December 21, 2014, 04:40:23 PM

Author Topic: DXOMark Compares the Sigma 50 f/1.4 Art to Zeiss 55 f/1.4 Otus  (Read 5012 times)

LetTheRightLensIn

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Re: DXOMark Compares the Sigma 50 f/1.4 Art to Zeiss 55 f/1.4 Otus
« Reply #30 on: April 18, 2014, 02:23:10 PM »
I think the world would be well-served if DXO just gave up on lens tests alltogether, nuked their lens tests database, and just stuck with sensor tests. (And furthermore, I think the world would be better served if DXO did away with scalar test "scores"...just as useless as the chunks and giblets that is their lens tests.)

+1

I mean comparing one lens at f/1.4 another at f/1.2 another at f/2 another at f/2.8? WTH?
And then for zooms they someone turn a zoom with a ton of different focal lengths and apertures into a SINGLE NUMBER for resolution?!? And it's not even a constant at wide open, or averaged over wide open, it's a single focal length and aperture, which they chose as best (even though their criteria for best, makes NO SENSE WHATSOEVER AT ALL IN ANY WAY SHAPE OR FORM), so you might have say the 24-70 II compared at 24mm f/2.8 to the 24-105 compared at 50mm f/5.6 to the 17-40L compared at 17mm f/4 to the 24-70 f/4 IS at 70mm f/4 (I'm just making those numbers up, but you get the point, didn't feel like bothering to go back and check what they exactly used) and then rating them each as so and so relative to one another based on that? WTH??


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Re: DXOMark Compares the Sigma 50 f/1.4 Art to Zeiss 55 f/1.4 Otus
« Reply #30 on: April 18, 2014, 02:23:10 PM »

sdsr

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Re: DXOMark Compares the Sigma 50 f/1.4 Art to Zeiss 55 f/1.4 Otus
« Reply #31 on: April 18, 2014, 03:21:00 PM »

There exist plenty of other review sites that test lenses.  Why keep looking at DxO?  You might as well read science fiction.  At least sites like LensTip and The Digital Picture will show you actual images.


Lenstip's review is now up:

http://www.lenstip.com/index.php?test=obiektywu&test_ob=400


Solar Eagle

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Re: DXOMark Compares the Sigma 50 f/1.4 Art to Zeiss 55 f/1.4 Otus
« Reply #32 on: April 18, 2014, 03:23:51 PM »
*Sigh*

DXOs Lens test results are so useless. They rate it less than the Otus, as they should, however all of the measures they choose to exhibit would otherwise indicate that the new Sigma 50 should be the better lens. Comparatively, it has the same resolution, better transmission, less distortion, and less CA than the Otus. Only in a footnote do you actually learn why DXO rates the Otus higher: It has sharper corners.

Bleh. DXO. Bleh. It's like they just barf up test results and let the chunks & giblets remain where they plop.

I think the world would be well-served if DXO just gave up on lens tests alltogether, nuked their lens tests database, and just stuck with sensor tests. (And furthermore, I think the world would be better served if DXO did away with scalar test "scores"...just as useless as the chunks and giblets that is their lens tests.)

Um... I'm pretty sure DxO scores are based on a specific "best" setting, where the "best" setting represents the highest achievable score on a given lens.  The sigma score is based on f/2, and the Otus f/1.4.  They both acheive similar sharpness at that setting, however that gives the Otus a full stop advatage on toward the score.  You should maybe figure out how they score before trying to put down their scoring method......

Viggo

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Re: DXOMark Compares the Sigma 50 f/1.4 Art to Zeiss 55 f/1.4 Otus
« Reply #33 on: April 18, 2014, 03:46:17 PM »
*Sigh*

DXOs Lens test results are so useless. They rate it less than the Otus, as they should, however all of the measures they choose to exhibit would otherwise indicate that the new Sigma 50 should be the better lens. Comparatively, it has the same resolution, better transmission, less distortion, and less CA than the Otus. Only in a footnote do you actually learn why DXO rates the Otus higher: It has sharper corners.

Bleh. DXO. Bleh. It's like they just barf up test results and let the chunks & giblets remain where they plop.

I think the world would be well-served if DXO just gave up on lens tests alltogether, nuked their lens tests database, and just stuck with sensor tests. (And furthermore, I think the world would be better served if DXO did away with scalar test "scores"...just as useless as the chunks and giblets that is their lens tests.)

Um... I'm pretty sure DxO scores are based on a specific "best" setting, where the "best" setting represents the highest achievable score on a given lens.  The sigma score is based on f/2, and the Otus f/1.4.  They both acheive similar sharpness at that setting, however that gives the Otus a full stop advatage on toward the score.  You should maybe figure out how they score before trying to put down their scoring method......

Is the "best setting" for the Canon 50 , f1.2?
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Solar Eagle

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Re: DXOMark Compares the Sigma 50 f/1.4 Art to Zeiss 55 f/1.4 Otus
« Reply #34 on: April 18, 2014, 03:57:08 PM »
Is the "best setting" for the Canon 50 , f1.2?

That's what they show.  The "best" setting shows f/1.2, which seems to be why the sharpenss score is so low on that lens at the "best" setting.  However it seems that scoring at such a fast aperture, with their scoring methodolgy, the advatage of the fast aperture outweighs the disadvatage of the sharpness at that setting, thereby making it the "best" setting for overall score. Thats how I understand their testing to work anyway....

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Re: DXOMark Compares the Sigma 50 f/1.4 Art to Zeiss 55 f/1.4 Otus
« Reply #35 on: April 18, 2014, 04:10:48 PM »
I'm really glade Sigma is making these super-awesome new lenses, but giant no compromise lenses aren't my preference.  I carry my 6D with no strap, so I like to go for light/compact lenses.  This would be a great lens to have, but I'm gonna hold out for whatever Canon turns out for a new 50mm.  Plus I like IS.  I went for the 35mm f/2 IS over the 35mm Sigma, and I'm guessing I'll take the 50mm F/1.8 IS, if thats what Canon is going to offer.  I also went for the 24-70mm f/4 IS, again because its the lightest option... Nevertheless good on Sigma for what they are up to these days.........

jrista

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Re: DXOMark Compares the Sigma 50 f/1.4 Art to Zeiss 55 f/1.4 Otus
« Reply #36 on: April 18, 2014, 04:19:17 PM »
*Sigh*

DXOs Lens test results are so useless. They rate it less than the Otus, as they should, however all of the measures they choose to exhibit would otherwise indicate that the new Sigma 50 should be the better lens. Comparatively, it has the same resolution, better transmission, less distortion, and less CA than the Otus. Only in a footnote do you actually learn why DXO rates the Otus higher: It has sharper corners.

Bleh. DXO. Bleh. It's like they just barf up test results and let the chunks & giblets remain where they plop.

I think the world would be well-served if DXO just gave up on lens tests alltogether, nuked their lens tests database, and just stuck with sensor tests. (And furthermore, I think the world would be better served if DXO did away with scalar test "scores"...just as useless as the chunks and giblets that is their lens tests.)

Um... I'm pretty sure DxO scores are based on a specific "best" setting, where the "best" setting represents the highest achievable score on a given lens.  The sigma score is based on f/2, and the Otus f/1.4.  They both acheive similar sharpness at that setting, however that gives the Otus a full stop advatage on toward the score.  You should maybe figure out how they score before trying to put down their scoring method......

If you look at all of DXO's lens tests, it's very clear that they are VERY HEAVILY weighted based on the T-stops value. That's a problem, because it makes comparing the overall quality of lenses with different maximum apertures practically impossible...it's why a 50mm f/1.4 lens scores higher than Canon's 600mm f/4 L II supertele. The 50/1.4 doesn't even come remotely close to comparing to the 600/4 II, but it scores quite a bit higher. Why? Because it's f/1.4, and the 600 is f/4.

The T-stops weighting effectively nullifies much of the value that could potentially exist in DXO's lens tests. There is a certain value to testing lenses that way...but not if the most important benchmark is T-stops.

BTW, DXO does not mix ratings for measures from different apertures. If they choose the measures for a lens when it is tested at f/1.2, then that means sharpness, distortion, vignetting, and CA are all based on the testing at that aperture. As far as I know, DXO tests all lenses at all of the full-stop apertures (plus the max aperture, in case it isn't a full stop faster), but when they score, it's based on whatever they deem is the "best" aperture. Since they put such a significant weight on T-stops, that is usually the maximum aperture, although not always.
« Last Edit: April 18, 2014, 04:43:36 PM by jrista »

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Re: DXOMark Compares the Sigma 50 f/1.4 Art to Zeiss 55 f/1.4 Otus
« Reply #36 on: April 18, 2014, 04:19:17 PM »

neuroanatomist

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Re: DXOMark Compares the Sigma 50 f/1.4 Art to Zeiss 55 f/1.4 Otus
« Reply #37 on: April 18, 2014, 06:21:45 PM »
To clarify, "Best at FL+aperture" refers to the Lens Score, which is based primarily on 'performance in 150 lux illumination' (like a dimly lit warehouse).  The Lens Score is only secondarily influenced by the optical metrics (sharpness, CA, etc.), despite those metrics being listed under the Score. That's why almost all lenses are 'best' wide open, even though the optical metrics are rarely highest at max aperture.

Consider that the Sigma 50/1.4 A is not 'best at 50mm f/1.4', but at f/2.  Since giving up a full stop of light is obviously not better for 'performance in 150 lux' that suggests that one or more of the secondary factors measured for the Sigma 50/1.4 A at f/1.4 were sufficiently bad to counteract the loss of a stop of light.  Or it could be that DxO just screwed up their testing, it certainly wouldn't be the first time.
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jrista

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Re: DXOMark Compares the Sigma 50 f/1.4 Art to Zeiss 55 f/1.4 Otus
« Reply #38 on: April 18, 2014, 06:26:42 PM »
To clarify, "Best at FL+aperture" refers to the Lens Score, which is based primarily on 'performance in 150 lux illumination' (like a dimly lit warehouse).  The Lens Score is only secondarily influenced by the optical metrics (sharpness, CA, etc.), despite those metrics being listed under the Score. That's why almost all lenses are 'best' wide open, even though the optical metrics are rarely highest at max aperture.

Consider that the Sigma 50/1.4 A is not 'best at 50mm f/1.4', but at f/2.  Since giving up a full stop of light is obviously not better for 'performance in 150 lux' that suggests that one or more of the secondary factors measured for the Sigma 50/1.4 A at f/1.4 were sufficiently bad to counteract the loss of a stop of light.  Or it could be that DxO just screwed up their testing, it certainly wouldn't be the first time.

LOL, no, not the first time.

I'm curious why the Sigma 50 A would bet the "best at f/2" treatment...but not the Canon 50L. It's quite clear that the 50L does not perform ideally (at least according to DXO's metrics) at f/1.2...and yet you can't even select f/1.4, f/1.8, or f/2 when comparing apertures with other lenses.

It's little things like that that always make me wonder if DXO really does have a bias against Canon. It seems they very often put Canon equipment in the worst possible light, and take special care to put other brand's products in the best possible light (such as the Sugma 50/1.4 A being best at f/2.)

tcg films

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Re: DXOMark Compares the Sigma 50 f/1.4 Art to Zeiss 55 f/1.4 Otus
« Reply #39 on: April 20, 2014, 01:26:53 PM »
Sigma has really come far in a short time.  I may actually buy one.

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Re: DXOMark Compares the Sigma 50 f/1.4 Art to Zeiss 55 f/1.4 Otus
« Reply #39 on: April 20, 2014, 01:26:53 PM »