1st Gen 70-200 2.8 IS focus issues

[dcsimages]

I'm having an issue with inconsistant focusing at 2.8 to 4.5. 

I'm doing tight portrait at 200mm, not at the closest focusing distance though and focus point from shot to shot is shifting from dead on to half an inch back or front focused at random. When I look at the focus points in DPP they're just where they should be, but around 30% of the time the focus is just slightly off.

I've just started try to shoot with this shallow a depth of field. I always tried to shoot with this lens in the past around ƒ8 - ƒ11 as that's where it's sharpest, but I'm working on a new shallow depth porfolio.

I'm shooting in single shot, half press shutter button, and picking the closest focus point and setting it on the inner corner of the closer eye.

Would either of the AI modes help? Does tracking help if the subject is moving very slightly back and forth and than across the frame?

Would shooting bursts help?

I've tried back button AF, but all the buttons I could use to start and stop it are awkwarding placed on the camera for my hands.

[dcsimages]

Testing the lens using the center point is useless because I'm not going to shoot with the center point.

I'm shooting vertically and using one of the focus points in the second row down, usually the end one on either side depending on whether the actor is facing slightly right or left.

Camera is on a tripod, although I have the head slightly loose so I cam adjust for the subject moving .

I have sequences of a dozen shots in a row, where the subject hasn't moved, the focus point is on the eye that I want it to be on, and the focus is randomly jumping between forward focus, in focus and back focus.

Before I send the lens in for service, or maybe upgrade to a Mark III, which I wanted to avoid since I might be buying an R5 and R6 when I can get my hands on one, I wanted to see if other people have seen the same behavior or if using a setting other than single point spot focus will help.

[ebiggs1]

"I thought this was about the lens, not AF points"

The answers, suggestions or advice is meant only to help. Nothing more.  It is, still, I believe, you not understanding how the lens and camera work together. A simple test using just the center focus point will tell you if it is the lens or your technique.

If the photos come out consistently OK, you know the answer.  If they do not call Canon. If you don't like our replies call Canon. 1 (800) 652-2666

[Waddizzle]

---

@dcsimages wrote:
The shots are not off consistently in the same direction, but a focus micro adjustment is the first thing I checked.

---

If this means the lens is not the problem, what other source of [error] is there?  

Like I said, contact Canon Support.  Let them help you firgure out the issue. 

FREE TIP:  I never use Spot Focus handheld, only on a tripod.

[dcsimages]

---

@Waddizzle wrote:

---

@dcsimages wrote:
The shots are not off consistently in the same direction, but a focus micro adjustment is the first thing I checked.

---

FREE TIP:  I never use Spot Focus handheld, only on a tripod.

I wrote several times that I'm shooting on a tripod, but apparently reading comprehension is not your strong suit.

---

[Porcha]

Be nice everyone! 

[ebiggs1]

Porcha may I ask what was not "nice"?  Perhaps some clarification would help us as I saw nothing not nice or offending.  If a person decides to reject our advice it isn't because we are not being nice.  It is what we believe will help.

[Porcha]

Please be respectful of everyone's opinions, belittling someone's opinion can be offensive. We can all agree to not agree on things. 

[ebiggs1]

Sorry I still do not know what I said to offend the OP.