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ANAMORPHIC LENS ON RED EPIC BODY


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#1 ANWAR SHAMSUDEEN

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Posted 30 May 2016 - 12:00 AM

HI, WHAT ARE THE THINGS TO BE TAKEN CARE FOR USING AN ANAMORPHIC LENS SET ON A RED EPIC BODY,ESPECIALLY IN SETTING MODES..!!

PREFERABLE CROP FACTORS,RESOLUTIONS..!!

POSSIBLITIES OF VIGENETTING EDGES WHILE USING WIDE LENSES..!!


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#2 David Mullen ASC

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Posted 30 May 2016 - 12:15 PM

Why are you typing in all capital letters?

 

That's quite a laundry list of issues.  I think the main thing you have to consider is that:

 

1) most anamorphic lenses made for cinema have a 2X horizontal squeeze (there are a few that have other squeeze ratios) 

 

2) most were designed to work on a 4-perf 35mm movie camera for a negative / print area that is 21mm x 17.5mm -- which is a 1.20 : 1 shaped area. Once the image is unsqueezed by 2X horizontally, this becomes 2.40 : 1.

 

The second item is particularly important to consider when using anamorphic lenses on digital cameras with different shaped and sized sensors, most of which are much wider than the 1.20 : 1 square-shape that 35mm anamorphic uses.

 

In particular, this means that more than likely you will have to crop the sides of the sensor to use a 1.20 : 1 area if you want a final unsqueezed image that is 2.40 : 1.  So even if the lens vignettes on the full sensor, it probably doesn't matter since you will have to crop the sides anyway.

 

It's basic math, your image has a 2X optical horizontal squeeze.

 

The Red Dragon sensor has a max recordable size of 30.7mm x 15.8mm (6144 x 3160 pixels).  That's a 1.94 : 1 aspect ratio -- if you used a 2X anamorphic lens on that and could use the entire sensor without vignetting, the unstretched image would have a 3.88 : 1 aspect ratio.

 

But even with that larger sized sensor, you'll note that it is only 15.8mm tall, whereas a 35mm anamorphic frame is 17.5mm tall.  So once you crop the sides to get to a 1.20 : 1 aspect ratio unsqueezed and your height is limited to 15.8mm or so, then your width will end up smaller than the 21mm wide area of a 35mm anamorphic frame, which means you will get a slightly less wide view on that anamorphic lens (it will be cropped more) than when that lens is on a 4-perf 35mm movie camera.

 

Red has a mode for anamorphic called "6:5" (i.e. 1.20 : 1) for 2X anamorphic photography so you don't have to record any more of the sensor area than you need to, it crops the sensor to 1.20 : 1 and then stretches the image for viewing on a monitor without the squeeze. So "6K 6:5" mode on the Red Epic Dragon is 18.95mm x 15.79mm (3792 x 3160 pixels).

 

Again, if you do some math, you can figure out the crop factor between the 21mm width of the 35mm anamorphic frame and the 18.95mm width of the Dragon sensor cropped to 1.20 : 1 -- which is a 1.11X crop factor.  Not much.  It means that your 40mm anamorphic would behave more like a 44mm lens, or conversely, you'd have to switch to a 36mm lens to match the view of a 40mm on a 4-perf 35mm camera.  You wouldn't have any vignetting issues to worry about since the recorded area is smaller than the 4-perf 35mm anamorphic area for which the lens was designed to fill.

 

See:

http://www.reduser.n...and-Data-Sheets

http://www.red.com/l...amorphic-lenses


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