Originally posted by falconeye .....
So, this is what I do when shooting with my K-5 and how the K-5 changed the way I use the dials:
Say, I normally would shoot with Auto-ISO 80-1600. Then, in many instances, I find myself setting the K-5 to Auto-ISO 80-400 and EV-2 exp.compensation at the same time. I do this whenever there is a chance for blown highlights like sky, sunsets, windows etc. I don't do it always because I sometimes want to use the full DR of ISO 80. YMMV
This isn't ISOless already. But it's a better approximation than with previous cameras.
Guys,
I don't want to beat a dead horse, but i want to understand the issue as understanding is key to getting the most of this or any camera. I've been reading this thread over and over.
Finally, i think i can understand the issue based on the histogram. Lets say for example that we have an image that encompasses a total of 10 ev. This total DR of 10 ev pixels are nicely distributed over the 256 tonal values of the histogram (because of my amazing skills no doubt
) as i took this first picture, call it SCENE A.
In the second picture I decide to use a new strategy, and badly underexpose the picture such that only 10% of the photosites have enough photons to register a tonal value. The good news is that none of the highlights have been clipped. Call this SCENE B. I try to correct the image in pp by using the exposure and contrast sliders. Yet despite my best skills, the developed image doesn't look right.
I think the problem with Scene B is that it was exposed in a manner that only allowed what would have been the brightest tones to even register. Although one can apply more gain using pp software, there will never be the richness (multiplicity of 256 tones) or the range of sampling of the real image. Dpreview has discussion of the histogram which describes a tone-poor image as having "combing".
Histogram: Digital Imaging: Glossary: Learn: Digital Photography Review
Obviously, scene B was an extreme example, and the tactic of falconeye to use -2EV to preserve the highlights, will likely have much more minor repercussions in the loss of some tonal values. Instead there will be advantages in 2 ways, preserving highlights and taking advantage of a larger DR because of a lower ISO.
Having some understanding of what's happening in the camera allows one to tailor the strategy to the image. If the image is a moody dark indoor image, then the clipping of highlights is of less concern than preserving a rich number of tones in the shadows. So one might want to put a +2ev onto a 400 iso setting. Is that conclusion right?