How Important is Exposure Data?

by | Oct 11, 2019

Thoughts for Today from Joe Farace

“Many amateurs reading these words are now engaged in scanning the data list (exposure data) with an eager eye, ‘Here,’ they are saying ‘Is how it was done.’ Could I reach them, I would answer: No kiddies, this is not how it was done. The (exposure) data are the bone and gristle from which all juices have been boiled away. The data is true in detail but (for the person who wants to make pictures) they are the least valuable information the book contains.”William Mortensen, writing in Monsters & Madonnas

You may have noticed that in some blogger’s posts they rarely, if at all, provide exposure data for the images on display but almost always describe the process and software tools used to make the photograph—or picture as Mr. Mortensen would have it. That’s because they believe, like Mortensen, that even if you were standing in the same place with the same camera/lens composition and even exposure, your photograph would look different because everyone’s vision is different. I know this is true because I’ve observed this phenomenon many times during my one-on-one workshops.

On this blog, I almost always provide exposure data for my photographs. My reasons for doing so are more complex and maybe a bit twisted. It may be glib for me to say it’s because that’s the format that photo magazines have used since Mortensen wrote the above words in 1936.

Closer to the truth is that when I wrote for another blog that shall remain nameless and unlinked, readers were always asking about exposure data and the gentlemen who ran the blog steadfastly refused to include it. When I started my own blogs I decided to include this data because people always wanted to know, even if I agree with Mr. Mortensen that the information seldom does them any good, except…

And you know there would be a but didn’t you? When I write about studio photography, as when testing Shanny speedlights I like to provide exposure data. For the photograph at left, it’s 1/125 sec at f/6.3 and ISO 200. In this case, the data tells you a lot about the power output of the light source, which in this case was a Shanny speedlight mounted inside a 12×36-inch Westcott Strip Softbox that was set on ¼ power. A second Shanny speedlight was aimed at the subject from just outside the door frame. The fact that these flashes produce that much power is significant and important, especially for anyone considering purchasing one of them.

Now as the man once said… you know the rest of the story.

If you enjoyed today’s blog post and would like to treat me to a cup of Earl Grey tea ($2.50), click here. And if you do, thank you very much.

If you’re interested in learning how I shoot portraits and use cameras, lenses and lighting in my in-home studio and on location, please pick up a copy of Studio Lighting Anywhere which is available new from for $17.07 and used, starting at $13.74, as I write this. The Kindle version is $11.99 for those preferring a digital format.