Focus Issue Experiment Round 1

kevingearykevingeary Registered Users Posts: 194 Major grins
edited April 21, 2011 in People
Ok...

So I didn't have time to set up the ruler test today, but I did have time after my wife and I ate lunch to grab a few pictures and let me experiment with focusing and apertures with the 50mm 1.4.

Some people had suggested my previous problems were generated by shooting at f1.8 and f2 (too shallow). So I decided to shoot from 2.8 to 5.6 and see what the results were.

This is on a 7D using spot focus and manually selecting the focus point over the eye.

This image was shot at f5.6 and was the best of the bunch (this is with processing and sharpening):

5635736907_efc5befe13_z.jpg

And now the problem...

This was also shot at F5.6 and is a 100% crop with no processing:

MG_4315-1.jpg

For F5.6, that's unacceptable to me. And this isn't the only one. It seems the only decent results were gained at 5.6 and doing closeups, but even then it wasn't consistent. And any shots that had any extra distance from subject to camera were worse, even at 5.6.

I've heard this lens is tack sharp from 2.8 and above and from where I sit, there's no way that's true. I wouldn't even call the first image "tack sharp."

What say you?

Comments

  • divamumdivamum Registered Users Posts: 9,021 Major grins
    edited April 19, 2011
    The first one looks absolutely sharp on this monitor at this resolution. Given the DOF falloff to her body, I'll guess you were shooting from pretty close to her.

    Second one, not so good. What was your shutter speed on that one? Is there anywhere at all in the shot that's crisply focused?

    Have you checked Ziggy's recommendations for focus testing in the gear forums? He's posted quite a few times, and generally suggests using a brick wall to check for front- or back-focusing; the texture gives you a reasonable amount of detail and information to start making informed guesses as to what's going on.

    My 1.4 is VERY sharp from about 2.2/2.8 - if you're continuing to have problems (and you're not experiencing similar issues with your other lenses which might suggest a problem with the AF in the bod), you might want to have the lens checked out.
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  • rwellsrwells Registered Users Posts: 6,084 Major grins
    edited April 19, 2011
    The three different copies of the 50 f/1.4 that I purchased would not focus consistantly on all three of the bodies I had at the time. Mico-Adjustment has nothing to do with focus jumping (two of those bodies didn't have that option anyway). I know lots of people (the majority) have great success with this lens, but after three copies of it, I just gave up on it. I won't own a lens that I can't 100% count on.

    My business partners copy worked just fine, on his bodies and my three. ne_nau.gif

    I don't think that I have a "moral to this story"... Good luck!
    Randy
  • kevingearykevingeary Registered Users Posts: 194 Major grins
    edited April 19, 2011
    I'm going to be getting an 85 1.8 and the 135 f2 soon. If those two have the same issue, then it's either my technique or my camera.

    If they don't have the problem, I'm going to assume it's the lens.
  • DeVermDeVerm Registered Users Posts: 405 Major grins
    edited April 21, 2011
    why don't use one of the test charts and tri-pod (read micro-adjustment threads) in a controlled test? I used this one with my 7D with great success:
    Focus test chart
    Copyright Tim Jackson 2004
    tim@FocusTestChart.com
    Version 2.1 – (24 June 2004) The latest version is always available at http://FocusTestChart.com

    it will show you if you reach sharp focus or not and if that is on the AF spot or elsewhere.

    ciao!
    Nick.
    ciao!
    Nick.

    my equipment: Canon 5D2, 7D, full list here
    my Smugmug site: here
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