topic Re: auto focus problems in EOS DSLR & Mirrorless Cameras

auto focus problems

ricosurfcat — Sun, 30 Jul 2017 20:56:51 GMT

I am having intermittent problems achieving sharp focus with my EOS Rebel T4i, and EF 100-400 f 4.5-5.6 L lens. I primarily shoot surfing, and I am getting mixed results. Often focus goes from sharp to soft between 2 consecutive shots of the same wave.

Re: auto focus problems

TTMartin — Sun, 30 Jul 2017 20:59:45 GMT

@ricosurfcat wrote:
I am having intermittent problems achieving sharp focus with my EOS Rebel T4i, and EF 100-400 f 4.5-5.6 L lens. I primarily shoot surfing, and I am getting mixed results. Often focus goes from sharp to soft between 2 consecutive shots of the same wave.

Are you using AIServo focus?

Re: auto focus problems

ricosurfcat — Sun, 30 Jul 2017 23:28:49 GMT

I am experiecing this problem when shooting from land. When I shoot from land, I use one shot. When I shoot from the water, where I am much closer to the subject I use AI servo.

Re: auto focus problems

TTMartin — Mon, 31 Jul 2017 12:38:37 GMT

@ricosurfcat wrote:
I am experiecing this problem when shooting from land. When I shoot from land, I use one shot. When I shoot from the water, where I am much closer to the subject I use AI servo.

The reason your second shot in the sequence is out of focus, is because your subject moves between shots. In One Shot focus is set at the position of the subject for the first shot and does not change when the subject moves for subsequent shots. If you want the subject to remain in focus, use AIServo anytime you have a moving subject.

Re: auto focus problems

Waddizzle — Mon, 31 Jul 2017 00:05:37 GMT

@ricosurfcat wrote:
I am experiecing this problem when shooting from land. When I shoot from land, I use one shot. When I shoot from the water, where I am much closer to the subject I use AI servo.

If you are using continuous shooting mode on a subject whose distance is changing, then use AI Servo mode.

Also, check your camera menus. There may be a setting that sets the priority for consecutive shots, Focus priority or Frame Rate priority. Set if for Focus priority. There is little point in being able to take a faster series of consecutive shots when they are out of focus.

Re: auto focus problems

Mr_Fusion — Mon, 31 Jul 2017 13:22:42 GMT

One thing to keep in mind is that distant objects are harder for the autofocus to pick up. While the depth of field gets much bigger with distance, things in the foreground such as small waves, can interfere.

Re: auto focus problems

ricosurfcat — Fri, 04 Aug 2017 12:18:00 GMT

Seems to help, thanks.