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Charles Green

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  1. Charles Green's post in Model Photography/Scheimpflug Principle was marked as the answer   
    For this post , I am placing cameras in the category of "Shop Tools". 
     
    Recently, I came across a topic from 2013 addressing the depth-of-field problem encountered when photographing a vessel's hull from an oblique angle.  Kathy Teel has recently submitted a number of photos of outstanding models in this site's "Images" section.  Her last photo (as of 12-13-20), depicting a hull's port, stern section, illustrates the depth-of-field problem I am referring to.  This problem is independent of lens quality or the photographer's skill - it is an optical fact-of-life and stopping a lens down will not overcome it.  The close focusing distances encountered in model photography exacerbate the problem. 
     
    Electronically manipulated "focus stacking" was the solution discussed in 2013, but there is another way.  An articulated camera/view-camera or an articulated lens fitted to a conventional camera can do the same, if not better job as focus stacking, while allowing a lot more freedom in camera position and composition.  And, you can see what's going on in the viewfinder - what you see is what you get.
     
    Film view-cameras are still in production by several makers, as is sheet film, but not everyone is interested in film photography, as I am.
    View-cameras with electronic backs - in place of film - are available but their price is astronomical.  However, If you own any F mount Nikon (film or electronic) or any EF mount Canon, both makers provide what they refer to as TS (Tilt - Shift) lenses.  TS lenses can achieve the same photographic effects as a view-camera. 
     
    Both makers provide TS lenses in a wide range of focal lengths.  In the past, Pentax made a 24mm, K mount TS lens.  They come up in the used market.  And there are TS adaptors.  Adaptors can couple any lens and camera, but - Any lens used for tilting or shifting must be designed to project an image circle wide enough to cover the film or electronic sensor when the lens is used off-axis.  Conventional lenses are not made to do this.  "Lensbaby" makes a number of lenses and articulated mounts.  I have no experience with them and cannot speak to their optical quality.  They cover a range of camera mounts and offer a relatively inexpensive way into TS lens use. 
     
    View-cameras and TS lenses allow the lens to be tilted/turned off axis, relative to the film/sensor.  In short, this brings the Scheimpflug Principle into play and solves the depth-of-field problem.  The shift function allows a lens to be shifted laterally, moving the image in the view-finder without moving the camera - but, not of much importance to this discussion.  The Scheimpflug Principle also allows correction of distortion inherent in photographing long, narrow objects (like ship's hulls) that seem to converge to a point in the distance.  Lines converging in the distance can be brought parallel, if you want.  The film/sensor must be able to be tilted relative to the lens to achieve this and this is where view-cameras come into play.
     
    The depth-of-field problem is an optical fact-of-life, as is its solution, the Scheimpflug Prinicple.  It has been in use since its discovery by Austrian army Captain Theodor Scheimpflug in 1904, for correcting distortion in WWI aerial surveillance photos taken from an angle.    
     
        
     
     
     
     
     
          
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