topic Re: 77D help with focusing using AI Servo in EOS DSLR & Mirrorless Cameras

77D help with focusing using AI Servo

michaeldwilson — Sat, 18 Apr 2020 13:27:23 GMT

Hey all. I have a question about a Canon 77d and AI Servo. I am practicing with trying to get sharp action shots (on my dog for now) and I'm not having a lot of luck. My question: Does AI Servo continue to hunt while I am pressing the shutter and taking pictures when it is set to High Speed Continuous. It seems like it loses focus on the third or fourth picture in the sequence. I have tried the shutter speed at 1/125 and 1/160. Should it be even higher? Could it be that the lens is not built to focus fast enough? It's an EFS 18-200. Also, if anyone has an tips on how to get sharp pictures, I'd appreciate it. Thanks!

Re: 77D help with focusing using AI Servo

Waddizzle — Sat, 18 Apr 2020 14:59:07 GMT

There is a lot to unpack. First and foremost, if you have not downloaded the full copy of the User Manual from the Canon Support page for your camera, then I suggest that you do so. It can be found on the same page where you downloaded the software to install on your PC.

"Does AI Servo continue to hunt while I am pressing the shutter...."

Yes, this is the point of AI Servo focusing mode over using One Shot mode, whose name should be self explanatory. How well it tracks is up to your skill with keeping the subject in the viewfinder behind an active AF point . You could be losing focus for a variety of reasons. Which AF point(s) are you suing?

"I have tried the shutter speed at 1/125 and 1/160. Should it be even higher?"

Action photography calls for FAST shutter speeds in order to freeze the motion of the subjects. You will need shutter speeds much fast3er than 1/125 to 1/160 to freeze your dog's motion. You will need much faster shutter speeds to eliminate the camera shake you create by moving the camera to track the dog. Which setting on the shooting mode dial are you using?

"Could it be that the lens is not built to focus fast enough? It's an EFS 18-200."

I have not used that lens. Seeing that it is an "all-in-one" zoom, I would not expect it to focus quikcly enough for most action shooting scenarios. The ratio of the longest focal length to the shortest focal length is more than 20 to 1. This type of lens compromises performance for the convenience of having one lens that ranges from wide angle to telephoto focal lengths. What other lenses do you have. If any?

Re: 77D help with focusing using AI Servo

ebiggs1 — Sat, 18 Apr 2020 15:49:00 GMT

"It's an EFS 18-200" "Could it be that the lens is not built to focus fast enough?"

Yes, you did not pick the best lesn for acton shots. Zoom ratios around 3 to 1 are considered good. A 24-70mm or a 70-200mm for instance even the popular 150-600mm are in the good range. You can not pack everything in one lens. You always give to get. In your case you gave up AF speed for FL. However, you should be able to take shots of your dog.

" Does AI Servo continue to hunt while I am pressing the shutter and taking pictures when it is set to High Speed Continuous."

Yes, it will "try" to focus as long as you press the shutter button. One shot focuses one time for each shutter press. AI Servo is not the end all answer to simple tasks like shooting the family dog. It might work but it may not be necessary.

"I have tried the shutter speed at 1/125 and 1/160."

People in normal daily activities can be stopped with a SS of 1/60. Most people just don't move much faster than that. Allegro if you will. Think 1/125th of a second, it's pretty quick. Dogs on the other hand do move faster. I think I would try to keep SS above 1/250 to 1/500.

Try this use Av mode. Fix aperture to f5.6 and set ISO to 400 or 800 depending on light. Higher if you are indoors. Average WB. Now switch off AI Servo and try One shot. Jpg should be fine unless you want to post edit, then use Raw format.

Lastly I would look for a better lens. Keep the zoom ration down as best you can. The 18-55mm zooms are super popular because they fit that sweet spot range and compromise well. Add the 55-250mm if you need that extra FL.

Re: 77D help with focusing using AI Servo

michaeldwilson — Sat, 18 Apr 2020 16:11:20 GMT

EBiggs,

Thanks for the great info! Much appreciated!

I am practicing on the dog. When I get better I intend to go to the marsh to take pictures of flying birds. It sounds like I might not have the best lens to get that done, though.

Mike

Re: 77D help with focusing using AI Servo

ebiggs1 — Sat, 18 Apr 2020 18:19:37 GMT

"... I might not have the best lens to get that done..."

Perhaps not, but you won't know for sure until you try. The lens you have is always better than the lens you wish you had.

BIF are a different matter then a dog. They (birds) can be quite difficult. I would start with stationary birds, preferably larger ones, until you get some practice.

Again use the same settings as for your dog except now you will have to up the SS especially for BIF. Even a hike in the ISO to 800 to 1600, daylight shots.