[Rover]

By the way, I just had a question for you gurus regarding the 24/1.4 lenses by Canon and Samyang - or, to be more precise, regarding the PZ tests of both.

 



The resolution graph for the Canon L implies that the IQ drops off the cliff at f/1.4 when it comes to the outer region. Fair enough; that is to be expected in a lens of this class. But then, there's the Samyang:



It has a completely different curve with smoother center resolution increase but way better corners. Is it really THAT better than the L?

P.S. The negligible amount of increase in IQ when going from f/1.4 to f/2 really seems to substantiate the theory suggested by Lenstip that the Samyang is not really a f/1.4 lens, more like f/1.8.

Waiting for the Sigma to be put through the motions, even if I'm not going to sell my 24 L for it now...

[Scythels]

The 24L is limited by primarily sagittal oblique spherical.  Coma grows by x^2 as you move away from the center so the performance will quickly "disappear" at wide apertures.  Coma is typically targeted for correction, often eliminated with an asphere, but sagittal oblique spherical is very difficult to correct.

 

Samyang's lens is limited primarily by strong spherical aberration and astigmatism.  The spherical grows by y^3 as you increase the aperture size so it hampers the performance of their lenses wide-open in the center but they quickly improve.  The astigmatism varies by y as you increase aperture and x^2 as you move away from the center so it is harder to correct by stopping down.

[Klaus]

The Sigma will start at 849US$

[JJ_SO]

bloody hell, I was betting a 
little bit higher 
:blink:

 

That's just half price of the Nikon - how do they do that?

[Studor13]

And in CHF?

 

I hope you will visit us again, Jo. I think you can leave the bike home and fly. You'll have more time for photography with the new Sigma which I'm sure you are already salvanating over already.

[JJ_SO]

Naaaah, Andy, if I wait for the Sigma to come back to Bohinj, it will be not before next year.   And I still prefer the night train, had often nice or interesting experiences with it.

 

How are you doing? Guess you had and still have lots of snow?

[Studor13]

Oh yes, I forgot about the train.


Some snow here but melting like icebergs in Greenland.


The Sigma 24mm is the only Art lens that I am really interested in, if it's anything like the other Art series.


I read somewhere though that corners are not that great wide open. That would rule it out for me as I want to do some night photography at f1.4 or thereabouts.

[Klaus]

Well, the corners at f/1.4 can't be worse than on the Canon 24L ;-)

[JJ_SO]

Yeah, but Studor13 is on the SunNikon side of life 

 

Seriously, my experience with the Sigma Art series tells me "wide open is very okay, one stop less great"

[Rover]

Lenstip gots 'un!

http://www.lenstip.com/2122-news-Sigma_A...eview.html