Originally posted by jfdavis58 Just curious Jonas; been read the older threads with exposure information. How did you get these data points: what was the experimental set-up and procedure, what sort of data reduction/manipulation to put this graph together? How many times did you run the experiment?
You could just point me at the original thread if that info has been shared. Thanks!
Hi jfdavis58,
Hmm... I don't know... last time you asked me about my color management setup and I really described it you never replied and turned me down...
But OK then, here we go:
The chart has many sources, most of them based on experience and reading good books on exposure, digital picture technology, raw converters and zone systems but I also take a few Internet opinions into account.
The first thing to mention is that the baselines for EV0, EV1 and so on in both directions are taken from my own experience and preferences. The EV0 line represents an RGB-value of 97 in the chart. Some prefer 110, some even higher figures. I am slowly moving towards 110. Knowing this you may move the lines upwards or downwards to your own taste. The values for the other lines are the results from my own experiments using a lot of cameras to see what happens when you take the double or the half exposure time with the same target.
Then we have the curves: In this case they come from one single camera only (my first K10D). They are the average result from three exposures with each lens and screen combo without changing target.
The target was a Kodak grey card (but could have been anything neutral) more or less filling the viewfinder. The background behind the card was a grey fabric and the room has grey tapestries. The light source were a couple of daylight type bulbs.
Exposure method was Av mode or M mode, spot metering against the center of the grey card and all pictures were shot raw.
Then the pictures were developed. I used ACR 3.7 and as usual I had all settings set to default, straight (curve), zero (sharpening, noise reduction). Only the WB was manipulated.
Finally we have the figures. They are all taken from ACR by setting a sample point in the center of the picture while having all pictures selected. By using the WB tool at the same point the RGB values all became very much the same.
Well, that's about it. Doing it didn't take long.
(I can add that I, having the flimsy *ist DS metering in mind, also moved out in the overcast daylight and took one series of pictures with one of the lenses allready tested while my friend held a white sheet giving some neutral and soft light to the grey card which was placed on a grey sheet. The results were to my surprise the same.)
Lucky me not being into statistics. That saved me a lot of money as I didn't have to test houndreds of cameras. and time, accordingly. The weak point is that I missed to try my Jupiter-9 and other M42 lenses. I was to focused on having my daily equipment "calibrated".
Now let me down.
regards,