Re: Exposure Value -- Follow Up
Re: Exposure Value -- Follow Up
- Subject: Re: Exposure Value -- Follow Up
- From: Andrew Yeo via colorsync-users <email@hidden>
- Date: Sun, 23 Jun 2019 01:41:06 +0000 (UTC)
Greetings all
re: "I suspect my camera “light meter” is kaput?"
One can quickly gauge the accuracy of the light meter by using the "Sunny 16"
rule - and the straight forward formula for shutter speed and aperture
combination is:
1/ISO @ f16
With you knowledge and equipment (ColorChecker Digital SG) you'd be able to
perform tests using the sunny 16 rule by making a series of varied exposures,
say for example, at 1/3 stop increments +1 stop thru -1 stop either side of
your camera set at 1/ISO @ f16.
Inspecting the RAW file information, possibly as LAB values of the mid-grey
Digital SG target could reveal which files provide the most accurate data and
then inspect the shutter speed and aperture used in that file. How far is it
from the 'recommended' 1/ISO @ f16 exposure? 1/3, 2/3, (or more) brighter or
darker?
Those findings could be used to reveal the 'true' ISO being applied during
capture, as opposed to what the camera alleges is ISO 100, 400, 6400 so on, and
can enable future adjustments by you by way of exposure compensation at the
point of capture.
Such a test can be done on each of you digital cameras, at different ISO's
paying particular attention to testing the higher ISO cameras claim to have.
As a result one should be able to calibrate all cameras and hand held light
meter so consistent and predictable exposures occur at various ISO's.
Position the colour target in a suitable spot and select a day that's cloud
free offering plenty of uninterrupted direct sun!
Feel free to contact me via email if you have any questions regarding the
testing as any additional info I can provide will generally be
photography-centric and less relevant to colour mgmt / colorsync-users.
CheersAndrew email@hiddentographerSpecial Collections and
Cultural Heritage ImagingLibrary | University of Queensland,
email@hidden
On Sunday, 23 June 2019, 8:39:56 am AEST, Roger Breton via colorsync-users
<email@hidden> wrote:
I had the chance to take a few more pictures today with my camera, under
direct sunlight. I fear I have egg on my face for I could not find much wrong
doing by my camera this time ☹
I need to further test with "live" subjects.
But I remain suspicious...
This is a link to my analysis.
https://1drv.ms/b/s!AkD78CVR1NBqkLVMSaCo3oELVlKP0A
Thank you for your patience and kind help.
/ Roger Breton
www.graxx.ca
_______________________________________________
Do not post admin requests to the list. They will be ignored.
colorsync-users mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden
_______________________________________________
Do not post admin requests to the list. They will be ignored.
colorsync-users mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden