Rear Focus Tutorial « Arthur Morris/BIRDS AS ART

Rear Focus Tutorial

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This Marbled Godwit was photographed at Nickerson Beach at 6:51 am on August 30, two days after Hurricane Irene. (If you missed “Surreal Hurricane Irene Experience” be sure to click here.) Marbled Godwit is uncommon at best at this location. The image was created with the tripod-mounted Canon 800mm f/5.6L IS lens, the 1.4X III TC, and the EOS-1D Mark IV. ISO 400. Evaluative metering +1 stop: 1/500 sec. at f/9 in Manual mode. Central Sensor/Rear Focus AI Servo AF and re-compose. Read on to learn about rear focus.

Lens/TC/Camera Body Micro-Adjustment: 0.


Blog-folks who read the captions carefully have noticed recently that I have been adding rear focus info to most images. In the Marbled Godwit image caption above I wrote, “Central Sensor/Rear Focus AI Servo AF and re-compose.” With the 800mm lens, the 1.4X III TC, and a pro body (the Mark IV), only the central sensor is active. Unless you know what you are doing having only the central AF sensor available can lead to problems. As I have written before, many folks become compositional slaves to the central sensor especially when working in AI Servo AF (as opposed to using One-Shot AF and re-compose). Nikon folks, not to worry. Nikon does offer rear focus. Please consult your camera body manual. Or better yet, get yourself a copy of our Nikon dSLR User’s Guide here. Note: Canon’s “AI Servo AF” is the same as Nikon’s “Continous” (C) and likewise, Canon’s “One Shot” is Nikon’s “Single Servo” (S).

Rear focus involves focusing by pushing a button on the top right back of the camera (rather than by pushing the shutter button). You need to change a custom function or two to set up rear focus. And with some systems you set up rear focus via the camera’s menu. You can consult your camera body to learn to set up rear focus. Canon folks are urged to consult our camera User’s Guides for detailed information on exactly how I set up my cameras for rear focus. Set-up is similar with the Mark III and the Mark IV and with these bodies I recommend swapping the functions of the Star and the AF-On buttons. Set-up with the 7D is totally different. In each case the User’s Guide contains detailed instructions for setting up rear button AF. (Many folks are simply unable to decipher their camera body manuals.)

For many years I used both the shutter button and rear focus, depending on the situation. Often I got confused. I’d forget which was set on which camera. I’d press the shutter button and the camera did not focus. Or I’d press the rear button and the camera did not focus. About five years ago I gave up and went shutter button AF all the way spending half my time switching from AI Servo to One-Shot and back again…. Robert O’Toole has always used rear button focus and about a year ago he convinced me to make the switch full time. He believes that when the shutter is released that AF tracking may be momentarily interrupted but that when you use rear focus the camera continues to track well even when the shutter is released. Canon’s top tech reps are noncommittal but concede that it could be possible.

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This young skimmer was photographed at Nickerson Beach at 8:26 am on August 19 at Nickerson Beach with the tripod-mounted Canon 800mm f/5.6L IS lens and the EOS-1D Mark IV. ISO 400. Evaluative metering +2/3 stop: 1/1600 sec. at f/6.3 in Manual mode. Two sensors below the central sensor/Rear Focus AI Servo tracking AF. See more below.

Lens/Camera Body Micro-Adjustment: -4.

Making the change from the shutter button to rear focus requires a big commitment and takes lots of getting used to; it takes a bit of retraining of the brain and the thumb to get used to rear focusing.. But I have stuck with it for more than a year now and will never go back.

Aside from possibly better AI Servo AF tracking for flight photography there are other advantages to using rear focus. In short, you have the best of all worlds all the time. When using rear focus you always have AI Servo (Continuous for Nikon) set. You will never need to switch back and forth from AI Servo to One Shot. To photograph flying birds or to focus track walking, running, or swimming birds (or perched birds that are changing their posture or head position almost continuously simply press and hold the rear button to focus track that you have set for AF and press the shutter button when you want to create an image.

If you are limited to the central sensor when photographing a static bird like the Marbled Godwit above, you first place the active sensor on the subject’s eye, face or neck. Then you press the rear button too set the focus and then you release it. This effectively “locks” the focus–the system will not begin to focus until you press the rear button again. Now you can recompose without worrying that the system will focus. Finally you press the shutter button to make an image. If the bird moves or takes off you simply press and hold the rear button to activate AI Servo tracking AF. With rear focus you have the best of both worlds available at all times: you always have what effectively amounts to One Shot AF (by pressing and releasing the star button or the AF-ON button, whichever one you use for rear focus) and you always have AI Servo Tracking AF by pressing and holding the star button or the AF-ON button, whichever one you use for rear focus.

Once I made the commitment to switch exclusively to rear button AF I stuck with it and have never looked back. I have it set 100% of the time with both my 800 and my 70-200. And I do feel that my percentage of sharp flight images with either lens has increased.

Hugely important note: when hand-holding and in many other situations where you are photographing a static bird and have access to all the AF sensors, it often makes sense to select a sensor that falls on the bird’s eye, face, head, or neck and push and hold the rear button. With the Marbled Godwit image above I had only the central sensor available so I needed to rear focus and re-compose.

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This BreezeBrowser screen capture shows what I mean by “two sensors below the central sensor” (in red). To create this image I pushed the rear button (I actually use the Star button) to acquire focus and held it in to track the bird. When the bird came into the zone I pressed the shutter button and held it down to create three or four images. This one was best by far.

Note the micro-adjustment and the perfect histogram. BreezeBrowser is the program that I use to edit (select the keepers) my images and to organize my image files both on my laptop and on the big computer in the office. If you are using a PC and you are not using BreezeBrowser you are wasting lots of time….

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Here, a juvenile Willet is holding its sand crab breakfast while an adult Sanderling is hoping that the young bird drops its prey item. This image was created at 6:21 am on August 31, 2011 at Nicerkson Beach with the tripod-mounted Canon 800mm f/5.6L IS lens and the EOS-1D Mark IV. ISO 400. Evaluative metering +2/3 stop: 1/1600 sec. at f/6.3 in Manual mode. Single sensor lower right/Rear Focus AI Servo tracking AF. I was able to get the manually selected sensor on the Willet’s right (far) foot. I do wish that that Sanderling had been more parallel to the back of the camera.

Lens/Camera Body Micro-Adjustment: -4.

The pretty pink reflections here were opposite the rising sun. On clear mornings always look to the west/southwest for the pink/purple/blue skies.

This image was created on the morning of Sunday, September 4, 2011 with the Canon 70-200mm f/2.8L IS II lens and the 1.4X III TC (hand held at 205mm) with the Canon EOS-1D Mark IV . ISO 100. Evaluative metering + 2 2/3 stops: 1/8 sec. at f/6.3 in Manual mode. Bottom row central sensor/rear-focus AI Servo AF.

Lens/camera body Micro-adjustment: -8.

For a greater appreciation of the image above, click on the photo to view a 1400 pixel wide version. Click on the enlarged version to close it.

Many beginning photographers think that pleasingly blurred images are created by accident. Nothing could be farther from the truth. If you would like to learn to create a variety of pleasing blurs, check out A Guide to Pleasing Blurs by Denise Ippolito and Arthur Morris.

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This image of a Semipalmated Sandpiper flapping after its bath was made at Nickerson Beach at 6:03pm on August 30, two days after Hurricane Irene. My big lens was on my Mongoose M3.6 head as usual. I lay behind my splayed, tripod-mounted Canon 800mm f/5.6L IS lens with the 1.4X III TC and the EOS-1D Mark IV. ISO 400. Evaluative metering +1/3 stop (as framed): 1/800 sec. at f/10 in Manual mode. Central Sensor/Rear Focus AI Servo AF; release and wait for the jump!

Lens/TC/Camera Body Micro-Adjustment: 0.

Most time when trying to catch a shorebird jumping after its bath I would keep the rear button down and try to follow the bird. On this afternoon I tried something new. I focused on the bird with the rear button as it splashed about. Then I would release the rear button and re-frame higher as the birds almost always just flies straight up out of the water. When the bird jumped, I held the shutter button down for an image or two. Here this new trick worked to perfection. To be sure that you understand completely: I was not actively focusing when this image was created….

BAA Bulletin 384

BAA Bulletin 384 is online and can be accessed here.


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This sleeping juvenile Sanderling image was created with the the tripod-mounted Canon 800mm f/5.6L IS lens, the 1.4X III TC, and the EOS-1D Mark IV. ISO 800. Evaluative metering at zero: 1/1000 sec. at f/8 in Manual mode. Central Sensor/Rear Focus AI Servo AF and re-compose.

Lens/TC/Camera Body Micro-Adjustment: 0.

This image perfectly illustrates one of the huge advantages of using rear focus. With the TC and an f/5.6 lens I was limited to the central AF sensor. I focused on the eye of the bird by pressing the rear button, let it go to effectively “lock” focus, re-composed, and then created the image with the bird right where I wanted it.

Shopper’s Guide

Below is a list of the gear used to create the images in today’s blog post. Thanks a stack to all who have used the Shopper’s Guide links to purchase their gear as a thank you for all the free information that we bring you on the Blog and in the Bulletins. Before you purchase anything be sure to check out the advice in our Shopper’s Guide.

Support both the Bulletins and the Blog by making all your B & H purchases here.

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Canon 70-200mm f/2.8L IS II lens. Man, I am loving this lens on my shoulder with the 2X III teleconverter. I also use it a lot with the 1.4X III TC.
Canon 800mm f/5.L IS lens. Right now this is my all time favorite super-telephoto lens.
Canon 1.4X III Teleconverter. Designed to work best with the new Series II super-telephoto lenses.
Canon EOS-1D Mark IV professional digital camera body. My two Mark IVs are my workhorse digital camera bodies.

And from the BAA On-line Store:

LensCoats. I have a LensCoat on each of my big lenses to protect them from nicks and thus increase their re-sales value. All my big lens LensCoat stuff is in Hardwood Snow pattern.
LegCoat Tripod Leg Covers. I have four tripods active and each has a Hardwood Snow LegCoat on it to help prevent further damage to my tender shoulders πŸ™‚
Gitzo GT3530LS Tripod. This one will last you a lifetime.
Mongoose M3.6 Tripod Head. Right now this is the best tripod head around for use with lenses that weigh less than 9 pounds. For heavier lenses, check out the Wimberley V2 head.
CR-80 Replacement Foot for Canon 800. When using the 800 on a Mongoose as I do, replacing the lens foot with this accessory lets the lens sit like a dog whether pointed up or down and prevents wind-blown spinning of your lens on breezy days by centering the lens directly over the tripod.
Double Bubble Level. You will find one in my camera’s hot shoe whenever I am not using flash.
Be sure to check out our camera body User’s Guides here.
The Lens Align Mark II. I use the Lens Align Mark II pretty much religiously to micro-adjust all of my gear an average of once a month and always before a major trip. Enjoy our free comprehensive tutorial here.
Canon EOS-1D Mark IV User’s Guide. Learn to use your Mark IV the way that I use mine.

80 comments to Rear Focus Tutorial

  • avatar Giovanni

    Arthie I ask your pardon ..but my enclish is bad.
    With Canon 1D mark IV and with Canon 5D Mark III I use the af/on button to take af on se subject and when I no put it all is stopped.
    To make this I must set the option in the menu…but this setting isn’t in DX

    • avatar Arthur Morris/BIRDS AS ART

      No worries. If I had the camera in my hand, I could–if it is do-able–probably figure it out.

  • avatar Giovanni

    Thanks a lot for all help.
    If I will use af-on on botton on the camera It no works as rear focus …

    • avatar Arthur Morris/BIRDS AS ART

      YAW. You need to figure out how to have the AF button do metering only, not AF…. artie

  • avatar Giovanni

    could help me ?
    I bought a Canon 1Dx (before I had 1D Mark IV) ; how I could set rear focus ?

    • avatar Arthur Morris/BIRDS AS ART

      Hi G,

      I am sure that you can set rear focus on an EOS-1D but I do not remember how to do it…. If you study the owner’s manual you should be able to figure it out. If anyone here knows how to do it, please chime in. artie

  • […] β€œback-button” focusing, this is your chance (See Artie’s great article on this topic here:Β  I use this technique 100% of the time at road races and when photographing birds in […]

  • Hello Art,

    I have switched to rear focus on my Nikon D3s and absolutely love it. Can’t imagine shooting BIF any other way!

    Can you however explain what you mean by Central Sensor “by necessity”? Are you only limited to the central sensor when you use your 800mm with the teleconverter, or is it something else I am not understanding?

    Appreciate the help.

    • avatar Arthur Morris/BIRDS AS ART

      :). You are understanding perfectly. Central sensor expand is now available at f/8 with both the 1D X and the 5D III.

  • If your camera doesn’t have this option, try going outside where the light is usually better. Don’t think you need an expensive camera and equipment setup either.
    Some cameras are simple point and shoot while
    others have many different modes for taking pictures.

  • Very interesting about the claim of better focus on subsequent burst images. I am trying the rear focus on my 7D and 5Dmk3. I have been using the rear button for focus stop – sort of the inverse of rear focus. The real problem in northern Illinois/southern Wisconsin is that those rear buttons are not usable with gloves. I wish there was a more prominent, assignable button location.

    • avatar Arthur Morris/BIRDS AS ART

      No claims. Just mentioned the possibility of…. I wear love liners with the fold away thumb and do fine with rear focus.

  • avatar erik vb

    i have a question about Rear button focus and IS, when i have the rear button to focus and i let it go (one shot) and then i press the shutter to take the photo , will there be no time loss as the IS will stop when i let go of the rear button and then the IS will start again with the shutter button ??

    When i focus with the shutter button , the shutter button is always halway so no time loss i reckon ??

    • avatar Arthur Morris/BIRDS AS ART

      Good question. Sometimes I assume too much. When I am using rear focus, which is all the time, I am always half-pressing the shutter button before making an image. When following a flying bird the shutter button is half-pressed. With a static subject, I half-press the shutter button before making an image. To do otherwise would be to jab at the shutter button and that is a very poor practice. We need to be gentle.

      • avatar erik vb

        Ok. Is it not best to use cfn 4.1 ( 1 d mark4 ) then., to use the rear button to stop the focus an to put the focus back to the schutter button. Then you can use also all the time servo and the IS is the whole time activited.

  • avatar Ray Rochelle

    I have a question on the Back Focus Button. I have a 600d Canon and have a question reguarding how to use the back focus idea. The question is this, Do you need to hold the *Button down while you release the shutter. Sorry to ask a question that you have already answered. But I am new and haven’t seen it answered. Thanks for your efforts. It is a great blog..
    Ray Rochelle

    • avatar Arthur Morris/BIRDS AS ART

      If you are tracking a moving bird, you need to keep the rear button pressed in and then release the shutter. For static subjects, just set the focus and release the button. Then press the whutter button whenever you want to. artie

      ps: that should of course be the shutter button….

      I made the correction above after receiving the following e-mail :):

      Thanks very much for your quick and thoughtful response. I had to think and study all of my manuals in an attempt to not look too novice. I had a tough time finding the “whutter” button?????? I figured you of all people would know what your talking about, no question there. So I busied myself finding that Whutter. I just knew that sucker had to be there and all my problems would soon be over!!!!! πŸ™‚ Finally it came over me that you have one of those keyboards like mine that refuses sometimes to type what my brain sends down to the fingers!!!!!!!! All kidding aside I think I have it now…..Focus with the *Button and Release, then trip the Whutter when you are ready!!! Thanks a bunch Artie. Ray Rochelle

  • […] great photos. Anyone interested in learning more and how to set it up should read Artie’s tutorial at I’m only here to point out situations in which I find the additional […]

  • Hi Artie. As per instruction manual; the AI Focus AF switches the AF mode from One-Shot AF to AI Servo AF whenever movement of the subject is detected.

    Wondering whether that works the same as Rear Button focus! Or else, should I always keep the AF Mode on AI Focus AF to backup the Rear Button focus!

    Could you please comment?

    Thanks in advance.

    • avatar Arthur Morris/BIRDS AS ART

      As per me AI Focus rarely works the way it is supposed to. If you read the tutorial and understood it you would know that you want to be in AI Servo AF 100% of the time with rear focus as you always have One Shot by pressing and releasing the button and you always have AI Servo when you press and hold the button. Therefore, your question does not make sense.

  • avatar mike braunstein

    I have tried rear focus but the camera refocuses when I press the shutter button. Is there a way to disable it using a Canon 5d Mark111?

    • avatar Arthur Morris/BIRDS AS ART

      Yes, you assign only Metering to the Shutter-Button as detailed in my 5D Mark II User’s Guide. Here is a free excerpt from the guide:

      “The first item in the left hand column is Shutter Button half-press. The default there is Metering and AF start. With the orange outline around this first item Press Set. You will see the orange outline around the Metering/AF symbol. Turn the Thumb Wheel one click clockwise so that the orange outline is around the metering (only) symbol. Now press set again.”

      You can learn everything that I know about the camera here. I hope that you get yourself a copy :).

  • avatar Nate O

    Wow thank you SOO much! I heard about this feature but figured it was only available on the big guy cameras so to speak! I only have the 550D as I blew my spare cash on primes but not having the ability to use the star button like this was driving me nuts! SOO many times I’ve had a perfect shot at like a football game or other low light scenario on my 85 1.8 or a 70-200 and the autofocus is perfect and then hunts! Sure I could choose One-shot and Servo back and forth but this is much easier and sensible. I’m picking up my Canon 6D tomorrow so I’m hoping its as straight forward as other cameras. Very eager to get some of the great features of the 5DIII on the 6D for 1500 less.

  • Many thanks for the rear-focus tutorial. I’ll try it out with my 50D. If it works; I’ll be happy, if not, that’ll be my failure or may be due to not being a full timer.

    On the focusing points; I never tried any other than the central one. Occasionally used all for tracking in-flight birds under a clear sky. Now, feel encouraged to use other focusing points as well depending on the situation.

    One thing Artie, I also photograph wild mammals whenever opportunity emerges and focus on the body. Do you recommend focusing on the eye in this case also particularly for large mammals like a Rhino or Deer?

    Thanks in advance.

  • […] Oh, is your AF still tied to half-pressing the shutter? If so, how are you going to use AF to focus on her eye and then recompose for the portrait? learn how to move AF automation to another button so you control it rather than fight it. Trust me, doing AF, shifting the lens to manual and then recomposing? It’s lame; you’re doing it wrong. (if you don’t understand what I’m suggesting, listen to Art Morris).  […]

    • avatar Arthur Morris/BIRDS AS ART


      Oh, is your AF still tied to half-pressing the shutter?

      Of course not :).

      • Still using the star button. Works so much better for me as it seems to be easier to get to. I am loving this idea and am glad to have taken your advice. Havn’t switched back.

  • Yes absolutely right on that one!

  • So… I took my MIV out today for the first test run and I am very happy with it. I am more happy with the fact that I used my rear focus all morning and was quite happy with how easily I adjusted to it.. I started with the af button and found it very difficult to blindly locate it so I changed it to the star button when I got home (since I couldn’t for the life of me figure it out in the field). I am certain I will love it and will stick with it. I highly advise Artie’s great advice on this issue πŸ™‚ Thanks again

  • I just recieved my 1DMIV and am setting up the custom functions. I am finally going to commit to staying on that rear focus button. Your tuturial helped make it crystal clear so Thank you. I will put it into effect in the am and see how I do. I Havn’t decided on af or star button yet but will see what is more comfy. Thanks again

  • I agree with Jim Neiger on all his points — but I also agree with Artie that it is very useful to have both AI Servo and One Shot modes available at all times. I solve this by using the CF to set up the AF-ON button to the AF-OFF function. Then I can bump focus like Jim Neiger and have my thumb free to do exposure compensation, and if I ever need to separate AF from the shutter button, I just press the AF-OFF button.

    • avatar Arthur Morris/BIRDS AS ART

      Thanks Peter. But it does not make sense to me πŸ™‚ It sounds as if you have to press and hold the AF-On Button to get the equivalent of One-Shot. Is that correct?

  • avatar Kelly Anbach

    Rear focus the same as back button focus?

  • Been using rear * button focus since the original Eos 1 camera in 1992. I prefer the placement of the * button over the AF-ONn button (fits my hand better )especially in horizontal mode. I like the feel of the AF-ON button shooting in portrait but you can’t seperate the function so I just just use the * button. IMHO the benefits of rear focus far outweigh the disadvantages.

    • avatar Arthur Morris/BIRDS AS ART

      I switch the buttons too. I don’t even remember any disadvantages of rear focus :). Thanks for stopping by! artie

  • avatar Tung Nguyen

    Hi Mr Arthur Morris,
    Do you think which is better between Canon Telephoto Lens 800mm f/5.6 IS and 600mm F/4 IS Mark II + TC 1.4x mark III for wildlife and Bird in flight?
    I’m confuse to choose it.
    Tung Nguyen

    • avatar Arthur Morris/BIRDS AS ART

      The 600 is more versatile. In the right hands both that you mention can make excellent images of birds in flight. And the 600 is lighter by 1 pound, 3.36 ounces making it easier to hand hold on occasion. I will be doing a blog post on this very topic in a week or so. If I forget remind me because everyone is asking similar questions πŸ™‚

  • Hi Arthur,

    I admire your work a great deal and am jealous you already have your Mark III. I’m still waiting for my body-only and it’s worse than waiting for Christmas was at 8 years old.

    I notice that you used the 800mm on nearly all the images posted here. I’ve been trying to decide which long tele to start with for water fowl. Do you ever use the 600mm (with and/or without extenders) ? Is this a reasonable road to go down or would you go straight for the 800?

    Love all these posts and the Osprey is really breathtaking … clarity, light ‘glow’, resolution … everything!

    I will try to catch up to you some time in Morro Bay.

    Brent A. Schoenfeld

    • avatar Arthur Morris/BIRDS AS ART

      Envious I politically correct :). Will the 5D Mark III be your only body? If not, what else? Yes, I have used both the old 600 and the old 500 with both TCs extensively. Your question tells me that you need to get a copy of ABP II fast if you would like to learn to improve your bird photography…. I’ll have a copy of ABP II in the car. Only $40.

      • One 5D Mark II ( I love this camera – too good to give up), One 5D Mark III ( I hope they will finally let me have one without having to buy a second 24-105), and a 7D for small sensor advantages. I’m considering a 60Da for deep sky, or I might modify another camera. I haven’t decided yet.
        I’ll check out your book. The cover is spectacular.
        As for political correctness … it has always given me a stomach ache. But if you want to parse more finely the distinction between envy and jealousy I’ll pay attention … just because I like that book cover so much.

        With those bodies the 600 L IS II is surely best for you. What is “deep sky”? As for jealousy vs. envy, using politically correct was a bad choice of words. And further investigation on the web reveals that neither is a healthy emotion :).

        ps: you may be confusing ABP with ABP II….

  • Is there anything on a Nikon D300 which will allow me to do this?

  • When using Back Button Focus, how do you use exposure lock? (it’s on the same button)

  • avatar Mike Forbes

    I have used Arthur’s camera set up instructions now for about 8 years. They are invaluable for anyone doing action shooting. I am having a problem trying to get my new 7D to work consistantly with the rear focus. I bought the book (great as usual) but even after FOLLOWING the instructions this one has me stumped.

  • avatar Jon

    I am weakening – I will try it again!

  • Robert convinced me a few years ago at his first workshop to switch to rear focus using the star button and after a few weeks it became so natural I never think twice.. The only time I ever have to turn it off is when I need to hand the camera to my wife. lol. I hope all is well with you Art.

    Thanks Mike. It took Robert years to convince me. artie

  • I also have been using ‘rear fucus’ on both my 5D Mark II and my 7D. I’m have lots of problems with ‘noise’ generated with the 7D, especially
    in low lit situations, I’m scared to go above 250 ISO. Which sensor do you primarily use on the 7D for birds in flight? I’ve been using the center only and aiming for the eye balls (heade area. I’ve noticed that a lot of your shots you use other sections of the sensor. Thanx, Sal

    So how do you like rear focus? Dan Cadieux, BPN Avian Moderator, creates the most beautiful images with his 7D; they look like Mark IV images. I have asked him to do a guest blog post on what he is doing both in the field and at the computer. So keep your eyes peeled. I use the central sensor for most flight stuff when I do use a 7D, usually with 19-point AF select as detailed in our 7D user’s Guide. artie

  • avatar Giovanni Frescura

    I like rear focus but I am not sure that it is the best because shooting the mirror is up and the AF sensor not see anything and resume operation when the mirror goes down (by holding down the shutter botton the middle or the Af button), at which point yhe goal is still with the setting fire of shot and if the subjet has not moved too much AF should not have trouble replace it. Could you confirm that this idea is right ?Thanks Giovanni

    I am not understanding you very well however I can tell you that rear focus has nothing to do with the mirror being up or down…. artie

  • Jon,

    I think its the same CF as the one that sets Af Lock. It’s just a different selection. If my memory is correct it may be CF IV-1 #2 & CF IV-2 selection #1. You also need to swap the Af ON and * buttons if you wish to focus with *.

  • avatar Jon

    Jim my set up is exactly the same as yours, I have no need for one shot with this set up, I wondered if I was missing something but I reckon it is nothing more than personal choice/horses for courses. I did wonder about Artie’s point regarding the possibility of the very last microsecond focus time but I am not entirely convinced as I think it is the same command albeit via a different button. I think this method is more intuitive, but having said that the rear button pressers are very clear – they would not change having undergone the committal to rear focus. I did try to make my 50D rear focus today just to have a play but I cannot see the way this can be achieved – I still do not want to dismiss this rear focus until I have tried it for a few hours.

    I think that with the 50D you simply change the function of the shutter button and the function of one of the rear buttons just as with the 7D. Details are in the 7D Guide. I am not however, positive that that is how you do it…. artie

  • Marina,

    I wasn’t very clear about this in my post, but I am always shooting in AI Servo and never switch back and forth between one shot and Ai Servo, when I’m shooting birds. I set the * button to AF lock. I use AF lock to recompose images of still birds. What I do is focus were I want the sharpest focus to be, then press and hold * button, recompose and shoot. I am still in AI Servo, but my camera does nnot re-focus when I recompose and shoot becuase I have locked the focus. Since I use my thumb for this and also for exposure adjustments on the fly, I too have two cold fingers when shooting in the cold. Good thing we live in Florida.

    When I’m shooting BIF, I only use my thumb for exposure adjustments. I don’t use AF Lock for BIF.

  • A few years ago I used rear focusing successfully for a short period of time until my camera came back from Canon with all default settings. I was often finding it necessary to switch from one-shot to al servo and finally recently switched back to rear focusing which I have set on the 1D3, 5D & 40D. It took a little bit of practice but worth the effort. I am not missing as many opportunities now b/c I don’t have to take time to switch from one-shot to al servo or visa versa. I spent 2 hrs yesterday photographing BIF and felt it worked flawlessly. I do however, agree with Jim N on one point. It wouldn’t be as easy in the winter if I had 2 cold fingers instead of 1.

  • avatar Alan Lillich

    Here’s another bit of info for Nikon users. The back button focus does not activate VR, at least not with my D300 and D700. So for Nikon folks it can pay to learn to still hold the shutter 1/2 way long enough to get the VR settled. Even so, I always use back button on Nikon and agree it is the best of both worlds. I think Canon bodies activate IS along with back button focus.

    Thanks Alan. I think that it is the same with Canon. I will check the next time that I get out. Right now I am trapped at my desk for a bit; I need to do last years taxes! Yikes. artie

  • avatar Bill Richardson

    Jim, I was talking about the auto exposure and shutter release being activated by the same button. I understand your number 4 advantage though. Unfortunately, I don’t have that level of coordination! Bill

  • avatar Bill Richardson

    Jim, I certainly can see why you would prefer using the shutter button to focus when you take exposure out of the equation. And I can see an advantage for your BIF photography although I don’t have a problem using the back button focus while tracking birds. I use both manual and auto exposure modes so I don’t want to be switching back and forth on my focus button. That just gets too confusing for me in the heat of action. I also do more focus and recompose shooting than BIF so the rear button focusing really helps when there is a lag between focusing and shutter release or a difference in exposure between the focus point and subject (when in an auto exposure mode). I also keep my cameras set to A1 Servo all the time and find the advantage of using the back button focus for that reason too as Artie mentioned. I really think it comes down to each particular photographer’s primary subject/style of shooting and his thumb/finger coordination. Bill

    Yes, it is a purely personal choice. As always my intent was not to tell folks “Do this!” but rather to share what I have been doing and let them decide πŸ™‚ artie

  • Bill,

    I think I may have mis-understood your previous comment. Were you talking about auto exposure and shutter release being activated by the same button or were you refering to my comments in reason number 4? My answer was based on AE and shutter on same button, not my reason #4 comments.

    If you were talking about my reason #4, then here is an example:
    Often, as a bird is flying its angle to the sun relative to you is changing. This may require an exposure adjustment of 1/3 to obtain the correct exposure. While I am shooting I can open up or close down a third to make the exposure adjustment without pausing to move my thumb or finger to another button. If I were using the * button to focus, I would have to stop shooting to make the exposure adjustment or I would have to go with the current exposure instead of the best exposure.

    Sorry if I mis-understood ytour comment.


  • Bill,

    I agree that exposure and shutter release are seperate things, but we are talking about focus and shutter release which are defintely related. I use manual exposure mode, so for me exposure is not related to this discussion. If you use any of the auto exposure modes, then it may become an issue depending on what you are trying to accomplish and how you have your camera set up.

  • avatar Bill Richardson

    I tried rear button focus several years back but gave up on it. I tried it again 2 years ago and got used to it and now love it. I also have it on both my SLR cameras so I don’t get confused. Since exposure and shutter release are separate concepts, it makes little sense to combine the 2 in my opinion. I think the key factor is committing to the technique until it becomes second nature.

  • Artie asked me to chime in on this so here are my thoughts on * vs shutter button focus:

    Todays cameras are very complicated and give us lots of options. There are often several ways to accomplish the same goal. In this case there are several ways to accomplish the same thing. So, which way is the best? My opinion is that it’s a matter of personal preference, but there are things to consider when deciding which method to use. I have tried using the * button to focus and have spent quite a bit of time shooting this way, but I returned to the shutter button focus method for 4 reasons:

    1. I use a technique I call bumping the focus. By bumping the focus I mean letting off of the focus button and then refocusing. If you want to learn more about the bump focus technique, visit my BPN thread here:
    Bumping the focus well requires some speed and finese. My index finger is much more coordinated than my thumb, so I can do a better job of this using my index finger on the shutter button than I can using my thumb on the * button.

    2. When I am ready to make an image I can simply follow thru with my index finger in one motion to trip the shutter. When using my thumb on the * button, I have to coordinate my thumb for focusing and my index finger for releasing the shutter. This seems more difficult to me than simply pressing harder with my index finger.

    3. The shutter button is larger and I like the feel of it better, particularly in cold weather when my finger tips get numb. (I use gloves with index finger tip and thumbtip removed from the right glove)

    4. When using the * button, I need both my index finger and my thumb to make an image. I also use my thumb and index finger to adjust exposure quickly on the fly. If I use the * button for focus this ties up both my thumb and index finger leaving neither to adjust exposure on the fly. Usualy, this isn’t an issue because I have time to adjust exposure and then return my finger or thumb to the * or shuuter button before making images. Sometimes things happen quickly and I need a free finger or thumb so I can adjust and shoot at almost the same moment. If I focus and shoot with the shutter button, my thumb is always free to adjust exposure using the large wheel on the rear of the camera.

    These reasons do not apply to everyone, and that is why I think the choice is a matter of personal preference.

    I think that the choice has no effect on the AI Servo focus capability of the camera. I have shot many flight sequences with both methods and have never noticed a difference in the AI Servo focus performance.

    If anyone has any questions about this, post them here and I will do my best to answer them.

    Jim –

  • avatar Harold Barnett

    I really enjoy your bulletins/tutorials. I don’t believe I could ever justify my owning an 800mm lens. I am looking at a Canon 400mm DO F4 lens. I am going to Galveston this weekend and have rented one to try out. My real question is about salt spray. Here in Texas the wind is blowing into shore about 90% of the time and is usually fairly strong. What precautions do you take with your gear and what if anything do you do after your shoot?

    Harold. Thanks for stopping by. I take no precautions. All of my lenses are protected by Lens Coat stuff which keeps off the spray. If things are bad enough, I will simply take a damp towel when I get back home or to the motel and pat the stuff down…. artie

  • I tried the rear back focus before but could not get used to it because of different cameras, MKIV, 5D, 7D. I have one question? What happens if you use a cable release for say macro work, will that focus the camera or do you have to re-set the camera to shutter focus to use a cable release? Bill

    Hi Bill, If you use rear focus with a cable release you simply focus with the rear button after the tripod is locked up and then make the image when the flower stops blowing. artie

  • avatar Charles Scheffold

    A couple of great things about rear-button focus for flight… first, it is quite a bit easier to keep your thumb firmly planted on the rear button than it is to try to keep your index finger half-pressed on the shutter while tracking a bird. Second, you can easily lift your finger off of the focus button for a second (without taking your finger off of the shutter) if something temporarily comes between you and the bird. At least for the muscles in my hand, I find both of these things to be easier with rear-button focus.

    Charlie. I agree on all counts, but some skilled folks like Jim Neiger do not. I will try to get him to comment here.

  • avatar Jon

    Artie I read with great interest your tutorial on rear AF. I did consider using it a while back but I too became a little confused over settings. I use Servo AF almost exclusively and if I need to stop the AF I have set the camera to to stop focusing by pressing the * button. This has a very similar effect to your rear focus and has the advantage of using one button to meter and focus and fire. Your method however does have additional potential regarding in flight. I am still wondering if your method has other additional merits or if my method is more convenient. It would be useful to read your view and that of others on this issue.

    Hi Jon, Great to see you here. Jim Neiger uses star button to lock and hold AF and I used that on and off for a year or two (even though I always kept it set. In fact, I recommended that in the MIV User’s Guide. I personally find rear focus more convenient but as I mentioned to Charlie here some very skilled folks do not. As far as the system focusing more accurately with rear focus that to is up in the air. It might just be a matter of FBC–faith, belief, and confidence. That said the question is this: does AI Servo tracking pause for an instant when the shutter is released when using the shutter button (since it controls both of those functions)? Remember that Jim Neiger is almost constantly bumping the focus. Does any of that make sense??? artie

  • I tried rear focus (* button) about 6 years ago out of curiosity after reading about it online somewhere (I forget where) and have never looked back. Rear focus is the first Custom Function I change when I get a new camera…as soon as I open the box! As per usual, great images.

    Thanks for chipping in Dan. artie (Dan is one of the crack Avian moderators on BPN and has been a co-leader on the SW FLA IPT two years running.)

  • avatar Gerald Kelberg

    I switched to rear focus about 18 months ago – having resisted Robert’s earlier suggestion. It quickly became natural and I regretted my stupid stubbornness in not changing sooner! It is just so much easier!

    I resisted Robert’s suggestions for years but I never regret my stupidity as I would spend too much time regretting πŸ™‚ artie

  • avatar Charles Scheffold

    That Godwit is a beautiful bird… nicely captured. I’m jealous!

    I think that you are supposed to be envious. IAC, the bird was OK but was not stupid tame. artie