Fair warning: this is a nerdy little post, of interest only to photo-techies and numbers junkies. Who’s left? Jack, I knew I could count on you. A reader took me to task several days ago for using the Adobe RGB green channel as a proxy for luminance when I measured focus accuracy and focus shift…. [Read More]

This is a continuation of a series of posts on the Nikon D850.   You should be able to find all the posts about that camera in the Category List on the right sidebar, below the Articles widget. There’s a drop-down menu there that you can use to get to all the posts in this series; just… [Read More]

The issue of the spectrum of the LED panels that I have been using for the autofocus tests has arisen. In the interests of full disclosure, here are some plots and stats. First, with the panels set to the 5500K setting that I’ve been using most of the time:     The blue excitation spike… [Read More]

[This post is revised as of 1/29/2018 with more accurate graphs.] This is a continuation of a series of posts on the Nikon D850.   You should be able to find all the posts about that camera in the Category List on the right sidebar, below the Articles widget. There’s a drop-down menu there that you can… [Read More]

This is a continuation of a series of posts on the Nikon D850.   You should be able to find all the posts about that camera in the Category List on the right sidebar, below the Articles widget. There’s a drop-down menu there that you can use to get to all the posts in this series; just… [Read More]