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Old Sep 11, 2003, 9:30 PM   #1
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Default 28-135 IS USM f3.5-5.6 soft corner normal? (with example)

For sake of seeing why pictures with this lense ae so impressive compared to old lenses I use(d) with EOS 35mm camera I did a shoot out.

I already noticed that the lower right corner had more blooming/ color abriviation than elsewere in photos with this lense.

What I did not expect was that the lower right corner to be significant unsharp compared to other areas. Next picture shows crops of EOS 10D pictures with the 28-135 IS lense and a 50mm lense. Both taken short after each other with tripod at a distance of roughly 1.25m

Is such fuzzy corner normal with the 28-135mm IS USM lense? Or should I return the lense?

Camera is aimed at 90' degrees at these (boring) stock newspages.
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Old Sep 11, 2003, 10:57 PM   #2
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That sure seems odd to me, but I have to admit to not owning many lenses. I would expect a more consistant OOF across the edges... but that is from ignorance, not experience.

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Old Sep 12, 2003, 12:19 PM   #3
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First of fixed focal lenses will likely beat zooms (ie they are optimized for only one and one focal lenght). Especially a standard 50mm where the manufacturers have years to perfect! Zoom however are designed for a whole range with good/bad spots... How about at other focal lenghts?

Secondly did you try to turn off the IS or mount the camera on a tripod? Depending on how thoses internal optical elements move about wouldn't one expect some varying out of focus areas? especially at the outer edges... small design trade off I would think for the IS, but that's just my pure guess

That's why closing down the aperture will increase the DOF... and voila`(but I wouldn't be shooting the Wall Street Journal)! :lol:
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Old Sep 12, 2003, 8:45 PM   #4
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NHL, indeed to my suprise this 28-135 zoom lense performed even better at some areas than the fixed focal length 50mm.

But I must say, the 50mm lense is a secondhand, I have no idea how good it used to be out of the box. Photos were taken with autofocus, on a tripod and with timer delayed shutter release.

When I posted this message I was a bit clueless if the sharpness in the other 3 corners was a lucky feature or the blur in 1 corner a bad construction. The camera did say that right area was sharp. Today I went to the shop and swapped the lense for another one, the problem is gone. No more wall street journals shot by me, it is time to shoot priceless pictures ;-)
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