On cloudy days, it seems like the amount of contrast available for shooting is greatly reduced.
For a specific test I did, the in-camera histogram shows a very narrow band in the middle - for instance, where 90% of all pixel values are in about 1/8th of the horizontal range, and 99% are in 1/4 of the horizontal range.
How can I increase the contrast so that the histogram takes up more or most of the range of pixel intensity values? I want to do this while shooting, not in post-processing. I'm already using the in-camera exposure settings to maximize contrast, but I assume this is merely involved in how the mapping is made between 14-bit RAW color and 8-bit JPEG color.
I did some searching and found one article that claimed to increase contrast one shout "shoot with the narrowest aperture possible for light conditions" and "shoot with the fastest shutter speed possible for light conditions". These are contradictory, and in fact in my test the opposite (of the first assertion) was true: shooting the same scene at 1/200 @f6.3 produced about 3 times as much contrast as shooting at 1/80 @f14.
This would seem to suggest that shooting with a wider aperature yields more contrast, but with the zoom I am using I am already as wide as I can go and I still need more contrast. Increasing or decreasing the exposure merely shifts the histogram right or left.
Are there any other tricks I can use to stretch the contrast when shooting?