Zeiss CP.2 Super Speed | Heavy CAs while wide open

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Benjamin_Albrecht

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Zeiss CP.2 Super Speed | Heavy CAs while wide open

PostThu May 18, 2017 8:50 am

Hello folks,

we just upgraded our system from the Sony FS700 with a couple of stills lenses to the UM4.6K EF including the 18, 35, 50 and 85mm Zeiss CP.2 Super Speed.

I know most lenses have their "sweet spot" at around t4/t5.6, but I noticed some really heavy chromatic aberrations when shooting wide open (T2/ T1.5) and in contrasty situations. Both in bright daylight and in lowlight situations.

Since I do not have that much experience with such lenses, I wanted to know if it is a common "issue" or if the solution is just to stop down to around T5.6 and shoot with a longer lens.

What do you guys think?

Thankful for every helpful answer!
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Krishna Pada

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Re: Zeiss CP.2 Super Speed | Heavy CAs while wide open

PostThu May 18, 2017 4:01 pm

Benjamin_Albrecht wrote:
we just upgraded our system from the Sony FS700 with a couple of stills lenses to the UM4.6K EF including the 18, 35, 50 and 85mm Zeiss CP.2 Super Speed.

I know most lenses have their "sweet spot" at around t4/t5.6, but I noticed some really heavy chromatic aberrations when shooting wide open (T2/ T1.5) and in contrasty situations. Both in bright daylight and in lowlight situations.

Since I do not have that much experience with such lenses, I wanted to know if it is a common "issue" or if the solution is just to stop down to around T5.6 and shoot with a longer lens.

What do you guys think?

Thankful for every helpful answer!


It's a known issue wide open in very contrasty condition, towards the corners.
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rick.lang

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Zeiss CP.2 Super Speed | Heavy CAs while wide open

PostThu May 18, 2017 5:22 pm

Did you buy the CP.2 primes? If not think about the less expensive SLR Magic APO T2.1 primes with far better control of CA. They have some near the edges on the 25mm, almost none on the 50mm, no concern on the 85mm.


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Uli Plank

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Re: Zeiss CP.2 Super Speed | Heavy CAs while wide open

PostFri May 19, 2017 3:46 am

It's normal for quite dated lens designs. The CPs are nice lenses, but they react similar to my Contax primes, many of those are based on similar designs. If you need something cleaner, get modern primes. But you may miss their character.
There's a fix in post, if the issue really gets annoying. Just split the channels in Resolve, scale them a tiny little bit an re-combine.
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Denny Smith

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Re: Zeiss CP.2 Super Speed | Heavy CAs while wide open

PostFri May 19, 2017 5:37 am

Also, the Zeiss CP2 prime lenses are Not Super Speeds, which are much different lenses, specifically designed for Cine cameras (originally film cameras), and most often a PL or Arri B mount. Super Speeds are called that, because they are T1.2 or 1.4 lenses, and a much different design than the CPs. I agree with Rick, the SLR APO primes have far less CA wide open, which is a characteristic of what a APO design is all about.
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Craig Marshall

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Re: Zeiss CP.2 Super Speed | Heavy CAs while wide open

PostFri May 19, 2017 9:56 am

Many in the RED community prefer the Zeiss Contax primes over the CP.2s with one or two of the later zooms being APO designs. The only CA I have noticed on my almost complete collection of Contax primes is the West German built 180mm f/2.8 AEG which I retain for it's unique and almost 'Cook look' - Ninja Star iris.
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Benjamin_Albrecht

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Re: Zeiss CP.2 Super Speed | Heavy CAs while wide open

PostMon May 22, 2017 1:59 pm

Thanks everybody for stopping by and commenting!

I was not expecting lenses being "that expensive" to have such strong chromatic aberrations.

Seems like we have to deal with them. Since they can be removed in DaVinci there are not that much worries left :)

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