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Laowa (Venus) 105mm f2 STF
#1
Soon to be officially announced portrait lens with apodization filter (think Sony 135mm 2f.8 t4.5 STF,  Fuji XF 56mm f1.2 R APD):

[Image: TB25dhMjXXXXXcPXXXXXXXXXXXX_!!2389857399.jpg]

 

[Image: TB2WcXYjXXXXXaOXXXXXXXXXXXX_!!2389857399.jpg]

[Image: TB2ck41jXXXXXX9XXXXXXXXXXXX_!!2389857399.jpg]

http://www.chassimages.com/forum/index.p...127.0.html

 

Looks pretty good....

#2
And soon in this theater ... ;-)

#3
 I'm afraid I have to show my ignorance.........

 

...............what's a apodization filter..................and do I need one?

 

OK I've found it, a high refractive index element which gives an increased smooth focus transition for soft OOF bokeh.

 

  Yeah I need and want one of those!.... -_-

 

 

 

  Oh and Klaus/BC/Airydiscus.......how about a "simple for idiots" explanation on interpreting resolution charts...... please?

Dave's clichés
#4
There's no universal truth how to read the results ... but an 'idiot's approach' would be as follows':

 

Say you have 2000 LW/PH.

3:2 screen ration 

2000 * 3/2 = 3000 LW/PW

 

2000x3000 = 6mp local resolution (equivalent pixel density at the center/border or corner).

Now see that in relation to the sensor.

If you got a 6mp sensor that would be superb. If you got a 50mp sensor ... then not so much.

 

Very simplified (Brandon would kill me for the above)

#5
Dave, apodization filters are an instrument to get a smoother bokeh, see: https://en.wikipedia.org/wiki/Apodization (there's also something about airy discs, so probably you get a "far beyond Wiki" lecture from master Airydiscus himself  Rolleyes

 

No matter what magic this thing can do with bokeh, I did bit of googling and I own the Laowa 15/4 macro, so I just throw in some thoughts:

 

A bunch of macro-enthusiasts is not the same as a bunch of high level optical designers, right? At the end they make and sell working lenses, that's now the third to come and will get buyers because it's exotic and promises lots of great features: macro lens and super bokehlicious portrait glass, reasonably fast. But after that? No AF, of course. No EXIF data because mechanics don't talk with electronics. Aperture goes down to f/32 and after f/8 every macro lens with a focus stack device and/or app will deliver better results, DoF-wise.

 

http://www.venuslens.net doens't list it yet, 3 days after "announcement" - that's Laowa's representation site and sometimes unavailable for whatever reasons. I won't go again into the debate "Chinese manufactures ignore European trading laws". But the Laowa lens, once broken, will cost you some trouble to repair. To be fair, if Nikon needs a month to fix a 300/4 PF E, within that time Laowa could do just the same.

 

Read the technical facts carefully, if you manage to find them. What's not in them, it will not be on board - for instance, the 15/4 macro doesn't even have an automatic diaphragm... I did some shots with the 15 mm macro and with LiveView I don't need to bother much about missing automatic diaphragm - but how often did I make a full session of portraits in LiveView? Never, if I recall properly.

 

A Nikon AF 105mm f/2.0 D DC does have that, plus AF and the minimum focus distance is just about the same and the price [Edit]: is about 35% more than the Micro Nikkor version and my estimated end-price after importing that Laowa to Europe [/Edit]. If I'm looking of such a special portrait lens, I would strictly go genuine!

 

Btw. there's also a Fujifilm Fujinon XF 56mm F1.2 R APD doing the same trick and costing about 45% more than the already nice non-APD. Thanks, I'm passing.

#6
Quote:There's no universal truth how to read the results ... but an 'idiot's approach' would be as follows':

 

Say you have 2000 LW/PH.

3:2 screen ration 

2000 * 3/2 = 3000 LW/PW

 

2000x3000 = 6mp local resolution (equivalent pixel density at the center/border or corner).

Now see that in relation to the sensor.

If you got a 6mp sensor that would be superb. If you got a 50mp sensor ... then not so much.

 

Very simplified (Brandon would kill me for the above)
OK Klaus thanks!
Dave's clichés
#7
Quote:Dave, apodization filters are an instrument to get a smoother bokeh, see: https://en.wikipedia.org/wiki/Apodization (there's also something about airy discs, so probably you get a "far beyond Wiki" lecture from master Airydiscus himself  Rolleyes

 

No matter what magic this thing can do with bokeh, I did bit of googling and I own the Laowa 15/4 macro, so I just throw in some thoughts:

 

A bunch of macro-enthusiasts is not the same as a bunch of high level optical designers, right? At the end they make and sell working lenses, that's now the third to come and will get buyers because it's exotic and promises lots of great features: macro lens and super bokehlicious portrait glass, reasonably fast. But after that? No AF, of course. No EXIF data because mechanics don't talk with electronics. Aperture goes down to f/32 and after f/8 every macro lens with a focus stack device and/or app will deliver better results, DoF-wise.

 

http://www.venuslens.net doens't list it yet, 3 days after "announcement" - that's Laowa's representation site and sometimes unavailable for whatever reasons. I won't go again into the debate "Chinese manufactures ignore European trading laws". But the Laowa lens, once broken, will cost you some trouble to repair. To be fair, if Nikon needs a month to fix a 300/4 PF E, within that time Laowa could do just the same.

 

Read the technical facts carefully, if you manage to find them. What's not in them, it will not be on board - for instance, the 15/4 macro doesn't even have an automatic diaphragm... I did some shots with the 15 mm macro and with LiveView I don't need to bother much about missing automatic diaphragm - but how often did I make a full session of portraits in LiveView? Never, if I recall properly.

 

A Nikon AF 105mm f/2.0 D DC does have that, plus AF and the minimum focus distance is just about the same and the price . If I'm looking of such a special portrait lens, I would strictly go genuine!

 

Btw. there's also a Fujifilm Fujinon XF 56mm F1.2 R APD doing the same trick and costing about 45% more than the already nice non-APD. Thanks, I'm passing.
Thanks JoJu for the link:

 

     OK ,so is this element semi opaque ....is it graduated opaque.... at the edges......are we talking a reduction in T stops here?

 

 Airydiscus......where art thou?


    Manual focus and no camera communication is one thing, but no automatic diaphragm would be just a step beyond frustration, like that 2:1 macro! 
Dave's clichés
#8
Quote: 

  Oh and Klaus/BC/Airydiscus.......how about a "simple for idiots" explanation on interpreting resolution charts...... please?
Uhmm... Simple (as far as I understand it then):

 

[Image: TB2WcXYjXXXXXaOXXXXXXXXXXXX_!!2389857399.jpg]

You see a grid, horizontally going from 0 to ~21..5 mm.

That represents the 135 format film/sensor, from center (0) to corner:

film = 36x24mm. Diagonal is 36^2 + 24^2 = 1872. square root from 1872 = ~43mm. Half the diagonal is then ~ 21.5mm.

 

Vertical represents the performance. 1 is when separation between black and white lines used to measure the lens is perfect, 0 represents no separation at all, just an even grey mess.

 

10 lines per mm (line pairs (b + w) per mm) is used to measure contrast, 30 lines per mm to measure sharpness, basically.

The solid lines are "Radial" or "sagittal" lines, they go parallel with the radius. The dotted lines are "Meridian" or "tangential" lines, they go at right angles to the radius.

 

We can see that this lens is pretty sharp, especially if this is from measuring wide open. We also can see that the lens is pretty contrasty.

 

When the sagittal and meridian measurement lines are close together, that shows pretty good performance with certain aberrations/distortions like astigmatism, and also shows the lens probably having smooth bokeh.

In this case, the lines are pretty close together, so we can expect pretty good bokeh (which the sample images concur).

 

We also can see that the lens performs better at the center than at the corners, but when we compare this MTF chart with those of other lenses, we can also conclude that the corner performance is pretty good for this lens.
#9
Quote:Thanks JoJu for the link:

 

     OK ,so is this element semi opaque ....is it graduated opaque.... at the edges......are we talking a reduction in T stops here?

 

 Airydiscus......where art thou?


    Manual focus and no camera communication is one thing, but no automatic diaphragm would be just a step beyond frustration, like that 2:1 macro! 
Yes, that is why there is such a big difference between f-value and T-value. The apodiation element is the cause.

 

No automatic aperture is not a big deal with this lens, as it will mostly be used wide open or close to wide open. Just like it is no big deal with my adapted 55mm f1.2 lenses for instance. The purpose of the lens is portraits with shallow DOF and smooth bokeh.
#10
One can really discuss if AF on portraits is a major necessity and I think it all comes down at how dynamic a setting in a portrait session changes. In a studio, with ready lit background and the "portrait chair" one could weld the focus ring ... Out in the wild, photographer and model tend to move. I'm not certain AF will always be better than manual focus - by the way, "better" is what? More precise? Quicker? An aid like optical glasses for people with eye problems? The older I get the more I tend to trust a good AF, especially at night.

 

As Laowa stated, phase detection AF is useless, we have to look at contrast detection (that's how Fuji's autofocusing their APD version Wink ) which brings up the question - is that a DSLR lens?

 

"Shooting wide open all time" is a statement I will not even remotely discuss. What sounds ridiculous to me might just be the thing for somebody else. Now, the Nikon lens is a quite dated version, no update in sight, and the Fuji... I could get one as a left over for 150 francs less but even then, I don't intend to spend more than 1k on a DX-only thing. I don't see this lens as something the market was longing for ages.

  


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