Help!! Problem with this lens - 28-135 IS

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justjase

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Not had this long, i bought from a member off this site. at first i thought it was just me getting used to the IS function, but as i have taken more shots (without IS) i have noticed a blur on all four corners. another work colleage has an identical lens and i have tried it on my body (still has a small amount of blur) but is considerably better.

Take a look at the pic in my gallery and tell me what you all think (pic has been rotated 90 degs) :thumbsdown:
 
There does appear to be a blur in the corners of this shot.

Have posted the shot to give it a bump and see if anyone can suggest a solution .... :thinking:

IMG_0822copy.jpg
 
Hi,

Using a little mathematics to work out what's going on here.

I suspect that you were about 1.5 metres from the wall. The diagonal field of view at 135mm on your 30D is 11.4 degrees.
This gives a diagonal distance of around 1.025 metres and at f/8, you are on the DOF limit.

Try retaking the shot by manually focussing again and then moving the focus ring a fraction further (to a slightly longer focus) and see if the corners sharpen at the expense of the centre.

Unless I screwed up somewhere, your lens is exhibiting very normal tendencies.

Bob
 
Cheers guys...
i have a couple of hundred images taken with this lens (some better than others), i will put a few more on here if thats ok?


IMG_0621a.jpg
 
That one certainly looks strange, it's less of a blur rather than a smear on the yellow building. What speed was it shot at?

Cheers,
James
 
Moos3h said:
That one certainly looks strange, it's less of a blur rather than a smear on the yellow building. What speed was it shot at?

Cheers,
James
Click to expand...


Here goes:

Aperture: f10
Shutter Spd: 1/320
ISO: 200
Focal Length: 95mm
 
Can't see anything wrong with those numbers, assuming you were hand-holding steadily and didn't hiccup when you took the shot!


I'm no expert, but if it's managed to focus fine on the word 'lifeboats' AND focus well on the building smack bang in the middle, I'd find it weird how it can make such a mess of the yellow building.

Strange.

Cheers,
James
 
spencer said:
I had a problem with my sigma lens here

Anyway sent it back & the replacement was spot on.

If your even slightly unsure I would send it back, apparrently its not uncommon for Sigma lens to be a little to soft!

Hope that helps

Spence
Click to expand...

I'm not sure if its under any warranty as i bought it from a TP member - i assume he bought it from new but can only speculate.

Failing that, would somewhere like Jessops be able to help?

as i said its a great lens but it seems to be a little too soft for me (my 18-55 stock lens is much much sharper).
 
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