Missing Focus

[jonney]

I shot some pics for a friend yesterday and had to toss the majority of the shots due to out of focus issues.

All examples are with a 40D & Sigma 30 1.4

1. 1/1000th , f2.5 , AV mode, +/- 0 EV , ISO 400, Spot metered off face, AWB, Focused with center focus point on left guys face, then recomposed to his chest.



2. 1/750th, f2.5, AV mode, +/- 0 EV, ISO 400, Spot metered off face, AWB, Focused with center focus point on left guys face, then recomposed to his chest.



Strange how that one is in focus ehh?

3. 1/1500th, f1.8, AV mode, +/- 0 EV, ISO400, Spot metered off face, AWB Focused with center focus point on left guys face.



I've got lots more examples like this.

Lemme know if you all have any thoughts, or tests you want me to do with the setup.

Thanks!

jf

[toverman]

Were you able to tell they were out of focus when you shot them. Usually when I have shots that are that far off I know immediately. Often I get surprised during processing when there's some camera shake or movement by subjects I didn't notice (your shutter speeds would have negated that).

[jonney]

Originally Posted by toverman

Were you able to tell they were out of focus when you shot them. Usually when I have shots that are that far off I know immediately. Often I get surprised during processing when there's some camera shake or movement by subjects I didn't notice (your shutter speeds would have negated that).

I didn't do too much chimping other than for blown highlights, so I didn't notice.

jf

[janetg]

basics...are you set to manual focus? i did that once, felt like an idiot...

[MT Stringer]

What focus mode were you in (One shot, AI Servo, etc)?
Did you focus and then re compose for the shot?
Just thinking out loud.
Mike

[rockpics]

For something static like this, I usually use one shot, and manually select a focus point that is on the eyes.

[jonney]

I was shooting in one-shot. AF was on. I put the details of how I focused on each pic.

Thanks for the thoughts so far. Maybe we'll get this sorted out :)

jf

[rockpics]

Originally Posted by jonney

I was shooting in one-shot. AF was on. I put the details of how I focused on each pic.

Thanks for the thoughts so far. Maybe we'll get this sorted out :)

jf

Sorry, I missed the details. It does seem like they should be better focused given the data. Maybe the 40D doesn't like the Sigma? Don't know. That might not be it.

[Daniel Bates]

Did you see focus confirmation before each shot? Sometimes I get OOF frames when my lens hunts in low light and I press the shutter button before it locks in.

[SnapItUp]

Depending on distance from subject with a shallow depth of field, focusing and then recomposing may have issues. Check out this article.

[jonney]

Originally Posted by Daniel Bates

Did you see focus confirmation before each shot? Sometimes I get OOF frames when my lens hunts in low light and I press the shutter button before it locks in.

This seems like the most likely explanation so far. I really didn't pay attention to the light.

jf

[rbalcom]

Do you use the shutter button to focus? I had problems like this until I moved the focus to the back of the camera. It was too easy to slightly lift my finger and then have the camera re-focus when I pressed the shutter. Just a thought.

[jonney]

Originally Posted by rbalcom

Do you use the shutter button to focus? I had problems like this until I moved the focus to the back of the camera. It was too easy to slightly lift my finger and then have the camera re-focus when I pressed the shutter. Just a thought.

I do use the shutter button. I change focus points a lot, and between that, and using the * button to set the exposure I haven't convinced myself to start using the AF-ON button to set focus.

jf

[CaptainTom]

Originally Posted by jonney

I do use the shutter button. I change focus points a lot, and between that, and using the * button to set the exposure I haven't convinced myself to start using the AF-ON button to set focus.

jf

How many out of focus images before you are convinced ?
Once you get used to it, you'll never like it on the shutter release except under very specific situations.

[darktiger]

Maybe it is a combination of things. I bet most of it happened when you were recomposing after you focused. What happens at home when you focus say a battery and shoot without recomposing your shot?