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Sigma EX 18-50 f/2.8 review
June 10, 2005
I have been completely obsessed with lenses the last few weeks. After recently getting my Digital Rebel, I had been anxious to go out and blow all the money I had saved by getting such a good deal on the body on a nice lens. I was torn between the Canon 17-85 IS, the Canon 17-40 L, Tamron 28-75 XR Di LD IF and the Sigma 18-50 EX f/2.8.
After reading numerous web reviews, and countless posts on forums, I decided to bite the bullet and bought the Sigma from Henry's for $750.00 Canadian.
First Impressions
I was impressed with the overall build and construction of the lens and with its size. On my 300D, it was an ideal size for a general walk-around and vacation lens. It felt very solid in my hands, and despite being constructed of plastic it felt like it was held together very well. I liked the fact Sigma included a handy carrying case and petal hood with the lens. The 67mm filter size hurt when I also purchased B&W UV filter for the lens.
I only managed to take a couple of quick shots around the office before my battery died. I plugged my battery in for recharging and took a quick look at the images. The results seemed impressive. The bokeh looked quite nice and I thought color rendition was good.
After my battery was fully charged, I took the new lens out for a spin and did some qualitative comparisons to my 18-55 EFS lens. I was expecting my new lens to completely blow away the old kit lens and was looking forward to taking many great pictures with my new Sigma. Boy was I dissapointed.
Tests
All tests were performed with:
- Digital Rebel (300D) mounted on a tripod
- ISO 200, RAW, AWB
Some cropping was performed, but no other photoshopping was done.
Sharpness
The first tests I performed were sharpness tests.
Click on the image for full size images.
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| Sigma 18-50 at f/4 |
Canon 18-55 at f/4 |
Sigma 18-50 at f/8 |
Canon 18-55 at f/8 |
To my admittedly untrained eye, it looks like the Sigma is soft. Also, don't worry about the reddish tint on the Sigma images, apparently that tint is a characteristic of the lens reported by many people. I was very dissapointed with these results. The bokeh was nice on the Sigma, but as for sharpness I really felt I wasn't getting my $750 worth. Now I was using AF to take these images, so I performed a focus test next using the Focus test chart by Tim Jackson.
Focus
The focus test was quite revealing.
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| Sigma 18-50 at f/4 | Canon 18-55 at f/4
As you can see, the 18-55 kit lens focuses perfectly (in fact it did so in all the test runs), the Sigma seems to front focus. I suspect this was the cause of the lack of sharpness from the Sigma. In all my tests the Sigma never seemed to focus correctly and always front focused.
Flare
The last test I performed was the quickly check lens flare.
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| Sigma 18-50 | Canon 18-55
As to be expected the Sigma fares much better than the kit lens on the flare test. This is at least one area in which the Sigma didn't dissapoint me.
Conclusions
In the end, I felt like I had been ripped off $750.00, so I promptly returns the lens. Now I fully concede that I may have had a dud copy of the lens as reported by others in forums on the internet, but for $750.00 I refuse to do Sigma's QA for them. Now I just need to decide which of the alternatives to go for.
| Good |
Bad |
- Good construction, feels solid
- Good flare performance
- Nice Bokeh
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- Terrible, noisy, slow AF
- Questionable sharpness
- Reddish tint on all images
- Poor QA
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