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Author Topic: Sony A900  (Read 48450 times)
Kenneth Sky
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« on: December 03, 2008, 08:19:09 AM »
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As usual, Michael has hit the nail on the head. As one of the first Canadians to have obtained the A900 retail, it's nice to have your decision confirmed by an expert. But who'd have thunk MR was a psychologist! Yes, I'm one of those "contrarians" that he speaks of. I'm also one of many, who have hung onto my Minolta prime lenses through Sony's earlier DSLR models that were far from pushing the envelope. What Sony continues to offer is enough Minolta DNA to make the user believe the camera was designed by & for photographers as opposed to engineers or marketing strategists. As for legacy lenses, some of my old primes such as the 35mm 1.4 & 85mm 1.4 are now giving me results better than when I used them on a Maxxum 9 (film camera for you youngsters). Another unique Minolta lens - the 500mm f/8 AF is hand holdable with the built-in stabilization offering oportunities other systems could only wish for. Thanks for the review Michael. Now, where do I pay for my psychiatric consultation?
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michael
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« Reply #1 on: December 03, 2008, 08:50:02 AM »
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Ken,

Thanks... you can leave payment with the receptionist on the way out.

BTW, I picked up the 500mm Mirror Reflex lens the other day and I'm quite impressed. Having autofocus in such a lens is a first, and when you add stabilization it really is quite unique.

No, it's not a sharp as a 500mm prime, but then again the size and weight are negligible, and the money you save in not having to have a Sherpa on staff is considerable.

I've only done a few quick tests, but results seem reasonable for what it is. I'm looking forward to some testing and use in the days ahead.

Michael

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ErikKaffehr
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« Reply #2 on: December 03, 2008, 09:11:17 AM »
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My favorite is the KM 400/4.5 APO. It's not to heavy and works well with 1.4X extender. I hope that Sony reintroduces it.

Very nice review, BTW. Much appreciated, now I just wait for RRS to develop an L-plate for it.

Best regards
Erik

Quote from: michael
Ken,

Thanks... you can leave payment with the receptionist on the way out.

BTW, I picked up the 500mm Mirror Reflex lens the other day and I'm quite impressed. Having autofocus in such a lens is a first, and when you add stabilization it really is quite unique.

No, it's not a sharp as a 500mm prime, but then again the size and weight are negligible, and the money you save in not having to have a Sherpa on staff is considerable.

I've only done a few quick tests, but results seem reasonable for what it is. I'm looking forward to some testing and use in the days ahead.

Michael
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Yanchik
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« Reply #3 on: December 03, 2008, 09:46:18 AM »
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"was designed by & for photographers as opposed to engineers or marketing strategists. "

As an ex-engineer and current marketing strategist (bigger game than cameras, though,) I resemble your remark...

However, as my photography trajectory goes X300 - A100 - Huh, I'm having a good month. We all are. Sony aren't heros or villains, neither are the other two firms. But with a thumping serious camera like the A900 coming out and receiving a solid review from someone who's widely listened to, a little bit more competition and innovation in the marketplace can do no bad thing. And for me personally, the thought that my gear is unlikely to get orphaned in the near future is very, very pleasant.

Good days to all of you,

Y
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ejmartin
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« Reply #4 on: December 03, 2008, 10:29:26 AM »
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Some remarks on the Noise/DR/Resolution section of the article:

Resolution vs pixel level noise is always the tradeoff, if one's criterion is noise at the pixel level.  That is simply because noise power rises with increasing fineness of scale in the image.  All other things being equal, decreasing the pixel size to increase resolution simply samples the scene at finer scales, and noise at those finer scales is necessarily higher due to the physics.  For instance, here's a plot of noise power vs image scale (spatial frequency) for a 40D and 50D (test images from Imaging-Resource; ISO 1600, converted from RAW in DPP):



The horizontal axis is scale in the image, the vertical axis is noise power; so each data point is a measure of the amount of noise at a particular scale.  The somewhat arbitrary units for the horizontal axis put the Nyquist frequency (the limit of resolution) at 256 for the 50D, and at 209 for the 40D.  The two cameras are more or less the same up to the point where the 40D stops resolving, while the 50D climbs a bit higher.  So, the pixel-level noise in the 50D is higher than that of the 40D, simply because it resolves more.  If one were to downsample the 50D image to the 40D pixel dimensions (I have done this and shown results in some threads over at DPR), the 50D plot would look like a clone of the 40D one -- the fine scale noise is thrown away together with the extra resolution upon downsampling.  So the noise and the resolution come hand in hand -- one simply has to decide what one wants.

As for the noise being less "grid-like" and more "stochastic", that is a property of the way the RAW converter is interpolating the Bayer data, and has little to do with the capabilities of the camera.  For some reason, Adobe products (ACR/LR) are extremely variable in the way they treat different cameras.  However, it should be said that with ahigh MP file, interpolation artifacts will be at a very fine scale regardless.

At high ISO, the DxO data does seem to indicate that the A900 is a poorer performer than the 1Ds3 and D3/D700, even when compared fairly by compensating for the scale dependence of noise.  It seems that Sony has some work to do in reducing the electronic noise of the sensor, in order to catch up with C/N.  I've not done any tests myself, but the DxO data seems to indicate that the S/N performance is poorer than the competition at high ISO, and better than the competition at low ISO (one might speculate that this is due to the column-wise parallel processing of data coming off the photosite array).  Since dynamic range is determined by S/N performance, that too is worse at high ISO than the competition and perhaps a bit better at low ISO than the competition, as Michael seems to be observing.

Bits -- the camera doesn't need 14 bits!  According to DxO, there are only 11.5 stops of DR maximum, so 12 bits is ample.  This will be more and more true as pixel counts grow, since the pixel level DR will go down as the pixel level (but not image level) noise increases; see above.  Less DR means fewer bits needed to encode it.

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emil
Kenneth Sky
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« Reply #5 on: December 03, 2008, 10:30:19 AM »
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Michael
As posted on another thread by someone else, my experience with high ISO arw files from both the A700 and the A900 are handled best by Aperture as opposed to LR. This is most noticeable with the chroma noise.
Ken
P.S. If you would like to try out any of my lenses, I live close enough to you to drop them off for a week or so. Just e-mail me.
KS
« Last Edit: December 03, 2008, 10:33:03 AM by Kenneth Sky » Logged
01af
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« Reply #6 on: December 03, 2008, 10:48:40 AM »
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Quote from: michael
I picked up the 500 mm mirror Reflex lens the other day and I'm quite impressed. Having autofocus in such a lens is a first, and when you add stabilization it really is quite unique.
It indeed is. With the Minolta AF Reflex 500 mm on the Konica-Minolta Dynax 7D, with Anti-Shake on I routinely get perfectly sharp shots hand-held at 1/125 s (at 750 mm equivalent!). When trying hard, you can also get away with 1/100 s or 1/80 s most of the time.


Quote from: michael
I'm looking forward to some testing and use in the days ahead.
The AF Reflex 500 mm will often show a hot-spot at the image's center---as most catadioptric lenses do---which will appear more or less pronounced depending on lighting conditions, exposure, and image content. Also contrast is not the highest, which again is a common flaw with most mirror lenses. But it's virtually free of chromatic aberrations due do the catadioptric principle, and pretty sharp. However to appreciate the sharpness, you'll have to make sure focus is accurate, and then crank up contrast a bit. In Camera Raw, using the "Strong Contrast" tone curve rather than the default "Medium Contrast" provides a good starting point.

To reduce the hot-spot and increase contrast---at least to a degree---, a decent lens hood will help significantly. The hood that comes with the lens is ridiculously short. I made a simple tube from black cardboard paper about the length of the lens with just slips over the original hood. Unfortunately, such a cardboard tube is delicate and hard to carry without smashing it in the bag; it will take a lot from the lens' own compactness. But the results are worth the hassle.

By the way, the rear-element filter drawer from the Minolta AF Apo G telephoto lenses will also fit the AF Reflex's filter slot exactly---and this does include the (elusive, expensive) integral polarizer filter unit.

-- Olaf
« Last Edit: December 03, 2008, 10:54:46 AM by 01af » Logged
Tony Beach
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« Reply #7 on: December 03, 2008, 11:17:15 AM »
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Overall I like the review; although I'm dubious of DxOMark references (I've corresponded with Thom Hogan about the DR claims DxOMark makes about the DR of the D90, and there's no way it exceeds the D3 or D700).  Reading MR's review though convinces me that carefully exposed images with best quality lenses will produce the landscape results I'm looking for; now all I need to finalize my decision about this camera is to see how the Sony 16-35/2.8 ZA compares to my Nikkor 14-24/2.8, right now it looks like Nikon is about to lose me fas far as any future purchases are concerned, but I will keep my D300 and a couple of my favorite Nikkors since I love those and I also have a D200 IR and may soon get a relatively unique D200 B&W (no AA or CFA filters).

Does anyone know how much those Hartlbei TS lenses are going to cost?  Does anyone want to buy a couple of modified Nikkor PC-E lenses?  No, I'm not really soliciting a sale here, I'm trying to make a point, because this is where Nikon will really lose me for good.  Once I sell off the Nikkor PC-E lenses and start buying those Hartlbei lenses, I will be more vested in the Sony system than the Nikon system; and switching back simply isn't going to happen.  For Nikon this is a critical moment, I believe they just might slip to third in DSLRs over the next two years if they don't deliver a reasonably priced "D700x", and deliver it fast because for a lot of us the clock is now ticking.
« Last Edit: December 03, 2008, 11:18:50 AM by Tony Beach » Logged
Quentin
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« Reply #8 on: December 03, 2008, 11:42:46 AM »
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I collect my A900 and Zeiss 24-70 F2.8 tomorrow.  The A900 really seems to be gaining traction in the market.  A long time Nikon user friend of mine has just purchased an A900 and is thrilled with the results he is getting.  I can hardly wait to try it out.

Quentin

PS the review is also the most thorough I have seen of the A900.
« Last Edit: December 03, 2008, 12:10:04 PM by Quentin » Logged

Quentin Bargate, ARPS, Author, photographer entrepreneur and senior partner of Bargate Murray, Law Firm of the Year 2013
tamerlin
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« Reply #9 on: December 03, 2008, 12:06:16 PM »
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Quote from: ejmartin
Bits -- the camera doesn't need 14 bits!  According to DxO, there are only 11.5 stops of DR maximum, so 12 bits is ample.  This will be more and more true as pixel counts grow, since the pixel level DR will go down as the pixel level (but not image level) noise increases; see above.  Less DR means fewer bits needed to encode it.

False.

If you take a meter stick and divide it into decimeters, then take another meter stick and divide it into centimeters, which one will give you more accurate results?

That answer should be obvious, and equally obvious is the fact that the meter stick is still a meter long, even though we've carved it into more chunks. The advantage in 14 bit a/d conversion over 12 bit is identical. The bit depth doesn't relate to dynamic range.
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douglasf13
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« Reply #10 on: December 03, 2008, 12:07:52 PM »
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Quote from: michael
Ken,

Thanks... you can leave payment with the receptionist on the way out.

BTW, I picked up the 500mm Mirror Reflex lens the other day and I'm quite impressed. Having autofocus in such a lens is a first, and when you add stabilization it really is quite unique.

No, it's not a sharp as a 500mm prime, but then again the size and weight are negligible, and the money you save in not having to have a Sherpa on staff is considerable.

I've only done a few quick tests, but results seem reasonable for what it is. I'm looking forward to some testing and use in the days ahead.

Michael

  Wonderful review, Michael.  I wanted to mention to you that the $10 Minolta hotshoe adapters on ebay are an easy solution for pocketwizards and such.  I keep a few of them around at all times, or I use the PC sync

  I agree with the above that, unfortunately, Lightroom/ACR is the worst RAW converter I've seen for the A900 in regards to noise.  I'm debating switching to the new Bibble 5 when it arrives, although I don't shoot high ISO too much, so I may just deal with it.  Capture One, Bibble and Aperture do a much better job with the A900

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MatthewCromer
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« Reply #11 on: December 03, 2008, 12:08:39 PM »
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Quote from: Quentin
I collect my A900 and Zeiss 24-70 F2.8 tomorrow.  The A900 really seems to be gaining traction in the market.  A long time Nikon user friend of mine has just purchased an A900 and is thrilled with the results he is getting.  I can hardly wait to try it out.

Quentin

Good luck with it.  I've started buying some used Minolta glass for an Alpha 900 purchase in January.

I picked up the 28-135/4-4.5, 50/1.4 and 70-210/4 (beercan).  All have been raved about on the 900, and I got them for $200 each on ebay.  For landscapes they should perform superbly (well the 50 is for occasional event photography).

I'll probably pick up a new Sigma 12-24 to cover the wide angles (I want to be able to exchange for a good copy) when I get the 900 and can make sure my 12-24 is up to snuff.

At some point I'll be able to justify buying some more expensive glass, but this should give me the best possible image quality for under $4500 using AF, bested only by spending $10,000+ for a Nikon D3x and a 12-24.


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ejmartin
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« Reply #12 on: December 03, 2008, 12:16:04 PM »
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Quote from: tamerlin
False.

If you take a meter stick and divide it into decimeters, then take another meter stick and divide it into centimeters, which one will give you more accurate results?

That answer should be obvious, and equally obvious is the fact that the meter stick is still a meter long, even though we've carved it into more chunks. The advantage in 14 bit a/d conversion over 12 bit is identical. The bit depth doesn't relate to dynamic range.

False.   Dynamic range in stops provides an upper bound to the required RAW bit depth:

http://theory.uchicago.edu/~ejm/pix/20d/te...e/noise-p3.html

I gave a better analogy than your meter stick, which takes into account the difference between accuracy and precision, in a discussion here a while back:

http://luminous-landscape.com/forum/index....mp;#entry202059
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emil
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« Reply #13 on: December 03, 2008, 01:52:06 PM »
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Hi,

Bibble has support for Noise Ninja at the raw conevrsion stage, that's a good thing in my book. Regarding ACR/LR there is more to that then just noise reduction. LR has a pretty good workflow. LR is pretty good at extracting shadow detail, i don't know about the other tools. I tried to look at DXO but it doesn't seem to work with my DNG-based workflow. I would suggest that LR needs to do a bit more like automatic removal of lateral color and correction of distortion. What I would love to have would be DXO as a parametric edit.

If you shoot a couple of hundred pictures each day I would say that work flow considerations are pretty important.

Partly due to Michael's review I just put an order on a Alpha 900 with a 24-70/2.8 ZA and a Sigma 12-24 wide angle zoom.

Best regards
Erik

Quote from: douglasf13
Wonderful review, Michael.  I wanted to mention to you that the $10 Minolta hotshoe adapters on ebay are an easy solution for pocketwizards and such.  I keep a few of them around at all times, or I use the PC sync

  I agree with the above that, unfortunately, Lightroom/ACR is the worst RAW converter I've seen for the A900 in regards to noise.  I'm debating switching to the new Bibble 5 when it arrives, although I don't shoot high ISO too much, so I may just deal with it.  Capture One, Bibble and Aperture do a much better job with the A900
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BJL
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« Reply #14 on: December 03, 2008, 02:25:02 PM »
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Quote from: tamerlin
False.

If you take a meter stick and divide it into decimeters, then take another meter stick and divide it into centimeters, which one will give you more accurate results?
What is missing from your analogy is that the quantity being measured is subject to random errors of about 14cm (1/2 stop more than the 10cm scale of your decimeter ruler) so reporting the extra decimal place adds little or nothing to the accuracy of the measurement. The same is true for bits 13 and 14 with a 11.5 stop DR.

Unless the DR limit is actually a limitation of Sony's on-sensor column-parallel ADU's rather than of the signal coming to them from the photosites and pre-amplifiers. The modified version of this sensor used in the D3x with a different 14-bit (off-chip?) ADC approach might be informative here.

What is stranger though is that with no DSLR sensor (excluding some MF backs) offering a demonstrated DR of greater than about 12 stops (4000:1), some people are clamoring for 16-bit A/D conversion rather than 14-bit.
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madmanchan
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« Reply #15 on: December 03, 2008, 02:32:31 PM »
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Quote from: tamerlin
The bit depth doesn't relate to dynamic range.

Yes, it does for digital still cameras because they are linear recording devices. Emil's article has more details.
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tamerlin
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« Reply #16 on: December 03, 2008, 03:19:03 PM »
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Quote from: BJL
What is missing from your analogy is that the quantity being measured is subject to random errors of about 14cm (1/2 stop more than the 10cm scale of your decimeter ruler) so reporting the extra decimal place adds little or nothing to the accuracy of the measurement. The same is true for bits 13 and 14 with a 11.5 stop DR.

I was just simplifying it, probably a bit too much, in the interest of clarity. And so far no one's actually contradicted me, in spite of the attempted counter arguments, because the counter arguments are based on the fact that the current sensors are noisy, although I suspect that in Sony's case the noise that's limiting the accuracy of the a/d converters is coming from the amplifiers, based on the fact that Nikon is able to do better with pretty much the same sensors.

That doesn't change the fact that bit depth and dynamic range aren't actually related...

Emil's explanation didn't change that, he pointed out why the dynamic range places a limit on necessary or useful precision, which isn't the same thing, though you can build a camera without dealing with both issues.

Quote
What is stranger though is that with no DSLR sensor (excluding some MF backs) offering a demonstrated DR of greater than about 12 stops (4000:1), some people are clamoring for 16-bit A/D conversion rather than 14-bit.

That's not so strange; people want more resolution in the a/d conversion. They may not realize that it's beyond the capabilities of current sensor technology, though.
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ejmartin
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« Reply #17 on: December 03, 2008, 03:31:27 PM »
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Quote from: tamerlin
I was just simplifying it, probably a bit too much, in the interest of clarity. And so far no one's actually contradicted me, in spite of the attempted counter arguments, because the counter arguments are based on the fact that the current sensors are noisy, although I suspect that in Sony's case the noise that's limiting the accuracy of the a/d converters is coming from the amplifiers, based on the fact that Nikon is able to do better with pretty much the same sensors.

That doesn't change the fact that bit depth and dynamic range aren't actually related...

Emil's explanation didn't change that, he pointed out why the dynamic range places a limit on necessary or useful precision, which isn't the same thing, though you can build a camera without dealing with both issues.

That's not so strange; people want more resolution in the a/d conversion. They may not realize that it's beyond the capabilities of current sensor technology, though.

If you'd read my initial post in the thread, I stated that the A900 didn't NEED 14 bits.  I didn't say bit depth and DR were related.  In my second post, I stated that DR bounds the bit depth needed for data encoding.  Again I didn't say that they were necessarily related.  One bounds the other.  The one time they are related is if the ADC has a bit depth less than the DR of the electronics that precedes it; then the bit depth and the encoded DR are equal.  

If you're now saying that your reply to my post was unrelated to what I wrote, that's fine.
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emil
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« Reply #18 on: December 03, 2008, 09:49:59 PM »
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Great review that is uniquely perceptive.  

I find both the Zeiss 24-70 f/2.8ZA and the 70-300G SSM, as excellent performers on my A900.  The Zeiss 85mm f/1.4ZA is excellent too and so is my Sony 50mm f/2.8 Macro.  

I will be adding the Zeiss 135mm f/1.4ZA Sonnar and the upcoming Zeiss 16-35 f/2.8 ZA to my list and I should be pretty much set as far as my lens requirements are concerned.  

Maybe it is my imagination but the performance on the A700 with these lenses, never wowed me at all (even though they were terrific images) but on the A900, they are standouts, probably because the lenses are deploying their full optical signatures onto the A900 images.
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Tony Beach
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« Reply #19 on: December 03, 2008, 10:05:45 PM »
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Quote from: aaykay
The Zeiss 85mm f/1.4ZA is excellent too...

Maybe it is my imagination but the performance on the A700 with these lenses, never wowed me at all (even though they were terrific images) but on the A900, they are standouts, probably because the lenses are deploying their full optical signatures onto the A900 images.

I am still going to keep my D300, mainly so I can use my Nikkor 70-200/2.8 VR on it, the bokeh of that lens is top notch and it makes a beautiful portrait lens with the D300.  Now my question for you is how is the bokeh on the Zeiss 85/1/4 ZA?  Do you have any sample shots that would convince me to sell my Nikkor?

TIA
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