135L - I can't get a sharp shot no matter what :(

[ddt0725]

<span style="line-height: 115%; font-family: 'Arial','sans-serif'; font-size: 10pt;"]I think it&rsquo;s possible that your 7D may have a focus calibration issue, but your other lenses almost cancel this out.<span style="mso-spacerun: yes"]

Hi Andy -

I am beginning to wonder about my camera. I am going to get another copy of the lens and see how it works out. But I think my camera is still under an extended warranty so after I get the second lens, I may send inthe camera &amp; have it checked out.

Denise

[neuroanatomist]

I think it&rsquo;s possible that your 7D may have a focus calibration issue, but your other lenses almost cancel this out.<span style="mso-spacerun:yes;"] With your 7D + 135L combination, the errors add together instead of cancelling.It&rsquo;s impossible for us to say how much of the +14 is due to the body and how much is due to the lens.<span style="mso-spacerun:yes;"] Both your 7D and 135Lare probably within their individual focus tolerance

Roger Cicala's (lensrentals.com) article on AFMA has a story (allegory?) of a forum poster who went through many copies of each lens he owned to find the 'perfect' lenses, then when he bought a new body, that new body 'sucked' because none of his perfect lenses focused properly on it.

[ddt0725]

My one year Canon warranty expires in February but I also have a 4 yr. Best Buy warranty so I will be sending it to Canon next month before my only choice ends up being Best Buy.

[Andy Stringer]

Denise, I don't think there's a serious problem with your 7D, because you've already taken lots of pin sharp pictures with your other lenses after a small adjustment. You've just been unlucky to get a camera and lens combination where the focus errors add together and need adjusting by 14.

If the next copy of the lens is good (i.e. if the adjustment required is less than 10), keep it. You will not benefit from sending your kit away if you are happy with your own adjustments.

If you need to go much beyond +/-10 with the second copy of the 135L, you might want toget the camera and all of your lenses checked out, just to make sure it's not the camera body causing the problem.

[Andy Stringer]

Roger Cicala's (lensrentals.com) article on AFMA has a story (allegory?) of a forum poster who went through many copies of each lens he owned to find the 'perfect' lenses, then when he bought a new body, that new body 'sucked' because none of his perfect lenses focused properly on it.

Good one. That's why I don't lose any sleep when I have to adjust my lenses by more than a few units. On my 1D IV, the average adjustment I need is +8, with one lens needing +17 and one just +2. I conclude that my body needs +8 and my lenses need between -6 and +9, so everything is within the +/-10 tolerance individually and within +/-20 in combination, no worries.

Denise doesn't (yet) have enough lenses to draw those conclusions.Either the 7D, or the 135L could be out of tolerance, but most likely both are fine. No harm in trying another copy.

[clemmb]

Denise doesn't (yet) have enough lenses to draw those conclusions.
<div style="clear: both;"]</div>

I disagree. Her lens assortment is:


EF 100-400mm f/4.5-5.6L IS USM
EF 70-200mm f/4L IS USM
EF 24-105mm f/4L IS USM
EFS 17-55mm f/2.8 IS USM

EF 135 f/2.0 L USM
EF 100mm f/2.8 Macro L IS USM
Sigma 85mm F1.4 EX DG
EF 50mm f/1.4
EF 35mm f/1.4L USM

[Andy Stringer]

My sincere apologies, I've been looking at other users profiles and flicking between threads and maybe enjoying too much Christmas spirit. I stand corrected. I thought I read somewhere that her other lenses needed a +2 correction, but that may have been another contributor.


Denise, can you tell us what microadjustment your other lenses need, if any?

[neuroanatomist]

Denise doesn't (yet) have enough lenses to draw those conclusions.

I think it also helps to have data from more than one body.Having 8 current autofocus lenses to test (actually 7 lenses plus one combined with a 1.4x TC) and two bodies, and also 6 previous lenses tested with just one body, I've had adjustments ranging from -7 to +9. I think that if I bought a lens that needed more than&plusmn;10 adjustment, I'd exchange it for another copy right off the bat.

[ddt0725]

My sincere apologies, I've been looking at other users profiles and flicking between threads and maybe enjoying too much Christmas spirit. I stand corrected. I thought I read somewhere that her other lenses needed a +2 correction, but that may have been another contributor.


Denise, can you tell us what microadjustment your other lenses need, if any?
<div style="CLEAR: both"]</div>

No problem, Andy! After buying and selling so many lenses, I'm having a hard time keeping track myself!

These are the settings of the ones I currently have. Of the ones I've sold, I know they were not anything over a +/- 5.



EF 100-400mm f/4.5-5.6L IS USM 0
EF 70-200mm f/4L IS USM 0
EF 24-105mm f/4L IS USM +5
EFS 17-55mm f/2.8 IS USM+1

EF 135 f/2.0 L USM
EF 100mm f/2.8 Macro L IS USM 0
Sigma 85mm F1.4 EX DG +3
EF 50mm f/1.4 -5
EF 35mm f/1.4L USM +1

[Andy Stringer]

Thanks, Denise. If you've never had to go beyond +/-5 with a fair number of lenses, I'd say you don't need to worry about sending in your 7D for a check. It can't be contributing more than +5 to the total adjustment, and more likely close to zero.


This points to the 135L being out of tolerance, but still perfectly usable at +14 on your 7D. Until you get a second camera, I agree with Neuro that you should return a lens if it needs more than +/- 10.