May 21, 2018, 03:22:55 PM

Author Topic: UPDATE: Next From Sigma? 14-24mm f/2.8 DG HSM Art  (Read 7494 times)

snoke

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Re: UPDATE: Next From Sigma? 14-24mm f/2.8 DG HSM Art
« Reply #30 on: February 09, 2018, 09:19:45 AM »
Sigma claim low "less than 1%" distortion. Amazing. Beat 16-35/2.8.

11mm field of view = 117.1 degrees
12mm field of view = 112.6 degrees
14mm field of view =  104.3 degrees
16mm field of view = 96.7 degrees

http://www.bobatkins.com/photography/technical/field_of_view.html

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Re: UPDATE: Next From Sigma? 14-24mm f/2.8 DG HSM Art
« Reply #30 on: February 09, 2018, 09:19:45 AM »

hendrik-sg

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Re: UPDATE: Next From Sigma? 14-24mm f/2.8 DG HSM Art
« Reply #31 on: February 09, 2018, 09:40:02 AM »
As far as the Canon 16-35 competition shows, the 2.8 Version has so terrible vignetting that it is faster than the 4.0 IS only in the frame center. So if there is only the background blur as advantage, i would take the IS version for half the price anytime.

According to DXOmark, the vignetting @16mm wide open is just about the same. So the "speed" advantage of the f/2.8 version is equally distributed.

This statement is interesting, i could not yet check it. My information was from Lenstip and TDP. More confusing is, that it seems not to be easy to even measure vignetting, even by routined reviewers. Same confusion about distorsion (for the 11-24 this time) which looks completely different at lenstip than at other reviewers.

ahsanford

  • Canon EF 600mm f/4L IS II
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Re: UPDATE: Next From Sigma? 14-24mm f/2.8 DG HSM Art
« Reply #32 on: February 09, 2018, 11:05:34 AM »
Vignetting data from LensTip (all values = wide open at widest FL on a FF sensor):

Canon 16-35 f/4L IS = -2.17 EV
Canon 16-35 f/2.8L III = -4.07 EV -- healthy discussion on that here
Tamron 15-30 f/2.8 VC = -1.79 EV

And in that discussion link the III vignetting data is corroborated elsewhere.  It's a function of focus distance, but largely you need to crank up the corners quite a bit in post to get back what the lens can't reel in, especially if you are shooting at 16 f/2.8.

So hendrik's comment that 'you lose your speed / you only get the true speed of the lens in the center' is not unfounded.  I think it's a bit harsh to imply Canon isn't really giving you an f/2.8 lens here so much as (possibly) recognize that the world's sharpest UWA zoom did not come for free -- 16mm vignetting appears to be the cost. 

One also might wonder if the magical combination of [sharp] + [has filter ring] + [f/2.8] + [low vignetting] might have been possible if Canon had jumped to a larger yet filter ring / front element diameter, say 86mm or higher.  I don't think they would have dramatically improved vignetting without moving to a more bulbous front element, but a larger outer diameter might have helped.

- A

NancyP

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Re: UPDATE: Next From Sigma? 14-24mm f/2.8 DG HSM Art
« Reply #33 on: February 09, 2018, 11:19:51 AM »
Astro-landscape photographers may be interested.

ahsanford

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Re: UPDATE: Next From Sigma? 14-24mm f/2.8 DG HSM Art
« Reply #34 on: February 09, 2018, 11:38:37 AM »
Astro-landscape photographers may be interested.

Yep, but Sigma -- for all it's butt-kicking on resolution -- has had limited success fighting coma.

I don't shoot astro, but it would appear from the posters here that coma performance is as vital as resolution with an astro lens.

And this has not been the strong suit of the wide/fast Art lenses:

Sigma 14 f/1.8 Art:  https://www.lenstip.com/506.7-Lens_review-Sigma_A_14_mm_f_1.8_DG_HSM_Coma__astigmatism_and_bokeh.html

Sigma 20 f/1.4 Art:  https://www.lenstip.com/457.7-Lens_review-Sigma_A_20_mm_f_1.4_DG_HSM_Coma__astigmatism_and_bokeh.html

Sigma 24 f/1.4 Art:  https://www.lenstip.com/430.7-Lens_review-Sigma_A_24_mm_f_1.4_DG_HSM_Coma__astigmatism_and_bokeh.html

Sigma 24-35 f/2 Art:  https://www.lenstip.com/447.7-Lens_review-Sigma_A_24-35_mm_f_2.0_DG_HSM_Coma__astigmatism_and_bokeh.html

- A

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Re: UPDATE: Next From Sigma? 14-24mm f/2.8 DG HSM Art
« Reply #34 on: February 09, 2018, 11:38:37 AM »