What is your technique to greatly darken the sky?

darktable

(Hans Petter Birkeland) #41

To compare with and without polarizer you .need to have the correct exposure in both images. That way the only thing that changes is the effect of the polarizer.


#42

Right. So here are two pictures with full-auto exposure.

With the polarizer rotated to brighten the sky:

With polarizer rotated to darken:

I took those pics a while back so I don’t exactly remember if I just rotated the polarizer away or removed it, but you can clearly see those two pictures are very different. You can also see how the polarizer is not uniform: the left side of the sky, is darker than the right side. I find that effect a little annoying, but it’s something that can be useful at times as well…


#43

I think it’s due to fact that sun is on the left. Birds can use light polarisation to locate sun in cloudy weather.


(Peter) #44

Most spectacular effects are when using filter with sun at 90°. Getting above grading from left to right is due to wide angel view of the lens so if we assume that the left side is at " 90° " to the sun, the right side is 90° - “angel view of the lens”. With normal and tele lens the difference is less visible. These two bellow aren’t taken at same conditions but shows difference with/without polarizing filter. Effect is amazing, starting from sky, clouds,and pines (reflecting wax on needles) and mostly on water. Photo made with 20mm m43 -> 40mm FF- > circa 50° angel view. So if is the sun is 90° to my right, left and right border of photos are only 65°. Photos are SOC, GX7 20mm/1.7