The Most Common Rear Button Focus/Focus Lock Technique Errors. « Arthur Morris/BIRDS AS ART

The Most Common Rear Button Focus/Focus Lock Technique Errors.


I will be away for almost a month while leading the 2018/2019 Falklands land-based IPT. I should be back in the office (and back in the pool) on the afternoon of Monday, January 14, 2019. Happy new year! I should have good internet access until Friday December 21 and then again on the weekend of January 12/13. I will surely not be online from December 23-27 and then again from January 4-7. I may or may not have limited internet access at other times.

Jim and Jen will be in the office weekdays to help you with your online orders and with IPT registrations.

I was thrilled recently to learn that first-timer Shonagh Adelman of Chattanooga, TN signed up for the 2019 Puffins and Gannets and Red Kites IPT. As he is the first registrant, we need three more for the trip to go. I am counting on it and hope for a sellout with ten plus the two leaders; there are lots of puffins and gannets. 🙂

I still need three or four folks for the Galapagos trip. If you would like to explore the possibilities, please get in touch via e-mail. No reasonable offer will be turned down.

  • 2019 San Diego 4 1/2-DAY BIRDS AS ART Instructional Photo-Tour (IPT) SUN JAN 20, 2019 thru and including the morning session on THURS JAN 24: 4 1/2 days: $2099. (Limit: 10/Openings: 4) Introductory Meet and Greet at 7:00pm on the evening before the IPT begins: THURS, 6 DEC.
  • The 2019 Hooptie Deux/Roseate Spoonbill Boat 3 1/2 DAY IPT — FEB 16 thru 19, 2019: $2599.00. Limit: 5 photographers/Openings: 2.
  • The New, Expanded 2019 UK Puffins, Gannets, & Red Kites IPT. Thursday June 27 (from EDI) through Tuesday, July 9, 2019 (on the ground; fly home on Wednesday July 10.): $9,999. Limit 10 photographers/Openings: 9. This trip needs four to run. Co-leader: Peter Kes.
  • The GALAPAGOS Photo Cruise of a Lifetime IPT/The Complete Galapagos Photographic Experience. July 23 to August 6, 2019 on the boat. 13 FULL and two half-days of photography: $14,499. Limit: 12 photographers/Openings: 4.


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Gear Questions and Advice

Too many folks attending BAA IPTs and dozens of photographers whom I see in the field and on BPN, are–out of ignorance–using the wrong gear especially when it comes to tripods and more especially, tripod heads… Please know that I am always glad to answer your gear questions via e-mail. Those questions might deal with systems, camera bodies, accessories, and/or lens choices and decisions.

This image was created on my last morning at Snow Hill Island, Antarctica, October 27, 2018, on the Emperor Penguin expedition. I used the Induro GIT 204/Mongoose M3.6-mounted Nikon AF-S NIKKOR 500mm f/5.6E PF ED VR lens, the Nikon AF-S Teleconverter TC-14E III, and my souped up Nikon D850. ISO 500. Matrix metering at about +1 1/3 stops: 1/1250 sec. at f/13. NATURAL AUTO WB at 10:55 am on a sunny morning with just a wisp of clouds in front of the sun. It was bright down there!

Nikon Focus Peaking fine-tune value: -2. See the Nikon AF Fine-tune e-Guide here.

Center AF point/Single AF Area Mode/AI Servo AF was locked by holding down the AF-On button after focusing on the eye of the closest chick.

Emperor Penguin adult grooming chick

The Situation

I moved right as much as I could to get close to sun angle. But as the rope protecting the colony angled away from us behind and to our right it was not possible to get right on sun angle. What do you think about the shadows of the two chicks?

Focus Lock with Nikon

I have the AF-On button set to AE/AF lock on my D5. As the D850 does not offer that option, I have the AF-On button set to AF lock on both my D850 bodies. I much prefer the former. Above I wrote, Center AF point/Single AF Area Mode/AI Servo AF was locked by holding down the AF-On button after focusing on the eye of the closest chick. To make that point clear, I first focused on the eye of the lower chick and then pressed and held the AF-On button down to lock the focus. In effect, I was using rear button focus but for the fact that I needed to hold the AF-On button down. When I wanted to make an image, I simply pressed the shutter button. Everything was fine as long as the lower chick did not change its position.

A Common Error

Whether you are using focus lock, or more commonly rear button focus, it is absolutely imperative that the camera not move after the focus is set. If you are hand holding without the lens completely braced, the movement of your body, even the movement caused when you breathe, is more than enough to throw off accurate focus. Best is to be on a tripod working with static subjects (as I was doing when I created today’s featured image). Being on a monopod does not really offer much help as your body moving even ever-so-slightly will move the monopod and the lens and throw off the focus. If you are not on a tripod and are using rear button focus or focus lock, the next best option is to be seated and using the knee-pod technique with your right 100% braced against movement. If you are free standing it is much better to select an AF point that will give you a sharp photo and keep AF active at the moment of exposure. If you opt not to do that as when you wish to create an image where the subject is way off center, you had better do your best to remain stock still. As insurance, re-focus after each frame while trying to remain still.

The Lesson

It is best to avoid using rear button focus or focus lock when hand holding. Working off a solid tripod is best. If you must focus and recompose while hand-holding, do your best to hold the lens completely still and in place to avoid throwing off accurate focus. And do take multiple images re-focusing and re-composing each time.

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8 comments to The Most Common Rear Button Focus/Focus Lock Technique Errors.

  • avatar Rob Stambaugh

    Hi Artie,

    The family’s intimacy contrasts beautifully with the sense of isolation the background creates. Really wonderful image. The shadows are not an issue for me.

    At first I was wondering why you focused/recomposed rather than using an off-center focus point. I now vaguely recall this may be one of those Canon versus Nikon things (?).

    Even with a tripod and a static subject, focus/recompose in theory misses focus with respect to the off-center subject, but I guess that shift in the focal place is inconsequential with long lenses (especially at f13, as here). I’ve always assumed it is inconsequential even at wider apertures with long lenses, correctly I hope (?).

    • avatar Arthur Morris/BIRDS AS ART

      Hi Rob,

      Thanks for your comments. Do note that the emperors have only a single chick.

      As for why I needed to lock focus, do understand that AF performance with a teleconverter with all of the lenses that I own (including the 600 f/4) suffers with Nikon as you move away from the center AF point. When using the AF points near the edge of the array, the lenses simply will not focus even after you have pre-focused manually.

      Several things with regards to your last paragraph:

      1- If you are on a tripod and lock the focus where you want it — in this case on the eye of the closest chick, and then recompose, you should come up with 100% accurate focus ever time even after recomposing (because the focus is set where you want and need it). And I believe that this is true all the time and that if you are “missing focus” then you are doing something else wrong. So in short, I am not understanding the theory you are referring to. As always, I stand willing to be corrected.

      2-Even at f/6.3 the total d-o-f for 700mm at 70 feet with a full frame body is about 1 foot, six inches in front of and six inches behind. At f/13 that increase to more than a foot in front of and a foot behind the subject … The main factor here is the distance to the subject. If you are working close to the lenses MFD then it is an entirely new ball game where d-o-f is measured in small fractions of a single inch. That said, I always like to focus exactly where I want to, in this case, on the eye of the closest chick.

      with love, artie

      • avatar Rob Stambaugh

        Here’s one explanation of the focus/recompose theory I to which I referred:

        and here is a dart-board demonstration of the issue:

        • avatar Arthur Morris/BIRDS AS ART

          Hi Rob,

          Thanks for the links. I read them both quite extensively including the comments on the second one. The math in the first one is a bit complicated and the diagrams could be a lot better. That said I do get the point (maybe). The reason that I am having trouble accepting the premise (even at close range with wide apertures) is that the focus distance is set and locked for the subject’s eyes not for the chest …

          I am not positive as to whether a problem will arise when working close to the MFD of a given lens at wide apertures. The tips on using the closest AF point to minimize the problem might be a good one. That said, doing so in the situation I described with Nikon gear is simply not possible (though you might get away with going one away from the center point). That said, I have made a zillion sharp images with long glass and wide apertures by focusing and recomposing as long as the subject is a good distance from the lens.

          The math might or might not be great but I think that most folks doing nature photography have a lot more important things to work think about and work on if they wish to make sharp images. But the next time I have a songbird at MFD the two articles might give me something to think about.

          with love, artie

  • avatar Warren Hatch

    Hi Artie,

    You might want to double check the options available on your D850 under Custom Function f-1. The high level options for the D850 for assigning the AF-On button are identical to those you can select on the D5. Some of the other programmable buttons are very different between the bodies, but not AF-On.

    More importantly, I think there is a typo in the blog post. The behavior you are describing would come from assigning the button ‘AF lock’, not ‘AE lock’.

    Safe travels,


    • avatar Arthur Morris/BIRDS AS ART

      Thanks Warren for catching my brain typo 🙂 I did have it correct in the image caption. Thanks for the AF-On button info.

      with love, artie

  • Dear Artie, I hope the trip has been a great success. Beautiful penguin image, I love the two layers of snow in the background and the positions of the birds. I personally quite like the minimal shadows as with this image I think it adds a little bit of extra depth.

    • avatar Arthur Morris/BIRDS AS ART

      Thanks Jake. The trip has been great. I am back in Stanley and will be home on Monday.

      with love, artie