Why are my subjects still underexposed with TTL flash in this photo?

<p>Below is a photo of a couple that I shot with my Panasonic micro four thirds camera with on-camera external TTL flash. I exposed for the sunset - to protect the highlight and also the reflection on the lake -, recomposed, and shot. Manual exposure and TTL flash.<br>

As you can see, the couple is underexposed. I did get a better shot by boosting the external flash in the end. But my question is, why didn't the TTL flash metering get it done right the first time? A clever TTL flash meter would have pumped up the output so the subjects would be better balanced with the sunset. Could I have done something differently to get a better balance from the first shot?</p>

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<p>A clever TTL flash meter would have pumped up the output so the subjects would be better balanced with the sunset</p>

 

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<p>And then someone would be posting "why does my flash look so unnatural". I imagine you set the exposure manually because you didn't want the camera to take the shot the camera wanted, you wanted to take the shot <em>you</em> wanted. Why would it be any different with flash? The camera doesn't know what you want. The camera only knows 18% gray... if you want more or less, that is what flash exposure compensation is for... or you could just simply use the flash manually (if that is available with this camera/flash) for the same reasons you put the camera in manual exposure!</p>

<p>The real question is: why do you assume that the camera knows that the off-center objects on the left <em>are</em> the subjects? My guess is that the system was fooled by the highly reflective marker tape on those two poles, which returned an unusually bright bounce. Especially that one near the center, an area that the metering is probably designed to favor.</p>

<p>As Ansel Adams said "85% of my finished images are completed in the darkroom." (paraphrased) Edward Weston (who invented one of the best exposure meters) said, "The exposure meter is only an aid. We have to know how to use it, then apply it to get what we want." <br>

A meter is a very basic computer. Exposure meters attempt to make ALL images look the same. The best computer, is our brain. Experience fed into it, helps us to make better decisions over time. We do not have to learn from experience, but can learn from everyone's experience here, and in books. The more reading we do, plus experimenting or practicing what we learn from others, gives us the ability to automatically produce what we desire. <br>

TTL flash metering will _never_ get it done exactly the way we want, it is still only a tool. We can not expect to create a perfect image with metering. Light exceeds the ability of the media used, to reproduce what is in our head. Something must be sacrificed, we have to determine what we want to sacrifice.<br>

NOW the potential may be in this image in this image, to create just what you wish. Photoshop is the Modern equivalent of the darkroom. Spend the time learning to use it, like the Masters learned to use chemicals to do what they desired. 85% of what we want to produce, can be completed in Photoshop. Just learn to create the finished images you desire. Ive used both for over 74 years, believe me its much easier in Photoshop than a Darkroom. :) It is also faster, and less expensive.<br>

The beauty of digital, is that if we do not have the ability or knowledge today, we can come back to it in the future and create something better than we did today. With Photoshop, we can use various techniques to change various portions of the image, to balance it the way we want. <br>

There are many courses on the Internet which can teach you Photoshop. Free tutorials are available on YouTube, etc... Just because some are free, does not mean they are not good... Watch them, listen, and practice what they teach, in a year looking back you can be very surprised how much you have learned or improved.<br>

Adobe's website has a lot of info in the forums. Anyone can log on the site and register a name to learn from what we find there. What is learned can also be used with other software with similar features, like Gimp which is free, but much like Photoshop.</p>

 

<p>I think Matt's right on the money here. To grossly oversimplify, TTL flash systems are generally looking at the center or where the focus is set—it's the only insight they have into what might be the subject—and then trying to illuminate that to the point you're just getting a little hot at the brightest points (where you'd expect your speculars to be).</p>

<p>In your case, the safety tape is doing exactly what it's designed to do: Reflect even a little light in a highly efficient, very bright way.</p>

<p>And the camera's doing what it's designed to do: Cut off the juice before your speculars completely blow.</p>

<p>The camera doesn't know the people are the real subjects, or that you don't mind if the poles are blown completely to hell.</p>

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<p>I think Matt's right on the money here. To grossly oversimplify, TTL flash systems are generally looking at the center or where the focus is set—it's the only insight they have into what might be the subject—and then trying to illuminate that to the point you're just getting a little hot at the brightest points (where you'd expect your speculars to be).<br>

In your case, the safety tape is doing exactly what it's designed to do: Reflect even a little light in a highly efficient, very bright way.</p>

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<p>I think you are probably right. As I tried to salvage this photo with PP editor (ACDSee, not PhotoShop), I got "exposure warning" not just in the sunlight portion but also from the reflective tapes, almost at the same time.<br>

The situation has led me to wonder: is there a TTL system (Nikon? Canon?) that enables you to designate an off-center area (the couple, in this case) that the TTL flash will meter? Better yet, I think a camera's TTL flash meter should remember where the user focused and use that area for flash metering as well, if the user decides to go with TTL, instead of manual flash exposure. In my case, I focused at the couple first, half-pressed the shutter to lock the focus, and recomposed to put the couple off center according to the rule of thirds. It would have made more sense if my camera remembered where I focused (the couple) and metered off that area. I know it can certainly remember "focused areas", because it can track faces.<br>

More generally, since external flash creates a dual exposure (one from the ambient and another from the flash), providing the user with another, separate metering tool for TTL flash would be very helpful.</p>

 

<p>When I shoot a scene like this using a Nikon body and their iTTL system, Ken, I use spot metering or exposure lock (similar to focus lock) to get the ambient light right, and then use flash compensation to bump the flash up or down as needed. It's so simple to chimp a couple of shots and quickly get the fill where I need it. Don't forget the importance of using a warming gel to get that fill to look natural, especially in the context of golden-hour ambient light.</p>

<p>A minor quibble : I don't think Edward Weston had anything at all to do with the meter of the same name.<br>

I can handle being corrected..</p>

Because your TTL meter without you setting the bias to a plus setting it was making the reasonable assumption that

the primary subject was the sunset. Cameras these days are very smart but they can't read your mind.

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<p>The situation has led me to wonder: is there a TTL system (Nikon? Canon?) that enables you to designate an off-center area (the couple, in this case) that the TTL flash will meter?</p>

 

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<p>Nikon has a <strong>great</strong> flash feature (probably under used) that solves this.<br>

It's called (FV Lock) or "Flash Value Lock." I am unaware if Canon has anything similar.</p>

<p>Essentially, you center your subject of interest, press a button that can be assigned to the camera body, the flash fires and records the (return) light.<br>

You are now free to recompose as the flash output is (locked) and will not vary.</p>

<p>As others have mentioned, full manual control will achieve this with some trial and error.<br>

Often we forget to swivel the flash head back to the target...another possibility.</p>

<p>Funny thing is, it <strong>was</strong> an Edward Weston whose company made those light meters, but it was Edward Weston the chemist / electrical engineer, not Edward Weston the Group f/64 photographer.<br>

<a href="http://www.westonmeter.org.uk/thecompany.htm">Weston -- The Company</a><br>

<a href="http://weston.ftldesign.com">Weston Electrical Instrument Corporation</a></p>

 

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<p>Nikon has a <strong>great</strong> flash feature (probably under used) that solves this.<br />It's called (FV Lock) or "Flash Value Lock." I am unaware if Canon has anything similar.</p>

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<p>Canon's got the same thing. Quite useful.</p>

 

<p>It is called FEL on Canon. If you are using auto flash exposure, it is better to have the camera underexpose or err on the side of underexposure. This can be fixed in PP, but overblown highlights can't be.<br>

Of course, with 4/3 you also need to be a little more careful with noise so I understand that you dont want to dodge too much.</p>

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<p>If you are using auto flash exposure, it is better to have the camera underexpose or err on the side of underexposure. This can be fixed in PP, but overblown highlights can't be.</p>

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<p>I understand the wisdom of underexposing in general pursuant to the logic you presented. But in this particular case, it wouldn't have helped and didn't help, because the sunset blows when I try to brighten the photo. I think achieving balance between the subjects and the sunset is really the key here.</p>