Exposure Compensation for Weddings - Why use it if you can do it in post?

<p>Hi all, my question is why would you use exposure compensation in-camera (this question only applies to those shooting in RAW) when you can modify it in post very easily. To my knowledge only 3 things affect exposure: ISO, aperture, and shutter speed. The way I see it, increasing brightness and using exposure compensation in post results in the same effect. So why do it in-camera? If you use exposure comp before shooting, does it meter the scene BEFORE recording the image and automatically change aperture or shutter speed (depending on what mode you're in) AFTERWARD?? Or is it essentially just increasing/decreasing the brightness after taking the image?</p>

<p>i'll let others respond....i don't even know where to start with this one.... @_@</p>

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<p>If you blow out the highlights in the raw file there's nothing you can do in post to recover the information...</p>

<p>If you AEB and edit them all, you will see that the 0 with added exposure in LR, doesn't look like the +1 photo straight out of the camera.</p>

<p>It's the same reason that when you do a real HDR image, it looks totally amazing compared to a fabricated one where the exposure was adjusted for just one image.</p>

<p>I often shoot Aperture priority, whereupon adjusting the exposure compensation effects the shutter speed. It's not simply a "brightness adjustment", it physically changes one of the 3 components effecting exposure. This cannot be duplicated in PP.</p>

<p>In manual mode, exposure comp does nothing. At least not in my camera.</p>

<p>It would seem if a photograph can be properly exposed in the camera to start with, that would be the most desireable way to go. It will be interesting to see what the "real" answer is though.</p>

<p>The practical answer is--you use exposure compensation in camera (actually, 'get the exposure right in camera') because you want to preserve the quality of your image/file. Underexpose and pull up the exposure in post, you will make noise worse. Overexpose and pull the exposure down in post, you will be unable to recover highlights past a small amount, even from a RAW file. The higher the ISO, the worse your efforts will look, because the dynamic range narrows.</p>

<p>Alan, I think you are misunderstanding what exposure compensation does. It is not like adjusting brightness afterwards. Depending on your settings, it will change shutter speed or aperture. You use it to try to get the best possible exposure, because experience tells you that the meter is not providing the best exposure in a particular situation (for example, backlighting.) As others said, getting it right in the camera will give you better results than fixing it put afterwards.</p>

<p><strong><em>"The way I see it, increasing brightness and using exposure compensation in post results in the same effect. So why do it in-camera?"</em></strong><br>

<br>

A flawed premise. <br>

Three pages of theory would follow from those who have great in depth knowledge, suffice to say, from my simplistic point of view - it is not the same.<br>

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<strong ><em >"why would you use exposure compensation in-camera (this question only applies to those shooting in RAW) when you can modify it in post very easily."</em></strong><br>

<br>

Bottom line: <strong ><em >"you have to get it right in the neg"</em></strong> is a basic Axiom of Photography. <br>

There is argument to support that this is more critical with digital, than with film capture, because most films have more latitude than digital sensors. <br>

I agree with this argument.<br>

<br>

WW </p>

<p > </p>

<p>LJ - i would say your response is the "real" answer. Nadine gives the details of WHY at both ends (under & over exposure)</p>

<p>:-D</p>

<p>Looks like my previous post didnt go through, thanks for the replies. I'm not saying shoot it randomly and fix it in post. I just wanted to confirm that exposure comp CHANGES one of the exposure settings (either aperture or shutter) before recording the image, and as some of you said thats exactly what it does. I just wanted to confirm this. So if you're shooting in manual, it can't change either???</p>

<p>No, because in manual, you are setting everything--<strong>you are</strong> the exposure comp.</p>

<p>Good to know :)<br>

So exposure comp is only useful in Aperture priority or Shutter priority mode.</p>

<p>In Manual on Nikon bodies it will change if you are using auto ISO.</p>

 

<p>Alen,<br>

To confirm that exposure compensations changes either aperture or shutter speed, the best way is to put your camera on a tripod in a place where the light isn't changing, and set it to either aperture or shutter speed priority. Then try different exposure compensation settings, and watch what happens to the aperture and shutter speed displays. For this, like many other things, the best way to learn it is to experience it yourself.</p>

<p>I also thought exposure comp is possible in Program mode. Exposure comp can take a different form as well, such as auto ISO, as Regas mentions, and flash exposure comp. On some Nikon bodies, flash and ambient exposure comp are related and used together.</p>

<p>Its use is to comp for the black and white dominating the exposure when you use auto modes.</p>

<p>alen - go out and try it. you will realize that what we call 'exposure compensation' is just a fancy word for correcting the camera's incorrect exposure when it's not smart enough to expose correctly, and you will see that getitng the right exposure in camera is a LOT better than trying to correct in post. especially if your frames are a bit hot. if they are under, you can usually work with them up to two stops (with low ISOs, you can push three stops pretty comfortably, but that's only as a last resort).<br>

if you shoot in manual, you won't have to worry about a thing about compensation.<br>

ce</p>

<p>Reasons are exactly as the others have told you. But I also wanted to throw in the fact that I don't want to spend an extra 2 hours in post-production because of something I could have taken half a second to do in-camera. </p>

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<p>So exposure comp is only useful in Aperture priority or Shutter priority mode.</p>

 

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<p>That all depends on how you look it. First, in shutter priority EC will adjust the aperture. In aperture priority, the camera will control the shutter (in Nikon cameras you can control how slow the camera is allowed to set the shutter). As pointed out, some cameras may have auto ISO which may kick in using a program mode. So if you dial in -1 your camera will adjust <em>something</em> to by -1 f/stop. But it's more than that as well. If I am shooting manual and I have -1 EC dialed in, then my <em>metering</em> will show me "correct" metering, that is to say the graph is centered, based on the -1 EC I have dialed in (at least on Nikons). Furthermore, if I have -1 dialed in, the effects my flash as well. Meaning my flash will fire based on the -1 metering obtained by the camera. So this can have a direct impact when shooting manual.</p>

 

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<p>Alen Z—Use a photo editing program to enhance correctly exposed photos, do not rely on them to fix incorrectly exposed photos. As others have stated PP will blow out highlights, bring in more noise, and the like. Too many photographers rely on Photoshop and its ilk rather than photography skills. The saying I hear most often is "I'll fix it in post...". That reminds me of the saying "why is there never enough time to do it correctly but, always time to do it over?". <br /> Why would you rather engage in time consuming post production adjusting what should have been correct in the camera? Do you want to be know for your photography or your computer skills? Your comment, "So why do it in-camera?", doesn't indicate photography skill, to me it indicates one that is more proud of their computer skills.</p>

<p> </p>

<p>Isn't there some saying about a silk purse from a sow's ear?</p>

<p>It's unclear if you're thinking about <a href="http://www.luminous-landscape.com/tutorials/expose-right.shtml">Expose To the Right</a> , but here goes... ETTR is not the same as setting +exposure compensation. Every scene is metered differently by the camera, so the over exposure to be applied will vary. This can be done only after looking at the histogram of a test shot.</p>

<p>More commonly, exposure compensation is applied either due to the way reflected light meters work, or for artistic reasons. Exposure is compensated with reference to part of the scene (subject, backlight, highlight, shadows etc...) because a reflected light meter will have metered it at neutral. Matrix metering aims to solve this.</p>

<p>Exposure compensation works on the metered value, before recording the image. The other one is called D-lighting (only for shadows). Possibly only the Fuji EXR sensor based cameras switch recording capability based on exposure conditions.</p>

 

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<p>I just wanted to confirm that exposure comp CHANGES one of the exposure settings (either aperture or shutter) before recording the image, and as some of you said thats exactly what it does. I just wanted to confirm this. So if you're shooting in manual, it can't change either???</p>

</blockquote>

<p>Assuming a fixed ISO value...</p>

<p>Aperture Priority Exposure Mode: Exposure compensation varies the shutter speed (as long as the limits of the camera's shutter speed range is not exceeded. Note: this may not work if you're using flash (camera dependent)).</p>

<p>Shutter Priority Exposure Mode: Exposure compensation varies the lens' aperture (as long as the aperture range is not exceeded. I.E. If your nominal exposure is 1/125th @ f/2.8 and you dial in a +1 EC, the lens cannot open up to f/2 if its maximum aperture is f/2.8).</p>

<p>Manual Priority Exposure Mode: Exposure compensation varies neither the aperture nor the shutter speed but adjusts the response of the camera's metering display (usually seen in the viewfinder).</p>

<p>Note: If you're using an auto-ISO setting, the camera has the option to adjust the ISO as well, so it's not clear whether the aperture or shutter speed will be altered by exposure compensation.</p>

<p>I suggest that you get your camera out and try it. Your particular model's exposure compensation behavior should become apparent within about five minutes.</p>

<p>The important point is that the sensor has an optimum exposure range. If you give the sensor too much light or too little light, it will not perform optimally, and your images could be irreconcilably corrupted.</p>

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<p>Every scene is metered differently by the camera, so the over exposure to be applied will vary. This can be done only after looking at the histogram of a test shot.</p>

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<p>One problem with histograms is that they don't show what's beyond their limits. You could have a peak off to the right that you'll never know about. The "blinking highlights" screen can let you know this if you have time to look at it, but it's difficult to find time for that much chimping when a lot is happening around you.</p>

<p>Another problem is that they're usually tuned to the limits of a JPEG file, not a RAW file. Plus, they can be biased by in-camera optimization settings (Contrast, Saturation, etc.). Don't bet the farm on a histogram.</p>