Quarantine - Photo things to do.

Mack

Mu-43 All-Pro
Joined
Jan 14, 2018
Messages
1,661
Bored of honey-dos, I decided to calibrate my laptop's LCD with an i1 Display Pro and their newest update for it. Set it to a default Color Management (I'm using Windows 10) setting of D65 and 100 cdm per the x-rite software.

Opened up "Windows Paint" to full screen for a large white window.

Took E-M1 Mark II and set it to Auto White Balance using the 40-150mm f/2.8 set to 150mm and Manual focus set to infinity so shutter would fire.

Used camera's ESP meter and to set Manual Exposure, I shot the Windows Paint white screen area while it was set to full screen. ISO 200, 1/1/25 at f/2.8. In theory, if meter and camera is accurate, it should give me a neutral RGB=117.

The above settings gave me a close to perfect RGB=117 reading off the image in Workspace, but with a little color error. So the meter and settings were good, but color was a bit off for being in "Auto White Balance" mode. The histogram in Workspace showed some colors to the sides of the white area so white balance was off a bit. (Aside, the older Olympus Viewer 3 has a white background for the histogram and is much easier to see the three RGB colors.)


The camera's SCP allows one to set a +/-7 in both the Amber/Blue and Magenta/Green. I punched in a +1 Blue (i.e. Blue/Amber, or what Olympus shows as R(ed) in their EXIF data), and a -1 Green. Result was a perfect RGB=117 a neutral Auto White Balance. The subsequent histogram shows little color to the sides of the white peak.

Two images below show the Perfect RGB=117, and the Not so Perfect Auto White Balance where I left the Blue and Green at the default of zero as shown in EXIF data beside "White Balance."


I need to check the Capture White Balance too, but I've got a feeling it may not be neutral either and need a B or G adjustment. I know I need to tune the Manual White Balance too.


Perfect Auto White Balance showing RGB=117 with a +1B and -1G now set in camera:
Perfect AWB +1B -1G.jpg
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Camera's default Auto White Balance showing RGB= 112 Red, 116 Green, and 115 Blue:
Not-Perfect-AWB-0B-0G.jpg
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Mack

Mu-43 All-Pro
Joined
Jan 14, 2018
Messages
1,661
Added on the above, I found the E-M1X a little better in Auto White balance as it only needed a -1G and the Blue was spot on.

***********************

Day two.

Decided that since the Auto White Balance is calibrated per above, and the exposure seems spot on, what would each stop of exposure look like from RGB=0 (Black) to RGB=255 and then printed?

I found the E-M1 Mark II takes about 12 stops to go from 0 to 255. The long toe (Blacks) has a lot of noise for about 3 stops before the curve rises more.

Below is what appeared for the SOOC JPEG , as read in Workspace, curve being one EV (One stop.) apart and the subsequent printed values under them. I can see the subtle tone at 3 but then it is for the most part black in print less than that. I put the Zone System scale under it.

Zone-Scale-of-Zone-Scale-of-E-M1-Mark-II-Exposure-EV-to-RGB-Graph-2.jpg
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Added later:

Since I usually have my Shadows set to +3 so I can see some detail in them instead of a lot of crushed blacks, I ran another series with the Shadows set to +3 and printed it out.

It lifts the toe end of the EV area very slightly, almost imperceptible in print. EV 5 (Zone II) stands out a little better against EV 4.

Zone-Scale-of-Zone-Scale-of-Shadow-+3-E-M1-Mark-II-Exposure-EV-to-RGB-Graph-3.jpg
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I added a Shadow +6 as well below.

Zone-Scale-of-Zone-Scale-of-Shadow-+6-E-M1-Mark-II-Exposure-EV-to-RGB-Graph-6-framed..jpg
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Day 3:
Decided I may as well try and bring the shadow's toe up as much as possible to see what becomes of the blacks once printed and how the zones will change. Below is the Shadows set to the maximum of +7 and you can see how Olympus moves the curve upward from about 80-90 RGB values compared to the prior ones.

Zone-Scale-of-Zone-Scale-of-Shadow-+7-E-M1-Mark-II-Exposure-EV-to-RGB-Graph-7-framed..jpg
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