Tony

[tzalman]

Shalom Elie! How's the weather over there in Israel? ;)
HOT.

[PhotosGuy]

It's always better to get the exposure right in camera, even if you are shooting in RAW. Your RAW file will have the best "flexibility" this way. The "correct" exposure will result in less noise in the image. In high ISO conditions, the "incorrect" exposure, chimped a bit over the right & corrected before RAW conversion, will result in even less noise in the image.

For me, EC is a PITA, & I don't ever use it. Why set it for a white person or car & then reset it for a black person (or car) 5 seconds later? And even in a scene where the light isn't changing, a slightly different camera angle will require a different EC. An example of how the subject can affect the exposure & why manual keeps me worry free:
Post #47 (http://photography-on-the.net/forum/showpost.php?p=5191658&postcount=47)

Click the "Thread: Need an exposure crutch?" link at the top-right if you'd like more info on exposure.

[Ceyber]

Thanks folks!

So, EC makes the difference in modes OTHER than manual, as it forces the camera to change settings because I'm telling it that it's wrong. Since I generally shoot manual, it has no effect, correct?

[krb]

Thanks folks!

So, EC makes the difference in modes OTHER than manual, as it forces the camera to change settings because I'm telling it that it's wrong. Since I generally shoot manual, it has no effect, correct?

There is no such thing as EC if the camera is set to M. Period. Perhaps you are confusing EC and FC. (Flash compensation)

[Ceyber]

Thanks - okay, so I suppose the next question is, I was under the impression that FEC and EC were the same thing - I'm learning new things everyday! :)

Does FEC change the physical exposure, or is it also an after effect. If I shoot flash in M, do I need FEC?

[egordon99]

FEC is when your flash in in ETTL mode. Say your camera's meter determines that it needs to fire the flash at 1/4 power (based on the chosen ISO/f-stop and the sending out of the pre-flash). You disagree, so you set FEC to +1. The flash will now fire at 1/2 power. Likewise -1 FEC would fire the flash at 1/8 power.

Unfortunately the power that is used for a particular shot is not stored in the EXIF anywhere, and you really can't determine WHAT power it's going to fire before hand in the same way you can see what shutter speed the camera chose for you in Av (for EC)

[egordon99]

Thanks - okay, so I suppose the next question is, I was under the impression that FEC and EC were the same thing - I'm learning new things everyday! :)

Does FEC change the physical exposure, or is it also an after effect. If I shoot flash in M, do I need FEC?

IF the FLASH is in Manual (ie YOU set the power yourself to 1/1, 1/2, 1/4, etc...), then FEC does not exist. If the flash is in E-TTL, then you surely can control FEC.

The general way most folks use flash is M mode on the camera, but E-TTL for the flash.

[CyberDyneSystems]

Thanks folks!

So, EC makes the difference in modes OTHER than manual, as it forces the camera to change settings because I'm telling it that it's wrong. Since I generally shoot manual, it has no effect, correct?

Correct.. it's an override for the camera's auto exposure

[gooble]

The "correct" exposure will result in less noise in the image. In high ISO conditions, the "incorrect" exposure, chimped a bit over the right & corrected before RAW conversion, will result in even less noise in the image.

For me, EC is a PITA, & I don't ever use it. Why set it for a white person or car & then reset it for a black person (or car) 5 seconds later? And even in a scene where the light isn't changing, a slightly different camera angle will require a different EC. An example of how the subject can affect the exposure & why manual keeps me worry free:
Post #47 (http://photography-on-the.net/forum/showpost.php?p=5191658&postcount=47)

Click the "Thread: Need an exposure crutch?" link at the top-right if you'd like more info on exposure.

Amen.

I typically shoot in M. The other day though, I was taking pictures of my sister and baby niece. I'm shooting in M like normal and I was gradually adjusting exposure as the kid moved around the room and everything was great.

Then I got it in my head that I didn't want to fuss with changing the exposure so I switched to Av. I took a shot and dialed in my EC, then all of the sudden she got kind of embarrassed about something and had the cutest expression. I took a couple shots. I chimped and realized I'd gotten a window in the shot and my exposures were ruined. Stupid, stupid, stupid!

If I hadn't switched to Av I would've nailed the shots. I can't tell you how often I get crap shots in Av cause the camera thinks it knows how to expose. Av is no better or quicker than M in most situations and is many times worse. End rant.

[PhotosGuy]

Stupid, stupid, stupid! BTDT! :D