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Sigma 18-50mm F3.5-5.6 DC

Reviews Views Date of last review
7 23,668 Mon December 1, 2014
Recommended By Average Price Average User Rating
43% of reviewers $57.50 5.43
Sigma 18-50mm F3.5-5.6 DC

Weight: 250g /8.8 oz
Length: 62mm/2.4 in
Filter Diameter: 58mm
Min. Focus: 25cm/9.8 in
Max. Magnification: 1:3.5
Diagonal FOV:
Horizontal FOV: NA
Horizontal FOV on Digital: 69.3 - 27.9 degrees
Min. Aperture: F22
Optical Construction: 8 Elements in 8 Groups
Autofocus: Yes, screwdrive
Mount Type:
Price History:

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Site Supporter

Registered: November, 2014
Location: Jacksonville, Florida
Posts: 273
Lens Review Date: December 1, 2014 I can recommend this lens: Yes | Price: $35.00 | Rating: 9 

Pros: Inexpensive, good image quality
Cons: It feels cheap (but it isn't)
Sharpness: 8    Aberrations: 8    Bokeh: 8    Handling: 9    Value: 10    Camera Used: K-m, K-3    Autofocus: 8   

I have shot thousands of photos with this lens over the past two years. I used it as my general walking around lens and had no problems with it. I don't expect the quality that you would get from a high end prime lens and that's not what this lens is capable of delivering. This is a good general purpose lens which you bring with you if you don't want to damage your better gear. This is the kind of lens that I throw in the backpack and take with us on a hike, to an indoor stadium event, or to some place where I think inclement weather is possible.

I would recommend this lens if you want something inexpensive to bring with you on vacation or a hike through the woods. If it falls then you may break the lens but you won't break the bank. I would also recommend it as a gift for a beginning photographer who has a Pentax camera body but needs a starter lens. These Sigma lenses are plentiful online and in the classifieds. It doesn't deserve a bad reputation.
Site Supporter

Registered: February, 2011
Location: Melbourne, Australia
Posts: 1,251
Lens Review Date: August 14, 2011 I can recommend this lens: Yes | Price: $70.00 | Rating: 5 

Pros: Cheap, versitile Zoom range
Cons: IQ, Bulid, AF
Sharpness: 5    Aberrations: 3    Bokeh: 2    Handling: 6    Value: 7   

I bought this lens with my k-7 just so I could start taking pictures straight away.

Considering the price I paid for this I never had huge expectations.
It struggles in the IQ and needs to be stopped down to get some sharpness. And color rendition quite poor in my opinion (a bit washed out). This is a sample photo ISO 800 F4.5 1/800 sec

The build is mediocre, with a bit of free play in the focus ring. the zoom ring is a little stiff for my liking but i will point out it feels inconsistent throughout the zoom range, some parts stiffer than others.

The Lens hood blocks the focus ring when reversed and 50-70% of zoom ring.
The lens barrel rotates when focusing so using Polarizing filters is a pain!

Auto Focus is a little slow, although I use manual focus for a lot of my shots. But then again I use this more as a scenery lens.
AF is very noisy and clunks at each end of the range when searching in low contrast or low light (low light being anything worse than an dull day)

I Hope this review helps you to make the correct decision regarding lenses.

Edit: Removed dead links, changed rating after a bit of practice I find I can achieve some reasonable results.
Community Manager
Loyal Site Supporter

Registered: March, 2007
Location: Toowoomba, Queensland
Posts: 22,720
Lens Review Date: July 24, 2010 I can recommend this lens: No | Price: $80.00 | Rating: 4 

Pros: Cheap price
Cons: Cheap IQ and build

I've used worse lenses but this is definitely my least inspiring AF lens ever owned. Had it for less than a month before I decided to go with the DA 18-55 as my first lens. I'm glad I did - this lens just pails in all aspects and needs perfect conditions to render decent images.

AF is very loud, build quality is very ordinary, image quality is very dull and having such a lens is degrading to the experience of owning and photographing with an SLR camera.

Just not worth it - go for Pentax's kit lens instead if you have the choice.
Site Supporter

Registered: January, 2009
Location: East Bay Area, CA
Posts: 5,863

1 user found this helpful
Lens Review Date: January 27, 2009 I can recommend this lens: Yes | Price: $45.00 | Rating: 7 

Pros: compact size, decent sharpness at f/8-11
Cons: low quality, slow AF
Sharpness: 8    Aberrations: 7    Bokeh: 7    Handling: 9    Value: 9   

I am new to DSLRs...

i got an array of lenses with my used Pentax *ist DL and prior to shooting with any of them, looked up some reviews online and somehow concluded that this lens should never be attached to my camera because it is supposedly very bad. Thus, i have been using my 18-55 Pentax kit lens instead, with OK results.

Well, today was a bright clear day and i was doing some comparisons of my zooms, to get a feel for their performance. I fixed my shot on a woven nylon shade sail (patio cover) illuminated by sunlight and included some deep blue sky and set my aperture at f/8 and took several shots at different FLs throughout the zoom range using AF for all. i did this for all 5 zoom lenses (Pentax, Quantaray, 3 different Sigmas). Then i repeated at f/11 for more data points. Later, i took all the shots and put them in order by FL (from the EXIF data) so i could not tell which photo was made by which lens. I spent time reviewing all and even made notes about sharpness, CA, and color. I zoomed images to compare pixels and got a good feel for what was better or worse. then, using the serial numbers of the shots, i matched up the lens names to each and made some interesting observations.

In my photos, the Pentax DA 18-55m/3.5-5.6 kit lens was very clearly beaten by this Sigma lens, not only at both ends of the focal length, but at all the in betweens as well. The Sigma was sharper and had better color. Both showed chromatic aberration to some degree.
I have the pics which tell all and if i can figure out how to post 'em here, can do so. This was just a single test, so other performance characteristics were not measured, though tonight i will take some low light shots as well.

Anyhow - i may go ahead and use this as my "everyday" short zoom and bench the Pentax kit lens.

Conclusion: this one may not be as bad as you've read. one thumb up.
Veteran Member

Registered: January, 2008
Location: Yurp
Posts: 4,669

1 user found this helpful
Lens Review Date: January 4, 2009 I can recommend this lens: No | Price: None indicated | Rating: 5 

Pros: Cheap!; light; reasonably well put together; has proper manual focus ring; comes with lens hood; decent macro capabilities
Cons: below average optical performance; front element rotates

Good if you absolutely feel the need to have a kit lens. Not as good as the Pentax DA 18-55; but I have found it better than other kit lenses (Canon/Nikon come to mind).

Use as a last resort only.
Inactive Account

Registered: June, 2008
Location: Brisbane Australia
Posts: 1
Lens Review Date: June 24, 2008 I can recommend this lens: No | Price: None indicated | Rating: 3 

Pros: Cheep as is in free
Cons: Flares badly, distorts upper third of the frame, cheep and nasty

If it wasn't used as a kit lenses and I couldn't get a DA18-55 at the time I would not have got it.

The Bokeh is not bad, however its not pretty, the distortion in the upper third of the frame is not noticeable till you do a portrait converging vertical shot.

The colours are a bit punchy and bright however the bleeding and the flairing is just not acceptible these days.

On the good side when you sell your next camera body you will have a autofocus lense to ship with it
Veteran Member

Registered: February, 2008
Location: Hawkesbury
Posts: 421
Lens Review Date: May 25, 2008 I can recommend this lens: No | Price: None indicated | Rating: 5 

Pros: Cheap (sometimes they give you money to take it), sharp enough to be usable, has it's own "character"
Cons: Cheap, Poor colour rendering, Contrast a little low, rotating front element
Sharpness: 8    Aberrations: 5    Bokeh: 5    Handling: 3    Value: 9   

It seems people are too embarrassed to admit using this lens so here goes.
I tried this lens on loan. Took some usable shots but colour balance was poor, particularly in lower contrast situations.
Rotating front element makes polariser use impractical. Build quality is cheap but it doesn't feel as though it is going to fall apart.
Sharpness is satisfactory.
There is significant colour separation at the corners.
Bokeh while nothing special, is not particularly ugly either.
Focus "fallout" is actually pretty good, possibly better than my copy of DA18-55.
Marginally outperformed by my copy of the DA18-55 in most situations except 18mm where neither is great. The Pentax handles a lot better (particularly with the recently added weather resistance).

If you get this lens for free and tend not to use this range of focal lengths much, then it is usable and worth having. The cheap Pentax option feels and mostly shoots better but does cost a little more and still has flaws.
Almost tempted to recommend because it is so cheap in a world where lens prices are getting silly, but that rotating front element and unavoidable green cast make me look this gift horse in the mouth.
I suspect, as with all Sigma budget lenses that the potential is there to get a good copy. Good luck.

Sample at 50mm and minimum focus:

1:1 crop:

Sample taken on a K10D.
Add Review of Sigma 18-50mm F3.5-5.6 DC

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