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mattuhry

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    mattuhry reacted to andy lee in How to get bargain 16mm cine lenses for the upcoming Blackmagic Pocket Cinema Camera and Digital Bolex   
    I shot on 16mm film for about 15 years - I also had 2 Bolex h16 cameras I used alot -  carted them all over the world during this time.
    You really need to consider the BOLEX PRISM before you rush out and buy lenses
     
    please read this carefully
    http://www.city-net.com/~fodder/bolex/truth.html
     
    The Bolex H16 RX cameras and the more recent Bolex models utilize a beam-splitting prism for reflex viewing and still allow lens interchangeability. This leads to optical complications. The prism being between the taking lens and the film must be regarded as an optical element of that lens. Even though it is a very simple element with no curvatures, it has optical significance.
     
     
    Lenses for the Bolex are designed to work with the prism it alters the light path to the film
    Black Magic Pocket camera has NO PRISM so your lenses will not be working as they where designed to properly
    Please make sure you understand the principles first before you buy as some lenses are affected more that others.
     
     
    and then read this to undertand the prism more
    http://www.bolexcollector.com/cameras/h16reflex.html
     
     
    this is the intersting bit from the above link......
     
    The Bolex H-16 Reflex was also designed with a 20% more powerful motor than earlier models. On a full wind, it was possible to run the camera for 40 seconds at 16 frames per second. [1]
    The camera could accept three C-mount lenses (1 inch thread diameter). However, the glass of the reflex prism between the lens and film plane affected the optical correction of focal length lenses equal to or less than 50mm. To solve this problem, Kern introduced a line of "RX" mount lenses which were distinguishable by red letters engraved on the front of the barrel. (More on RX and standard C mount lenses.)
    It was still possible to use standard C-mount lenses of 50mm or less, but for best results it was recommended they be stopped down to at least f/5.6. [2] However, it was later suggested that non-RX lenses of 50mm focal lengths and less would likely produce satisfactory results only when stopped down to f/8 or smaller. [3]
  2. Like
    mattuhry reacted to mattuhry in How to get bargain 16mm cine lenses for the upcoming Blackmagic Pocket Cinema Camera and Digital Bolex   
    I'm glad I've finished my Kern Switar hoarding program before you wrote this article.   There's one important things you should include.   The lenses designed for a RX Reflex Bolex were built to correct for the optical problems induced by the 9.5mm thick prism that was used to split the light path to the viewfinder and film gate.    These RX lenses don't resolve very well and suffer from significant spherical abberation without the presence of the prism, it's most severe on the wides and when at the wider open stops.    
     
    Kern lenses that have the designation AR were designed for non reflex cameras and function like normal lenses, in most cases they offer very good performance... think 60's vintage leica M's... yeah that good.     I'm excited to try them on the Pocket. 
     
    Matt Uhry
    www.mattuhry.com
  3. Like
    mattuhry got a reaction from Andrew Reid in How to get bargain 16mm cine lenses for the upcoming Blackmagic Pocket Cinema Camera and Digital Bolex   
    I'm glad I've finished my Kern Switar hoarding program before you wrote this article.   There's one important things you should include.   The lenses designed for a RX Reflex Bolex were built to correct for the optical problems induced by the 9.5mm thick prism that was used to split the light path to the viewfinder and film gate.    These RX lenses don't resolve very well and suffer from significant spherical abberation without the presence of the prism, it's most severe on the wides and when at the wider open stops.    
     
    Kern lenses that have the designation AR were designed for non reflex cameras and function like normal lenses, in most cases they offer very good performance... think 60's vintage leica M's... yeah that good.     I'm excited to try them on the Pocket. 
     
    Matt Uhry
    www.mattuhry.com
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