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04-14-2010, 06:32 AM   #76
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QuoteOriginally posted by nater Quote
I didn't realize it has a bad rap... I recently bought a second-hand Sigma 17-35mm EX DG f2.8-4, and so far I've been very happy with it - as a full-frame lens on an APS-C body, there's no vignetting to speak of and corner sharpness is very good. 77mm is my most common filter size, and I can use a polarizer on it at 17mm for outdoor shots (unlike some super-wide lenses), while f2.8 is usable indoors without a flash. I think it fits nicely between my Pentax 10-17mm f3.5-4.5 fisheye and my Tokina 28-70mm f2.6-2.8.

The only thing that surprised me about it is that it is lighter than the Sigma 28mm f1.8 EX DG, while being almost the same physical size. (Perhaps Sigma has been using more metal lately in their lenses?)
I like the 17-35, too. I use it on film at full frame as well.



04-14-2010, 11:18 AM   #77
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Can someone confirm the weak performance lenstip.com had with their lens?
Their review: Sigma 28 mm f/1.8 EX DG Aspherical Macro review - Introduction - Lenstip.com on a Nikon D200 and D3x.

For some time now I'm trying to find a used Sigma 1.8/28 macro but their test quite shocked me.
The few user opinoins I've found were very positive in total and still the tested sample they had performed so badly.

So was it the Nikon they used or a malfunctioning lens or is the lens simply that crappy?

As you can see from my sig I currently have its predecessor and while I don't like its built or bokeh, sharpness never was one of my concerns - up to f/2.8 it is the best lens I own - even beats the F 1.7/50.
04-14-2010, 03:18 PM   #78
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QuoteOriginally posted by Egg Salad Quote
Can someone confirm the weak performance lenstip.com had with their lens?
I can only say I have the Sigma 28mm EX DG f1.8 and have had no issues on my K200D. I can dig up some photos if you'd like - what are you looking for specifically?

A quick google search resulted in some other sites with people asking about the lens and people saying that it's "well known" that Sigma has focusing issues on Canon mounts, and that it's common for people to have to send their lenses back to Sigma for re-calibration to work properly on Canon. Not sure if that was the issue at lenstip or what.
04-14-2010, 11:02 PM   #79
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QuoteOriginally posted by asw66 Quote
As for this last hypothesis, I know that photozone.de say that lens tests cannot be extrapolated across different mounts, but I don't understand why this would be so.
Dan provides the answer:

QuoteOriginally posted by audiobomber Quote
- test cameras don't have equal resolution and capabilities
They measure the system resolution and because of different resolutions and AA filter strengths you cannot compare results between different mounts. The problem is not that lenses differ in performance but the cameras used to test them.


QuoteOriginally posted by Egg Salad Quote
Can someone confirm the weak performance lenstip.com had with their lens?
I'll read the test, but for now I can confirm that the lens performs just fine on my K100D. It certainly is not a crap lens. On the contrary.

04-14-2010, 11:57 PM   #80
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QuoteOriginally posted by Egg Salad Quote
Can someone confirm the weak performance lenstip.com had with their lens?
I've read the review and remembered that I've read other tests from them. They seem to be very critical amateurs. Their other tests did not have much praise for products which elsewhere are well respected. They may have had two bad copies and I'm not sure how well they execute resolution tests.

Also note that my Sigma 28/1.8 DG EX looks differently. The focus ring is prominently different. It seems Sigma has at least two models of this lens without differentiating them by name.

Having said all that perhaps there is some truth to what they write and to be honest I wouldn't buy this lens to get sharper images compared to a very good zoom. I think the lens is OK sharp but not razor sharp. Not as sharp as a FA 50/1.4 at f/5.6. I bought the lens for its speed, very decent bokeh and close focusing abilities. Have a look at three shots I posted in a 28mm bokeh thread. I've got a shot of a bee on a flower at f/4 and there is plenty of detail, so much that everyone mistakes the crop for a shot with a macro lens.

I also bought the lens since it represents a normal focal length on APS-C, i.e., is the equivalent of what the fifty (should have been a 43) was for FF. It is a fun challenge to create interesting images if you don't have angle exaggeration from a wide angle or perspective compression from a tele lens. Of course, the Sigma 28/1.8 EX allows you to cheat with its close focusing.

BTW, I like the MF focus clutch. It gives you the choice of either fully embracing the lens when you use AF since there are no moving parts, or to use MF with a wide focusing ring (no trying to find a thin rim somewhere). Of course the optimum would be a non-moving big ring with a Quickshift option, but given the price of the lens, I think the solution chosen has its charm.
04-15-2010, 12:07 AM   #81
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There are 2 versions of the Sigma 28mm f/1.8. The earlier 58mm filter size version and the later 77mm filter size version that Lenstip reviewed. So if you got the earlier version, you can't directly correlate it with the current version as the optical designs are different. Sigma does have an uneven reputation for QC issues as copies can and do have variations in quality. Best is to test thoroughly before buying.
04-15-2010, 12:31 AM   #82
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QuoteOriginally posted by creampuff Quote
So if you got the earlier version, you can't directly correlate it with the current version as the optical designs are different.
I've got a later version with a 77mm filter ring but it is not the same as the one shown in the lenstip review.

QuoteOriginally posted by creampuff Quote
Sigma does have an uneven reputation for QC issues as copies can and do have variations in quality.
Is that a perpetuation of an old Sigma stigma or does Sigma really have more QC issues than other manufacturers? I haven't heard more QC complaints about a single lens than about the Pentax DA 16-50/2.8. Yet, Sigma still gets the stick for bad QC. I really don't know where the truth is but I sometimes wonder whether Sigma gets unduly scolding for a shoddy past.
04-15-2010, 03:23 AM   #83
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QuoteOriginally posted by Class A Quote
Is that a perpetuation of an old Sigma stigma or does Sigma really have more QC issues than other manufacturers? I haven't heard more QC complaints about a single lens than about the Pentax DA 16-50/2.8. Yet, Sigma still gets the stick for bad QC. I really don't know where the truth is but I sometimes wonder whether Sigma gets unduly scolding for a shoddy past.
I think, a lot comes from Canon users, who need to talk down the Sigma lenses to justify their L-glass

My own experience with Sigma is very good. I have 5 EX zooms and they all are very good for what they are. I simply do not expect the Bigma to perform like a three times as expensive 500mm prime. But the versatility and the comparatively low price make it a very worthy investment. Other lenses were and still are simply not available from Pentax lime the 10-20 ot the 70-200, well and ofcourse nothing comparable to the Bigma.

Given that my only DA* lens litterally stopped doing anything after three months (the 16-50) my Sigmas have a much better track record in terms of reliability and QC. They never failed me.

Ben

04-15-2010, 06:30 AM   #84
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Well I had a Sigma EX lens that had the exterior finish flake off in less than 6 months of use. The lens looked like it was worn and beat-up. Simply unacceptable and it affected the value of the lens. Quite a few friends who have Canon and Nikon versions of the Sigma 30mm and 50mm lenses have encountered focus issues at shorter distances and had to get the local Sigma service center to re-calibrate. Also here in the tropics, fogging of the internal elements is known to happen with some Sigma lenses, apparently the internal grease evaporates and affects the internal elements, or so they say, cause I got a couple to prove it. Don't get me wrong, I do like a few Sigma lenses but I also do maintain their mixed reputation is not unfounded.
04-15-2010, 06:54 AM   #85
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Didn't know there where 2 versions of the EX DG Macro. Only thing I noticed is that the one they had has an aperture ring and slightly different focus ring ribbing/structure.
And yes, I know the one I have is totally different from the newer one (except being f/1.8). But as I said it is the best lens up to f/2.8 in terms of sharpness alone. That's why I didn't expect it to do so bad.

Glad to hear it is as good as I thought before reading their review.
Also have to say that their conclusions for the Sigma 70-200 (HSM II) fit my experience - although I find it to be better than they tested - especially at <135mm. Totally usable even at f/2.8.


Nater: I'm specially looking for full sized close focus pictures at big aperture. There are some few pictures from it on the net but only very few full sized ones - not to mention these are mostly ones with focus set at infinity. So since I'm also wanting it for being a "fast" lens while also offering pretty normal FOV that's my main concern.


OK, maybe I'll write more later.
Thanks for your recommendations.
04-15-2010, 07:56 AM   #86
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I have said it tons of times: The Sigma EX DG 28mm f/1.8 is my favorite lens.
04-15-2010, 11:32 AM   #87
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I know you did and you also did in my other thread about this lens.
But a review is a review and well, it is an objective measurement.

They even have full sized pictures there and true, they don't look that special.
But it has to be the other systems, then.
So I'll continue my quest for one of these lenses (used ones are like an endangered species).
04-15-2010, 03:57 PM   #88
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QuoteOriginally posted by Egg Salad Quote
They even have full sized pictures there and true, they don't look that special.
If they had provided great images you could have concluded that the lens is capable of creating them. The absence of special images doesn't say anything unless you believe the photographers are capable of squeezing every potential out of a lens. One can create far better images with this lens (and most other lenses) than they did.

EDIT: The one Tamron 90 macro shot I looked at from them shows blur due to camera shake. Not great.

Last edited by Class A; 04-15-2010 at 05:18 PM.
04-15-2010, 04:50 PM   #89
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QuoteOriginally posted by Egg Salad Quote
But a review is a review and well, it is an objective measurement.
A review is only reliable if measurements are carried out reliably. Not sure about this with lenstip. They might be OK, but I'm really not sure.

Also, unless you made sure you got a good copy, you are only measuring the individual performance of a copy which could be suboptimal. Even DPreview stopped getting more DA* 55/1.4 copies after three (or more?) of them arrived with optical issues.

I'm not saying that the Sigma 28/1.8 DG EX is the lens you need but I wouldn't let myself being influenced by that one review too much.

A year ago, I saw a short review of the Sigma 28/1.8 by popular photography or so. They used "A+" to "D" ratings for image quality. It was a combined review of the 20, 24, and 28 Sigmas. It showed very good results. Strangely, I cannot find that review on the web anymore.

EDIT: I save a copy of the review and found it. Below is the text for the 28mm. If you compare the results with the lenstip findings you'll find that the lenstip figures are all much worse. Why that is, is up to anyone's judgement.

POP PHOTO review (from November 2002):
QuoteQuote:
SQF data for the 28mm f/1.8 indicate excellent overall imaging performance. Barrel distortion was minimal (0.43%). Exposure at the film plane was extremely accurate, with 2⁄3-stop underexposure at f/1.8 due to light falloff, less than 1⁄10-stop underexposure from f/2 to f/16, and 1⁄3-stop under at f/22. At closest focusing distance of 71⁄2 inches (1:2.9), center sharpness was excellent at all apertures. Corner sharpness was poor from f/1.8 to f/2.8, acceptable from f/4 to f/5.6, very good at f/8, excellent from f/11 to f/16, and very good at f/22. Optimum performance was at f/11. Overall, distortion correction was extremely low.

In the field:
Test slides taken with all three lenses were uniformly sharp and contrasty from center to corners at all apertures, with the following exceptions: Corner images shot at f/1.8 (20mm) from f/1.8 to f/2 (24mm), and center-to-corner images at f/1.8 (28mm) were slightly soft. Flare was very well controlled with all the lenses. AF timing was average, and autofocus action was judged slightly noisy.

Conclusion:
These three lenses provide superior picture-taking performance at their respective focal lengths. That this high level has been achieved at such extremely fast apertures is outstanding! We have no reservations in recommending any of them to pros or critical amateurs who need a really fast wide-angle lens.
I even found the review on the web. The only difference to my local PDF copy seems to be that the latter features SQF charts for each lens as part of the text but you can get to the charts by clicking on the respective links in the article.

Last edited by Class A; 04-15-2010 at 05:36 PM.
04-16-2010, 04:33 AM   #90
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QuoteOriginally posted by Egg Salad Quote
I know you did and you also did in my other thread about this lens.
But a review is a review and well, it is an objective measurement.

They even have full sized pictures there and true, they don't look that special.
But it has to be the other systems, then.
So I'll continue my quest for one of these lenses (used ones are like an endangered species).
Reviews are by no means objective. There are some measurements, for sure. But how were they carried out and which limiting parameters were in place. Lens tessting is complicated and time consuming and results between different testers vary widely, because slight differences in lighting or in the accepted contrast limit, at which the measurement is done, will influence the result greatly.

The testers also choose, what parameters will be measured and which one ignored. So, wahts is about colour rendering, bokeh and other contributing factors to the overall image?

Then, the conclusions and comments written by the testers are not objective, but subjective evlauations. A very good example are the German photo mags. I have seen several tests over the years, where Pentax products delivered measurements equal or better, than Canon or Nikon. But in the final conclusion (and I am talking about major mags), Pentax was either left out completely or they concentrated on one point, where the CaNikon performed a bit better, ignoring their own measurements.

I regard reviews as helpful indicators at most, but never use them as the sole base, when I decide upon buying a lens. I feel, that real world experience reported by real photographers, not by lab wizzards, is far more valuable to me.

Ben
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