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MTF graphics of Cooke S4 and Cooke mini S4


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#1 Luz Escobar

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Posted 11 November 2018 - 07:20 AM

Hi!

I'm looking for the MTF graphics (Modulation Transfer Function) of the set of lenses Cooke S4 and Cooke mini S4. Can't find them on the internet, can anyone share them or recommend a webpage where to find them please!

Thank you on advance!

Luz


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#2 James Compton

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Posted 11 November 2018 - 02:51 PM

 Luz,

 

 ZGC has always been a good source for COOKE optical info. Contact them directly.

 

https://www.zgc.com/...er-manuals.html


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#3 Luz Escobar

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Posted 12 November 2018 - 09:50 AM

Thank you! I already contacted them, no response still, but thanks!

Any other advice on where to find MTF charts would be very useful!


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#4 James Compton

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Posted 12 November 2018 - 09:39 PM

 Luz,

 

  Contact Andree Martin at www.amcamera.com. He worked at Clairmont Camera for 33 years. He will probably have access to MTF charts for COOKE lenses. You will find some very interesting technical info in this mini-book "The COOKE book". Open the PDF file in a PDF reader and search for "MTF". Denny Clairmont (the founder of Clairmont Camera Rental house) talk about COOKE lenses and MTF. :

 

https://www.cookeopt...FDTimes-300.pdf


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#5 Gregg MacPherson

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Posted 12 November 2018 - 10:51 PM

 

I scrolled through that document and never saw one MTF graph. Did I miss some links to those..? Do Cooke not like them, MTF graphs, that way of notionalizing the data?


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#6 James Compton

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Posted 13 November 2018 - 01:21 PM

 Greg,

 

     No, there are not any MTF charts in that document-I did not say that there was. There is a healthy dose of "inside baseball" talk about the MTF performance from COOKE lens techs and guys like Denny Clairmont. Again, open the file in a PDF reader and search for MTF in the search function. You will find the instances that I mentioned.


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#7 Gregg MacPherson

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Posted 13 November 2018 - 02:28 PM

It would be a simple thing to show some MTF graphs. But why should us simple folk struggle with the interpretation of those when we can just accept the interpretations of those in the know.  And as Iain Neil put it on page 113, "...perhaps the worst

way to look at the lens is on the projector. I think it’s very important not to look at the textbook and get too caught up with MTF and
test charts..."

 

I would vote for less self congratulatory glitz, and more facts. Agree...?


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#8 Dom Jaeger

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Posted 13 November 2018 - 06:34 PM

Hi!
I'm looking for the MTF graphics (Modulation Transfer Function) of the set of lenses Cooke S4 and Cooke mini S4. Can't find them on the internet, can anyone share them or recommend a webpage where to find them please!
Thank you on advance!
Luz


Can I ask why you want them?

Unlesss you're a lens technician or a manufacturer looking for ways to objectively maintain a certain quality control, I honestly don't see much use in MTF charts. I also suspect most people have no idea how to decode MTF readings into something with real world meaning.

The only online MTF info I've found is this test report that Alphonso Parra did on Cooke S4 minis (then known as Panchros) which includes very basic Imatest MTF curves:
http://www.alfonsopa.../panchro_en.pdf
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#9 James Compton

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Posted 14 November 2018 - 01:54 PM

@ Greg

 

Agreed.

 

 

@ Dom

 

Thanks for that link. I found it quite useful.


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#10 Gregg MacPherson

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Posted 14 November 2018 - 09:52 PM

James, i was winding you up a little there, though my opinions were genuine...Graphical representation of data can be quite powerful, provoking our intellect towards a more global or wholistic comprehension,  but it can be quite challenging.  With some time spent in design, design engineering, defacto mechanics, and some cinematography in the 80s, the MTF graphs are a very attractive thing to my intellect, but not normally easy to read.  

 

I would rather see people struggle to interpret them (MTF graphs) rather than simply accept the interpretations or opinions of others.


Edited by Gregg MacPherson, 14 November 2018 - 10:04 PM.

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