5dII and EF500/4.5L AF micro adjustment fails

[Frank Kolwicz]

I've run through the whole range of the micro adjustment with this setup and don't see any difference among the 30 or so frames at 100 or 200% magnification (3 each at every 5 steps, plus some mistakes). The test was done with Live View, AF at the 5dII's built-in 10x viewer, manually going to infinity before every shot and waiting for the camera to stop moving for each shot. The target was a small colored-pencil design levelled and squared-up to the camera location about 90 feet away; the camera was levelled by using a level on the front of the lens and the target was moved to be centered on the center AF sensor, which was selected. There was no discernable out-of-square softness to the Live View image at 10x with an LCD magnifier. The images were examined side-by-side in Photoshop after opening the CR2 files and cropping in Lightroom and exported as 16bit TIFFs, all with the same minimal LR settings.

When I used the system outdoors, I could clearly see that it was focusing 6 to 8 feet behind the subject (small ducks at a considerable distance, so that the individual I focused on was not much bigger than the center AF square), so I know it's off.

[Frank Kolwicz]

Canon says: "AF adjustment cannot be done during Live View shooting in Live modes." Despite what it says on another website.

Frank

[Bob Atkins]

I guess it would depend on what focus mode was being used in live view. Contrast detection works off the image on the sensor, while normal phase detection (the one that AF micro-adjustment affects) is done by a dedicated optical system which requires the reflex mirror to be down (and hence no live view display during focusing).

Certainly the best way to check focus is to record images as normal, then examine them at high magnification in your favorite image editor on your PC.

[Frank Kolwicz]

Working in normal fashion, not Live Mode, did the job with a correction of +10 being the best I found. A test of a real subject (part of my lawn) showed that focus was now on the selected object, not 6 feet behind it.

I would suggest to others that Canon's recommended procedure isn't the optimum, it presupposes that your correction will be in the +/- 5 range. Actually, you probably don't have any idea how much correction you need, so I suggest this: make one exposure starting at -20 and every 3 units to end at +20 (the order - and + doesn't matter). Just one frame each. When you can see the best of those, then narrow your range to +/-1 unit, again only one frame each until you're pretty sure you've got it narrowed down to one of 3 steps; THEN do 3 frames of each to verify!

It took me all morning to get this done with the mistake of using Live View, then using the 3 frames sequence Canon recommended, then doing it my streamlined way. It should have taken less than an hour, even allowing that I had to repeatedly pull my CF card and take it into the house to view the images on my editing computer in order to see the differences well enough.

[Frank Kolwicz]

After field testing the lens after the first round of adjustment, I found that it was still focussing behind the subject when the 1.4x extender was installed. So, back to another round of testing this morning with it on the lens.

The longer focal length required me to find a location that had at least 115 feet between the camera and the test target ($5 bill). Since the field test showed that the focal plane was still behind the subject I figured that it needed more than the +10 I found for the lens alone. After repeated tests, +12 looked the best. Now I have to adjust the camera every time I switch from the bare lens to using the extender to get critical focus.

Note that there was some variation in the quality of focus with the extender, just as Canon and others say. Focus is neither fast nor totally reliable, but it was good for about 5 out of 8 shots and the other 3 were better than I can get by eye, so it's still a desirable option.

Here's a question for the techincally inclined: why didn't film cameras require this kind of ultra-sensitive adjustment? I've never heard of one that had that ability. The manufacturers did offer to fix badly out of focus problems, but I also don't remember reading that it was often used.

[Bob Atkins]

In the days of film, few people put all their slides under a microscope, while now with digital people routinely blow up all their images to very high magnification. So they see all sorts of faults that used to go pretty much unnoticed and probably wouldn't be noticed in a print anyway.

I'm surprised you get any AF at all with the 500/4.5L and Canon 1.4xTC. I thought the 5D MkII cut off AF with lenses slower than f4 with a 1.4x. The 1D series bodies allow AF with f4.5 and f5.6 lenses and a 1.4x TC.  Maybe you are taping pins?

I use the Tamron 1.4x with my EF500/4.5L. Seems to work pretty well.

[Frank Kolwicz]

I taped the pins, you're right. Since I use a full frame camera, the third party teleconverters are much less attractive versus taping the pins.

Without that minimum level of functionality, spending the money on the AF version of my converted FD500L would not be worth the money since all I would get is wide-open focussing with the 1.4x converter, no AF confirmation light and no AF whatsoever w/o the extender. Even slow, fluttery, unreliable AF with the extender is better than I've been doing with the converted FD, much to my surprise, but then my previous experience with an FD600L was on film.