PS processing question

I've seen a few posts on the web and on this site on how best to sharpen digital photos using Photoshop. What I'm wondering about is a best method in PS to change exposure. PS gives a number of ways to change the exposure of a photo (curves, exposure, shadows/highlights, etc., etc). Some methods seem to result in more grain than others. Some methods seem to lose resolution. Does anyone have a tried and true method out there?

Charlie,

A couple questions before we can adequately address your query. Do you capture in RAW (NEF)? If so, do you use the RAW converter in PS (ACR) for your conversions?

I pretty much use all methods, depending on the situation.

I recently shot an indoor martial arts tournament at a 1/2 stop underexposed for more shutter speed and found that the exposure tool was a quick, consistent method to get all of the pictures back up to a correct exposure. With ISO 800, this might not have been one of my better ideas...

I usually use shadow/highlights when I specifically want to hit either, only slightly. Gross adjustments tend to look rather, well, gross. If I have to go more than 7-10 units, this is the wrong choice for me.

Levels when I am feeling lazy. I had Elements for years and am pretty comfortable with this tool, but at times, both this and shadow/highlights are like using a sledge hammer for finishing nails.

Curves I am just beginning to understand. It is not that I don't know how to use it, but it is a jump from the technical understanding of the tool to the intuitive "I need to do this here" without thinking piece that I don't have yet.

Hi Bob,

Yes, I'm shooting RAW (NEF) files, and yes I am using the Adobe RAW converter.

Charlie, as Bob suggests the best place to change the effects of exposure (not exposure itself which is what amount of light was allowed into the camera and cannot be changed after the fact) is in the raw converter.

Note that this setting is a global adjustment and determines where the histogram is on the tone scale. It doesn't change the shape of the histogram as some of the tools you mentioned do - these are really more tone/color-mapping tools rather than exposure.

Artifacts such as grain and noise are resulting from the capture medium and making post-exposure adjustments doesn't create them (though it can certainly make them more noticeable).

Perhaps what you're looking for is a good noise reduction solution instead (something like NeatImage or Noie Ninja).

Guy

OK then... The most important thing you can do when adjusting "exposure" in post processing is to do it as non-destructively (to the pixels) as possible. My experience, and from what I've seen written, says that this should be done during RAW conversion. So, you'll want to take advantage of the various adjustments in PS ACR to get the exposure as close as possible to perfect during the conversion process. In ACR, the three settings that matter most for exposure are: Exposure (white point), Shadows (black point), and Brightness (mid-tones). For the Exposure and Shadows adjustment, you can use the clipping values preview (similar to doing a Levels adjustment once in PS). To do this you hold down the ALT key while moving the adjustment slider. The screen will go black initially, and when you've move the slider too far, pixels will light up against the black background. These lit up pixels indicate clipping (think "blown" or over exposed for whites, "blocked" or under exposed for blacks). Personally, I would start by setting a white point (Exposure), followed by the black point (Shadows), and then adjust the mid-tones (Brightness) to suit. If you do these correctly, there should be little left to do inside PS other than minor tweaking or selective adjustments.

I should also point out that there are other adjustments to make in ACR prior to conversion. You want to be sure to get the white balance (color temperature) set correctly for the conditions you photographed under. I tend to leave the Contrast and Saturation settings alone for the most part, but there are definitely situations where you would want to make minor adjustments to those. An example of the need to make a Saturation adjustment comes from a discussion I had with my friend Kwan Choo this week. He's been shooting a Vermilion Flycatcher and having problems keeping the intense red plumage from clipping during conversion. By reducing the saturation a little during RAW conversion, we kept the reds in check while getting a balance exposure for the rest of the scene.

You may also want to click on the "Details" tab in ACR to adjust the Sharpness to suit. Be careful here though, too much global sharpening at conversion can leave you with artifacts in your image. I prefer to do most of my sharpening in PS after conversion.

So, there you have it. A "very" brief primer on adjustments in ACR. Keep in mind, there's no magic bullet for a poorly exposed image. You're objective should always be to get it right in the field. Any major adjustments you do to an image in post processing may result in the enhancement of noise or the destruction of pixel data. That said, having blown plenty of exposures myself, I can fully appreciate the value of understanding how to make these adjustments.

Thanks guys for taking time to provide this great explanation. You've given me some work to do here. I had a few things right, but some things less than right. I've been doing more of the adjustment in PS, and not in the RAW converter.

I agree that the best situation is to get it right while shooting. This actually happens once in a while.

Best Regards,
Charlie

I have made several tutorials about sherpening
This is the first part is a series
http://www.microstockpix.com/article13.pdf

Thanks for mentioning the 'alt' key Bob.
I had no idea........

Excellent tutorial Bob, I need to work on this myself.