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Samyang-Rokinon and Zeiss CP2's crop factor

J

Jess Gill

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HI
I'm in market to build a cheap kit of prime lenses for a friend having epic with canon mount. We are considering Samyang-Rokinon or Zeiss CP2's. We do know as far price-value consideration and optical quality between these two sets...however we do have couple of doubts in our head and hope someone from reduser can help us out.

Since both Rokinon- Samyang and Zeiss have full frame lenses ( with exception of few APS-C lenses ), what is te crop factor when using them with Red epic at 5k Full frame. What is the crop factor on Zeiss CP2 and rokinon ??


Also if some users of rokinon-samyang can throw us some light as to which lenses to buy ... We are thinking of getting 14-24-35-50-85-135 full frame ones !!

Thanks
 
Thanks Bob !!
We just want to know what field of view would be like in reference to s35 designed lenses. I have never used these lenses on my epic as I got my own Ultra primes.
 
Hey Jess,

It's very simple:
The field of view of any of those 50mm lenses would be exactly the same as the filed of view on a 50mm Ultra prime.

The field of view is determined only by the size of the sensor, so any format lens (MF, FF, EF-S) on the camera would have exactly the same field of view as a similar focal length S35 lens.
 
If you are using the MP 50mm T1.3 and say a Rokinon 50mm you will see the approximate same field of view. Any variation would be rather slight which would be due to differences in manufacturing and tolerances.

These lenses both project an image circle that covers a your format. Where a crop factor comes into play is if you are shooting on a different sized format and that's where you'll want to learn that difference. Meaning if you are shooting Dragon 6K versus Dragon 5K (which is about the same size as Super 35mm) you would get a wider field of view from Dragon 6K because it uses more sensor real estate.
 
Obviously, the two lens sets you reference are in different price categories. Personally, I wouldn't consider the CP.2s "cheap" but they're not Ultra Primes, either.

As others have pointed out, crop factor is not an issue. Lenses are lenses; 50mm is 50mm, etc.

As for Rokinon/Samyang, I think you'll more frequently find the Rokinon name available here in the US. They are the same lenses. They are excellent for the money. Get the cine-style versions. I have all the lenses you list except the 135. There is also now a 100 on the way (any day). Some people feel the 24 is too soft but it fits nicely into the set.
 
Thanks everyone for helping out !! I use to think otherways but now I know clearly about fov. Thanks again !!
 
this is nice FoV calculator

http://www.abelcine.com/fov/

in a way 50 is a 50 but... lessens are designed for the format so if we look at Zeiss T2.1 Distagon for 1960's modern Zeiss UP, Zeiss MP and Zeiss CP2 wee will see 4 different diameter of dispersion cyrcle and therefore film plain coverage and resolution. smaller CoC more resolution so 1970's Zeiss or Contax 50mm will have far less lines per inch then T2.1... Roki's are really good for price and optics are really good for what they are but thon expect more then 45 lines out of them, simply because they are designed to have 37mmCoC. CP2 would be better pick but for way more money. hope this helps
 
Last edited:
Luka Sanader said:
this is nice FoV calculator

http://www.abelcine.com/fov/

in a way 50 is a 50 but... lessens are designed for the format so if we look at Zeiss T2.1 Distagon for 1960's modern Zeiss UP, Zeiss MP and Zeiss CP2 wee will see 4 different diameter of dispersion cyrcle and therefore film plain coverage and resolution. smaller CoC more resolution so 1970's Zeiss or Contax 50mm will have far less lines per inch then T2.1... Roki's are really good for price and optics are really good for what they are but thon expect more then 45 lines out of them, simply because they are designed to have 37mmCoC. CP2 would be better pick but for way more money. hope this helps
Click to expand...

Everything you're saying is true. I have some 70's Zeiss T2s, and they are INSANELY sharp. Then again we also have some Zeiss s16 SuperSpeeds, and those are no sharper than our Contax. So depends.

But in general, I agree - glass covering a smaller image circle can be much sharper (that's why many Medium Format lenses are not "wicked" sharp, only a few are).

But some designs...like s16 SuperSpeeds (or even s35 Super Speeds) clearly sacrifice some sharpness in order to achieve SPEED. To be fast wide open. Whereas other more conservative designs, like Zeiss 60/70's T2's, and just SHARP wide open and across the board. Because by not trying todo TOO much, they manage to do what they're designed for EXCEPTIONALLY.
 
Jess Gill said:
Also if some users of rokinon-samyang can throw us some light as to which lenses to buy ... We are thinking of getting 14-24-35-50-85-135 full frame ones !!
Click to expand...

I'd get the latest Rokinon Cine DS ones.
Personally I'd go instead for 16-24-35-50-85-135
I'd also get the 10mm if you tend to have a frequent enough need for UWA, and likewise add the 100mm macro as well if do macro shots on a regular enough basis.

Why 16mm and not 14mm? Because the 14mm is designed for 135 format, not Super 35mm sized sensors, and thus to achieve that it ends up being a much much weaker design than the 16mm when used on Super 35mm bodies. Plus the gap between 24mm and 14mm is *HUGE*, at least the gap from 24mm to 16mm to 10mm is smaller (though still waaaay too big! Really really wish there is a Rokinon 20mm!), and I find 16mm would just simply be a more frequently used focal length on a Super 35mm camera than 14mm.

btw, I have a set of Rokinon Cine DS lenses myself (in Nikon F mount), and I've blogged out them in a little bit more detail over here:
http://ironfilm.co.nz/rokinon-cine-lenses/

As for "crop factor".... I often issue this term was never started to be used (the fact it was, is a brilliant marketing success by Canikon, kudos to their marketing team! Am sure it has lead to more sales of their more expensive 135 format bodies and lenses). As evidence clearly demonstrates time after time after time, that it leads to *greater* confusion with people rather than less.
 
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