AF Microadjustment for Canon

I have never really been happy with the way my 100-400mm Canon len AF focus with either my Canon Rebel XT or Canon 7D. I have sent my len back to Canon twice to see if it was the len that was not focusing properly. Both times they sent it back stating it was within specs. I have read that a len can be in spec and a camera can be within spec but yet distance apart on the focusing scale. My question is - Has anyone else had this issue and by doing an AF Microadjustment either professionally or by themself help?

Equipment Canon 7D camera

EF100-400mm F4.5 - 5.6 IS USM Len

Great post. I haven't tried micro adjustments with my 100-400 because I've read it doesn't work with zooms. I hope someone here has experience.

Before I got rid of my 100-400, I micro focused all my lenses, and Lance in right, it does not work with zooms. You have to select your optimum shooting distance, say 300, and micro adjust at that distance. Bottom line is micro adjustment does wonders for primes, and doesn't do much for zooms. I also have a 7D like Paul, and a 1D IV, and finally realized the 100-400 is just a softer lens and will not give that tack sharpness I needed. I might get 1 out of 100 shots that hit the mark, but there was no consistency, and certainly no control. So I said 'screw it', sold it and bought a 500 and have never looked back

Garry Revesz
Toronto

I do not have any micro adjusting experience but I want to comment because of the negatives about the 100-400 ability to produce sharp images. I have two 100-400's and have used them on a huge variety of bodies all the way back to the EOS3 film body and through the generations of digital: D60, 20D, 30D, 40D, 1D MkII, 5D, 5D MkII, 7D, 1D MkIII and I have not had any issues with tack sharp images. When I have shots that are not sharp, it's almost always explainable or my fault and not the fault of the lens.

I don't want to flog a dead horse here, but John's comments about 100-400 are noted. I do know the odd person that has a good version of that lens, but I know a lot more people that felt the same as me; it just doesn't have the consistent sharpness a lens of that calibre (and price) should have. Comments I have heard like "if you're lucky enough to get a good one..." I think sums up it's status. It's not a bad lens, but neither is it Canon's best effort.

Garry
Toronto

I had similar problems with my 100-400 on the 40D and my 7D. One day I let a friend who shoots with a 100-400 hook up my 300 2.8 to his 5D body and try it out. I hooked up his 100-400 to my 7D and gave it a whirl on a perched Tree Swallow. When I went over my images that night, I found that about 75% of the images were sharp and I used various focal lengths. Go figure.

Skip Harris

I have heard the exact same thing about the 100 - 400 mm Canon len - you never know which lens you are going to get: A good or bad one (so much for quality control) I have never really been lucky with chance - I guess I got a bad one - John I am happy for you for getting a good one.

I'll speak from my own experience of performing AF microadjustments with a 7D and a 100-400mm (as well as other zooms): it works quite well. After performing a simple test, the 100-400mm only required a very minor adjustment. I have zero complaints about the degree of sharpness from that lens. I'm sure it is less sharp than a 400mm single focal length lens, but the convenience of that lens fits my needs for shooting birds and sports.

For adjusting AF, I follow the procedures listed here:

http://www.northlight-images.co.uk/article_pages/cameras/1ds3_af_micoadjustment.html

According to the article, Canon suggests setting the focal length to its longest reach. It has worked well for me.

ME

Thanks, Michael!!!