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02-07-2008, 08:07 PM   #1
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Sigma 18mm f2.8 vs Pentax DA21 f3.2 : pics/comments inside!

LBA in the worst way, picked up a sigma 18mm f2.8 from a fellow forumer, "dkittle " (my 2nd lens purchase from him, haha)

this is a manual focus but auto-aperture lens

this makes it the 3rd lens in my wide angle line up, along with a 16mm fisheye and the DA21, with a sigma 10-20 on the horizon....


the point of this purchase was to see if the sigma could hold its own against the pentax, not only does it have more field of view (3mm counts at the wide side), its faster, and compatable with a film camera.

its only downside is that its big and clunky





now for pics, these are barely processed with a slight touch of sharpening, personaly i would never leave photos as is, too bland, but anyway..

this is off a tri-pod in low light conditions, using ISO 200 aperture priority, all done in RAW and converted to jpeg through lightroom.

i will do an outdoor test some time later when the snow melts and my hands dont freeze


SIGMA F2.8



PENTAX F3.2





SIGMA F4



PENTAX F4





SIGMA F8



PENTAX F8





SIGMA F16



PENTAX F16






here are pictures at wide open that i took some care in fixing up using a whacky pre-set that i have

SIGMA F2.8


PENTAX F3.2



02-07-2008, 08:08 PM   #2
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for the pixle peepers, here is the gallery, you can download the originals, go nuts

Zenfolio | Serge Guschin | Sigma vs Pentax
02-07-2008, 08:11 PM   #3
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its quite obvious that the sigma is soft focus compared to the DA, but pixle peeping on my end reveals little difference in detail, i can read the fine print on the cigarette box just as well on both lenses.


i guess the outdoors test with lots of light might show a different view..
02-07-2008, 08:48 PM   #4
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From these shots the first 2 things I notice are the colour quality of the Pentax is much better and deeper/richer. But the camera seems to handle the exposures differently with each lens. Sigma might be +1/2 EV? Also the Pentax handles glare and hotspots better. Must be the SMC coating?? The front edge of the table in the Sigma shots are all blown out in the glare. The Pentax doesn't suffer that issue much at all. Detail seems better as you said..

Congrats on getting banned!! So what did you say?

02-07-2008, 09:01 PM   #5
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I noticed the color rendition of the Sigma lens as well. It's certainly not all that pleasing compared to the DA 21/3.2 Limited. However, I'm noticing that pictures taken with the Sigma are also comparatively brighter, so I'm going to be that some shots were overexposed. Each lens behaves differently, so that's no fault of your own. Also, detail is better with the Pentax lens. How much does the Sigma costly? I just want to know what we're dealing with.
02-07-2008, 09:28 PM   #6
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its interesting that the exposures were different even though the apertures were the same (other than the first two)

i might do it again and do fully manual mode to eliminate that little bit.

maybe it has something to do with the physical larger size of the front lens element of the sigma, more side rays getting in, i dont know.

and you guys are right, i didnt notice the glare on the table, its more controlled in the pentax.



i got banned because i told some guy that sending a christmass card with the words "merry christmass" to all of his clients MIGHT be detremental to his business, and that there are people out there that take offence when one wishes them a happy holiday of a particular brand that they dont follow.

this is the social education of Toronto in me, since people get pretty touchy about this sort of thing, ive learned to be religion neutral while dealing with.. well, anyone!

i made the mistake of not looking at his profile, Texas! Egad, then him and his lackies took offence at my "suggestion"..

this erupted into a 150 post discussion of religion and its plance in business (what a silly thing), freedom of speech, christianity #1, and all that jazz.

somehow, appernatly, it was all my fault because when i argue i just get straight to the point and say it how it is...

anyway..

02-07-2008, 09:32 PM   #7
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the sigma cost me 140 cash and a nice chat with Dan (Dkittle)

i mainly bought this lens out of curiousity and collectors factor... since googling this thing is near impossible.

the DA21 is brand new and i got it with the standard rebate they had around november
02-07-2008, 09:44 PM   #8
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Yeah the old Sigma lenses rarely impress me.. Most of all it seems to me the contrast is rather poor, though I think the detail is there as seen in your conversion..

02-07-2008, 09:55 PM   #9
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"actual pixles"

honestly?

i dont know.... LOL

things like contrast and colour rendition are barely important to me since i dont really have any "true colour" photographs, all of my stuff i post process in one unique way or another,

i dont know, i'll have to run the streets with this see how it goes.


sigma


pentax

02-07-2008, 10:18 PM   #10
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I can safely say that the image from the DA 21/3.2 Limited is definitely more saturated than the image from the Sigma. In accordance, the colors are also a little darker in the image from the Pentax. Those colors are closer to the actual colors, as the ones in the Sigma image are a bit light.
02-07-2008, 10:45 PM   #11
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I am pretty sure the Sigma looks like it is overexposed by 1/3-1/2 stop. Judging contrast and colors might be a bit unfair due to this difference in exposure. That said, the 21/3.2 does look very impressive! I hope Pentax gets those rebates back soon
02-08-2008, 01:47 AM   #12
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I think the Sigma's overexposure indeed hurts its performance in this case. Though if you look carefully at the table area in front of the cigarette's case, the Sigma does show all those micro scratches while in the Pentax case, you barely see them. It might be because of the variations in focus. Nevertheless, the DA 21 is an impressive performer.
02-08-2008, 02:07 AM   #13
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At the risk of being labelled a 'fan boy', I give a very clear nod to the Pentax lens.
Why?
Using the coke can as a realistic colour guide ( & I'm assuming that is a constant across the planet.....sad isn't it!) the Pentax re-produces the colour the best.
At the end of the day "we" are trying to re-produce what is actually there...aren't we?

Pros tending to artistic creation excepted.

Apologies to Ben, no disrespect intended or implied..
Cheers

Last edited by Mallee Boy; 02-08-2008 at 02:09 AM. Reason: spelling
02-08-2008, 08:01 AM   #14
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Do you really need a 16mm, an 18mm, a 21mm and a 10-20mm?
And that Sigma is going to have some baaaad CA, I can already see the "glow" from those white papers on your desk at 2.8.
02-08-2008, 08:13 AM   #15
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QuoteOriginally posted by hudsong Quote
Do you really need a 16mm, an 18mm, a 21mm and a 10-20mm?
And that Sigma is going to have some baaaad CA, I can already see the "glow" from those white papers on your desk at 2.8.
i want to test them all, then stick with one.

plus it would make me somewhat of an authority on the wide angle spectrum, which is where i'm heading with my overall photography anyway.
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