AF Microadjustment Help!

[Mark Elberson]

After reading this article "This lens is soft" and other myths I decided that I am doing myself a huge disservice by not "calibrating" each of my lenses to my body using the AF Microadjustment tool provided in my 50D.


What is the best/easiest way to do this? I am assuming I need to take some exposures using a tripod and cable release at varied Microadjustment settings but would be a good target to shoot? I wish I had a ISO 12233 Chart to do so but what can I use that's just lying around my house? A page from a magazine? When I evaluate each exposure should I do it at 100%? Should I shoot wide open?

[Oren]

I feel the same - I'm not taking advantage of my AF Microadjustment. Mainly because of fear and lack of time. My fear is that I screw up something... if I do, is there a "reset" setting which will bring back my lens to the same state it was before?

[Mark Elberson]

I feel the same - I'm not taking advantage of my AF Microadjustment. Mainly because of fear and lack of time. My fear is that I screw up something... if I do, is there a "reset" setting which will bring back my lens to the same state it was before?
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You can always put it back to "disable"

[Mark Elberson]

So I tried to calibrate 2 lenses this morning with little success. I took 11 pictures ranging from -5 through +5 for each lens. The weird thing is that when I examined the results I noticed that best be sharpness was at -4 and +3 for one of the lenses. That didn't make any sense to me. This how I did it. I would love some advice on how to achieve better results!

• Tripod mounted with cable release
• Magazine page on wall at about minimum focusing distance for lens
• Wide open
• RAW

[Daniel Browning]

I think it is faster and more accurate to set microadjustment in liveview with a high-res LCD and 10X magnification like on your 50D. For example:

1. Setup the test chart at 45 degrees, cable release, yadda yadda, etc.
2. Live view
3. Initiate one shot autofocus
4. Check for front- or back-focus in the 5X view and 10X view.
   
5. Initiate one shot autofocus a few more times to make sure it wasn't a fluke.
6. Make a guess about how much microadjustment is needed. (E.g. try +10)
7. Autofocus again and examine at 5X and 10X.
8. Too much? Try +5 instead of +10.
9. Autofocus again and check liveview. Now not enough? Try +7.
10. Ahh... just right.

Liveview is a revolution. I can't live without it.

[Oren]

Did you take photos just from -5 to +5 or these 2 points where the 2 with the best results?

[Mark Elberson]

Thanks Daniel. I'll give that a try!


Have you done all of your glass? What's the largest adjustment you had to make?

[Bob]

<p class="MsoNormal" style="margin: 0in 0in 10pt;"]<span style="font-size: small;"]<span style="font-family: Calibri;"]Mark -- Something to consider:<span style="mso-spacerun: yes;"]
<p class="MsoListParagraphCxSpFirst" style="text-indent: -0.25in; margin: 0in 0in 0pt 0.5in; mso-list: l0 level1 lfo1;"]<span style="mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"]<span style="mso-list: Ignore;"]<span style="font-family: Calibri; font-size: small;"]1.)<span style="font: 7pt 'Times New Roman';"] <span style="font-family: Calibri; font-size: small;"]Make sure the distance that you focus from will give 2 to 3 pixels for marks on the test target.<span style="mso-spacerun: yes;"] &ndash; Otherwise, very small movements on the tripod will give a pixel shift causing the image to look different &ndash; less or more clear.
<p class="MsoListParagraphCxSpMiddle" style="text-indent: -0.25in; margin: 0in 0in 0pt 0.5in; mso-list: l0 level1 lfo1;"]<span style="mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"]<span style="mso-list: Ignore;"]<span style="font-family: Calibri; font-size: small;"]2.)<span style="font: 7pt 'Times New Roman';"] <span style="font-family: Calibri; font-size: small;"]Lens&rsquo; IS is turned-off
<p class="MsoListParagraphCxSpMiddle" style="text-indent: -0.25in; margin: 0in 0in 0pt 0.5in; mso-list: l0 level1 lfo1;"]<span style="mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"]<span style="mso-list: Ignore;"]<span style="font-family: Calibri; font-size: small;"]3.)<span style="font: 7pt 'Times New Roman';"] <span style="font-family: Calibri; font-size: small;"]Mirror lock-up is enabled
<p class="MsoListParagraphCxSpLast" style="text-indent: -0.25in; margin: 0in 0in 10pt 0.5in; mso-list: l0 level1 lfo1;"]<span style="mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"]<span style="mso-list: Ignore;"]<span style="font-family: Calibri; font-size: small;"]4.)<span style="font: 7pt 'Times New Roman';"] <span style="font-family: Calibri; font-size: small;"]Take 2 to 3 photos at each setting &ndash; keeping the sharpest image to judge the adjustment.
<p class="MsoListParagraphCxSpLast" style="text-indent: -0.25in; margin: 0in 0in 10pt 0.5in; mso-list: l0 level1 lfo1;"]

[pierlux]

Hi all!


Bryan describes a method to perform AF microadjustment on his 50D review: http://www.the-digital-picture.com/Reviews/Canon-EOS-50D-Digital-SLR-Camera-Review.aspx.


Chuck Westfall reports an (excellent) unofficial procedure for micro focus adjustment on his tech tips of December 2008 relatively to the 1D/1Ds MkIII which is applicable also to the 5DII/50D: http://www.digitaljournalist.org/issue0812/tech-tips.html .


Additional useful information is available here: http://regex.info/blog/photo-tech/focus-chart and here: http://www.northlight-images.co.uk/article_pages/cameras/1ds3_af_micoadjustment.html .


Hope I wrote exactly what I meant to say...


Pierluigi