Canon 1D MkIII AF Microadjustment really works

Harv

I decided to play with this MkIII function to see if it would really make much of a difference. Short answer... YES.

I set it up with all my lenses. My 500/4 and my 100/2.8 Macro needed about +10 point adjustment. My 70-200/2.8 needed about +5 point adjustment. My 300/2.8 didn't need any. I didn't bother with my 24-105/4 as I don't see it being critical.

Below are the results with the 500/4. I shot 3 frames with and 3 frames without the adjustment to verify consistency. Tripod mounted, 430EX flash, cable release, ISO400, f/4, 1/250 second, 100% crops, distance about 25 feet.

WITHOUT adjustment



WITH adjustment



This was a printed book cover and not necessarily the best test subject but it did show the difference well enough.

Summmary... Glad I went to the trouble.

ziggy53

Thanks for sharing this.

I suspect that someday dSLRs will semi-automatically adjust microfocus using TTL SIR autofocus coordinating with live view contrast detection autofocus.

The evolving technology of photography is just astonishing.

Harv

ziggy53 wrote:

Thanks for sharing this.

I suspect that someday dSLRs will semi-automatically adjust microfocus using TTL SIR autofocus coordinating with live view contrast detection autofocus.

The evolving technology of photography is just astonishing.

Most of the evolving technology is beyond my limited level of understanding. I'm old. Some days I feel like a dinosaur. Hell, most days I feel like one.

kdog

Great! When the MarkIII came out, that was one of the top features that got my attention. It must be very satisfying to know that you're wringing every last bit of performance out of your lenses. Not that your photography needed it, mind you. :giggle

Great job, and thanks for sharing your data.

-joel

Harv

kdog wrote:

Great! When the MarkIII came out, that was one of the top features that got my attention. It must be very satisfying to know that you're wringing every last bit of performance out of your lenses. Not that your photography needed it, mind you. :giggle

Great job, and thanks for sharing your data.

-joel

Thanks for looking in, Joel. I had the opportunity to do it. So why not? As for my photography, it still needs all the help it can get.

KED

Harv wrote:

I decided to play with this MkIII function to see if it would really make much of a difference. Short answer... YES.

Glad I went to the trouble.[/B]

The MK III manual is as clear as mud on this. It looks to me like a rather random process of shooting at various adjustment levels and seeing what, in the end, looks sharpest. Had you had a suspicion going into the exercise that you were experiencing front focus with the lenses for which you adjusted?

Interestingly, Rob Gabraith's final report on the MkIII autofocus issue recommended an across-the-board adjustment of -1. I couldn't bring myself to buy into that.

Harv

KED wrote:

The MK III manual is as clear as mud on this. It looks to me like a rather random process of shooting at various adjustment levels and seeing what, in the end, looks sharpest. Had you had a suspicion going into the exercise that you were experiencing front focus with the lenses for which you adjusted?

Interestingly, Rob Gabraith's final report on the MkIII autofocus issue recommended an across-the-board adjustment of -1. I couldn't bring myself to buy into that.

Actually I had read a post somewhere (don't remember now) that the individual needed to adjust a number of lenses on the plus side. What I did was start with a +5 point adjustment and checked to see how it looked. If it looked better, I kept moving up until it started to go the other way and then backed up. Initially started at close focus distance and used the full magnification of the LCD to see the result. I later confirmed with actual images shot. Yes, it's tedious, but I don't know of any other way to do it.

KED

Harv wrote:

Actually I had read a post somewhere (don't remember now) that the individual needed to adjust a number of lenses on the plus side. What I did was start with a +5 point adjustment and checked to see how it looked. If it looked better, I kept moving up until it started to go the other way and then backed up. Initially started at close focus distance and used the full magnification of the LCD to see the result. I later confirmed with actual images shot. Yes, it's tedious, but I don't know of any other way to do it.

Ugh! Your original post tempted me to invest some time in it this weekend, but now I'm thinking that until I am convinced beyond a reasonable doubt that the bigger AF issue is, in fact, no longer an issue for me, I think I'll wait. I get to shoot sports again a week from tomorrow, and that should tell me where I stand on the AF matter.

Harv

KED wrote:

Ugh! Your original post tempted me to invest some time in it this weekend, but now I'm thinking that until I am convinced beyond a reasonable doubt that the bigger AF issue is, in fact, no longer an issue for me, I think I'll wait. I get to shoot sports again a week from tomorrow, and that should tell me where I stand on the AF matter.

I don't think this microadjustment has anything to do with the "AF issue" of the past. This is just a way to tweak a bit more into the final adjustment. I shoot a lot of small birds as well with a wide open aperture so for me this is improtant. I don't know that it would make a lot of difference in a sports environment.

KED

Harv wrote:

I don't think this microadjustment has anything to do with the "AF issue" of the past. This is just a way to tweak a bit more into the final adjustment. I shoot a lot of small birds as well with a wide open aperture so for me this is improtant. I don't know that it would make a lot of difference in a sports environment.

It sounds like you have been spared the AF issue; believe me, if you saw the goo that I got on some perfectly well-shot images, you'd understand my point that micro-adjustment wouldn't have mattered.

Sharp is sharp, and as another poster said, might as well get every last bit of performance out of your lens/body combination, so first I'll address the "macro", then the micro.

Harv

KED wrote:

It sounds like you have been spared the AF issue; believe me, if you saw the goo that I got on some perfectly well-shot images, you'd understand my point that micro-adjustment wouldn't have mattered.

Sharp is sharp, and as another poster said, might as well get every last bit of performance out of your lens/body combination, so first I'll address the "macro", then the micro.

No argument here. My camera has a serial number outside the range of affected units. Two of my friends were not so lucky. I guess that's the price of being an early adopter. I waited until December to buy mine. Good luck with your unit. If it's been updated by Canon you should be fine.

KED

Harv wrote:

No argument here. My camera has a serial number outside the range of affected units. Two of my friends were not so lucky. I guess that's the price of being an early adopter. I waited until December to buy mine. Good luck with your unit. If it's been updated by Canon you should be fine.

The scary thing is that I was NOT an early adopter, had a body way outside the range, and still had the issue. I returned it for a body that's "blue dot" (inspected and approved by Canon) INSIDE the range. This is my third Mk III body, hence my "wait and see" attitude -- it's just that the current one came to me just in time for autumn outdoor sports season to end. So now we find out.

GSPeP

I only took a few 100 pictures with my new 1D MkIII and I'm under the impression that each of my lenses will need microadjustment on this camera.

I had the 28-135 IS on it and it seems that focus is more in front of the point where I wanted it. The 24-105 IS L had the best result, but I only took pictures in the dark (iso 1600) and with flash. I still have to try this one in daylight.

Yesterday, I took some pictures with the 28-300 IS L and got the same impression as with the 28-135 IS.

Last week I took some pictures of the full moon with the Sigma 50-500 at 500 mm. and it wasn't as sharp as I wanted.

I will have try this microadjustment thing as soon as I have the time.

John Mueller

What are you do if you can't tell if it's front or back focusing?
Like my blue dot......................

KED

John Mueller wrote:

What are you do if you can't tell if it's front or back focusing?
Like my blue dot......................

Call Canon help, arrange to send them some images, they will review them and presumably acknowledge that the problem is with the camera, and arrange for you to send it in for "the fix", even though you thought, because you had the blue dot, that you had already been fixed.

Just to save you some needless agita, Canon disavows knowledge of the "blue dot". Instead you should go on their website and verify that your serial number has been listed as "in the range but not affected" - they had a specific posting about that. The blue dot may have been a B&H thing.