did the focus test on my 24-105L...do I need calibration?

Last night I did the focus test on my 24-105 and it looks like there's a little backfocus. Could I be wrong? Based on the picture do you guys think my lens needs calibration? I did the test on a more shallow angle do get a better DOF but i'm not sure if I should have done that. Procedure says it should be on a 45-degree angle.


Sharpened with USM.

Looks perfectly acceptable to me. Area of focus is supposed to be wider behind the focus point compared to in front.

peanuthead wrote in post #2670557
Looks perfectly acceptable to me. Area of focus is supposed to be wider behind the focus point compared to in front.

So I guess the only factor to determine perfect focus is the sharpness of the middle line then and to ignore the front and back areas? Cool!

peanuthead wrote in post #2670557
Looks perfectly acceptable to me. Area of focus is supposed to be wider behind the focus point compared to in front.

I agree, take a face for example. Focus is usually on the eyes or more often the face if you are a ways away. There is way more of the head behind that plane than in front of it.

I would be quite happy with this result.

Test looks good to me. Why did you do the focus test? Where you having any real world issues?

MarK

Mark_Cohran wrote in post #2671494
Test looks good to me. Why did you do the focus test? Where you having any real world issues?

MarK

No issues at all. I think I got so brainwashed by this forum because of all the "bad copy" discussions about lenses that I wanted to test it out myself.

baboymo wrote in post #2671605
No issues at all. I think I got so brainwashed by this forum because of all the "bad copy" discussions about lenses that I wanted to test it out myself.

That is an easy thing to do, it is a natural tendancy to focus with negatives and not report the good things, kinda like watching or reading the news.

I have had mine just over a month now can say that it is one sharp zoom lens, glad I bought it.

The area of focus - 1/3 is in front, 2/3 is in back of the area of critical focus. Looks like it performed exatcy to spec. Note macro lenses are a 50/50 split.

Where did the testing print copy come from?

Photo-John wrote in post #2671681
Where did the testing print copy come from?

http://www.focustestch​art.com/chart.html

orisky wrote in post #2671694
http://www.focustestch​art.com/chart.html

Excellent - thanks!

Looks excellent to me.

baboymo wrote in post #2671605
No issues at all. I think I got so brainwashed by this forum because of all the "bad copy" discussions about lenses that I wanted to test it out myself.

You know, I've been shooting for a long time and I've never felt the need to test a lens. As long as it works for real world shooting, that's enough testing for me. I'm sure there are bad copies of lenses out there, but I'm also sure they're not as prevalent and some people believe.

But that's just me.

Mark

Mark_Cohran wrote in post #2672197
You know, I've been shooting for a long time and I've never felt the need to test a lens. As long as it works for real world shooting, that's enough testing for me. I'm sure there are bad copies of lenses out there, but I'm also sure they're not as prevalent and some people believe.

But that's just me.

Mark

can we have this as a sticky? Forum header maybe?

Thanks for the link.