Thursday, June 04, 2009

Sigma 18-50 2.8-4.5 DC OS lens hands-on


7/28 UPDATE: For those who haven't been following, the original lens I did this test with was replaced as defective (it clearly wasn't working right some of the time). I took a few new test shots over the past weekend with the new lens and while it may just be wishful thinking on my part, I do think it's slightly better optically. The overall conclusions below still hold, as do the general design conclusions I reached, but I think my new lens is just a slightly better example than the old one even beyond simply working correctly :)

I'll post the new shots in a few days - sorry, you'll have to check back one more time.

Anyway, the original post continues below.

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I just wanted to post something quick about this, because I know a lot of people (including myself) have been waiting for this lens, and I just happened to find it here in Japan, at one particular Yodobashi Camera, available only in a Canon mount. It was right at $300 (29,800 yen).

I haven't had a chance to do any exhaustive tests so far but generally I'm really happy with it as an upgrade to my old Rebel XT kit lens.

Pros:

* Built like a tank, at least for a consumer-level lens (looks almost exactly like their 18-50 f/2.8 EX lens, minus the gold stripe)
* Image stabilization works really well
* Non-rotating front element
* No lens extension during zoom - all movement is internal
* Hypersonic motor is very quiet (though not silent, nor all that fast)
* Includes a hood

Cons:

* Actually slightly less sharp in the corners than my kit lens (though I've been told I had an exceptional copy of the old Canon 18-55 non-IS)
* Corner sharpness is noticeably lower than center sharpness
* Heavy

These were taken in my backyard and have not been retouched at all. So some of the exposures are not exactly right, white balance might be a bit off, etc. I did not want to damage the purity of the images as the lens saw them. The shots were all taken on a tripod, using a delayed exposure (completely hands-off), using AF. I also took shots using MF but didn't do any better on a consistent basis - I will say the comparisons themselves were the same (the "winner" at any given aperture did not change based on whether I used AF or MF). The Canon lens used as a comparison is the 18-55 non-IS kit lens, which might have some slight differences to the IS version beyond the obvious, but they perform similarly in the tests I've seen. But you can keep that in mind, at least.

My thoughts on what the shots show are below.

Clicking the thumbnails will take you to that image on Photobucket, where you can view them at 100% full size (just click anywhere on the image once it opens in Photobucket). I know, kind of clunky to compare shots, but that's why God invented tabbed browsing :)

Sigma @ 18mm f/5.6:
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Canon @ 18mm f/5.6
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Sigma @ 50mm f/5.6
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Canon @ 55mm f/5.6
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Sigma @ 18mm f/8
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Canon @ 18mm f/8
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Sigma @ 50mm f/8
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Canon @ 55mm f/8
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Sigma @ 18mm f/11
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Canon @ 18mm f/11
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Sigma @ 50mm f/11
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Canon @ 55mm f/11
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Sigma @ 50mm f/8
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Canon @ 55mm f/8
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Now, the stuff I know a lot of you guys are waiting for - a couple of wide open aperture shots. Clearly the Sigma lens is not as sharp there, but my thoughts on that after the photos.

Sigma @ 18mm f/2.8
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Sigma @ 18mm f/2.8
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Sigma @ 18mm f/3.5
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The interesting thing is how much sharper the Sigma lens is at f/3.5 than f/2.8. It's almost like they designed the lens for 3.5 and then just widened it to give it better specs, even though the lens is obviously not happy about it. (I'm not sure if that's really possible.)

One thing I will say is that you would obviously only be using f/2.8 in low light handheld situations, which this really was not. In low light when shooting handheld, you're going to be a lot more satisfied with "acceptable sharpness", especially from a consumer level lens. With a lens that has no OS and can only open up to f/3.5, you will have a hard time shooting handheld even acceptably in low light. With this lens, the f/2.8 coupled with the OS gives you the ability to shoot in very low light without unnecessary blur from camera shake, although you will not get "tack sharp" images out of it no matter what you do at that aperture.

Sigma @ 50mm f/4.5
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Compare to the similar shot above. Again, it is noticeably softer at 4.5 at this end of the zoom than at f/8 or f/11, which is really its sweet spot.

Generally I am really happy with this lens, and if you look at the overall lens market, I think Sigma did what they needed to do here. This is not an EX lens designed to compete with Sigma's own 18-50 f/2.8. It is designed more to fill a hole just above Canon's cheap 18-55mm kit lens, and it costs about $100 more. The optical quality of the two lenses is about equivalent - the Sigma may be slightly sharper in the center at certain apertures, the Canon better in the corners.

For that extra $100, though, you are getting much better build quality, an included lens hood, a non-telescoping zoom, a non-rotating front element, and (from what I've read, at least), more capable image stabilization. You're also getting a wider aperture, though whether or not that's really useful given the performance is up to you (though I know I will be happy to have it when I need it). I personally think all of that is easily worth the extra cost over the Canon lens.

The other major difference between the Canon and Sigma lenses are that the Canon seems to be at its best at f/5.6, whereas the Sigma is at its best at f/8 or f/11. A lot of people will find the Canon sweet spot to be more useful in more situations, and I don't disagree with that. It's kind of odd - and my one real criticism of the Sigma lens - that its specs suggest it is designed for low light, but it's really happiest in bright light. Still, that isn't unusual for Sigma, who often seem to design their lenses this way.

Summing up, I can highly recommend this lens given the price, but you shouldn't be expecting EX (and certainly not Canon L class!) performance. It is what it is - a better quality alternative to Canon's 18-55 IS.

23 comments:

  1. Anonymous6:26 PM

    Could you please add more photos? Would love to see more at 18mm and 2.8/4.0/5.6/8.0 aperture, I just can't believe how soft this lens is - simply unacceptable at 5.6; there must be something wrong, could you retest it at 18mm? and if possible compare to C18-55mm.


    Thank you for the preview!

    ReplyDelete
  2. I'll try to take some more comparison shots - that one probably isn't really representative and if I wasn't in such a rush, I probably wouldn't have posted it at all. I shot it handheld, for one thing, though I had my elbows propped up against a railing.

    I don't think the lens itself is all that soft, as I said in my update I think the focusing is more of an issue. I don't notice any softness in the real-world shots I've taken.

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  3. One thing I'm trying to figure out is when the lens stops down the aperture. It goes from 2.8-4.5 across the range, but where in the zoom range does it do that?

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  4. sterno:

    It's pretty linear. I don't know exactly where it happens (you'll probably need to wait for dpreview or some big photo mag to test for it), but it's probably at about 1/3 up the range that it goes to 3.5, then about 2/3 up that it goes to 4.5. That's what it feels like, anyway.

    Just for anyone else reading this, I took some more comparison shots over the weekend and I'm working on posting them. The Sigma comes out better in my new tests than it did in the two shots above - really, I'm pretty happy with the lens.

    ReplyDelete
  5. Excellent, thanks! I've been wanting to get something that would be good indoors in low lighting. If what you're saying is true, then it should have 2.8 up to about 28mm. I'd been assuming that was the case, but wasn't sure. Thanks!

    ReplyDelete
  6. sterno:

    I'll see if I can get you a more exact number on where it clicks off f/2.8, if that's what you're most concerned with.

    However, I will say this lens really doesn't like f/2.8 much. That's definitely something I learned in my new tests - it's got low-light specs but it's definitely happier in bright sunlight.

    ReplyDelete
  7. Ok, here's the approximate breakdown of the max aperture by zoom:

    18mm - f/2.8
    22mm - f/3.2
    26mm - f/3.5
    35mm - f/4.0
    48mm - f/4.5

    Obviously, OS works at any aperture, so even f/3.2 is no slouch as far as getting acceptably sharp stuff in low light. It's not going to be *very* sharp, just because the lens itself is not all that sharp wide open, but it'll be a lot sharper than a lens that's f/4.0 at, say, 30mm, with no OS in low light.

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  8. Do you have any rough estimate for the effectiveness of the OS? How many stops slower shutter speed can you hand hold reliably with OS working?

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  9. I haven't fully tested that to be able to give you an exact number, but it's pretty effective. You can see it through the viewfinder. This is my first lens with OS or IS so I don't know if every system works like this, but when you switch it on, the viewfinder image is suddenly like looking through a Steadicam. It was actually a little weird for me at first.

    I know I've gotten shots I never could have without the OS. I did do a little test in the hotel room just taking a picture of a printed page from across the room at 55mm in low light... I think it was something like f/3.5 at 1/8 second and the text was still readable. The exposure in the "don't look down" post I put up right before this one was something like 1/25 second and it's pretty sharp - definitely sharper than I could have gotten without OS.

    ReplyDelete
  10. Anonymous6:11 PM

    Thanks for the great review. I have been looking for a lens with stabilisation to add to my Sigma 17-70mm, still not sure about this one though and it's not readily available in the UK. Thanks again. Super test!

    Martin

    ReplyDelete
  11. Anonymous6:39 PM

    Hi! have you tried the older version which is a full time F2.8 18-50 macro( non os)?
    If yes, which is better?

    ReplyDelete
  12. The 18-50 f/2.8 isn't really an older version of this same lens, it's a totally different lens. I haven't tried it, but it's probably a little better optically. It is an EX lens. It's also more expensive.

    You do give up the OS with it, though. The tradeoff is you get a couple more usable stops at 18mm with the OS lens, but probably not at 50mm (since it only opens to 4.5), with somewhat worse optics than the 2.8 lens.

    I didn't want to spend $450+ and I have more of a need for low light performance at 18mm, so for me the new OS lens made more sense.

    The 18-50 f/2.8 lens is also a lot heavier, like twice the weight. And the 2.8-4.5 is already pretty heavy.

    ReplyDelete
  13. btw, Sigma's pattern seems to be to slowly add OS to their old lenses over time while making some minor changes or improvements, so I'll bet there will be an 18-55 f/2.8 OS EX lens at some point. But it will be really expensive. I have their old 135-400mm non-OS lens, which cost me $600, and the new version of that lens which only adds OS and maybe a new glass coating is something like $950.

    I think you can take whatever the current lens costs and add 30% onto it when they add OS.

    ReplyDelete
  14. Anonymous8:07 AM

    Thank you Jeff for taking time. Btw, I'm Lyza, a lady photographer here in the Philippines, actually I look in the same way, I've been waiting for the OS version since it was introduce a few months ago on the web, but it isn't available yet here in our country. I have a wedding to cover by the mid of July, so I guess I'll be lucky if the OS version will come out before the schedule, if not, I'll be taking the EX instead.

    Bye!

    visit my works at: emcportraits.multiply.com

    ReplyDelete
  15. I don't think you will be disappointed in the EX lens! I'm sure most photographers would think of the EX lens as a step up. I would also be surprised if the EX lens was not sharper at f/2.8 - that's really the one thing I'm sort of disappointed in with the OS lens.

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  16. by the way, very nice photos! I'm a little embarrassed by my photos in this post now :) though they weren't intended to be artistic.

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  17. Anonymous9:49 PM

    Thanks for your samples. Very helpful. But about the OS on EX lenses, dont bet on it, at least not on zoom constant aperture. Their reply to me stated that they do not use it on EX lenses... My request (question) was for OS on already existing lenses...

    Carlos Roncatti

    ReplyDelete
  18. Anonymous8:45 PM

    Thanks very much Jeff, you're a big help in my floating decision . I shoot but not very well in technical specs.

    Just keep on posting your new reviews, I'm sure many will find them useful. Bye!

    ReplyDelete
  19. Anonymous8:45 AM

    I got a copy of this lens from Amazon to try out, and I completely agree with Jeff's pros and cons.

    The build quality and image stabilizer performance are very good for a lens of this price. Center sharpness is quite good, certainly better than the kit lens.

    However corner sharpness (in fact anything much further than 1/2 way from the center) is rather poor, even at f/8 to f/11. There's quite a lot of chromatic aberration and it seems like there's some kind of radial blurring or smear. I actually checked several times to see if I'd got something smeared all over the front.

    In the end, I decided to return this to Amazon, and I'm thinking about getting the 2.8 EX Macro version instead, since the sharpness looks much better. I will miss the useful image stabilizer, but my main use will be for landscapes, and the DC OS version is just not sharp enough away from the center for that.

    ReplyDelete
  20. Anonymous8:50 AM

    I should add that the above comments refer to the Canon mount version on my EOS 350D, and by 'kit lens' I mean the 18-55mm f/3.5-5.6 II non-IS). Overall I was very disappointed with the sharpness vs. my Canon 28-105mm 3.5-4.5 II USM. Hopefully the Sigma 18-50 2.8 DC EX Macro will be what I'm really looking for.

    ReplyDelete
  21. Anonymous8:11 AM

    Yeah definitely! After having my Sigma 18-50 ex dc macro on my Canon 450D, I certainly get sharp photos!

    ReplyDelete
  22. Anonymous5:10 PM

    Yeah definitely! After having my Sigma 18-50 ex dc macro on my Canon 450D, I certainly get sharp photos!

    ReplyDelete
  23. Excellent, thanks! I've been wanting to get something that would be good indoors in low lighting. If what you're saying is true, then it should have 2.8 up to about 28mm. I'd been assuming that was the case, but wasn't sure. Thanks!

    ReplyDelete

About This Blog

This is increasingly not a blog about Alphabet City, New York. I used to live in the East Village and work on Avenue B, but I no longer do. Why don't I change the name if I'm writing about Japan and video games and guitars? Because New Yorkers are well-rounded people with varied interests, and mine have gone increasingly off the rails over the years. And I don't feel like changing the name. I do still write about New York City sometimes.

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