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01-13-2016, 07:07 AM   #16
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QuoteOriginally posted by jeffshaddix Quote
Does anyone know if the K mount version will have KA contacts?
So far the K-mount versions of their other lenses lack even auto-aperture linkages.

01-13-2016, 08:54 AM   #17
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Laowa is making some really interesting glass. I have the 60mm macro, but to be honest I don't use it enough. Esp since its focus ring is very stiff. The 15mm macro is fascinating as well, but I'm still not sure whether I should add it to my kit. It would allow novel macro images... tempting...

And now this. A nice bokeh lens would be great, esp for my bokehrama shots. Now I use the DA*50-135/2.8 for this mostly while traveling far away, and either the FA77/1.8 or my revuenon 55/1.2 when shooting closer to home. It *is* a bit long on APS-C though, and I'm not intending to move to FF anytime soon... I was considering the Samyang 135/2 for this reason as well (and also for its astro potential), so it's going to be a toss up. Of course the Samyang is a A-lens and this is a M-lens...

Wim
01-13-2016, 11:20 AM   #18
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QuoteOriginally posted by Ishpuini Quote
The 15mm macro is fascinating as well, but I'm still not sure whether I should add it to my kit. It would allow novel macro images... tempting...
But it is not that difficult to do.
Basically any WA lens is a macro lens.

DA10-17:
01-13-2016, 11:41 AM   #19
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QuoteOriginally posted by blende8 Quote
But it is not that difficult to do.
Basically any WA lens is a macro lens.

DA10-17:
The maximum magnification of DA 10-17mm f/3.5-4.5 Fish-Eye is 0.39x. The one of DA 15mm f/4 Limited is 0.15x.

The maximum magnification of Venus Optics Laowa 15 mm f/4 Macro is 1.0x. In addition, it's a shift lens.

01-13-2016, 01:13 PM   #20
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QuoteOriginally posted by Class A Quote
It puzzles me why not more lenses using an apodisation filter are offered.
Partly because it's an element and not a filter, the difference being that as an element it's engineered into the optical formula. I think, and I admit this is conjecture, that the reason has to do with how the element has to be concave. The edges HAVE to be thicker to introduce more light loss and, through that, feather the perimeters of the out of focus circles of confusion to a greater extent. I was surprised, actually, to see how little difference there is between the center and edge thickness of their apodization element. And it shows, too, in the one image of the monk where a specular highlight is visible that there is not really that much light drop-off in the out of focus circle of confusion (there's not a great deal of feathering).
01-13-2016, 03:38 PM   #21
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QuoteOriginally posted by Ishpuini Quote
I was considering the Samyang 135/2 for this reason as well (and also for its astro potential), so it's going to be a toss up. Of course the Samyang is a A-lens and this is a M-lens...
Also keep in mind, if you want this for astrophotography, that it is a T3.2 lens, meaning it has a huge light transmission loss of 1.3 stops from its nominal f/2.0 aperture (the Samyang 135mm is T2.2, or ~0.3 stop loss).

Last edited by Cannikin; 01-13-2016 at 03:50 PM.
01-13-2016, 04:22 PM   #22
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QuoteOriginally posted by Cannikin Quote
Also keep in mind, if you want this for astrophotography, that it is a T3.2 lens, meaning it has a huge light transmission loss of 1.3 stops from its nominal f/2.0 aperture (the Samyang 135mm is T2.2, or ~0.3 stop loss).
Agree. That's the trade off between bokeh and aperture.
01-13-2016, 04:30 PM   #23
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QuoteOriginally posted by blende8 Quote
But it is not that difficult to do.
Basically any WA lens is a macro lens.

DA10-17:
Nice shot, but something should be done in PT to avoid the awfull area around the tree

01-13-2016, 05:13 PM - 1 Like   #24
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Well, as a long term Sony Alpha user my self, I can also say this LAOWA STF lens is a nice effort but not as nice as the Minolta/Sony 135 STF lens. If you notice the photo of the man in red, the yellow light highlight to the left is rendered with a football shape while Sony 135 STF would render as a smooth circle. Also the transition from the highlight is little too hard.

Here is example of 135 STF render vs normal lens. The LAOWA looks like a normal lens.

http://www.glaringnotebook.com/zimages/mgoc4.jpg
01-13-2016, 05:53 PM   #25
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QuoteOriginally posted by Mistral75 Quote
According to the available literature, phase-detection autofocus cannot work with an apodisation filter.
I had read the explanation on the 135 STF website and the FAQ entry on Michael Hohner's page before, but I don't find these accounts convincing.

In the presence of an apodisation filter, an AF module has less light to work with, but I don't see a reason why the phase shift principle shouldn't work anymore.
01-13-2016, 06:06 PM   #26
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QuoteOriginally posted by K David Quote
Partly because it's an element and not a filter, the difference being that as an element it's engineered into the optical formula.
While I'm not an optical engineer, I don't think you have a point with "element vs filter".

The purpose of the apodisation filter -- it is indeed called "filter" at the STF 135 page about "apodisation" -- is to achieve a tapering off of the point-spread function (PSF) of the lens so that diffraction is reduced.

This effect should be achievable with any graduated filter element, even a flat one. Indeed, apparantly photon sieves have been used for apodisation and Markus Keinath has created his own film-based apodisation filter which is flat and working as intended.

QuoteOriginally posted by K David Quote
I think, and I admit this is conjecture, that the reason has to do with how the element has to be concave. The edges HAVE to be thicker to introduce more light loss and, through that, feather the perimeters of the out of focus circles of confusion to a greater extent.
I believe using an element with a constant density but varying thickness is just one of many approaches.

Also, I do not think that the rest of the optical design needs to be build around the apodisation filter. The purpose of the filter is to smooth out the discontinuity represented by the aperture blades so every lens can be turned into an STF lens by placing an apodisation filter close to the aperture mechanism. I'm not saying that it does not make sense to optimise the optical formula for the special purpose and special characterista an STF lens has, but I think your criticism of the Fuji lens, for instance, is unjustified.
01-13-2016, 10:12 PM - 1 Like   #27
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QuoteOriginally posted by K David Quote
Interestingly, and somewhat coincidentally, I released a YouTube video last week about the Sony STF lens. It explains how an STF lens works, why the apodization filter causes the STF effect, and what the STF effect is. I'm also finishing up a forum article about it, and the forum article is much more detailed than the video.

https://youtu.be/GXUoeE3fQVM

---------- Post added 01-12-16 at 11:51 PM ----------

That lens looks like it's going to have two apertures, just like the Sony. That's very exciting. I hope the Pentax mount is PKA.
Excellent video - I look forward to your article!
01-14-2016, 01:13 AM   #28
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QuoteOriginally posted by blende8 Quote
But it is not that difficult to do.
Basically any WA lens is a macro lens.

DA10-17:
Nice shot!!

You're absolutely right, actually that is one of the reasons why I didn't buy the 15mm. Though its having shift as well does add something to its appeal. Regardless, I have too many lenses covering a similar angle already (Sig 8-16, DA10-17, DA15/4, Samyang 16/2, DA*16-50/2.8), i.e. another reason not to add one more.

The 105 is more appealing though...

tx, Wim

---------- Post added 01-14-2016 at 09:18 AM ----------

QuoteOriginally posted by Cannikin Quote
Also keep in mind, if you want this for astrophotography, that it is a T3.2 lens, meaning it has a huge light transmission loss of 1.3 stops from its nominal f/2.0 aperture (the Samyang 135mm is T2.2, or ~0.3 stop loss).
Tx for the tip. I was indeed referring to the astro capacities of the Samyang 135, versus the out-of-focus capacities of this new Laowa. The optical qualities of the Laowa glass didn't impress me too much until now, contrary to Samyang. However, I might buy both in the end... For the Laowa I'll wait to see some real life results first...

grtz, Wim

Last edited by Ishpuini; 01-14-2016 at 02:14 AM.
01-14-2016, 01:36 AM   #29
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Wim, buy both and impress us with a direct comparison!
01-14-2016, 03:13 AM   #30
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QuoteOriginally posted by ColiNiloK Quote
Well, as a long term Sony Alpha user my self, I can also say this LAOWA STF lens is a nice effort but not as nice as the Minolta/Sony 135 STF lens. If you notice the photo of the man in red, the yellow light highlight to the left is rendered with a football shape while Sony 135 STF would render as a smooth circle.
That effect on highlights is called coma, it is a complex effect caused by optical/mechanical occlusion of the COC. All lenses suffer from it to some extent, it is most visible at close focusing distances even the Minolta (R.I.P) 135mm STF would suffer from it, probably even with the apodization filter in full effect.
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