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Author Topic: What you pay forů (Jim Kasson has some interesting findings on the Otus)  (Read 3544 times)

ErikKaffehr

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Hi,

Jim Kasson is testing what I would call short telephoto lenses on his blog. One of his recent postings shows what you pay for buying an Otus and that is axial chromatic aberration being essentially zero.

Axial chromatic aberration is causing the magenta/green fringes often seen in OOF areas, here is a link to Jim's posting:
http://blog.kasson.com/?p=13423

Now, this is not exactly news. Hubert Nasse has a nice video talking about the Otus and discussing this.  But, sometimes three curves say more than a thousand pictures.




Best regards
Erik
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BernardLanguillier

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Re: What you pay forů (Jim Kasson has some interesting findings on the Otus)
« Reply #1 on: February 25, 2016, 07:00:00 pm »

Gosh, I would like to see similar tests performed for the corresponding Phaseone and Hassy MF lenses.

Cheers,
Bernard

Slobodan Blagojevic

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Re: What you pay forů (Jim Kasson has some interesting findings on the Otus)
« Reply #2 on: February 25, 2016, 09:14:45 pm »

What does the "image distance" (x-axis) represent?

jng

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Re: What you pay forů (Jim Kasson has some interesting findings on the Otus)
« Reply #3 on: February 26, 2016, 12:16:56 am »

What does the "image distance" (x-axis) represent?

My understanding is that the x-axis represents the offset (in mm) in peak focus for each of the three wavelengths, where each lens was focused on a target at a distance of 3.3 meters (see original link to Kasson's blog). So, for the Otus the greatest peak-to-peak difference in focus points is between red and green wavelengths (~ 1mm/3.3 m = 0.03%). The Nikkor shows much broader peaks and a max difference of ~2 mm (0.06%). Sharpness/resolution issues aside, in terms of fringing (longitudinal chromatic aberration) I wonder whether this difference (i.e., 0.03% vs. 0.06%) would be so noticeable in real-life usage.

Gosh, I would like to see similar tests performed for the corresponding Phaseone and Hassy MF lenses.

Cheers,
Bernard

I'm not sure I want to know - ignorance is sometimes bliss!  :P
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ErikKaffehr

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Re: What you pay forů (Jim Kasson has some interesting findings on the Otus)
« Reply #4 on: February 26, 2016, 12:19:01 am »

Hi Slobodan,

It is movement of the focus rail translated to shift in the image plane. So, if you check the Nikon at f/1.4, what you see is that the "red" has optimum focus at 1.44 and green at 3.30, so there is a shift of about 1.86 mm in the image plane. I don't recall if it towards or behind subject. Obviously, 1.86 mm is to many digits. Say that the focal plane is shifted around 1.9 mm between red and green.

See Photozone
s "ruler shot" below:



Best regards
Erik

What does the "image distance" (x-axis) represent?
« Last Edit: February 26, 2016, 01:15:54 am by ErikKaffehr »
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Erik Kaffehr
 

ErikKaffehr

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Re: What you pay forů (Jim Kasson has some interesting findings on the Otus)
« Reply #5 on: February 26, 2016, 12:23:05 am »

Hi,

If you check Doug Petersson's still life test that includes a focusing rulers you can observe quite a lot of axial chroma on the Schneider lens he used with the Phase One. The Sony 55/1.8 had a lot of that, too.

Best regards
Erik

Gosh, I would like to see similar tests performed for the corresponding Phaseone and Hassy MF lenses.

Cheers,
Bernard
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Erik Kaffehr
 

Paulo Bizarro

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Re: What you pay forů (Jim Kasson has some interesting findings on the Otus)
« Reply #6 on: February 26, 2016, 04:37:10 am »

Yup, the Otus series is a "no compromise" line of lenses, where they try to correct this stuff with glass. Similar thing Canon did with their new 35 f1.4 L MKII lens.

For mere mortals like me, I am already quite happy with the Batis 85:)

ErikKaffehr

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Re: What you pay forů (Jim Kasson has some interesting findings on the Otus)
« Reply #7 on: February 26, 2016, 05:41:21 am »

Hi Paulo,

Jim also tested LoCA on the Batis and I think it was very good.

My guess is that Otus, Batis and Milvus (in part) are a new generation of lenses where Zeiss uses more complex design.

Regarding the Milvus series, the 50/1.4 and the 80/1.4 have major upgrades.

With the Otus they make some money no objection kind of corrections, but I guess all new designs are very good.

Best regards
Erik



Yup, the Otus series is a "no compromise" line of lenses, where they try to correct this stuff with glass. Similar thing Canon did with their new 35 f1.4 L MKII lens.

For mere mortals like me, I am already quite happy with the Batis 85:)
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Erik Kaffehr
 

kers

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Re: What you pay forů (Jim Kasson has some interesting findings on the Otus)
« Reply #8 on: February 26, 2016, 06:05:23 am »

Again a very good test by Jim Kasson.
This LoCa; is this the one that could be compensated for in software?
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BernardLanguillier

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Re: What you pay forů (Jim Kasson has some interesting findings on the Otus)
« Reply #9 on: February 26, 2016, 06:10:20 am »

Again a very good test by Jim Kasson.
This LoCa; is this the one that could be compensated for in software?

LoCa seems much harder to compensate.

Cheers,
Bernard

ErikKaffehr

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Re: What you pay forů (Jim Kasson has some interesting findings on the Otus)
« Reply #10 on: February 26, 2016, 06:28:23 am »

Hi,

It can be hidden by local desaturation but not corrected.

Best regards
Erik

LoCa seems much harder to compensate.

Cheers,
Bernard
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Paulo Bizarro

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Re: What you pay forů (Jim Kasson has some interesting findings on the Otus)
« Reply #11 on: February 26, 2016, 09:42:08 am »

Hi Paulo,

Jim also tested LoCA on the Batis and I think it was very good.

My guess is that Otus, Batis and Milvus (in part) are a new generation of lenses where Zeiss uses more complex design.

Regarding the Milvus series, the 50/1.4 and the 80/1.4 have major upgrades.

With the Otus they make some money no objection kind of corrections, but I guess all new designs are very good.

Best regards
Erik

I am not complaining:) The Batis 85 actually looks better than the Nikon 85, but... whereas the Otus has all three colours peaking at the same location, for the Batis, the red is lagging relative to other two. Out of curiosity, why is the red colour the one to always be out of phase relative to green and blue?

Canon did something similar (I think) with their new EF 35 f1.4 MKII lens, applying what they call Blue Refractive Technology. It corrects chromatic aberration very effectively; the downside is the steep cost.

Zeiss really have hit it on, today they have a very high quality and consistent line up of 85mm lenses (well, excluding the ZM mount). As you mention, the new Milvus 85 f1.4 is another top quality lens.

BernardLanguillier

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Re: What you pay forů (Jim Kasson has some interesting findings on the Otus)
« Reply #12 on: February 27, 2016, 06:33:30 pm »

I did a series of family portraits yesterday with the Otus 85mm f1.4 on the D810 and was again amazed by the rendering of this lens. There is a perfect rightness about the detail at 100% in PS that is so incredibly sexy. The only thing getting close is Sigma files, even the P1 samples with Schneider glass I've seen are IMHO behind.

Cheers,
Bernard
« Last Edit: February 28, 2016, 01:35:28 am by BernardLanguillier »
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