Setting the table straight about digital exposure

[akimartymar]

I'm always reading on here about not blowing the hightlights because they are unrecoverable and that you should expose for the highlights and not the shadows. However, after reading Bruce Frasier's bookon Camera Raw he says the opposite. He explains that while a completely blown highlight is not recoverable, Camera Raw does a good job of saving highlights if only one of the channels are blown. Conversely, underexposure almost always leads to noise in the shadows. He states that "if you are going to err on one side or the other, it's better to err on the side of slight overexposure." This goes against a lot of what I have read on this forum.

[CaptainTom]

I'll be the first to jump into this potential inferno.

Since the beginning days of photography, exposure has been a topic that has evoked debate. "thin negatives vs. thick", "transparencies must be underexposed to saturate color", digital images need to be exposed for the shadows and not the highlights, and vice versa".

So much of these arguments focuses on the specific type of shooting and conditions you are dealing with. If the "average" shooter over or under exposes the recording media, they usually do it drastically. This leads to badly exposed photos. When "pros" under or overexpose the media, they generally only do it by not more than one stop. Of course, this ALL depends on what each person considers as a proper exposure.

Yadda Yadda Yadda, and then you get digital vs. film, nikon vs. canon, full frame vs. factored, glossy vs. matte. What have I forgotten ??? If there were set rules that could not be broken or stretched or completely ignored, this would be a boring profession.
Read all the books, listen to all the advice, and then come to your own conclusions after taking a zillion exposures, and learning what you like and what works best for you....... not me, or anyone else.

[xseption]

I have to agree with Captain Tom and all I have learned form this forum and seminars is to overexpose (slightly) when using digital.

Like Tom said, try it until it fits your needs/style/etc

[DigiSLR]

I found this article to be a great read...

http://www.luminous-landscape.com/tu...se-right.shtml

[billbunton]

Realistically, as Tom says it comes down to experience and judgment. Sure, clipping one or two channels will probably still leave recoverable detail, and if that's not where you need the best detail that's great -- it leaves a bit more lattitude to play with. On the other hand, if you're going for feather detail in a white bird, you really don't want to clip any of the channels if you can avoid it.

You need the experience to be able to control the exposure to get what you want, and the judgment to determine what it is you want :-)

[kenw]

the reality is that it is more likely that in a blown highlight, the details are NOT recoverable since blown highlights tend NOT to be of one channel (last I looked, white has all 3....fairly equally, too).

What gets blown in my shots? The sky typically.

Underexposed areas, while subject to noise, are more recoverable in my experience. Noisy detail beats no detail in my book...... Again we're not talking gross amounts, I think this conversation is pointless in those gross cases, you've got bigger issues.

I've had a lot of experience pulling the detail out of the shadows under bridges where the rest of the shot is fine, including the sky. But try to get that blown cloud detail back around that well-exposed bridge underside? no way Jose...

That's based on my experiences: outdoors, landscapes and no flash.

[Bartman01]

Fraser's reasoning on 'expose for the highlights' goes beyond the noise issue. It gets to the heart of how digital sensors capture the data. From his book:

Given a sensor with 6 stops of dynamic range and that CMOS and CCD sensors record light in a linear fashion and record 12 bit data, that gives us a total of 4096 levels:
The brightest stop holds 2048 of the levels
The next holds 1024
The next holds 512
The next holds 256
The next holds 128
And the last holds 64 of the total available levels.

Based on that, you are better off overexposing and pulling the exposure down in post than underexposing and trying to pull the exposure up.

Of course things get really difficult when the scene has more dynamic range than the sensor. The 'ideal' RAW capture is an image that puts the brightest detail you wish to capture right on the edge of blowing out (but not over).

[akimartymar]

I didn't read him as saying "expose for the highlights". To me, he is saying to expose for the shadows, then bring down the highlights.

[jeffkohn]

I try to expose to the right, but avoid clipping. Clipping one channel is usually recoverable, although if it's badly clipped the highlight recovery could introduce a color cast in the highlights. Clipping 2 or 3 channels is more damaging. Also if the channel you happen to clip is one that's important to subject, for instance clipping the red channel when shooting a read flower, in my experience the highlight recovery process doesn't work very well.

Where it gets tricky is that you may not always know if you've clipped a channel, due to the fact that the in-camera histogram shows you data after white balance has been applied, which shift the individual color channels and could mask overexposure in some channels.

So while I agree with the expose-to-the-right concept, I still try to avoid even mild over-exposure.

[raevyncent]

Alot of good advice has been given so far, but one thing has not been mentioned. The camera! One can get used to over or under exposing to fit their style, but if you switch from one camera to another, the setting you are used to may be as much as 2 stops off from the desired effect. I found that when I upgraded from my A530 p/s to the 10D, I now tend to set my camera between 2/3-1 stop on the underexposure side to keep everything from blowing out. So, bear in mind when you pick up a new camera, or even switch metering settings, run a few test shots to re-establish your "normal" baseline, then over or under expose from there.

Anthony