AndreasE Offline Upload & Sell: Off
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LMT1972 wrote:
Honestly Nikon should have you on their payroll
Then I would stop posting ....
MackDaddy1962 wrote:
I certainly do appreciate it!
Glad you can use the information provided.
When I was walking back to the exit of the park, it became quite dark. Streetlights went on and on my way out I tried to capture a scenery, I wouldn't have thought I could do it reasonable without a tripod. The scenery is from a content perspective a mediocre image, but I'd like to run you through the combined effects of the progress the D600 and the AFS 70-200mm/4 VR put in people's hands and should be considered as well. Imagine to have this liberty in a beautiful scene and you are able to capture a stunning picture more easily.
I did this shot handheld. Easy, you might think. So did I. Nothing special, capturing the image, quick check on the screen for sharpness and blur and moving on on my walk. Later, when I processed the photo in CNX2, I realized, that the shutter speed was down to 1/10 sec. Considering that the focal length in this particular image was 140mm. 4 stops below the recommended reciprocal shutter speed. (1/160, 1/80, 1/40, 1/20, 1/10).
As said, it was going darker by the minute and for this particular ambient light, ISO 1600 was the minimum requirement. To makes things technically worse, the street lights were sodium discharge lights (those with the yellowish/orange color). In case you haven't looked into the spectral power curve of SD lights, let me share it here.
This is the power distribution of sunlight. Energy is dispersed via a relatively broad spectrum
http://www.pbase.com/andrease/image/131695416/original.jpg
Sidekick: It isn't relavant for what I want to tell, but this is the SPD of incandescent light. See the high energy level in the red which we normally see as well?
http://www.pbase.com/andrease/image/131695420/original.jpg
Resetting the WB to match the "normal" whitebalance as provided by sunlight, software has to get the red channel down, slightly lift the green and strongly pull up the blue channel. Pulling a channel up introduces all sorts of artefacts. This is the reason, why most often the blue channel is the noisiest channel in indoor photos under incandescent light.
Increasing the volume of pain for a sensor is mercury light. There is no continous spectrum, but verry narrowband kind of light peaks. Red is practically non existing, but the key challenge is the uneven distribution. Nikon cameras have a bayer filter in fron of the sensor, the famous RGB filter (or CFA called). Marianen Oelund did a few years a wonderful post to describe the way how cameras see color. To simplyfy it for here, a typical sensor is designed to have peak sensitivity for the red channel at 660nm, for green 540nm and for blue 420nm. See how high the gain factor for red need to be for a proper white balance.
http://www.pbase.com/andrease/image/131695423/original.jpg
Sodium vapor lights add another level of pain, as you can see in this graph.
http://www.pbase.com/andrease/image/131695428/original.jpg
There is not much power "distribution", there is basically only orange light. In case you wondered in the past that some of those pictures you made weren't easy to process, that's why.
Coming back to my scene.
It was dark, so I had to use ISO 1600 to even barely made the 1/10 sec of exposure at a focul lenght of 140mm. Raising the ISO usually limits the dynamic range the sensor is able to gather. The combined effect of all this usually triggers my temptation to discard those photos as they are barely recoverable. But this time I tried.
This is the original image. D600, AFS 70-200m/4 VR, 1/10 sec, handheld, f4 (the weakest aperture), sodium vapor lights, ISO 1600 and underexposed - a perfect start.
http://www.pbase.com/andrease/image/146924072/original.jpg
Despite previous experiences, I gave it a try in CNX2.
Setting WB to a more reasonable vaule (red channel had to go back to 0.3 and blue had to go up to 2.3) People familiar with CNX2 Žknow how extreme these settings are. So we basically pulled up the non existing blue channel of an ISO 1600 image. Thanks for all the noise we get
As the image was underexposed, I pulled up EV by 1. Again, introducing noise accross the frame
The image was still quite dark, I used DL (dynamic lighting) to pull up the dark areas. Remember that the blue channel was already pulled up in the previous step and here it was pulled up again in the dark areas of the ISO 1600 image. My previous experience was: Just don't do that. But I did.
I added the usual low level of USM sharping (5,5, high quality) (This increases noise as well)
Noise reduction is turned off
So with all this steps on a rather suboptimal original photo produces after a few seconds in CNX2 this result. People with more skills could have for sure improved this one a lot, but I was positively suprised how much information the D600 sensor was able to capture in the very low power blue channel.
http://www.pbase.com/andrease/image/146924071/original.jpg
Here is a 2560x1700 resolution version
As said, it is not a perfect picture, but the ease of recoverability with the new FX entry level camera was a very positive experience. Sure, good practice and planning and excellent execution provide better results, but for those situations where not everything all is under control, it is a good feeling to know that the level of "reserves" moved up a bit with the new lens and the D600.
Cheers,
Andy
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