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Next PZ lens test report: Nikon AF-S 200mm f/2 G ED VR (DX)
#11
[quote name='you2' timestamp='1295441790' post='5641']

Wow; the bokeh and loca look almost perfect but that flare - ouch. I thought the nano-coating was suppose to make that a thing of the past <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/smile.gif' class='bbc_emoticon' alt='Tongue' />



[/quote]





The tested version does not have the Nano Crystal Coating...<img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/wink.gif' class='bbc_emoticon' alt='Wink' />
#12
[quote name='PuxaVida' timestamp='1295440110' post='5640']

I personally use "pleasant" for the bokeh quality. And by pleasant I consider the "nature" of the blur more than the "amount" of it. I believe the amount of the blur highly depends on the size of the entrance pupil. So, depending on the subject and background distance, you have more playground with the fast lenses (I'm not sure when it comes to the front bokeh). But the nature of blur depends on the (corrected) spherical aberrations. The image of CoC is almost homogenious in terms of brightness (no harsh outlinings or no harsh brightness transitions for example). In the bokeh test shots of this lens, the blurred highlight disks in background seem to be exceptional in that manner. And I think if the the word "creamy" could be used for the combination of both amount & nature of the bokeh, the bokeh of this lens is "creamy".



However, it still confuses me, howcome the statement "true APO lenses, which have less (or no) spherical aberration, don't show LoCAs and they're usually slower primes in tele field" could be true. I can't explain this to myself with regard to this lens. You guys have any idea?



Serkan

[/quote]

CoC? Are you confusing two things? You can not see a CoC, the CoC is an imaginary entity to try and express how for instance print size and view distance influence perceived depth of field and sharpness.



Also, the shape and homogenous quality of out of focus highlights have no one on one relation to the smoothness of bokeh. In fact, there are lenses that show very homogenous and round highlights, and yet have awful bokeh.



Bokeh should be called "creamy" when the transitions are very smooth, when the blur is silky and effortless. Not a quality of this particular lens, in all fairness. That the background gets blurred a lot, yes, that is evident. And one would expect nothing less with f2 at 200mm. But, besides the blur, it is just not a lens which bokeh can be described as "creamy".



Examples to illustrate that:

[Image: 4045067676_d240ce7b36_z.jpg]



[Image: 4045069254_20e0e7a1b5_z.jpg]



(from http://www.flickr.com/photos/grobarek/40...otostream/)



[Image: 424882088_KQur8-O.jpg]



[Image: 424882152_XjbAU-O.jpg]



Compare that to the bokeh of the 2 images posted by genotypewriter. They have no perfectly creamy bpkeh either, but it looks at least more smooth.



Yes, the Nikon 200mm f2 VR is an impressive lens. No, its bokeh is not creamy at all.
#13
[quote name='PuxaVida' timestamp='1295448081' post='5646']

... and my question is, why is that so? How does being a slower lens helps correcting spherical aberrations? Is that because of the coating (which allows less but collimated light) or polishment applied to the glass etc...

[/quote]

A slower lens has a smaller aperture and hence light that's going through the corners need to bend less -> less chances for spherical aberration.



Longer lenses usually fair better because, due to their narrow FOVs, the glass used don't have very high refractive indices like fast/short lenses do. Also longer lenses get the good stuff - fluorite elements. Canon's 200 2, 300 2.8, 400 2.8, 500 4, 600 4, 800 5.6, 1200 5.6 all have expensive fluorite glass that's used for reducing CA. AFAIK, only the very expensive/special purpose 60mm f/4 UV-VIS-IR APO macro has fluorite elements in a non-tele lens (iirc, it has 4!).



Coatings have very little to do with CA.
#14
[quote name='Brightcolours' timestamp='1295451179' post='5651']

Compare that to the bokeh of the 2 images posted by genotypewriter. They have no perfectly creamy bpkeh either, but it looks at least more smooth.



Yes, the Nikon 200mm f2 VR is an impressive lens. No, its bokeh is not creamy at all.

[/quote]

In all fairness it's not reasonable to expect nostalgic large format creamy bokeh from highly corrected, fast 35mm lenses. Can't think of an ordinary and fast lens (e.g. not the STF type) that'll be sharp and still give creamy bokeh and the chances of such mythical beasts coming up in the future are even slimmer.



Also the smoothness of the bokeh also depends on the viewing magnification. For example try viewing the different resolutions of this shot done using the 300 2.8 IS:

http://www.flickr.com/photos/genotypewri...3/sizes/l/



GTW
#15
[quote name='Brightcolours' timestamp='1295451179' post='5651']



Yes, the Nikon 200mm f2 VR is an impressive lens. No, its bokeh is not creamy at all.

[/quote]



I don't see an indication from those samples indicating that the IS lens is "better" here.

The VR shot with the poles will look nervous on most lenses except the Sony STF maybe - this is too much of a stress for a conventional lens.



The shown Canon samples are far simpler scenes - closer main objects thus more blur. No surprises that they appear to be "better" but they're just different.
#16
[quote name='Klaus' timestamp='1295459348' post='5659']

I don't see an indication from those samples indicating that the IS lens is "better" here.

The VR shot with the poles will look nervous on most lenses except the Sony STF maybe - this is too much of a stress for a conventional lens.



The shown Canon samples are far simpler scenes - closer main objects thus more blur. No surprises that they appear to be "better" but they're just different.

[/quote]

Well, if you don't see any indication of that, I don't know what to say.



The poles one can be rendered a lot better with many lenses, including of course the Sony 135mm STF. But even a zoom lens of mine does a smoother job (although it of course can't reach the same level of blur).



It is not about the "simpler scenes", and it can't get more simple than the seagull shot. In every shot of the VR one, you will start to see double shapes/edges/lines and highlights that start their own "object" (shape). In contrast to the IS lens, which just shows smoother transitions.



Other example of the two lenses (even though it should just be about the 200VR's "creaminess"):

200VR:

[Image: NV3_1041-edit.jpg]

200IS:

[Image: Jackie-P_nyc_131-blog-900.jpg]



I would like to have either lens, no doubt. But creamy is not what comes to mind with the bokeh of the Nikon.
#17
Sorry, but the rendition of the background guy doing the V in the Canon shot is not smooth either.

I'm not a Nikon fan but I don't spot the superiority you're talking about in the IS shot.
#18
[quote name='Klaus' timestamp='1295470208' post='5665']

Sorry, but the rendition of the background guy doing the V in the Canon shot is not smooth either.

I'm not a Nikon fan but I don't spot the superiority you're talking about in the IS shot.

[/quote]

I just love how people take two photos taken under fundamentally differnt lighting conditions and with different camera to subject distances and seriously believe they can darw any valid conclusions from such comparism. In any event, whatever lens is better, the Canon lens is not going to fit anybdoy's Nikon mount (at least not with AF enabled) so what the heck is going on here?
#19
[quote name='Brightcolours' timestamp='1295451179' post='5651']

CoC? Are you confusing two things? You can not see a CoC, the CoC is an imaginary entity to try and express how for instance print size and view distance influence perceived depth of field and sharpness.

[/quote]



No I'm not... By CoC I mean the spot consisting of non-perfect focussed points produced by the light cones coming through the lens. The brightness over this spot is homogenous if the lens does not suffer from spherical under- or over-correction. In that respect, I think the CoC has an effect of bokeh characteristics.



Quote:Also, the shape and homogenous quality of out of focus highlights have no one on one relation to the smoothness of bokeh. In fact, there are lenses that show very homogenous and round highlights, and yet have awful bokeh.



I never said that the shape of the aperture iris image has an effect on smoothness of the bokeh. I'm saying that the homogenous light disks result in smooth transitions in bokeh. I that context, I accept the idea that this defines the nature of the bokeh, and additionally the amount of the bokeh (which highly depends on the maximum aperture) together with this can tell a lot regarding the "creamyness" of it. OTOH, the characteristics of the bokeh depends on other things outside the lens barrel: picture format, distance to subject, brightness of subject back/foreground, shapes and patterns of the subject etc... So I think one should be very meticulous when comparing sample images.



In fact, checking the test shots in PZ again, I think that the bokeh of 200mm VR is as creamy as it can be for a that much fast lens (especially when stopped down a bit). I find the Voigtlaender APO Lanthar 90mm f/3.5 to have more creamy bokeh at it's maximum aperture, but the Nikon is still exceptional I think.



Serkan
#20
[quote name='jenbenn' timestamp='1295508403' post='5671']so what the heck is going on here?

[/quote]



As usual - GTW hijacking the topic <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/laugh.gif' class='bbc_emoticon' alt='Wink' />
  


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