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View Full Version : Digital Lenses Sigma 18-50mm f2.8 Macro Lens



tspore
10-09-2006, 05:12 PM
Lens Construction 15 Elements in 13 Groups
Angle of View 69.3 - 27.9 degrees (SD format)
Number of Diaphragm Blades 7 Blades
Minimum Aperture F22
Minimum Focusing Distance 20cm/11.0 in.
Maximum Magnification 1:3
Filter Size Diameter 72mm
Dimensions: 3.4 x 3.1 x 3.1 inches
Shipping weight 2.0 LBS
Weight: 15.9 oz
Date avaliable Oct 4th, 2006
Sigma website (http://sigmaphoto.com/lenses/lenses_all_details.asp?id=3320&navigator=6)
price ~$400
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4180

Cogsci
11-19-2006, 08:37 PM
The mentioned specs refer to the old version of this lens built for other mounts than 4/3s. The new version has a min focal dist. of 20 cm, filter size of 72mm, ...
As of yesterday Adorama and B&H list this lens as in stock. Price $418.

ziggy
12-25-2006, 06:41 PM
Description, a "normal" zoom, constant aperture.
18-50mm 2.8

Specifications as above.


Cons compared to competitors (14-54 Olympus)

Not weatherproof

not as wide - 18mm compared to 14mm

Manual focus is not by wire - requires that the camera is only set to AF or MF and the switch on the lens only be set to the corresponding setting, negating the af+mf settings in camera, however in use this is not a big issue, and I am finding using the lens switch to fine tune focus manually is a fine workaround, however auto focus is fast and accurate.

Slightly different colour rendition to Zuikos but hard to call this a con as colour is accurate
Pros
Constant aperture min 2.8

Very sharp, I do not have a 14-54 to compare , but would possibly rate it slightly higher. Very sharp at 2.8, but closing one stop improves it even further.

Works extremely well with 1.4 TC , the aperture loss seems to bring improved performance wide open, similar to closing the lens one stop

Macro is probably slightly better than 14-54 , but not a lot in it, however adding 1.4tc increases magnification , will do some test shots when time is free.

I guess you could call manual focus a plus as well as a con.

Some testing to follow, however I feel real world usage is far more conclusive than test charts, and in use I like it a lot

.oldboy
04-22-2007, 10:08 PM
pros: constant f2.8 throughout the zoom range. less bulkier (shorter) compared to 14-54mm although specs say its a tad bit heavier. lens cap comes off easier than 14-54mm caps. image quality comparable or better than 14-54mm - SHARP!. visually the large lense in the front looks good and i like the hood better than the 14-54mm. Easily accessible switch for AF-MF. Nice lock option for zoom. Macro ability!

cons: not weather proof, looks like dust can get in there easily (just watch out for this!). Sometimes the AF-MF switch can be accidentally tripped and disables the AF.

Overall the image quality looks great. Check out some of my test photos:
http://www.flickr.com/photos/coolinbox/sets/72157600096348330/

olyinaz
04-25-2007, 09:25 PM
to me, and faster at 50mm than the Zuiko. I've got both and while I've not tested the two head to head with a controlled subject, I do seem to be coming to the conclusion that the Sigma is sharper than the Zuiko.

I have been thrilled with my 11-22 and 50-200 as far as sharpness is concerned but my ZD 14-54 has not lit my hair on fire, thus my purchase of the Sigma. Maybe it's wishful thinking at work here but I can't complain at all with images like this:


http://www.pbase.com/olyinaz/image/77759470/original.jpg


And look at the bokeh at f/5.6 - much better than the Zuiko I'd say.

Still, I'm concerned about flare and contrast issues and I'd like to hear from others re. their experiences. At times it seems like that big lovely front glass allows so much light in that it bounces around inside the lens (which does not seem to be as well blacked as some lenses I've got) and can cause a loss of contrast due to a reflection. Perhaps that's all in my mind as well...

Here's a gallery of shots just for a few more examples: http://www.pbase.com/olyinaz/sigma1850

Best,
Oly
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Maddogmd11
10-31-2007, 07:42 PM
Pros: VERY SHARP. Reasonable Price. Almost no distrortion throughout the range of the lens. Can focus from as close as 10 inches for Macro work.

Cons: A little heavy. I have found that sometimes holding the camera my fingers get in the way of the focus ring when the lens is in autofocus. Not a big deal but you have to be aware of it. Zoom is alot stiffer and takes some getting used to.

Bottom line is that this is a great lens once you get use to it.

http://www.pbase.com/maddogmd11/image/87611150.jpg

ghenton
11-02-2007, 09:58 AM
Sigma 18-50mm DC EX f2.8 macro
not to be confused with the Sigma 18-50 f3.5-5.6 DC

pros

a little less money than a Oly 14-54
Constant aperture min 2.8
Great color
Great contrast
Great detail
no noticable Vignetting
no noticable Distortion
no noticable Chromatic Aberration
Solid Well Built
fast focus
Very Good bokeh
Very good Macro

Cons

Miss the extra range 14mm (14-54) or 12mm (12-60) would bring
manual focus ring moves in auto mode
doesnt work with the oly ex25

I really like this lens, the extra brightness and great sharpness/contrast/color this lens has over the kit lens, it is worth the money. I do miss the extra width the kit lens (14-45) had but I cant give up the quaility of images that I get. I will get the width by picking up a 11-22. If I was to do it agian I would wait to get the 12-60 as that lens will cover the range provided by two lenses and work out to less money.

olyinaz
11-04-2007, 08:00 PM
Let me add after some time now that this lens is indeed very very sharp anywhere near the middle (comments obviously refer to my copy - your mileage may vary) but it's a bit soft at the corners when wide open. By f/4 it's very sharp and this lens holds that sharpness going past f/16 which is very helpful for macro shots. Most of my Zuikos by comparison are starting to get soft going past f/11.

I've also got the Zuiko 12-60mm lens in hand now and, frankly, it's far better than any of these other lenses but alas it costs twice as much (or more). Still, I can recommend this lens as long as one understands the strengths and weaknesses and those will work for them.

Best,
Oly