Blocked up shadows VS. Blown out highlights

[CaptainTom]

We are constantly worried about blown highlights. I think this is a valid concern. If a photo has a "lot" of blown highlights I consiger it to be a failed photo.
But, in our effort to limit blown out highlights we need to keep in mind that the shadow area of the photo is probably going to "block" up and just show as a dark area with no detail.
When you blow out a highlight, the image information is gone forever and usually can't be recovered. A blocked shadow has the ability to be opened up and the detail restored.

I suggest that as we compose, expose for our photos that we stay away from blowing out the highlights, but that we also keep in mind that we not block out the shadow areas.
Learn how to bring out these details and you will discover a whole new dimension in your images.

This is not a new concept, and is something that film shooters ( you remember those dinasours?) were constantly striving for.

[PIC]

Digi Photo is kinda like color slide film in exposure lattitude {+- 2 stop}.
Some extended range Negative film was more like +- 5 stops.
Ansel Adams and the film Zone system was all about expose for the shadows and dev for the highlights ... some of you might remember expose for zone 3 detail in shadows and N +- xx dev times to control the highlights ...

Good Digi Sensitometry is the opposite.
Expose for the highlights and PS for the shadows ... or dont blow out the highlights and ramp up the shadows with fill flash, contrast, masking, etc.
CS3 camera raw is very good for this.
The recent HDR rage is a way to extend this exposure range and have detail everywhere.
Happy Attitudes on Latitude ...

EL

[jeffkohn]

As EL said, the conventional wisdom for film depended on whether you're shooting negatives or slides. Expose for shadows with negatives, expose for highlights with slides. For digital it's generally best to expose for the highlights. Fortunately digital has more dynamic range than slides, about 8-10 stops (depending on how you measure) versus only 5-6 stops for slides. Digital cameras also tend to have more open shadows than film anyway, so this isn't such a bad compromise.

The problem with exposing for shadows on digital is that the eye tends to be naturally drawn to the brightest part of an image; and you usually don't want the viewer's attention drawn away from your subject by bright areas with no detail. Also, with digital the transition from very light tones to clipped highlights can often be harsh and abrupt which is not pleasing to the eye, while having shadows 'fade to black' isn't such a big deal and can actually enhance an image by anchoring the tonal range and giving it a sense depth.

Of course there are exceptions to every 'rule'; sometimes you're shooting high-key, or in a situation where specular highlights are pleasing; and sometimes getting strong detail in the shadows is critical to the success of an image. Generally speaking though, it's easier to 'fix' shadows than highlights. And of course in a studio setting no compromise should be needed at all, since you have enough control of the light to make sure you can fit the full tonal range into your capture.

When the scene contrast is just too much for a single exposure, I'm finding the exposure fusion technique as implemented in Tufuse Pro and PTGui 7.8 to be very useful. It's much easier to avoid the 'fake' look you often get with Photomatix, as well as the noisy shadows. Exposure fusion actually tends to average out the noise in the shadows due to the exposure averaging technique it uses.