18-35mm Sigma Art Lens

[Abitconfused]

I recently acquired the Sigma 18-35mm Art lens and I am having limited success with it. Focus seems slow or inaccurate on my D7100 especially in lower light. The sharpness is not what I expected from reviewers. Does anyone else have this lens? If so, what have you learned?

[Abitconfused]

OK This is my problem: http://www.dpreview.com/lensreviews/sigma-18-35-1-8/6

[Stagecoach]

Ed, have you put the lens on a tripod, used mirror up, remote release, adjusted for correct exposure and shot at a subject that has good edges for analysing it's performance with respect to sharpness?

I recently purchased a lens that a number of reviews said was not very sharp, others said it was decent and one ridiculous comment made here was that if I was to buy it for £35 it would be a 'good' buy. As far as I'm concerned it produces adequately sharp images for what I want, but I put sensible criteria to what I expect.

You say you are having 'limited' success, does that infer that you are having 'some' success?

Grahame

[Abitconfused]

Well I went out again and made certain that my one focus point (centered) was in an area of high contrast and then recomposed. These results were much better. I took similar photographs with my Canon Mark ll 24-70mm and after comparing eight shots I concluded that the resolution and quality of the images were about identical.





So if I am not actually adding a superhero of a lens to my collection, then why bother keeping the lens at all? Well I am starting to grow fond of the FOV. I like the way it feels and handles.

And often it is surprisingly good...



Especially for a cropped sensor.

I TOTALLY agree that often we...me neglect best practices for good capture. A bargain lens in the hands of a craftsman is better than the best lens in the hands of those who neglect the details of the craft of photography.

[Donald]

A bargain lens in the hands of a craftsman is better than the best lens in the hands of those who neglect the details of the craft of photography.

Never a truer word was written.

[pnodrog]

The shots on the left of your comparison seem to have better contrast and sharper.

Seems like a good lens and one well worth working with its idiosyncrasies.

[Black Pearl]

The example with the halloween head is captured at 200% magnification - why?

There is no practical reason to go well beyond pixel peeping enlargements to see if a lens is usable. Also from the example you presented it looks far superior even at those mad percentages to the one from the Canon. You should also bare in mind that very few lenses ever made perform at their best wide open.

[aliraza8]

acquired the Sigma 18-35mm Art lens and I am having limited success with it. Focus seems slow or inaccurate on my D7100 especially in lower light. The sharpness is not what I expected from reviewers. Does anyone else




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[JR1]

why/what is an "art" lens for, really...

Is it a lens made by a chap called Art at Sigma (sorry)

[xpatUSA]

. . . The sharpness is not what I expected from reviewers. . .

Pixel peeping can sometimes help, especially with a good utility. The house shadows are instructive, IMHO:



We see that the captured brightness goes from 10% to 90% in less than two pixels. Considering that the D7100 has 3.9um pixel pitch, two pixels is a pretty good resolution for that lens in that spot- somewhere in the region of 65 lp/mm in the image plane.

Then, looking in the shadow area, the Bayer mush is remarkably muted - indicating that some noise reduction may have been applied to the image, which can soften edges.

All in all, the lens sharpness looks pretty good to a peeper

Was this image a 100% crop from the original 6000x4000px image? If not, my results are less valid.

[Abitconfused]

Peepers Unite. We have nothing to lose! (Disclaimer: Does not apply to our sanity, finances or personal hygiene).

[xpatUSA]

why/what is an "art" lens for, really...

Is it a lens made by a chap called Art at Sigma (sorry)

lol.

http://www.sigmaphoto.com/lenses/art-lenses/

Art is top of their new line of lenses. The 18-35mm is particularly well-regarded.

[xpatUSA]

Peepers Unite. We have nothing to lose! (Disclaimer: Does not apply to our sanity, finances or personal hygiene).

But was the image a 100% crop from the original 6000x4000px image, un-obfuscated by re-sampling and post-processing?

[JR1]

lol.

http://www.sigmaphoto.com/lenses/art-lenses/

Art is top of their new line of lenses. The 18-35mm is particularly well-regarded.

Thanks, so no need to change my Nikon 14-24 then, nothing to do with soft focus, or curved iris blades, just the name

[JR1]

Pixel peeping can sometimes help, especially with a good utility. The house shadows are instructive, IMHO:

We see that the captured brightness goes from 10% to 90% in less than two pixels. Considering that the D7100 has 3.9um pixel pitch, two pixels is a pretty good resolution for that lens in that spot- somewhere in the region of 65 lp/mm in the image plane.

Then, looking in the shadow area, the Bayer mush is remarkably muted - indicating that some noise reduction may have been applied to the image, which can soften edges.

All in all, the lens sharpness looks pretty good to a peeper

Was this image a 100% crop from the original 6000x4000px image? If not, my results are less valid.

OMG, spend more time out taking photos

[xpatUSA]

Art is top of their new line of lenses. The 18-35mm is particularly well-regarded.

Thanks, so no need to change my Nikon 14-24 then, nothing to do with soft focus, or curved iris blades, just the name

Glurk . .

OMG, spend more time out taking photos

I know I should take a comment like that in good humor - but to put a good amount of of work into downloading an image, opening it in a utility, taking a screen capture, uploading it to CiC and providing some thoughts . . . all of that, only to get a demeaning crack like that in response is less than enthralling, IMHO.

Queen Victoria said it best

[JR1]

Glurk . .



I know I should take a comment like that in good humor - but to put a good amount of of work into downloading an image, opening it in a utility, taking a screen capture, uploading it to CiC and providing some thoughts . . . all of that, only to get a demeaning crack like that in response is less than enthralling, IMHO.

Queen Victoria said it best

Note to me, "remember to ass emoticons to comments"

I should have added this to my comment


What I meant, in a light hearted way is, it never fails to amaze me that people spend so much time trying to "pull apart" and do down images by "P Peeping" and 100/200/300x magnifying, chimping and more when in fact they would have more fun taking photos.

It is like computer nuts (I was one once) spending more time running sysanalysis software, defragging, peak tuning than using the gear just to get 1 more split second of speed from it.

[Stagecoach]

when in fact they would have more fun taking photos.

This of course begs the question Jeremy as to how you know it is a 'fact' that they would have more fun taking photographs.

[Abitconfused]

I have enormous fun trying to stretch every last living bit of potential out of lenses and cameras. This includes not only examining ways to enhance resolution but also contrast, color and something mysterious I guess you can call depth. Consistent results also ranks up there. I find the net result of such activity better prepares me for those Kodak moments when they pass or almost pass by.

My conclusion with regard to the Sigma 18-35mm is that it is a keeper. However, I must be certain to locate the focus point (I almost always use AFS Auto Focus Single with one centered focus point) over an area rich in contrast, press the shutter halfway, recompose and ease that shutter down. I wish the lens was both DX and FX because I plan to Buy a Nikon FX 810?? as soon as I win the lottery (tonight would be nice).

[Abitconfused]

In closing, one last shot with the 18-35mm...



Should have stuck with this. It understands me