full sized pics taken by sigma 20mm f1.8?


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wind30

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Mar 14, 2004
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Hi people,

does anyone know of any full sized pics on the web taken by sigma 20mm f1.8?

I just for my new 20mm f1.8 and I find it very soft at f2.

here is a sample pic. It is a hazy day so the edges blur are due to the morning haze.

http://www.pisduck.com/d7d/pict0738.jpe

any comments?

Taken handheld shutter speed was very fast so should not have shake
 

bigmouse

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I remember reading some review of the 20mmf1.8. This lens is known to be soft at f1.8 to about 2.8. That is why I chosed the 24mm. So far quite satisfied with it.

The landscape snap u took at F2 is expected to be soft with this lens. Avoid <F2.8 unless no choice.

http://www.photo.net/sigma/sigma20-vs-canon2035

Taken at f1.8 & f10 with 24mm. Focus point at left "man".



 

wind30

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ya the 20mm is rather soft at f2.

Do U have any 100% crop or full size pictures taken with your 24mm f1.8?
 

bigmouse

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wind30

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your 24mm at f1.8



mine 20mm at f2

 

bigmouse

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Don't expect too much wide open. Even 50mm f1.8 also soft wide open. It helps if you compose subject at centre when wide open. Somemore Sigma QC is quite loose.

Setting above f2.8 improve a lot. Sweet spot is f8-10. If your pics at above f2.8 still soft then maybe its a bad copy.

Most important for a new lens is does it front or back focus on your cam.

Some of my past posts taken with 24mm. (ambient light)

http://forums.clubsnap.org/showthread.php?t=121419

http://forums.clubsnap.org/showthread.php?t=121225

With ext flash at sweet f-spot.
http://forums.clubsnap.org/showthread.php?t=125441
 

wind30

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it is much better at 2.8. There is a lot of improvement from f2 to f2.8 but not much already from f2.8 to f4.

One more thing I like about this lens is that it can do macro :) sort of, a wide angle lens which can focus very close up.

your pic of the granny and kid is VERY SHARP :bigeyes:

Must try some shots are f8- f11 and PSed it to see if I can get as sharp.

The focusing is spot on for my lens :)
 

marcwang

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#8
I had the Sigma 20mmf1.8 and I have done extensive testing on the lens. It is a decently sharp lens stopped down, but no more sharper than a Nikkor 12-24 and marginally sharper than the 18-70 kit lens at its peak.

F1.8 should be avoided, unless camera shake is an issue.
Lens improves alot by f2.8 in the centre, but in the corners its still soft.
Peak performance comes abt around f5.6, but even then, it is only as sharp as a Nikkor 18-70mm and 12-24 mm at f8. Do not use the lens above f16. F22 the softness is similar to f1.8.

This lens is good for indoor and low light photography. If sharpness is your thing, it will satisfy 90% of the people out there... I wouldnt say it is the sharpest 20mm lens around.
 

hongsien

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Mar 11, 2002
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#9
Firstly: many lenses are soft wide open.........

Secondly: big openings are more for ease of manual focusing.........

Thirdly: hazy days are no good subject to do testing..........

Good luck!

HS
 

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