Dreaded MkIII OOF shots? - FM Forums

Register · Search · Software · Join Upload & Sell · Hosting

Moderated by: Fred Miranda

FM Forum Rules
Canon SLRs, primes, and zooms lenses reviews

FM Forums \| Canon-mount SLRs \| Join Upload & Sell	Search Used
1 2 end

Archive 2008 · Dreaded MkIII OOF shots?

corndog
Online
Dedicated FM
Upload & Sell: On

p.2 #1 · Dreaded MkIII OOF shots?

The third shot makes me think the lens is back focusing. Take a shot of a wall at an angle, use center point af, and see if the wall is sharp in the center. Shoot wide open too.

Sep 27, 2008 at 01:19 AM

omarlyn
Offline
Dedicated FM
Upload & Sell: On

p.2 #2 · Dreaded MkIII OOF shots?

Just to add my two-cents worth...While I don't own a Mark III, I have had plenty of Sigma lenses over the years and the one thing I can say is they have all had more inconsistent focus when compared to my Canon lenses. I am down to just one last Sigma lens, a 28-70 f/2.8. While it focuses perfectly most of the time, I can not get it to focus properly under certain daylight conditions. I know many people will extoll the virtues of Sigma lenses, however, my experience (when compared to comparable Canon lenses) is that they have a greater OOF tendency.

Omar

Sep 27, 2008 at 02:17 AM

RobertLynn
Offline
Dedicated FM
Upload & Sell: On

p.2 #3 · Dreaded MkIII OOF shots?

Gary Petersen wrote:
Made me go out and check mine last night. Just pointed it out here and shot wide open with the 70-200mm f2.8 L.

Gary! You have to say it's the IS 2.8L, there's only a few of us that actually think they can be sharp

Sep 27, 2008 at 02:21 AM

Gary Petersen
Offline
Dedicated FM
Upload & Sell: On

p.2 #4 · Dreaded MkIII OOF shots?

RobertLynn wrote:
Gary Petersen wrote:
Made me go out and check mine last night. Just pointed it out here and shot wide open with the 70-200mm f2.8 L.

Gary! You have to say it's the IS 2.8L, there's only a few of us that actually think they can be sharp

It is in fact the Canon EF 70-200mm f2.8 IS USM.

Sep 27, 2008 at 04:05 AM

morganb4
Offline
Dedicated FM
Upload & Sell: On

p.2 #5 · Dreaded MkIII OOF shots?

I took a bunch of shots the other day, focused on a window, trees in front but the line of sight between centre AF and window was clear yet the cam repeatedly focused on the tree, as if it was being influenced by data from the adjcent AF point.

odd.

Sep 27, 2008 at 01:25 PM

Numfar
Offline
Upload & Sell: Off

p.2 #6 · Dreaded MkIII OOF shots?

That looks like the problem. I have about 500 shots from Alaska that look like that.

Sep 27, 2008 at 01:28 PM

morganb4
Offline
Dedicated FM
Upload & Sell: On

p.2 #7 · Dreaded MkIII OOF shots?

Numfar wrote:
That looks like the problem. I have about 500 shots from Alaska that look like that.

annoying...

Sep 27, 2008 at 01:47 PM

Gravitytoy
Offline
Upload & Sell: On

p.2 #8 · Dreaded MkIII OOF shots?

Keep in mind your depth of field. If you're using a focus/recompose method, it's pretty easy to move the plane of the sensor around enough to throw the shot OOF. I also have the Mark III, and I do sometimes get weird OOF shots, but none look like yours. In my OOF shots, there is no discernible focus area at all -- Everything is soft and blurry. In your shots, it appears that the camera did focus on something... just not what you intended. Knowing how difficult it can be to work with narrow DOF conditions, I would urge you to test your combo out in more controlled conditions using a tripod and a static subject. Otherwise there are too many variables (and too much bad mojo about the Mark III) to solicit any kind of rational opinion from the shots you posted. Good luck, and I hope you get it all sorted.
-Rich

Sep 27, 2008 at 02:22 PM

morganb4
Offline
Dedicated FM
Upload & Sell: On

p.2 #9 · Dreaded MkIII OOF shots?

Gravitytoy I agree, if its front focused its kinda tricky for the OP to see so he needs a controlled test with a bunch of foreground clutter too.

Sep 27, 2008 at 02:28 PM

morganb4
Offline
Dedicated FM
Upload & Sell: On

p.2 #10 · Dreaded MkIII OOF shots?

I tried this and it still looked like it was considering data from adjacent points, I only use On-Shot.

john660 wrote:
A VERY typical 1D III AF problem from my experience shooting wildlife with the various 1D Mk III bodies I have owned. In general, the camera works fantastically well in almost all situations for One-shot AF (as everyone knows, the Al Servo is a different issue altogether), but it has at least one serious flaw in it that causes front focusing and I'm pretty sure Canon still has no clue what's causing it. I find it occurs most in subjects that are black and white in a coloured setting, for instance, a badger in a sunny green field.

I have put in a long and detailed research request to Canon and Canon research development here in Calgary, Alberta and am waiting for their analysis of my shots and my findings.

There are two ways to try to mitigate the AF problems in these types of situations. One, just use center point AF (I rarely use surrounding assist points unless it's an action sequence) and two, if you suspect your camera is not focusing properly, focus and refocus continually and take shots the whole time. This helps ensure that you get one or two sharp shots out of the series. It's not ideal, but then again, neither is the 1D III as it currently is.

Sep 27, 2008 at 02:31 PM

1 2 end
FM Forums \| Canon-mount SLRs \| Join Upload & Sell 1 2 end