[Steve400]

Hi all,

i've recently picked up on a lot of comments about lenses being a decent example/bad copy/best of the batch type things.

is there a high chance of getting a less sharp lens than what it could/should be? is there usually comeback if this is the case (assuming the lens is bought from a good supplier)?

the sigma 10-20 i bought recently is good but it doesnt produce 100% crisp sharp images, maybe its just me and i know i haven't used it enough to say there definitely is a problem with it!

any help?!

Steve

[_MB_]

Sigma had a bad rep for disappointing QC, I don't know if this is true anymore.

I think poor technique, not looking after lenses, not servicing lenses after not looking after them, using them outside their optimum conditions probably figure more often than "bad copies".

[orangepeel]

Originally Posted by Steve400

the sigma 10-20 i bought recently is good but it doesnt produce 100% crisp sharp images, maybe its just me and i know i haven't used it enough to say there definitely is a problem with it!

depends on the aperture probably.

Coz I shoot pretty much only landscapes with mine and I am at F11 - F16 and it's absolutely fine in that range. That said, i've used it at F29 and it was appauling. I've heard tho that that's down to diffraction and is common on most lenses when used at their smallest aperture.

[Charlotte]

Steve, can I suggest that you do a little test with your 10-20 ... Set it up for a (landscape) shot, then shoot at each f/number (using aperture priority mode), then compare the shots on pc. This may answer your question, i.e. if none of the shots are sharp (even after taking care to set up properly + focus properly, of course) then maybe you got a dud. If, however, it's sharp at one or more setting/s, then you've found your lens' "sweet spot" (very often the second- or third-smallest aperture setting)

The one lens in particular I read a lot of comments like this in the reviews, was the 70-300 VR. Some said it's sharp all the way through 70-300, while others said it's a bit soft. Some said there's no lens creep (when pointing the camera downward) while others said there is.

So yes, I believe there is such a thing as a 'bad batch' of lenses, and if you're not 100% happy with your 10-20 then it's worth testing it and, if necessary, see if you can return it, if it's really bad. If you're going to return it, don't leave it too long to do so Also check the supplier's terms + conditions re: returns, e.g. are they likely to 'repair' it or replace it. Their terms + cond's should stipulate this (probably repair, which will leave you without the lens for a fair time, especially if it's a HK supplier; although some HK suppliers designate a local dealer for repairs - again, see their terms + cond's).

Next plan of action, if your own testing doesn't enlighten you, is to take it to a local photographer or dealer to test for you (in your presence, of course).

Hope it turns out to be your technique that's off ... well, you know what I mean

[silkstone]

It's not just Sigma. The first Canon 10-22 I bought was not up to scratch, so I returned it and the replacement was a whole lot better. With anything mass-produced there is bound to be some variability, and I'm not sure how you get around this other than by having an array of lenses in front of you and sampling each one.

We're also more prone to dissatisfaction by 'pixel-peeping' with digital. Most lenses/cameras look a bit soft, especially at the edges, if you view at 100%, but that's not how you see photos in reality. If the image looks soft at the centre at around f/8 or f/11, and there's no risk of camera shake, you may have a bad lens.

[Charlotte]

Originally Posted by silkstone

It's not just Sigma.

Indeed, the 70-300 VR I mentioned is Nikkor.

[Dave Canon]

I originally considered the Sigma 10-22mm but a number of reviews (2 years ago now) found examples of problems due to poor quality control. It appeared that a good examples of the lens did perform reasonably well. Several responding to the reviews had returned their Sigma's and had them replaced. Partly because of these reviews, I bought the Canon version as Canon were reputed to have much better quality control. However, you can get the odd faulty lens from almost any manufacturer.

If you are not able to conduct a lens resolution test, try photographing a Newspaper at various aperture settings and also compare with a lens of known performance. Make sure that you use a tripod.

Dave

[spxxxx]

Originally Posted by Steve400

Hi all,

i've recently picked up on a lot of comments about lenses being a decent example/bad copy/best of the batch type things.

is there a high chance of getting a less sharp lens than what it could/should be? is there usually comeback if this is the case (assuming the lens is bought from a good supplier)?

the sigma 10-20 i bought recently is good but it doesnt produce 100% crisp sharp images, maybe its just me and i know i haven't used it enough to say there definitely is a problem with it!

any help?!

Steve

The general rule with Sigma is buy it and then send straight in for calibration - 9/10 when it comes back it will be stellar and for the other 1/10 send it again........

[Steve400]

thanks for all the replies!

i havent tested the sigma enough to say for sure. i may do one of them 'Av' tests as recommended!

i take it the lens is expected not to be pinsharp at the edge of the photo when shooting at 10mm?

i really need to get out with the camera more!!!

Steve

[Steve400]

i had the sigma out today and can now say it was my poor skills that were the problem not the lens!

it worked well today!

[Charlotte]

Originally Posted by Steve400

i had the sigma out today and can now say it was my poor skills that were the problem not the lens!

Oh good! I think

Originally Posted by Steve400

it worked well today!