Simple tests: Sigma 30mm/1.4 vs Nikkors

Basic tests to see for myself, using visual inspection, whether the Sigma

30mm/1.4 was truly what it claimed to be. These tests were done using D2X, on

tripod, MC-30, MLU, untouched images, Nikon CaptureNX.

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It's pretty clear on test charts, when wide open, the Sigma 30mm/1.4 has

<li>distinctly visible chromatic aberration under normal lighting

<li>distinctly visible spherical aberrations (double edges)

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It appears that the aberrations and resolution did not really diminish until

f/2.5 and beyond. So, is the f/1.4 really for show, you tell me. At f/2.3, the

image is as good as it any Nikkors. I have included 2 other images shot with

Nikkor 50mm/1.4 and 35mm/2 (all opened wide) for your comparison to see the

difference in aberration levels.

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<b>DISCLAIMER</b>

This test was done for my own personal fulfillment and shared on a friendly

basis. Samples of this can vary so, yours may be different. Point source

lighting were not done in this test, so coma aberration is not determined here.

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<img src="http://farm3.static.flickr.com/2065/2188208116_94167c9a96.jpg">

Sigma 30mm/1.4 @ f1.4

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<img src="http://farm3.static.flickr.com/2372/2188168612_9529897e2f.jpg">

Sigma 30mm/1.4 @ f1.6

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<img src="http://farm3.static.flickr.com/2316/2188168688_6edc04021d.jpg">

Sigma 30mm/1.4 @ f1.8

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<img src="http://farm3.static.flickr.com/2230/2187380829_efd019eed7.jpg">

Sigma 30mm/1.4 @ f2.0

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<img src="http://farm3.static.flickr.com/2348/2188168860_ce20f3a099.jpg">

Sigma 30mm/1.4 @ f2.5

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<img src="http://farm3.static.flickr.com/2317/2188168966_f5c7765f7f.jpg">

Sigma 30mm/1.4 @ f3.2

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<img src="http://farm3.static.flickr.com/2048/2187383099_cfa2c58793.jpg">

Nikkor 35mm/2 @f2.0

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<img src="http://farm3.static.flickr.com/2195/2187385809_a4d47301bb.jpg">

Nikkor 50mm/1.4 @f1.4

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Arthur had the 35mm/f2 image twice. I deleted one of them. -- SC

The higher-res and EXIF info can be found in this link

 

>It appears that the aberrations and resolution did not really diminish until f/2.5 and beyond.

 

Sorry, I meant to say that the aberrations did not diminish & the resolution did not improve until f/2.5 and beyond.

In actual low-light shooting situations these problems with the Sigma prove fairly inconsequential. I don't think any lens at f1.4 is going to be without some optical compromises. I reiterate that the main problem with this lens is the inaccuracy of the autofocus mechanism.

Thanks for sharing, Arthur. The 35/2 wide open isn't without problems on the D2X, it seems.

 

If you could, would you try it on the D3 (APS-C crop mode) and let us know how it fares there?

 

I found a cool demo on Chromatic Aberrations here: http://www.youtube.com/watch?v=KZl9Cfhp-5o&NR=1

 

Douglas, Auto focus problems- wouldn't that be camera/light dependent?

 

I have had excellent attrition rates on a D40x compared to a D70, for example.

I have the two Nikkors here but not the Sigma. I picked the 35mm f/2 over the sigma lens only because of weight considerations. Although seeing how much nicer the Nikkor performs at f/2 than the Sigma stopped down to f/2 does, I'm all the happier with my decision. It is rare that I want wider than f/2 and also specifically want a 35mm lens. If I want wider than f/2 I can usually happily switch to the 50 f/1.4.

 

The difference between the 50 f/1.4 lens and the 30 f/1.4 lens at f/1.4 is simply outstanding. Maybe you have a poor sample of the Sigma 30mm lens?

 

Also, you have two images labeled: "Nikkor 35mm/2 @f2.0". I assume the second one is f/2.5?

>The difference between the 50 f/1.4 lens and the 30 f/1.4 lens at f/1.4 is simply outstanding. Maybe you have a poor sample of the Sigma 30mm lens?

 

Yes, that's in my disclaimer. :) Based on my experience, Sigma lenses tend to have a wider variation among the samples. So, mine is, possibly, not representative of the average.

Just to add, my copy of the Nikkor 50mm/1.4 was made in China. :)

Arthur, Seriously, I am looking for 1 (or two) more samples of the Sigma 30/1.4.

 

If you want to sell yours, please drop me a line. Thanks.

I tend to agree that no f1.4 lens is going to be really excellent at f1.4. If you must use an f1.4 lens wide open, you have to accept some compromise.

 

Arthur, how far was the camera from the subject in those tests?

>Arthur, how far was the camera from the subject in those tests?

 

They were about 5 ft away.

>Arthur, Seriously, I am looking for 1 (or two) more samples of the Sigma 30/1.4.

 

Why are you getting so many copies of the same lens?

Oh, one reason, the paint on the polycarbonate housing comes off easily.

 

I had a 105/2 DC Nikkor with similar polycarbonate shell but that paint is a strong Nikon paint and does not rub off.

 

Another reason is that I would like to dissect a sample for a special project.

>Another reason is that I would like to dissect a sample for a special project.

 

Whoa ... baby ... that sounds painful ... ouch! :)

The Sigma 30mm f1.4 seems to have front focusing troubles with the D200 and D300. I chatted with the woman who runs the tech support office at Sigma. Canon-mount lenses have troubles, as well. The focusing problems are (she claims) solvable, but sometimes they actually need the camera body in order to resolve the problem. This seems like a lot of trouble to me.

 

And yes, Sigma remains notorious for quality control issues with lenses, which is too bad, considering that some of their lens designs are very good.

The rear cap that comes with this lens is very bad and should be replaced with a genuine Nikon cap as well.<div></div>

What portion of the frame are these crops from?

>The Sigma 30mm f1.4 seems to have front focusing troubles with the D200 and D300.

 

Doug,

 

Focusing problems results in soft images, which in the case of the f/1.4 shot, it is soft but it does explain the purple fringing and doubles edges. Somehow, the Extra-low Dispersion (ELD) element is not good enough to correct the CA at f/1.4. At smaller aperture, the ELD worked fine.

 

I also have another image (somewhere) which depicted very clearly how bad the coma issue was. The coma issue raised a big question about the aspherical element's ability.

I found the image that shows coma ... notice that point light source are pretty round at the foreground but as we sweep our eyes to the rear, they becomes more and more butterfly shaped. Click on image to get details.

 

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<a href="http://www.photo.net/photo/6831311

"><img src ="http://d6d2h4gfvy8t8.cloudfront.net/6831311-md.jpg

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Vivek, did you call Sigma and complain about the chipping paint? On my Sigma, to forestall

this problem, I placed a rubber "friendship" bracelet around it....

Zenon, Nah, that will perhaps distort the bracelet as well. I value my friendship bracelets.

 

Arthur, Cool shot. I wonder how this would look like had it been shot wide open and with the added CA and fuzziness.

Arthur, have you ever tried the Sigma 28mm f1.8 on the APS-C Nikon D200?

This is a FF lens that should perform better on the cropped format since it is operating in the center sweet spot. At the time that Sigma came out with it was the best of its series of faster than normal wide angle lenses. The extra few degrees wider would make this lens effective focal length is 42mm a very useful street lens focal length.

Here is a handheld wide open with CA and comas....

Vivek, you're absolutely right on that rear-cap issue -- it will only go on if you line it up absolutely exactly with the 'open' label aligning with the lens release area. I have a sigma 150mm f/2.8 macro and the rear-cap is awful and has been replaced with a Nikon one. I also replaced the front cap as it was objectionable too (can't be removed with the hood attached).

Nice test Arthur, thanks for sharing.

 

BTW, how big is the test chart (or rather what distance to the camera)? Did you bracket the focus?

 

Peter