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Am I reading these MTF charts wrong or is Kodak claiming that the slowest Vision 3 stock has the least resolution?


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#1 cole t parzenn

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Posted 24 March 2015 - 11:26 PM

500250200, and 50.


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#2 John E Clark

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Posted 25 March 2015 - 12:52 PM

From the look of the MTF curves, and looking specifically at 'red', all have 'red' crossing the 50% line at about 30-40 cycles/mm.

 

What is different about the ISO 50 chart, is that R, G, and B cross the line near the same place, while the others seem to have B, and G, crossing at a higher c/mm value.

 

Whether this difference is a 'usable' difference I don't know...


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#3 Kenny N Suleimanagich

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Posted 25 March 2015 - 01:13 PM

It's important to consider grain structure when looking at these MTF charts, since 50D will obviously have far-tighter grain than any of those listed here. Hypothetically, if 500T had the same or similar MTF curve (in terms of resolution) as 50D it would be a blotchy mess, so therefore "sharpness" needs to increase with speed, to keep a consistent look across each stock. Less grain does not equal more resolution, but more grain does warrant/justify more c/mm when you are producing a line of stocks to be used interchangeably. 


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#4 cole t parzenn

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Posted 26 March 2015 - 12:23 PM

Could you elaborate?


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#5 Kenny N Suleimanagich

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Posted 26 March 2015 - 01:38 PM

I am not an engineer, and this is fully based on my own reading/understanding, so bear with me... The Vision3 line of film stocks is designed to be used completely interchangeably. In such a way that you could use every stock for the same production, and have a uniform look. Because 50D is inherently "sharper" due to its tighter grain structure (smaller grains, less sensitive to light), faster stocks like 200 and 500 EI require a more "straight" MTF curve to bring them to the same plane of sharpness that 50D achieves. The larger grains of faster films would otherwise be very noticeable and result in a less "sharp" film by comparison. 

 

Where is Dennis Couzin when you really need him? 


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#6 cole t parzenn

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Posted 26 March 2015 - 02:01 PM

I get that intercuttablility is desirable but, since such disparate speeds are rarely intercut, I expected Kodak to have independently optimized the resolutions of the slow and fast stocks. How do you make a low resolving slow stock, anyway? And can it really be said to be inherently sharp? The MTF never gets significantly above 100, so there's no coarse detail enhancement, to make up for the fine detail loss. Did you mean that there was less apparent noise?


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#7 Kenny N Suleimanagich

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Posted 26 March 2015 - 02:26 PM

Noise plays a large role in it. That is indeed what I meant. I think you can say that 50D Vision 3 is inherently sharp in appearance (although not resolution). But sharpness also has very little to do with resolving power when applied, as demonstrated here. There are people much more qualified than me to speak on the subject. This link lends some insight. 


Edited by Kenny N Suleimanagich, 26 March 2015 - 02:27 PM.

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#8 cole t parzenn

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Posted 26 March 2015 - 08:44 PM

Could Kodak just be very bad at making MTF charts? According to the Vision 1 500T data sheet, it out-resolved Velvia, in blue and green. And EXR 500T wasn't far behind. This is interesting...


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