bmcd308 0 #1 November 26, 2002 Have any of you had problems with Canon Servo AI failing to autofocus on swooping jumpers? I am using a Reble Ti with Sigma 100-300 telephoto, and I have had good results with this lens and pictures of the plane. However, I have two rolls of people landing where all the shots are out of focus. I am using the Canon Sports Idiot mode. I am going to try using aperture priority to try to get more depth of focus in order to make it easier to get the subject in focus, but I had wanted to use sports mode with its larger aperture to try to blur the background more to emphasize the subject. Any tips? BTW, I really do not think it is the lens, as this lens has done a good job for me in other situations, such as taking pictures of the Mullins King Air at take-off. It is only the jumper pictures, particularly the ones with blue sky in the background, that are out of focus. Thanks. BMcD... ---------------------------------- www.jumpelvis.com Quote Share this post Link to post Share on other sites
Deuce 1 #2 November 26, 2002 I'm not familiar with your camera, but can you change the focus target size? I'm using the wrong terminology, but my Nikon's let me choose the point the camera focuses on. It has settings from pinpoint to about the middle third of the image. Try using a larger focus target. Since your subject is hauling ass, your camera might be focus hunting from the swooper to the background to the foreground. Quote Share this post Link to post Share on other sites
quade 4 #3 November 26, 2002 QuoteBTW, I really do not think it is the lens, . . . Well, now, hold on there a second. It's entirely possible that the electronics and mechanics in the Sigma lens aren't exactly the same as the electronics and mechanics in the Canon lens and that they wouldn't respond exactly the same way. As a matter of fact, that would be one of my guesses right off the bat. I also agree with Deuce that it's possible that maybe you don't have the best focusing area selected for the exact thing you're doing. For instance, on my Canon camera (just as an example) there's at least three different basic modes just for where you want the emphasis to be when in auto-focus. It's possible that the empty blue sky portion that you're talking about is filling up a significant portion of this area of emphasis you've selected and since it's basically all one thing -- it just doesn't know what to do with it. As I'm sure you're aware, the focus actually comes from the electronics being able to "see" a certain amount of contrast -- less contrast = soft focus, higher contrast = higher focus. IF the area of emphasis is only seeing one thing (blue sky) that could definately be an issue. What I -think- you're probably going to have to do is (shudder) break out the manual and see exactly how you -have- this thing set up as opposed to how you -want- to have it set up.quade - The World's Most Boring Skydiver Quote Share this post Link to post Share on other sites
bmcd308 0 #4 November 26, 2002 >>Well, now, hold on there a second. It's entirely possible that the electronics and mechanics in the Sigma lens aren't exactly the same as the electronics and mechanics in the Canon lens and that they wouldn't respond exactly the same way.<< That is why I added the comment - that would have been my first guess also, except that the lens does well with other moving subjects (more on this in a minute). As to the focusing area question, you actually can't select the focusing area in the idiot modes. Supposedly, the camera's computer is smart enough to figure out what the moving subject is then follow it. It works well for some types of subjects, but poorly for others. And actually, as I go through all the pictures I took that weekend, it appears to do better with certain backgrounds than others. The blue sky is the background that seems to give it fits. The AE appears to work well or occasionally slightly underexpose, but the AF really does not work well unless there is at least some terrestrial background in the frame. Unfortunately, the manual for this camera, like all Canon manuals, is pretty vague on technical details about what is going on in the idiot modes. I was really just shooting to see how well the idiot mode worked for my purposes, and it appears that the answer is "not very." Next time out, I'll force a slightly smaller aperture using aperture priority mode, dial in half a stop of overxposure and let the camera pick the shutter speed. That should take care of the underexposure of the subject I am getting, and it will also give the camera's AF system a little more leeway in terms of focus. In sports mode, the camera seemed to want to run max aperture / max shutter speed all the time to freeze the action, and that puts a good bit of pressure on the AF system to get the focus perfect. Whenever I get some decent shots, I'll post the settings that I found gave the best results. BMcD... ---------------------------------- www.jumpelvis.com Quote Share this post Link to post Share on other sites
dragon2 2 #5 November 26, 2002 I've taken alot (like, 2000 with my last camera, D30, alone) pics of landings and chutes in the air using various canon eos camera's. Usually i use the P mode. I can only get a jumper in focus when i focus on the *body* of the jumper. I tend to use only the focus point in the middle (my camera's all have just 3 focus points) for this, you can fix it on most camera's so that's the only focus point it uses, but i haven't had to. Because of the body being in the middle, i have to edit my pics a bit before i post them otherwise i end up with rather a lot of sky and/or grass at the bottom of the picture... Have had a lot of comments about this, but haven't figured out any other way yet. This way the camera focusses reliably, and *keeps* doing that in AI mode, and lighting is usually ok (sometimes a problem with a jumper against a lot of blue sky). I get really out of focus pics when i aim at the lines for instance. A nice way to get the background blurry is panning along with the jumper as he swoopes past. ciel bleu, Saskia Quote Share this post Link to post Share on other sites
murrays 0 #6 November 27, 2002 This is a situation where there is no easy answer. Taking pictures of people zooming past at high speeds is difficult even with the most up-to-date cameras. I have a few thoughts, most of which involve using manual settings. If you are taking shots of people who will be swooping past a certain point..i.e. - through a course, I would figure out by, perhaps by watching a few landings, where to be to get the vantage point that you want. Have a friend stand in the middle of the course and focus on him/her. At the same time, you could walk up to them and take a meter reading of their face/body or get an 18% grey card and meter off of it and use that reading to determine your combination of shutter and aperture settings. What you do next depends on several variables, such as focal length of lens, whether the movement is going to be straight towards you or you will be a bit further back and shooting from the side. If you use a smaller aperture (larger number) you will have more depth of field and shots taken closer to and further from your focus point will have reasonable sharpness. If you have a longer lens, you will always have less depth of field at a given aperture than with a wider angle lens. You will need a higher shutter speed to stop the movement of an object moving across the field of view than something moving straight towards you. You can also use panning to great effect to blur the background, as previously mentioned by another poster. Blurred backgrounds will give the impression of speed. You will have to plan out your shots using manual settings but if you know where people are going to land you should be able to get good results. Hope this helps in some situations, Murray-- Murray "No tyranny is so irksome as petty tyranny: the officious demands of policemen, government clerks, and electromechanical gadgets." - Edward Abbey Quote Share this post Link to post Share on other sites
novacaine 0 #7 November 28, 2002 Like Quade, I'm going to say check your lens. I shot with a sigma 100-300 lens and a Canon Elan7. In the last 5 months I've had to get my lens replaced (by Sigma) 3 times. The trouble that I had with my Sigma is that the lens would slide out from the 100mm position to the 300mm position by itself. This caused the motors to burn out. Sigma has 4 motors in their lens. Only one motor needs to fail to have a bad photo. I know I'll never go with another Sigma Lens again. I've lost too much time and money pissing with their products. Quote Share this post Link to post Share on other sites
