Author Topic: Irix 15mm f/2.4  (Read 36450 times)

simsurace

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Re: Irix 15mm f/2.4
« Reply #60 on: September 12, 2016, 15:12:00 »
Very strange and obnoxious blur in that milkyway+mountain image's lower right corner. OTOH, the other samples look mostly fine, I would say they superficially look almost as good as any other lens in that focal length. We don't know what caused the bad performance in that case (warped mount, decentered lens, field curvature). Certainly a try-before-buy lens. I'm waiting for some retailer in Switzerland to have the lens available to try it out.

There has to be an optical edge over the Samyang lens for this lens to sell at all.
Simone Carlo Surace
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Bjørn Rørslett

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Re: Irix 15mm f/2.4
« Reply #61 on: September 12, 2016, 15:58:04 »
When three out of four corners are bad and  the last one just fine, plus all parts of the scene effectively at infinity, one cannot have field curvature ...

Actually the zone of sharpness in that bad image goes along the diagonal, from top left corner about 2/3 down to the right. This is decentering.

Why such a picture was posted in the first place still escapes my imagination. Unless they consider any PR is good and push forth a really poor image to make people discuss the product ?? Apparently the PR side of this has succeeded on NG, but it remains to be seen whether our members are tempted to line up as customers. Probably not.

Jan Anne

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Re: Irix 15mm f/2.4
« Reply #62 on: September 12, 2016, 17:19:39 »
We'll have a closer look at Photokina  ;D

Also very curious about their new 11mm lens compared to the Voigtlander 10mm and 12mm offerings.
Cheers,
Jan Anne

simsurace

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Re: Irix 15mm f/2.4
« Reply #63 on: September 12, 2016, 17:35:36 »
When three out of four corners are bad and  the last one just fine, plus all parts of the scene effectively at infinity, one cannot have field curvature ...

Actually the zone of sharpness in that bad image goes along the diagonal, from top left corner about 2/3 down to the right. This is decentering.

Why such a picture was posted in the first place still escapes my imagination. Unless they consider any PR is good and push forth a really poor image to make people discuss the product ?? Apparently the PR side of this has succeeded on NG, but it remains to be seen whether our members are tempted to line up as customers. Probably not.

I think your explanation is very plausible, but I cannot exclude that there is a different explanation that escapes my imagination.
I agree that the picture should have been caught as unsuitable for publication and triggered an internal quality control investigation since it presumably has been shot well before the first shipments.
Simone Carlo Surace
suracephoto.com

stenrasmussen

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Re: Irix 15mm f/2.4
« Reply #64 on: September 12, 2016, 18:09:07 »

Akira

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Re: Irix 15mm f/2.4
« Reply #65 on: September 12, 2016, 18:14:13 »
"The eye is blind if the mind is absent." - Confucius

"Limitation is inspiration." - Akira

Roland Vink

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Re: Irix 15mm f/2.4
« Reply #66 on: September 12, 2016, 23:07:23 »
The race for ever-wider, ever-faster lenses continues ...
Where are the high quality compact SLR lenses?

Tristin

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Re: Irix 15mm f/2.4
« Reply #67 on: September 12, 2016, 23:14:38 »
The race for ever-wider, ever-faster lenses continues ...
Where are the high quality compact SLR lenses?

I think the idea is that photographers looking for compact are going for Fuji and Pentax, while the Nikon and Canon people are looking for capability without worrying about size.
-Tristin

bjornthun

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Re: Irix 15mm f/2.4
« Reply #68 on: September 13, 2016, 01:05:11 »
The race for ever-wider, ever-faster lenses continues ...
Where are the high quality compact SLR lenses?
With the high ISO capabilities of modern cameras, compact lenses with f/2 or f/2.8 max aperture would be more usable than ever before, even in poor light.

pluton

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Re: Irix 15mm f/2.4
« Reply #69 on: September 13, 2016, 02:29:41 »
The recent f/1.8 Nikon series...which by all accounts are optically very good... could be substantially smaller if they weren't AF. 
Keith B., Santa Monica, CA, USA

Tristin

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Re: Irix 15mm f/2.4
« Reply #70 on: September 13, 2016, 03:01:08 »
The recent f/1.8 Nikon series...which by all accounts are optically very good... could be substantially smaller if they weren't AF.

True, but we all sadly know that Nikon will release a hot dog scratch n' sniff lens before new MF lenses happens.

Another round of samples for the thread's subject.  I am not at my computer, so have not really looked yet.
http://www.lenstip.com/2199-news-Irix_15_mm_f_2.4_-_sample_images.html
-Tristin

bjornthun

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Re: Irix 15mm f/2.4
« Reply #71 on: September 13, 2016, 13:16:20 »
The recent f/1.8 Nikon series...which by all accounts are optically very good... could be substantially smaller if they weren't AF.
Tokina announced an all metal manual focus, manual aperture 20mm f/2 lens today for Sony full frame mirrorless with a 62mm filter thread weighing 490 grams. Compare that to around 350 grams and a 77mm front thread of the Nikon 20/1.8. So it could easily be a choice between weight or size. (The Tokina Firin 20/2 is for mirrorless only. It has got a CPU, so it's a Sony mirrorless equivalent to Nikon Ai-P, though with stopped down metering.)

Maybe a new f/2.8 line could be made as an old school MF lenses, but with a CPU. Btw. Nikon Ai lenses have nicer build than Nikon Ai-S, and may have a more generous focus throw. Zeiss does it, so maybe Nikon too?

Manual focus is by no means not out of fashion. :)

Bjørn Rørslett

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Re: Irix 15mm f/2.4
« Reply #72 on: September 13, 2016, 13:52:39 »
...
Another round of samples for the thread's subject.  I am not at my computer, so have not really looked yet.
http://www.lenstip.com/2199-news-Irix_15_mm_f_2.4_-_sample_images.html

Here again the maker's photos confirm that the Irix is troubled with decentering and bad corners, in particular at the wider stops. Stopping down helps, like for any other lens. However, uneven left-right performance is seen (although much reduced in magnitude) even at f/8.

Akira

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Re: Irix 15mm f/2.4
« Reply #73 on: September 13, 2016, 15:30:03 »
Tokina and Sigma announced fast cine lenses.  All Tokina lenses except for the 16-28 zoom are newly designed.  Sigma uses the optics from their ART line models.  I wonder if 85//T1.5 is newly designed (maybe yes).
"The eye is blind if the mind is absent." - Confucius

"Limitation is inspiration." - Akira

bjornthun

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Re: Irix 15mm f/2.4
« Reply #74 on: September 13, 2016, 15:43:08 »
Tokina and Sigma announced fast cine lenses.  All Tokina lenses except for the 16-28 zoom are newly designed.  Sigma uses the optics from their ART line models.  I wonder if 85//T1.5 is newly designed (maybe yes).
I seem to recall that the Sigma 85/1.5 Cine has a different, higher, number of lens elements than that the current DSLR version, so there might just be an Art 85mm on its' way.