Lens Files

[Matt Redmond]

What's the situation with "lens files" with the RED one?

I assume it's going to be a little different setting up lens files for PL mount glass than with 2/3" ENG style lenses, especially when you're looking to keep the "desired" characteristics of the glass.

[Matt Redmond]

Should have been posted in lens section

[Brook Willard]

There will be collimation issues... but is that not what you're referring to?

[Martin Drew]

I am not quite sure what the question is. What do you mean by "lens files"?

[Matt Redmond]

There will be collimation issues... but is that not what you're referring to?

Each lens is going to be a tad different from the other, especially if it's not new glass. If you have a closely matching set of primes it does give you the option of finding the one you like most and matching them all pretty darn close.

Better to have matching lenses in the field than giving the grader unnecessary work.

With ENG lenses you'd want to make sure that white light going into the lens equals white on the other end of processing. However the beauty of some PL glass is the colour shift and tone it adds to the picture. This means (if needed mind) if want to match your glass you could use a lens file for each lens (or each problem lens) that would have them all matching the characteristics of a "reference lens" in your set.

Talking to a highly knowledgeable Sony technician, he mentioned that Lens files are still used on single chip cameras, like genesis, where in its case the camera has had it's lens files set up for Panavision glass.

For those wanting a quick overview of Lens files in general:


In general, each camera lens introduces different 'offset'
characteristics, which are electronically compensated for on
a lens basis by making appropriate adjustments to the camera.
However, when multiple lenses are used on the same
camera, these different characteristics require the camera to
be readjusted each time the lens is changed.
In order to eliminate this burden, most high-end professional
cameras have a so-called Lens File system. With this system,
camera operators can store lens compensation settings
for individual lenses within the camera as lens files. Since
each lens file is assigned a file number designated by the
operator, pre-adjusted lens-compensation data can be
instantly recalled simply by selecting the correct file number.
Simply put, once the setting for a given lens has been made
and stored as a lens file, all that need to be done to use this
lens again is to select the file number associated to it.
Some large studio-type lenses take this a step further by
automatically recalling the correct lens file by registering the
same number in the lens's memory as that used for the associated
lens file.


I don't know if RED uses lens files, or if they even care for them much. Remember that there is a B4 mount option on RED, so I assume that it would have a Lens file set up.

Goodness...setting up a Cooke S4 at 4K....where on earth would you get a scope to handle that???

[Martin Drew]

Graeme has said that you will have control of the transfer function in RedCine as a set of curves, so you could shoot a test chart like the CamAlign ChromaDuMonde on each lens and use that is a reference to set up compensation for the lens.

M