Author Topic: LAOWA STF105mmF2.0 Smooth Trans Focus lens  (Read 2488 times)

Dr Klaus Schmitt

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LAOWA STF105mmF2.0 Smooth Trans Focus lens
« on: January 02, 2016, 14:21:29 »
Pre production samples available and test shots here: http://forum.xitek.com/thread-1533456-1-1-1.html
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Michael Erlewine

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Re: LAOWA STF105mmF2.0 Smooth Trans Focus lens
« Reply #1 on: January 02, 2016, 14:32:41 »
What does "Trans-Focus" mean here?
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Dr Klaus Schmitt

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Re: LAOWA STF105mmF2.0 Smooth Trans Focus lens
« Reply #2 on: January 02, 2016, 14:43:16 »
What does "Trans-Focus" mean here?

my guess is that it delivers a very smooth image behind and in front of the sharp plane of focus.
Minolta and others had made such lenses before, often by using apodisation filtering techniques
https://en.wikipedia.org/wiki/Apodization
In other words: sharp image with a very smooth gaussian bokeh (so exactly the opposite as
you described it in your "impressionistic" thread)
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bjornthun

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Re: LAOWA STF105mmF2.0 Smooth Trans Focus lens
« Reply #3 on: January 02, 2016, 15:34:07 »
The lens schemayic on the page linked to mentions an "apodization filter". Note also the ring on the lens with T stops on it. Maybe this lens works the same way as the Minolta/Sony STF lenses.

Does anyone know which mount(s) it's for?

John Geerts

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Re: LAOWA STF105mmF2.0 Smooth Trans Focus lens
« Reply #4 on: January 02, 2016, 16:44:18 »
Interesting. Photo number 2 is amazing.

Erik Lund

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Re: LAOWA STF105mmF2.0 Smooth Trans Focus lens
« Reply #5 on: January 02, 2016, 18:49:39 »
Looks like a Micro Four Thirds Bayonet.
Nice rendering indeed!
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Akira

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Re: LAOWA STF105mmF2.0 Smooth Trans Focus lens
« Reply #6 on: January 02, 2016, 20:05:21 »
Interesting lens, Klaus!

The lens seems to be produced 100 pieces per lot, and You would have to pre-order one.

The spec. sheet looks questionable.  The AOV is indicated as 110 degrees for F (apparently it means "Full") and 85 degrees for APS-C.  ???  The MTF chart suggests that it covers a full frame.

The apodization filter seems to be, unlike that of Minolta/Sony STF 135mm, a simple concave lens dyed in gray: it automatically becomes lighter towards the center and darker towards the edge.  I think it's a smart idea.

If it covers full-frame, the mount would be Sony E.  Judging from the position of the rear element, it won't fit any DSLR.
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Dr Klaus Schmitt

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Re: LAOWA STF105mmF2.0 Smooth Trans Focus lens
« Reply #7 on: January 17, 2016, 11:52:36 »
Here examples from working lens, they are shipping now (site in Chinese language, but the Images are in English ;) ):
http://forum.xitek.com/forum-redirect-goto-findpost-ptid-1444928-pid-64672058.html
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Bjørn Rørslett

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Re: LAOWA STF105mmF2.0 Smooth Trans Focus lens
« Reply #8 on: January 17, 2016, 12:06:18 »
Strange transition halos in some of these examples (see the contours of the camera/lens slung over the shoulder of the Canon guy), background bokeh appears smooth in general though.

There are squished highlights in some of the portraits of that burly canon shooter (the guy with the 'Jeep Romance(sic)' jacket). Tricky to say whether this is caused by lens or camera.

Apparently the lens lacks a CPU as the example with Nikon D800 reports a fictive 'f/1' aperture.

Fons Baerken

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Re: LAOWA STF105mmF2.0 Smooth Trans Focus lens
« Reply #9 on: January 17, 2016, 12:13:49 »
My first thought is indeed the 105/2 DC. ???