In Dubai we have a place called Ras Al Khor where we have mangroves and where we can see flamingo's year round. I went there this evening to take some pictures of the flamingo's. Now I have two problems to discuss:
a). My camera is Canon 60D and I used my Canon 500mm f4.5L USM (non IS)lens and also fixed TC1.4x on it to get close ups. As soon as I fixed the TC 1.4x the auto focus function stopped. (the click sound and the light stopped). I removed the TC and the auto focus started.
I then took my Canon 70-200mm f2.8L USM (with IS) and with this lens used the TC1.4x and there was no problem at all and the auto focus also worked.
Could you please tell me why the auto focus did not work when I put the TC on the Canon 500mm ?? Your advice will be very helpful.
b). Removing the TC from the Camera/Lens I took some pictures with the flamingo's flying. The setting were ISO320, f/8 and f/10 shutter speed between 1/500 to 1/1200sec, spot metering. All Servo focus. I was not able to get any sharp focus images. Could you please advice??
I am planing a trip to Tanzania this August to see the migration and before that I get to get my hands set to sue my new toy..... Thanks in advance everyone for your kind help...
Posted by Ramamohan Pai on June 14, 2011 at 12:36 PM
I believe this lens will not Auto Focus with the TC attached on some bodies . Not sure what you can do about it though other than shooting it without the TC. Since these are bigger birds, I am not sure you would need this long a focal length but then I am not a Bird Photographer.
I am sure someone who is good at birding will come and help you soon.
What I am seeing here (second picture) looks like a manual focus problem, or else you are not holding focus on the birds. I am a Nikon user, but this would describe the problem on my gear. There is an explanation for the other, which has to do with the coupled lens, which I am sure someone here can explain. Also, you are pushing it at 1/500 with that lens, unless you have a rock solid platform. I would suggest a larger focal opening, say 6.3 or 7.1.
The 1.4X TC causes the loss of a stop of aperture, so your maximum aperture with that lens and the TC is ~f/6.5.
The 60D won't autofocus with any lens combination with a smaller max aperture than f/5.6. (I believe all Canon cameras except the pro 1-series have autofocus disabled above a max aperture of f/5.6.)
With the 70-200, your maximum aperture is f/4, so you'll retain autofocus, but not with that 500mm.
As far as the OOF images, in the second image shown, the focus has clearly jumped to the BG. You need to watch where your autofocus sensors are placed, and possibly bump focus (force a re-focus) when things miss. You can also try to pre-focus manually to get the camera close. Basically, it's having trouble deciding what to focus on. There are lots of bird flight experts on here who can hopefully provide more detail.
David pretty much covered it all. Autofocus apparently needs a lot of light to function properly on APS-C cameras, so it appears that you have three possible options if you want to use autofocus with a long lens:
1. Use a lens with a maximum aperture of f/5.6 or faster, or f/4 or faster if you use a TC that cuts the light in half
2. Use a camera that will autofocus at smaller apertures. If you use Canon equipment, I know that the series 1 bodies will work, but you will lose magnification because the crop factor on these lenses is 1.3, rather than the 1.6 on the APS-C bodies.
3. One last option I have heard about, but have no experience with is to alter the lens by taping two of the electronic contacts in order to force the camera to try to autofocus. I have heard that this may force the camera to try to focus, but that it will do so very slowly, or sometimes not even find a focus point, so using it for flight shots is probably just asking for problems. Do a Web search for something like "taping contacts on Canon lenses" for more info on this.
As for the second question, keeping your center focus point on moving objects is somewhat like trying to shoot a moving target with a rifle instead of a shotgun -- it requires practice.
You have gotten some good advice already Hussain. That body won't AF with the teleconverter attached. I generally try to keep my shutter speed at at least 1/1000 so an aperture of 6.3 or so would have yielded a faster shutter speed.
I would add that for flight photography I get the best results selecting the center autofocus point with the nearby assist points activated.
Thanks everyone for your replies. Yes I know that the min f stop for the 500mm lens is f/4.5 and if I want to add the TC1.4x then I will loose 1 stop and I cannot auto focus below f/5.6, but in this case I had my setting at f/8 and even at f/10. Even at f/8 and at f/10 the auto focus did not work. What could be the reason for that ?
Regarding point 2. I will try again and again to make sure that I focus properly on the birds. Thanks once again and awaiting for some clearification on the first issue.
"Even at f/8 and at f/10 the auto focus did not work."
OK - there's some explanation in order. Camera apertures get larger the smaller the f-number is. f/2.8 is twice as big as f/4, which is twice as big as f/5.6. The "maximum aperture" or "max aperture" of a lens is therefore the smallest f-number. Saying that you need a larger aperture means you need a smaller f-number. (For more info on apertures, see this Cambridge in Colour tutorial.)
Your camera auto-focuses by opening the shutter as wide as possible (the max aperture), to let in the most light possible, focusing, THEN closing the aperture down to whatever you have it set to. So what aperture you're actually using to take a picture has no bearing on the auto-focus system. Only the max aperture matters.
So when we say that your camera can't auto-focus below a max aperture of f/5.6, that mean you need a lens that has a larger aperture, and a smaller f-number. As soon as you attach the TC to your 500mm, your max aperture is about f/6.5, which is a smaller opening than f/5.6. So auto-focus is then disabled no matter what your camera settings are.
I've shot Canon 20D, 30D, 40D, a couple of Rebel models and now shoot the 7D for avian and wildlife. Probably 10 - 15 percent of the time the autofocus algorithm on these cameras selects a plane of focus other than what I want. This is frustrating to me but certainly true. It actually seems to happen more to me with still shots than with flight shots. We take autofocus for granted but if you consider the complexity involved in trying to determine the desired plane of focus from spots in the viewfinder, I think it's understandable. I'm actually amazed that it works as well as it does. I think the algorithm has a library of shapes that it recognizes and gives priority too. It seems to prefer tress and buildings in particular. I've also had many instances though where it will go for the largest area of dark or the largest area of light in a scene. For instance, autofocus almost always fails for me in trying to shoot a pheasant against a broad snowy bg (autofocuses on snow). I also have a problem with colorful birds (goldfinches, orioles) against a dark bg (autofocuses on dark bg as in your image above.). For pelicans against a building structure, the autofocus almost always goes to the structure.
The more expensive pro camera may address this (I think it's the Mark IV now.) but given all the problems Canon has had with autofocus on their pro cameras I'm hesitant to spend the money to find out.
You can usually tell immediately for still shots if the autofocus has misidentified the focal plane and in that case I move the center autofocus point elsewhere in the image, let the autofocus change and then come back to my subject. This works about 2/3 of the time for me. Of course I may have missed the shot by then. For pheasants in the snow and goldfinches, I usually just start in manual focus mode and try to get enough shots that one of them will actually be sharp - so I try to bracket my images with slight adjustments to the focus ring.
I'm sorry but I rarely do flight shots and certainly for me, manual focus is not an option there.
You might rent a Mark IV, if that's an option in your area, take it to the mangrove swamp and try it. Also it will autofocus, with the 1.4tc on the 500 as does the 7D.
Best of luck. Nice thing about flowers is that I can always shoot with manual focus. I haven't had one fly away yet.
Hey, If you discover that the MarkIV addresses the problem for you, please let me know. In that case I'd break down and buy one. (smile)
I thought this little tid bit may help. Just so you know, I have shot Canon primarily ever since I picked up a camera. I have shot an EOS 3, which utilized an Eye Point AF system, the first one of it's kind, the original Digital Rebel, EOS 1Ds, and I now shoot with a 7D.
Purchasing a top of the line camera seems an extremely expensive option, expecially since I believe the Mark IV uses the same AF system as does the 7D. I am not familiar with the 60D, however, working with cameras that predate the 60D I am confident in what I am about to advise.
Canon cameras utilize an autofocus assist system that can usually be turned off. The way it works is that you choose an autofocus point, usually the center AF point. Most Canon cameras will put emphasis on the center AF point, but utilize nearby AF points to "assist" in obtaining focus. With birds or moving subjects, some of these assist points will not be on the subject and cause the AF system to focus on the background, or some other very well defined hard edge. With all of the cameras I have used this is a behind the scenes type of action that the user doesn't know is happening. With the 7D, the camera tells you which AF points have been activated. For photographing moving birds, you want to look in the manual and figure out which custom function will turn this off. Also, set your camera for the center AF point only, and as you said above, use AI Servo Mode. In this way, using the center AF point only will use less of the cameras processor, resulting in a faster AF. The processor doesn't have to be concerned with other possible points of focus.
Try to keep the center AF point on the Flamingo's head, preferably the eyes if you are in close enough. Using this method I have had incredible success with my Canon system, especially with the 7D. However, even with the 7D, if settings are different the camera is not always sure where you want to focus. That is why it is imperative to let the camera know that you want only to use the center AF point and turn off the nearby AF point assist system.
Hope this helps,
Keith
Thanks a lot Keith. I appreciate it. I'll check my settings and let you know how my next session goes. Most of my problem isn't with motion but with still subjects. I know I played with this some when I got the 7D but to be honest I don't remember what I tried. I will give it a try.
Discussion
11 repliesa). My camera is Canon 60D and I used my Canon 500mm f4.5L USM (non IS)lens and also fixed TC1.4x on it to get close ups. As soon as I fixed the TC 1.4x the auto focus function stopped. (the click sound and the light stopped). I removed the TC and the auto focus started.
I then took my Canon 70-200mm f2.8L USM (with IS) and with this lens used the TC1.4x and there was no problem at all and the auto focus also worked.
Could you please tell me why the auto focus did not work when I put the TC on the Canon 500mm ?? Your advice will be very helpful.
b). Removing the TC from the Camera/Lens I took some pictures with the flamingo's flying. The setting were ISO320, f/8 and f/10 shutter speed between 1/500 to 1/1200sec, spot metering. All Servo focus. I was not able to get any sharp focus images. Could you please advice??
I am planing a trip to Tanzania this August to see the migration and before that I get to get my hands set to sue my new toy..... Thanks in advance everyone for your kind help...
I am sure someone who is good at birding will come and help you soon.
The 60D won't autofocus with any lens combination with a smaller max aperture than f/5.6. (I believe all Canon cameras except the pro 1-series have autofocus disabled above a max aperture of f/5.6.)
With the 70-200, your maximum aperture is f/4, so you'll retain autofocus, but not with that 500mm.
As far as the OOF images, in the second image shown, the focus has clearly jumped to the BG. You need to watch where your autofocus sensors are placed, and possibly bump focus (force a re-focus) when things miss. You can also try to pre-focus manually to get the camera close. Basically, it's having trouble deciding what to focus on. There are lots of bird flight experts on here who can hopefully provide more detail.
1. Use a lens with a maximum aperture of f/5.6 or faster, or f/4 or faster if you use a TC that cuts the light in half
2. Use a camera that will autofocus at smaller apertures. If you use Canon equipment, I know that the series 1 bodies will work, but you will lose magnification because the crop factor on these lenses is 1.3, rather than the 1.6 on the APS-C bodies.
3. One last option I have heard about, but have no experience with is to alter the lens by taping two of the electronic contacts in order to force the camera to try to autofocus. I have heard that this may force the camera to try to focus, but that it will do so very slowly, or sometimes not even find a focus point, so using it for flight shots is probably just asking for problems. Do a Web search for something like "taping contacts on Canon lenses" for more info on this.
As for the second question, keeping your center focus point on moving objects is somewhat like trying to shoot a moving target with a rifle instead of a shotgun -- it requires practice.
I would add that for flight photography I get the best results selecting the center autofocus point with the nearby assist points activated.
Regarding point 2. I will try again and again to make sure that I focus properly on the birds. Thanks once again and awaiting for some clearification on the first issue.
OK - there's some explanation in order. Camera apertures get larger the smaller the f-number is. f/2.8 is twice as big as f/4, which is twice as big as f/5.6. The "maximum aperture" or "max aperture" of a lens is therefore the smallest f-number. Saying that you need a larger aperture means you need a smaller f-number. (For more info on apertures, see this Cambridge in Colour tutorial.)
Your camera auto-focuses by opening the shutter as wide as possible (the max aperture), to let in the most light possible, focusing, THEN closing the aperture down to whatever you have it set to. So what aperture you're actually using to take a picture has no bearing on the auto-focus system. Only the max aperture matters.
So when we say that your camera can't auto-focus below a max aperture of f/5.6, that mean you need a lens that has a larger aperture, and a smaller f-number. As soon as you attach the TC to your 500mm, your max aperture is about f/6.5, which is a smaller opening than f/5.6. So auto-focus is then disabled no matter what your camera settings are.
I've shot Canon 20D, 30D, 40D, a couple of Rebel models and now shoot the 7D for avian and wildlife. Probably 10 - 15 percent of the time the autofocus algorithm on these cameras selects a plane of focus other than what I want. This is frustrating to me but certainly true. It actually seems to happen more to me with still shots than with flight shots. We take autofocus for granted but if you consider the complexity involved in trying to determine the desired plane of focus from spots in the viewfinder, I think it's understandable. I'm actually amazed that it works as well as it does. I think the algorithm has a library of shapes that it recognizes and gives priority too. It seems to prefer tress and buildings in particular. I've also had many instances though where it will go for the largest area of dark or the largest area of light in a scene. For instance, autofocus almost always fails for me in trying to shoot a pheasant against a broad snowy bg (autofocuses on snow). I also have a problem with colorful birds (goldfinches, orioles) against a dark bg (autofocuses on dark bg as in your image above.). For pelicans against a building structure, the autofocus almost always goes to the structure.
The more expensive pro camera may address this (I think it's the Mark IV now.) but given all the problems Canon has had with autofocus on their pro cameras I'm hesitant to spend the money to find out.
You can usually tell immediately for still shots if the autofocus has misidentified the focal plane and in that case I move the center autofocus point elsewhere in the image, let the autofocus change and then come back to my subject. This works about 2/3 of the time for me. Of course I may have missed the shot by then. For pheasants in the snow and goldfinches, I usually just start in manual focus mode and try to get enough shots that one of them will actually be sharp - so I try to bracket my images with slight adjustments to the focus ring.
I'm sorry but I rarely do flight shots and certainly for me, manual focus is not an option there.
You might rent a Mark IV, if that's an option in your area, take it to the mangrove swamp and try it. Also it will autofocus, with the 1.4tc on the 500 as does the 7D.
Best of luck. Nice thing about flowers is that I can always shoot with manual focus. I haven't had one fly away yet.
Hey, If you discover that the MarkIV addresses the problem for you, please let me know. In that case I'd break down and buy one. (smile)
pat
I thought this little tid bit may help. Just so you know, I have shot Canon primarily ever since I picked up a camera. I have shot an EOS 3, which utilized an Eye Point AF system, the first one of it's kind, the original Digital Rebel, EOS 1Ds, and I now shoot with a 7D.
Purchasing a top of the line camera seems an extremely expensive option, expecially since I believe the Mark IV uses the same AF system as does the 7D. I am not familiar with the 60D, however, working with cameras that predate the 60D I am confident in what I am about to advise.
Canon cameras utilize an autofocus assist system that can usually be turned off. The way it works is that you choose an autofocus point, usually the center AF point. Most Canon cameras will put emphasis on the center AF point, but utilize nearby AF points to "assist" in obtaining focus. With birds or moving subjects, some of these assist points will not be on the subject and cause the AF system to focus on the background, or some other very well defined hard edge. With all of the cameras I have used this is a behind the scenes type of action that the user doesn't know is happening. With the 7D, the camera tells you which AF points have been activated. For photographing moving birds, you want to look in the manual and figure out which custom function will turn this off. Also, set your camera for the center AF point only, and as you said above, use AI Servo Mode. In this way, using the center AF point only will use less of the cameras processor, resulting in a faster AF. The processor doesn't have to be concerned with other possible points of focus.
Try to keep the center AF point on the Flamingo's head, preferably the eyes if you are in close enough. Using this method I have had incredible success with my Canon system, especially with the 7D. However, even with the 7D, if settings are different the camera is not always sure where you want to focus. That is why it is imperative to let the camera know that you want only to use the center AF point and turn off the nearby AF point assist system.
Hope this helps,
Keith
Thanks again for the input.
pat