puzzled by focus points

Looking at my soccer pics from yesterday, I am puzzled by focus points. Both shots below were taken by 1DII, AI Servo, center AF point, using Sigma 100-300 f4 lens. Each shot is from a burst of two, and in each case both shots in the sequence look the same.

The shots are screen captures from ZoomBrowser.

In the first one, no focus point is ahown, yet the shot is in focus.
In the second one, the focus point is on the player, yet the shot is way out of focus.

Can anyone explain, please?

1.

HTTP response: 404 | MIME changed to 'image/gif' | Byte size: ZERO | PHOTOBUCKET ERROR IMAGE

HTTP response: 404 | MIME changed to 'image/gif' | Byte size: ZERO | PHOTOBUCKET ERROR IMAGE

I don't know why zoombrowser does not show the active point in the first one.

In the second the focus is well behind the subject. My guess is that immediately before this shot was taken you let the AF point walk off the subject and the focus went to the background. Then you got back on target and snapped a shot before the focus could move back onto the subject.

Jeff, thanks for the reply.
I have a question or two on how Servo works.

1- Does the camera continually try to focus when shooting in Servo/burst mode?
2- If so, when shooting in burst, does the burst rate impact the focusing ability of the camera? In other words, does the camera do better in keeping up with focus when the burst rate is low and the camera has more time between shots to keep the focus up?
3- When the initial shot in the Servo/burst mode is out of focus, shouldn't the camera eventually regain focus when shooting long bursts? Or must the first shot be in focus for Servo to continue staying in focus?

1 - Yes, the AF system works between shots in burst. That's why the mirror keeps flipping down.

2. - Burst should not affect the accuracy, but we are a little bit into speculation here if more time before the shot improves the AF prediction or not.

3. - My 1D3 will catch up. I've shot bursts where the first shot was OOF because I was acquiring the subject (this happens a lot in volleyball) and then the rest of the burst is in focus as the lens hits the mark.

The 1D3 has a lot of custom functions for the AF system and the 1D2 is a little different so I can't give you specific advice on how to perfect that camera for a given situation.

With the first shot, are you sure you didn't have all focus points selected?

I find that if I'm unable to completely fill the frame with my subject when shooting field sports, I'm best off setting the camera up for AF expansion (7 points). It's very easy to slip off of your subject when your subject is that small in your viewfinder.


Also, have you tried using the * button for focusing?
I'll sometimes use single point for soccer, but usually I'll just leave it on 7 point expansion. Kind of depends on my mood.

Thanks for the replies

DDCSD wrote in post #8985805
With the first shot, are you sure you didn't have all focus points selected?

yes, I am sure

I find that if I'm unable to completely fill the frame with my subject when shooting field sports, I'm best off setting the camera up for AF expansion (7 points). It's very easy to slip off of your subject when your subject is that small in your viewfinder.

I'll try that next weekend.

Also, have you tried using the * button for focusing?

I was using the * button for that game.

I'll sometimes use single point for soccer, but usually I'll just leave it on 7 point expansion. Kind of depends on my mood.

Don't have an answer on the first one, but with the second one my guess is that the AF went "hunting" on the grey shorts, possibly due to the lack of contrasting colours for it to pick up.

philwillmedia wrote in post #8988651
Don't have an answer on the first one, but with the second one my guess is that the AF went "hunting" on the grey shorts, possibly due to the lack of contrasting colours for it to pick up.

Ah, that sure is a possibility. I forgot all about AF looking for contrast. Thanks for that reminder.

Sibil wrote in post #8988639
I was using the * button for that game.

The first one doesn't show an active AF point because you weren't actively "mashing" the back button when the shutter fired.

You can also set the speed of the AI servo under custom functions. I had to do that w/ the MkIIn because of having all black uniforms and it seemed to help. Take a look at C.Fn-20.

FarmerDave8N wrote in post #8994215
The first one doesn't show an active AF point because you weren't actively "mashing" the back button when the shutter fired.

bingo! this is what my 50D shows in DPP. The focus point is red in DPP only if I was pressing focus (*) when the shot was taken. If not, I don't see red. Ironically, my most infocus shots are those with the red focus square showing!

dave

snyderman wrote in post #8995650
Ironically, my most infocus shots are those with the red focus square showing!

Why is that ironic? I would expect sharper pics when the AF is actively locked and tracking.

I also wonder if the AI Servo was somehow previously locked in on the referee (yellow striped shirt) behind the player and then started to hunt when the player "obscured" what it mistakenly thought was the intended subject?

P.S. I know how to get the focus points to display in DPP, but how do you save them on the output image? Are you just taking a screenshot?

clarence wrote in post #8995724
P.S. I know how to get the focus points to display in DPP, but how do you save them on the output image? Are you just taking a screenshot?

Yes, I take a screen shot, paste into Powerpoint, crop, and then save as JPEG.

Now, How do you get the focus point to show in DPP? I installed DPP just last week, after I decided to give the RAW world a try. Although the interface looks simple enough, I am still trying to figure things out; for example, getting DPP to show focus points.

Interestingly, as a side note, my very first impression with DPP has been the big difference I see (in sharpness) when I compare the camera JPEG to DPP created JPEG without any further processing. But I digress.

Sibil wrote in post #8996337
Interestingly, as a side note, my very first impression with DPP has been the big difference I see (in sharpness) when I compare the camera JPEG to DPP created JPEG without any further processing. But I digress.

I think this could be caused to the fact that when you load a camera JPEG into DPP and sharpen it you are in effect applying a second round of sharpening. First from the camera when writing the JPEG and second from DPP when processing the image.