Friday, May 6, 2022

Using a Grey Card to Nail Exposure and White Balance

In this issue:

  • Grey card techniques
  • Computational Photography Talk for the Royal Photographic Society
  • Real Letters from Real Readers - Back Button Focusing (BBF)
  • In the Pipeline
  • Next time in Cameracraft Magazine
  • Parting Shots

Using a Grey Card to Nail Exposure and White Balance

A long time ago, photographers used film and were literally “shooting blind” – they weren’t sure if their built-in reflective light meters were metering for non-average subjects properly (like brides with white dresses, or grooms with black tuxes).  Nor were they ever sure if the color balance was “correct” when it came time to make prints from negatives in the darkroom.  In both of these cases, serious photographers would use a grey card to nail the exposure and the white balance – and it would be perfect every time.

Meter off the grey card to nail the exposure in photos that have non-average subjects.  You can also use the grey card as a neutral surface from which to set your white balance accurately.

Today we have digital cameras with Live View, which makes things easier but in extreme circumstances (like really bad or non-white light, or really non-average subjects like brides in white dresses or grooms in black tuxes) the grey card will still nail it.  Here’s how to use this ancient technique:

·         Have your subject hold the card in front of them

·         Spot Meter for the grey card (here’s where assigning the AEL button to Spot AEL Toggle really comes in handy) and take a test shot for later.

·         That’s it!  Recompose and shoot.  Brides in white dresses and grooms in black tuxes will all be exposed correctly.  No exposure compensation needed.  The exposure will be locked until you either turn the camera off or hit the AEL button again.

How to Nail the White Balance using the Grey Card

·        Do one of the following:

o   With the subject holding the card in front of them, do a Custom White Balance in your camera.  The white balance will be locked until you change it. 

o   When you’re processing your images on your computer, use the test shot taken in Step 1.  Use the White Balance Selector tool (commonly referred to as the “Eyedropper Tool”) on the grey card to set the white balance, then apply that setting to all the images in that session.

·         That’s it!  



In the pipeline

Please help spread the word about these releases.

My Talk to the Royal Photographic Society

I continue to get invitations to talk to photo clubs remotely.  One of my best talks of all time covered the emerging topic of Computational Photography.  It was given to the Royal Photographic Society, with over 500 people in attendance!

This talk is too good not to share.  And so you can access it for free on youtube here!  (You're welcome. :-) ) 


I can talk for your photo club too, even if you're not that large!  The most popular topics are listed here.  Shoot me an email and let's schedule a time slot.


Next time in Cameracraft

In the current issue (in the mail now), I talk with nature photographer Kyriakos Kaziras who goes to great lengths to get some amazing polar bear images.  How does he do it?  Does it even make sense for a nature photographer to storyboard an assignment if he's not shooting video for a documentary?

Find out more by subscribing to the last great photo magazine on the planet. :-)  


Have an interesting article you'd like to pitch for Cameracraft magazine?  Have you done any interesting or noteworthy projects with your camera?  I know my reader base is filled with amazing talent - we'd love to hear from you and possibly showcase your work!


Real Letters from Real Readers - Back-Button Focus

Hi Gary, I hope you and your family are all well.

I bought your Olympus OM-D EM-5 mark ii book, which I refer to CONSTANTLY. So thank you again for that.

You mention briefly about how it’s possible to do “back button focusing” with a certain lever setting for this camera. I googled that phrase, but still don’t understand what it means, why/when I’d use it, etc. If it’s something I should practice doing, then I’d like to learn about what it’s for, etc.

Anywhere you can send me that explains it? Especially with regard to the EM-5 camera?

Many thanks, Robin

===

Hi, Robin!

Great to hear from you again.  Okay, here's the short answer: Once upon a time, autofocus cameras had something like 3 autofocus points (it varied by model), and high-stress photographers (like those who shot weddings) would use the "Focus Lock - Recompose - Shoot" method quite a bit.  Having the shutter release button serving two functions (focus lock and shooting the picture) sometimes led to accidental shots, an expensive proposition in the days of film.

And so Back Button Focus was invented, which allowed the photographer to assign the "Focus Lock" function to another button (usually one on the back of the camera).  So you would focus lock with your right thumb and then shoot with your index finger.  That's all it was.

Today's AF systems from all manufacturers are so sophisticated that normal users don't really need it anymore - cameras can automatically identify the subject / the subject's face / the subject's eye and so that kind of manual intervention is less necessary.  The feature is still offered on newer cameras to cater to ancient photographers like me who grew up using it and now feel more comfortable telling the camera what to focus on in situations where the camera gets confused.  (That's the same reason "average" metering mode persists - modern algorithms do much better but it's still being offered for us old dinosaurs who invested quite a bit of time understanding how their unsophisticated exposure meters work.)

For what it's worth, I don't use BBF anymore.  The camera does a better and faster job than I can with 30 years of regular practice.  (On the other hand, I still keep the center button of the control wheel set to "Focus Standard" on my Sony bodies just in case!)

Hope this helps!  Sincerely, Gary

P.S. - Tony Phillips will be thrilled to know how much you've been using his book on the E-M5 II!


Parting Shots

in February the grandkids visited and they helped me shave off the beard.  (Click on any image to view larger and sharper.)



This look lasted a day.  I've already grown it back to the way it was before the pandemic.

Thus endeth a 2-year stretch of not caring how I looked.  Here's a marvelous look back.

Until next time,
Yours Truly, Gary Friedman

27 comments:

  1. Gary, congratulations on the talk. Thanks for sharing it and the grey card advice. Moreover, thank you for explaining "the why" about BBF. I'm no longer a youngster, but I didn't start a more serious journey into photography until Sony's SLTs and very first NEX cameras in 2010. I've been spoiled from go by AF and EVFs. Tons of tutorials drove me to try to incorporate BBF, and I failed, every time. I didn't get it. I still don't. Your explanation of "the why" helped me understand what drove photographers to need it ... and why I don't. I'm free! haha. Thanks again.

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  2. Pieter van RoijenMay 14, 2022 at 12:49 AM

    Years to grow, seconds to mow ;)

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  3. Much better without the beard.

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  4. I use the grey card as you describe; but often the camera refused to focus on the grey card, so I drew a cross on it, so now the camera focuses immediately. Not a big thing, but it makes work easier and gives a better impression for models, waiting to be photographed.

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    1. I usually put the camera into manual focus first before shooting the grey card, but your solution is brilliant and faster. :-) Thanks for sharing!

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  5. Thanks for the info on using a grey card. I have several that I regularly use and it has saved my bacon more times than I can count. Incidentally, I get my grey cards from Home Depot paint samples: Martha Living zinc (MSL267) works well for me.

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    1. What a great idea! Back in my day, the official Kodak grey cards were ridiculously expensive.

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  6. C'mon Gary, taking good pictures of Polar bears is easy! https://imgur.com/a/6bj1N2b

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    1. Ha! (Actually, a white polar bear against a black sea is exactly the scenario where a grey card would be useful, as automatic exposure meters will almost certainly guess wrong(ly).)

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    2. P.S. - I had to look at the picture three times before I got the joke. :-)

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    3. But Gary, how do you get the polar bear to hold the card?

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  7. Thanks for the background on the back button focusing. I've tried to incorporate that into my workflow without much luck. Now I can let it go without feeling like I'm giving up.

    I have Tony's EM-1 book. Any idea when the new book covering the Mark II will be out? Can you give us any hints about the video course that goes with it?

    Mickey

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    1. The book about the E-M1 II has been out for awhile: https://friedmanarchives.com/olympus-e-m1-ii/ And you'll have to wait for news about the video course...

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  8. Duh! Turns out that's the book I have, bought back in 2019. Guess I'll just have wait to check out the video course.

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  9. I received my formal training in photography from the US Army way back in 1966. When we got to the class on using an exposure meter rather than estimating with Sunny-16, our instructor sergeant told us about grey cards. But then he pointed out we might have a problem fumbling it out of our pocket when we were out in the Vietnamese jungle. So as a quick alternative he told us that people of all races have 16% reflective palms on their hands. I have successfully used that bit of gear ever since.

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    1. Yes! That trick works regardless of race. Although I always heard that the palm of the hand reflected back about 36% of the light, so when using that trick I would spot meter for my palm and then overexpose by about a stop. Now I have to go confirm the reflectivity of my palms... :-)

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    2. One of my all time favorite nature photogs, Galen Rowell (RIP), used this method, except the back of his hand. He was known for taking amazing images while rock climbing, so had to get creative to nail exposure. IIRC, he said back of his hand was one stop over.

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  10. Can't set the Multi-Slc Center Btn to Focus Standard per page 125 of your A7 IV book. On my new A7 IV, it appears that Focus Standard can only be set to the knobbed button above the Fn button. My A6600 does allow the Multi-Slc Center Btn to be set to Focus Standard.

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    1. The knobbed button above the Fn button IS the Multi-Selector button, and on my A7 IV I have both the center of the multi-selector button and the center of the rear wheel set to Focus Standard. (Redundancy.) Did you look on page 18/32 of the button assignment selection screen?

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  11. Back in before digital took over, I did a lot of research on grey cards and use of such. I found that not all grey cards are the same and the 18% "standard" varies quite a bit. The original Kodak Gray Card was very precise and justified the cost, but subsequent versions were made to looser specs and suffered from fluorescence (high UV reflectivity). In fact, many so-called 18% grey cards suffer from this UV issue. My methods involved testing with an X-Rite reflection/transmission densitometer and various spot meters.
    My background is in commercial/advertising photography going back to the 70's and I have been shooting digital since the 1990's using digital cameras from Fuji, Leica, Olympus, Nikon among others. I have also published numerous technical articles on color, exposure, and other photographic subjects.

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    1. I never even thought about UV reflectivity, especially since most films block it out. But I understand completely how this might throw off an exposure meter with no such filters. I guess I complained about Kodak too much. :-) Thanks for sharing your experiences!!

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    2. Most TTL camera meters do not give an 18% response. One of the first things I do with a new reflective meter is check it with a grey card (I use a Sekonic calibration grey card).
      I take an incident reading (more on this below) next to the grey card and adjust the spot meter to read the same on the grey card. This results in my reflective (spot) meter being calibrated against the incident meter, then I calibrate the camera meter to match the spot meter - most pro camera TTL meters allow such adjustment.
      The Sekonic calibration grey card (there are two versions that I use) is designed for this and is not printed on UV brightener-treated card stock. The down side is they are priced as the high spec tools that they are.
      I currently use the Sekonic L-858D-U meter for shooting and testing, but have used every pro-level meter for these tests including Minolta, Gossen, Weston, among others. The point is to establish a reference standard to be used for all other testing.
      When I mentioned calibrating the spot meter with a gray card, I first take an incident reading of the light hitting the grey card and then adjust the spot meter to match. Most incident light meters are factory calibrated to 18%, but spot meters have a .5 to .7 EV bias. This is true even with dual reading reflective/spot modes like the Sekonic L-858D-U mentioned above. This is not a defect but within parameters set for photo meters. Sorry for the long reply...

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    3. Interesting! Thank you for sharing this.

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  12. Hi Gary: While I hear what you are saying about bthe efficiency of modern cameras, especially mirrorless cameras, I have to respectfully differ about the Back Button Focus. (BBF)
    Once the menu is set for the AF-ON button at the back of the camera body takes over the focussing function only, t
    he front shutter / metering button then has only two functions. 1) To meter the image, and 2) to trigger the shutter. The AF-ON button is comfortably placed for you to rest your thumb at all times, and once your muscle memory understands that the three functions are now separated, there is never any doubt, even when shooting under extreme action circumstances.
    As a wildlife and surfing photographer, BBF is my "go-to" choice of focussing. It works, and I never miss!
    In action circumstances once I press the AF-ON button, it stays jammed down,, while I do shoot in bursts, using my forefinger. In the fashion the subject remains in focus at all times, even if I shoot in small bursts.
    Using the shutter release/metering button set to also focus the subject, every time you shoot in bursts, the camera focussing system has to refocus, and there are gaps which do provide opportunity to miss focus.
    So why not just play it safe, and use BBF?
    https://timdrimanphotography.co.za/

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    1. There's no wrong way, and as you said, for sports photography BBF might indeed be a better tool. Thank you for balancing out my opinions. :-)

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  13. I realize that I am pickier than many people but I have never seen samples from any smartphone that didn't look artificial and overprocessed.

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    1. A lot of photographers think that. And a lot of normal people like the output of their smartphone and see no reason to learn how to shoot raw and post-process if it means it will look just like the output of the smartphone. :-)

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