Every software program that I’m familiar with includes some automatic adjustments, and without fail, until recently, I’ve been opposed to using them. The reason is that any auto adjustment is a software engineer’s best guess of what adjustments usually work for most images with similar characteristics. I prefer to make adjustments that are image specific. I do use batch processing via the Lift and Stamp tool when images have been shot under similar lighting conditions. But even when taking advantage of the Lift and Stamp tools, I often tweak the adjustments for individual images. So until recently I could accurately claim to never use auto adjustments. But you’ve heard the old adage, “Never say never!”
Not long ago I was experimenting with some underwater photography. I’m new to this type photography and left my camera set on Auto White balance. (OK, some of you are saying, “See, you do use auto adjustments,” and perhaps you’re right. But that’s an in camera setting not a software setting.) As is often the case with underwater shots, there was a strong cyan/blue cast to the images. I tried adjusting the Temperature slider in Aperture but that wasn’t enough and there isn’t a red/cyan white balance slider. I also tried increasing the red saturation and decreasing the cyan saturation, which improved the image somewhat, but the cyan cast was still present. Out of curiosity ( I clicked the Auto Levels buttons that are under the histogram in the Adjustment HUD. And to my surprise the colorcast was gone!
The Auto Levels button with the colored RGB histogram sets the black and white points individually for each of the three channels. Unfortunately the algorithms Aperture uses introduce a fair amount of highlight clipping in each of the channels - more than what I generally use. But it did remove the colorcast. You can manually accomplish the same thing by going into Levels and setting the Black and White points individually for each channel. I opted to use the Auto adjustment but then to reduce the clipping by tweaking the white point settings.
The other Auto Level button sets the Black and White points using the Luminance histogram. It also introduces clipping in the highlights but didn’t eliminate the cyan cast. I still don’t have a use for this auto adjustment. For that matter I don’t use the Auto Exposure button either that’s to the left of the Auto Levels buttons.
I’m curious. Do you ever use Auto adjustments? If so, when and why? If not, is there any way you could foresee them being beneficial to you?