Sending a lens back to Sigma?

feenster

feenster

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Hi folks,
I have a Sigma 18-125mm for my 350D. I bought it used from Jessops last June. I am finding more and more that I am not happy with the pictures it produces - they just aren't any way near as clear and *nice* as from my 50mm. I know they are 2 different types of lenses, and I shouldn't expect miracles from the Sigma, but I have read about a lot of people who praise it for its sharpness etc.

Is it possible to send a lens back to Sigma under warranty for them to re-calibrate it or some such thing? I may be grasping at straws, but i'm sure it should be performing better than it is. Anyone sent a lens back?

Matt
 
I would ring them and tell them whats happening and see if they can suggest anything.
Is the problem the same all the time, or is it only when the lens is wide open?
Tried it on a tripod with the mirror locked up?
Might be worth doing some side by sides on a tripod with your 50 and seeing if the differences change or if you can reproduce the problem at certain settings.
The more information you can give Sigma the better imo.
 
Well, i've done a test shot at f9.0 to compare the 2 lenses @ 50mm. The Canon smokes the Sigma for sharpness and clarity. I know the 50mm is renound as a sharp lens, but the Sigma is supposed to be pretty decent too.

Perhaps I will take some test shots to email through to them. The pictures just look "muggy" :(

Matt
 
Have you tried a test against the kit lens ? You're on for a hiding testing against the 50mm. Here is a side by side test I did with the Nikon 17-80mm kit lens, that is considerably better than the Canon kit lens btw. Even here you can see the 50mm wins hands down. Both 100% crops at f/5.6

50vs18-70.jpg
 
I would ring Sigma direct and ask the question, if its a yes then all is well, if its a no at least you will be able to ask what their standard charge is for test and calibrate before sending it off.

Am I right is assuming that when you say Canon 50mm, you are talking about the 50mm 1.8 MkII? If so I think that the Sigma is at a disadvantage to start off with and even if correctly functioning will not match the quality of a prime, especially the Canon one which is extreamly well recieved. Don't let the cost of the cheap Canon fool you. ;)
 
Matt, if you get a chance put up a comparison here and see what the general consensus is.
:)
 
Right - 'budget' prime lenses from the major players will always be better than even their own zooms in the same range. And if you buy a 'slower' prime, it'll be even better optically, as typically the compromises made to increase max aperture speed tend to affect image quality. Not by much, but noticable under test conditions.

My best lens is an old Summicron-M 35mm f/2 which is still mounted onto my Leica M6. Leitz optics are the DBs - they set the standards by which many others are judged - the 50mm f/2 Leitz optic was, I think the sharpest lens ever tested by AP and may still be for all I know.
 
Can you get an EOS adapter for one of those!
 
Doubt it - M-series onto an SLR? Nah, don't think so...
 
feenster, I had much the same problem with a 70-300DL I bought a year past september. I sent it back to Sigma who checked it out and "found nothing wrong with it" however "as a courtesy at no charge" they changed out all the optics in it. When it came back it was much better. I later sold it on and bought the APO version which it streets ahead. It is more than possible that you have a bad example of your lens, Sigmas quality control can be poor, though I found their after sales service to be first rate.
 
Steep said:
f, Sigmas quality control can be poor,...
Click to expand...

Exactly the reason I paid an extra £30 to get my 10-20mm from jessops instead of HK.
 
If Sigma stick to their apparent plan to not honour guarantees on imports then I can't see any reason to buy abroad any more, a saving of £30 or so just isn't worth it.
 
i have a pdf on this, i need to get it uploaded to the front of site, but its a pdf, and i want to show it, so bear with me
 
Right, here are the test pics. I'm afraid I think I have picked a poor subject. The idea was to have something with obvious lines and a texture in the background. These are all 100% crops straight from the camera set to JPEG Small. The 350D was set on Auto white balance (hence the Tungsten glow to the pictures), set on a tripod operated from a remote cord. ISO 100 was used, as was Aperture priority. The Sigma was set to 51mm (couldn't get it back on 50mm!) - this limited the minimum aperture to f5.0, so that was my starting point for both lenses.

f1.8 (just for fun ;))
Canon 50mm:
canon_1.8.jpg



f5
Canon 50mm:
canon_5.jpg

Sigma 18-125mm:
sigma_5.jpg



f8
Canon 50mm:
canon_8.jpg

Sigma 18-125mm:
sigma_8.jpg



f11
Canon 50mm:
canon_11.jpg

Sigma 18-125mm:
sigma_11.jpg
 
f14
Canon 50mm:
canon_14.jpg

Sigma 18-125mm:
sigma_14.jpg



f22
Canon 50mm:
canon_22.jpg

Sigma 18-125mm:
sigma_22.jpg



Ok, so I know I have made a horrible job of those pictures - need a nice sunny day so I can do some outdoor tests. What do you think though? I think I might try and send it back to Sigma anyway, it can't do any harm - plus, I'd like the zoom mechanism tightening as it slips quite a bit.

Edit: The layered PSD can be downloaded here too: http://homepage.ntlworld.com/matt.feeny/lens_test/test.psd (5.76MB)

Matt
 
Personally I think that's pretty good for a zoom lens.

But if you're gonna try to send it back I'd be interested to hear what happens.

:)
 
I agree with Sammy, those are pretty good, the Sigma seems to hold up well especially when you are comparing it with one of the best prime lenses available (ok, best at the price). The trouble is you can't compare like with like, you'd need to have two 18-125 Sigmas to get a real comparison.
 
Hehe, thats shot me down ;) I thought it was pretty poor. But you are right, its not like with like i guess. I've had a reply from Sigma already and they have offered to have a look at it and fix the loose zoom barrel at least. Ill let you know how I get on.
 
Matty said:
i have a pdf on this, i need to get it uploaded to the front of site, but its a pdf, and i want to show it, so bear with me
Click to expand...


Any joy on that PDF?
 
Marcel said:
Any joy on that PDF?
Click to expand...

its on my machine chief, not sure how best to get it on the site though!:confused-
 
Well, its back, and they said "it's fine". They have cleaned the glass, but thats about it. I guess I must have been looking for things that weren't there.

Anyhow, I think i have decided I need to get a more targeted wide angle lens - something like the Canon 17-40mm, Sigma 18-50 2.8, or perhaps the Canon 17-85mm for a bit more flexibility.

More money to spend :confused:

Matt
 
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