A question about my canon lens sharpness

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Your problem may be a matter of lens focus calibration.

I just went through a Sunday of checking lenses, and the results we
eye-opening. I have been shooting a new Canon 1DsIII, that has the ability
to store a focus compensation for each lens and the combination of a lens
and a 1.4x and/or 2x extender. I finally had enough free time to run
through my 'normal' through tele lenses.

I ran tests on 6 of my 'L' lenses from 50mm to the 400mm and I was amazed on
how far off the focus was on the test photos. I used a 60" long steel scale
set at 45 degrees with a pieces of a white and a black mat board taped
together to give me a good vertical line for focus. The line should be
positioned at the center of the scale. Then you can see the focus point very
easily. Do multiple exposures, moving the lens off focus each time so that
the autofocus has to move from an out of focus position.

I have 2 lenses that are going back for adjustment, because I need to use
the max compensation I have available to get them in.

Hope this helps,
Emil



"Eatmorepies" <jcf.TakeThisOut@ali.co.uk> wrote in message
news:61fqemF1uesu8U1@mid.individual.net...
> Hello
>
> My Canon ef 24-70mm f2.8 L is not producing images as sharp as they were
> last year. I've compared it with my 100mm f2.8 macro and my 24-105mm f4
> L - both are sharper then the 24-70 at comparable apetures and shutter
> speeds. Photographs I took with the 24 - 70 last year are much sharper
> than ones I took yesterday (at comparable apetures and shutter speed).
>
> It's not camera shake as I took some this morning at 1/4000s - on a
> tripod.
>
> The lens doesn't rattle and as it's seen little use from new (1000 shots
> max) so the problem can't be wear.
>
> Any ideas what's happened? Has anyone experience of sending a lens to a
> Canon service centre for adjustment?
>
> Regards
>
> John
>
>
>
 >> Stay informed about: A question about my canon lens sharpness 

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 >> Stay informed about: A question about my canon lens sharpness 

Let me count the ways you are wrong... uhhh, no, can't reason with a Canon
hating Troll.

I use Canon because people purchase what comes out of my camera... that's
it.

Body and lens autofocus calibrations had better be independent, at least
that better be the goal... think about it.




"Rita Berkowitz" <ritaberk2008.TakeThisOut@aol.com> wrote in message
news:13r64t1edemqk0f@news.supernews.com...
> Sbc News wrote:
>
>> Your problem may be a matter of lens focus calibration.
>>
>> I just went through a Sunday of checking lenses, and the results we
>> eye-opening. I have been shooting a new Canon 1DsIII, that has the
>> ability to store a focus compensation for each lens and the
>> combination of a lens and a 1.4x and/or 2x extender. I finally had
>> enough free time to run through my 'normal' through tele lenses.
>
> You're being too kind! Eye-opening isn't the terminology I would use.
>
>> I ran tests on 6 of my 'L' lenses from 50mm to the 400mm and I was
>> amazed on how far off the focus was on the test photos. I used a 60"
>> long steel scale set at 45 degrees with a pieces of a white and a
>> black mat board taped together to give me a good vertical line for
>> focus. The line should be positioned at the center of the scale.
>> Then you can see the focus point very easily. Do multiple exposures,
>> moving the lens off focus each time so that the autofocus has to move
>> from an out of focus position.
>
> Sadly, most Canon shooters consider this normal and accept mediocrity.
> Sure, there are going to be manufacturing tolerances, which weren't met in
> this case, and normal wear. This goes beyond norm and is more of a QA
> problem. It's great that the Mk III's have AF adjustment, but all the
> other
> poor slobs that don't have one are sentenced to suffer with substandard
> glass.
>
>> I have 2 lenses that are going back for adjustment, because I need to
>> use the max compensation I have available to get them in.
>
> You better send the camera back with the lenses or you'll get nowhere
> fast.
>
>
>
>
>
> Rita
>
 >> Stay informed about: A question about my canon lens sharpness 

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 >> Stay informed about: A question about my canon lens sharpness 

"Rita Berkowitz" <ritaberk2008 RemoveThis @aol.com> wrote in message
news:13r6amk2rvht36c@news.supernews.com...

> There are people
> that literally buy six of one L lenses and pick the best of the litter.
> Now
> tell me again about how wrong I am?

There are obsessive-compulsive people who wash their hands hundreds of times
in one day.

And your point is?
 >> Stay informed about: A question about my canon lens sharpness 

"Rita Berkowitz" <ritaberk2008 DeleteThis @aol.com> wrote in message
news:13r6amk2rvht36c@news.supernews.com...
> Sbc News wrote:
>
>> Let me count the ways you are wrong... uhhh, no, can't reason with a
>> Canon hating Troll.
>
> Huh? Name one? Here's a hint, "I have 2 lenses that are going back for
> adjustment, because I need to use the max compensation I have available to
> get them in." You're not the first to experience this. There are people
> that literally buy six of one L lenses and pick the best of the litter.
> Now
> tell me again about how wrong I am?
>
>> I use Canon because people purchase what comes out of my camera...
>> that's it.
>
> Well, people purchase anything, that doesn't mean it is good or even
> acceptable.
>
>> Body and lens autofocus calibrations had better be independent, at
>> least that better be the goal... think about it.
>
> I did. Now your turn. Do you think it normal that you have such a wide
> variety of tolerances between all these lenses? Another thought, the
> constant here is the surface of the lens mount to the sensor plane. Why
> do
> you think it so difficult that Canon can't match this constant between
> different lenses and bodies? In theory, one should *NEVER* have to use AF
> calibration on the Mk III's if proper QA was adhered to. And since you
> are
> looking down on people that have 40Ds and other consumer cameras that
> don't
> have AF adjustment it is clear you don't care about them. What would a
> 40D
> user do the correct the problems you have with your six lenses?

Ditch the whole enchilada and go Nikon


--
Sosumi
 >> Stay informed about: A question about my canon lens sharpness 

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 >> Stay informed about: A question about my canon lens sharpness 

"Rita Berkowitz" <ritaberk2008 DeleteThis @aol.com> wrote in message
news:13r5g4j8o4vnq41@news.supernews.com...
> Eatmorepies wrote:
>
>> My Canon ef 24-70mm f2.8 L is not producing images as sharp as they
>> were last year. I've compared it with my 100mm f2.8 macro and my
>> 24-105mm f4 L - both are sharper then the 24-70 at comparable
>> apetures and shutter speeds. Photographs I took with the 24 - 70 last
>> year are much sharper than ones I took yesterday (at comparable
>> apetures and shutter speed).
>
> I'm not sure what climate zone you live in? You might want to check and
> see
> if the internal lens coatings are delaminating. This problem is more
> predominate in colder climates. Just hold the lens up to a light source
> and
> see if there is any type of noticeable haze. You might want to send it
> back
> to Canon for servicing. If they determine it is delaminating they will
> repair the lens for free even if out of warranty.

Eh, is that why NASA choose Nikon?
Starts making sense ...


--
Sosumi
 >> Stay informed about: A question about my canon lens sharpness 

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 >> Stay informed about: A question about my canon lens sharpness 

"Rita Berkowitz" <ritaberk2008.DeleteThis@aol.com> a écrit dans le message de news:
13r72gdm22c9l75.DeleteThis@news.supernews.com...
> Sosumi wrote:
>
>>> to Canon for servicing. If they determine it is delaminating they
>>> will repair the lens for free even if out of warranty.
>>
>> Eh, is that why NASA choose Nikon?
>> Starts making sense ...
>
> It makes one think why a highly technical agency like NASA won't use
> Canon.
> They might know something we don't?
>

Marketting and product placement, give a few cameras and lenses and get free
publicity. Why do all the CSI shows use Nikon?

Jean
 >> Stay informed about: A question about my canon lens sharpness 

Rita Berkowitz <ritaberk2008.TakeThisOut@aol.com> wrote:

> It makes one think why a highly technical agency like NASA won't use Canon.

They aren't?
Can you prove that? (Of course not!)

> They might know something we don't?

If you loose Nikon gear in space, you won't cry over it.

-Wolfgang
 >> Stay informed about: A question about my canon lens sharpness 

Sosumi <sosumi.DeleteThis@home.nl> wrote:

> Eh, is that why NASA choose Nikon?
> Starts making sense ...

Hasselblad is Nikon?

-Wolfgang
 >> Stay informed about: A question about my canon lens sharpness