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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

New Zeiss Compact Primes preview...

Roberto Lequeux said:
Thank you David.

And what would be the additional stop required to make the DOF the same as S35?
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Well, wouldn't an additional stop in either direction change the exposure you're trying to match? I don't think there's a way to match Exposure and DOF with lenses of different speeds. You can only get one or the other...Am I wrong?
 
Well it would mean that if Mostro were rated at 640ISO you could stop down to T2.8 and be able to shoot without adding lights to something you were previously able shoot on R1 at T2 on Red One and keep the footage at 320ISO.

However, if you could bump up the ISO a bit more, and with the down conversion to 2k still get noise levels you deemed acceptable, then you could stop down further to get a deeper DOF.

My second question was to find out how much you would have to close down a FF35 lens (shooting FF35), to match the DOF that a S35 lens gives on a S35 camera. Say, you want the DOF you get on S35 at f2, what would you need to set the Iris on a FF35 camera to get the same DOF. I suppose it would be much more than f2.8.
 
Evin Grant said:
(This is from the superb 28mm T2.1, WFO at minimum focus distance)
OmegaZCP.jpg
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Does this mean that most of the ZF optical qualities will remain regardless of the new barrels?

I guess it would be so, since the glass is the same, however the ZF's didn't have internal focusing, at least I don't think they did since they expanded. Also the coatings would be different, plus the glass selection could be more demanding leaving the rest to go to ZF lenses. They could have changed the process a lot actually and only retained the specs making the whole manufacturing have to work with tighter tolerances...

Despite how great and so very sharp ZFs are, they did show quite a bit of CA.

Is there anything we know about or could derive from what we do know that would allow us to compare them?
 
Roberto Lequeux said:
Well it would mean that if Mostro were rated at 640ISO you could stop down to T2.8 and be able to shoot without adding lights to something you were previously able shoot on R1 at T2 on Red One and keep the footage at 320ISO.

However, if you could bump up the ISO a bit more, and with the down conversion to 2k still get noise levels you deemed acceptable, then you could stop down further to get a deeper DOF.

My second question was to find out how much you would have to close down a FF35 lens (shooting FF35), to match the DOF that a S35 lens gives on a S35 camera. Say, you want the DOF you get on S35 at f2, what would you need to set the Iris on a FF35 camera to get the same DOF. I suppose it would be much more than f2.8.
Click to expand...

Sure you can increase ISO ratings in order to stop down and increase DOF, at the risk of more noise, so the question will be how noisy is the system?

If you compare horizontal view only, FF35 is 36mm wide and S35 is 24mm wide, so that's a 1.5X magnification difference and also a 1.5-stop depth of field difference once you compensate in focal length to match FOV.

But in practical terms, if you are used to lighting to f/2.8 at 320 ASA and you can shoot FF35 at 640 ASA and shoot at f/4, that's better than nothing and no one is going to spot a remaining 1/2-stop difference in depth of field characteristics.

---

The ironic thing is that when anamorphic (CinemaScope) and FF35 (VistaVision) came out for movies in the 1950's, they were considered to have extra "depth" because filmmakers used them to shoot wider views -- wider-angled wider shots -- not compensate by using longer focal lengths to get the matching views on tighter shots.
 
Evin Grant said:
Just to be clear the Compact Primes are not rehousing, they are completely ground up designed barrels using the glass and formulas from the ZFs. Rehousings use the internal mechanics as well as the optics of the original lens.
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That's an excellent explanation. I've talked before about the RED 18-50/Sigma 18-50 and I think your description of the ground up design using glass and formulas is a more accurate representation of what was done - and an important distinction.

Given my excellent experience with the C/Y zeiss's I think people will find these compact primes an excellent option, particularly on the faster midrange lenses, and also if they are looking at full frame in their future.
 
Just to clarify people seem to be getting the Zeiss ZF's and the Zeiss C/Y lenses confused. From what I've looked at the ZF's are a different beast and share some things, but take into account some of the improvements in optical design that the last 20 years has given us.
 
David Mullen ASC said:
If you compare horizontal view only, FF35 is 36mm wide and S35 is 24mm wide, so that's a 1.5X magnification difference and also a 1.5-stop depth of field difference once you compensate in focal length to match FOV.
Click to expand...

So half a stop more sounds encouraging. And I suppose for those concerned with 2.4 aspect, horizontal view is a very accurate estimation. Thank you for explaining the relation.

Say the new systems are rated at a more conservative 500ISO, and they end up being close to R1 in noise. R1's noise seems to be mostly in the bottom end I think. If all of that happened, that should put us well over the top. In the wonderful case all of that came true, most wouldn't even consider it an issue after downconversion from 5k to 2k. It might be a bit hopeful, but in my humble understanding of sensors and so on I see it as a strong possibility. Even if Mostro ended up close to R1 noise at 500ISO, the resolution should make up for an other little bit of noise reduction...

David Mullen ASC said:
But in practical terms, if you are used to lighting to f/2.8 at 320 ASA and you can shoot FF35 at 640 ASA and shoot at f/4, that's better than nothing and no one is going to spot a remaining 1/2-stop difference in depth of field characteristics.
Click to expand...

I am very happy to hear this. 1st ACs might complain though... right? I don't really know much about light levels... so my hypothetical analysis can't go any further... but if f2.8 was your wide open end of the spectrum and you mostly were able to shoot a little more closed down, then it might not be much of an issue.

David Mullen ASC said:
The ironic thing is that when anamorphic (CinemaScope) and FF35 (VistaVision) came out for movies in the 1950's, they were considered to have extra "depth" because filmmakers used them to shoot wider views -- wider-angled wider shots -- not compensate by using longer focal lengths to get the matching views on tighter shots.
Click to expand...

I see. Perhaps the longer focal lengths compensation could work for those seeking the best 4k digital projection or the best Imax prints. Though I personally do see it as a tool for real wide shots... if I can find a fast and wide FF35 lens. Perhaps the Duclos Tokina at 13mm or the Ruby Nikon at 14mm already answered that question! The tokina can go up to 11mm with a little bit of distortion, but at 13mm it seems perfect. It also offers up more MTF than R1 can handle, which should be plenty sharp for most people, even at 4k digital projection... I suppose.

I am not 100% sure how to use the calculators so this might be a bit fudged up:

13mm in S35 = 85.4° horizontal FOV
13mm in FF35 = 108.3° horizontal FOV
~21% wider FOV!!

Thanks for your posts David! (please let me know if I am way off track anywhere) :)
 
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Mike Prevette said:
Just to clarify people seem to be getting the Zeiss ZF's and the Zeiss C/Y lenses confused. From what I've looked at the ZF's are a different beast and share some things, but take into account some of the improvements in optical design that the last 20 years has given us.
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The only difference is the coatings.
 
Pawel
They say what they want to say on their website.
What's funny is the resolution +++ on MPs and + on CPs
That, I don't get.
 
Everything I've read has said that they are slightly different. Cosina has changed a great deal in the last 20 years. And if what they say about the 100mm being modeled after things learned on the Master/Ultra primes I don't see how they could be the same. I'd have to dig up some old c/y spec sheets and compare the diagrams.

( should preface this with the fact the 50mm's 85mm and 100mm are planar designs that have been around in some cases since the late 1890's in some form or another)

Take a look at these speck sheets for the current Contax 85mm 1.4 and the ZF The optical groups are very different.

http://www.contaxcameras.co.uk/assets/pdf/Planar1.4_85_e_09-09-02.pdf

http://www.zeiss.com/C12567A8003B8B6F/EmbedTitelIntern/Planar_1-4_85_ZFen/$File/P1_4_85ZF_EN.pdf
 
Mike Prevette said:
Everything I've read has said that they are slightly different. Cosina has changed a great deal in the last 20 years.
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I'd completely forgotten that the Zeiss ZF/ZM's are made by Cosina in Japan.
 
As well as all the modern Voigtlander rangefinder/SLR lenses. They hands down build the best must unique optics out there. Mr. Kobayashi is a lens nut, much like Jim. In fact I think they might have bought and sold cameras to each other in the past.
 
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