Gray cards : the 12% - 18% controversy

Started Apr 13, 2013 | Questions thread
Roland Karlsson
Forum ProPosts: 21,105Gear list
Re: Gray cards : the 12% - 18% controversy
In reply to xpatUSA, Apr 15, 2013

xpatUSA wrote:

Roland Karlsson wrote:

xpatUSA wrote:

Not only that, ISO gives what they call "latitude" so, when you set ISO 100 on the camera, it could be anything between about 75-125. A good indication might be to shoot a gray card metered to zero plus half a stop and check the histogram (with as little processing as possible, esp. brightness and saturation) - it should show a narrow distribution in middle of the horizontal axis.

The middle? How do you define that?

A trick question, I suspect

I define the middle of the histogram's horizontal axis (assuming 0-255) as 127.

Of course, it could also be defined as 118 depending how gray you like your mid-gray . . .

Yes, it is s trick question

So - you assume JPEG with a gamma curve?

 Roland Karlsson's gear list:Roland Karlsson's gear list
Sigma DP3 Merrill Sigma DP2 Quattro Sony Cyber-shot DSC-RX100 III Pentax K-3 Pentax smc DA 15mm F4 ED AL Limited +8 more
Reply   Reply with quote   Complain
Post (hide subjects)Posted by
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark post MMy threads
Color scheme? Blue / Yellow