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The Scheimpflug Line

Added on by Bill.

Looking inside a view camera can be quite startling.    

There is nothing there.  

This is in stark contrast to the innards of modern cameras which are packed with various technologies used in the production of an image or are related to that process.  

This emptiness quite clearly exposes how simple it can be: A lens; a gap; a piece of film.  

It's easy to be mislead by the wood and brass construction that there is no technology at all.  But there is; the various knobs, levers and slides provide capabilities not available on most cameras: swing, tilt and shift.  

In the normal camera the film plane, lens plane and focus plane are all parallel.   

Swing and tilt (of the lens) change the relationship among these planes.  Tilting the lens forward, for example, tilts the plane of focus proportionately such that it slides under the camera and projects off into infinity.  

As I explored the subject of tilt I came across Scheimpflug.  Captain Theodor Scheimpflug was an Austrian Army and Naval officer, born in October 7, 1865 and died in August 22, 1911. In the early 1900's he used cameras suspended from balloons for aerial photography for the purpose of creating accurate maps.  To resolve the various distortions that result from imperfect alignment he developed a number of principles, one of which bears his name.

In order for a view camera image to be sharp, the rules of optics state that the film plane, the lens plane and the plane of sharp focus must intersect along a common line in space. That line is the Scheimpflug line. [Merklinger, Focusing the View Camera].

The objective of my first experiment was to get a sense of how it works--the set up and the execution--by walking through the steps. The first step is to establish the things to be in focus. Or more precisely, what is the plane of focus?  Standing in a field (picture below) I picked the distant trees and a spot just under the camera.   With the plane picked I determined how far below my camera the plane passed (J).  With J, I could then calculated the necessary tilt of the lens [a = arcsin (f/J), where f = the focal length of the lens in meters]. I estimated the plane ran 1 meter below the plane of the lens, which was just about ground level. The result was a tilt angle of 8.62 degrees.  [Note: implicit in the equation above is some a relationship between the tilt angle and the angle of the plane of sharp focus which I do not yet understand.]

I levelled the camera and then tilted the lens the prescribed amount. Rather than calculate the depth of field I set the aperture to f/22 and the speed accordingly.  

Inspection of the shot confirmed the angled plane of focus was present.  Point #3 corresponded to my estimation of the far point of the plane and point #2 the near point.  Both have focus.  In contrast is point #1 (which is on the approximately the same vertical plane as point #2) that is completely out of focus.  

I have more work to do to fully understand the maths, but given the results are there to be had, I'm encouraged to explore further along this path.   


Added on by Bill.

For the last month I've been working on my darkroom.  It has been a long process, but a satisfying one.  This phase of the project was to build a sink for the wet area.

As noted in my previous post, phase one of the project completed the dry area which hosts my PC, scanner, printer and a work area for framing prints.  Phase three, and it is hoped to be the last phase, will connect the sink to the plumbing.

The sink, located on the left, is 2 feet deep by 4 feet wide. The bowl of the sink is 6 inches deep.  It is made of PVC on a wood frame. The PVC sheets (three 2'x4') were purchased on eBay from a store in Missouri as I was unable to find any locally.   The wood was sourced from my reserves (that is, I had a lot of extra wood that I wanted to get rid of).  I only had to buy one 2'x4' sheet of plywood for the sink base.

The original idea for building the sink was described in an article, How to make a custom darkroom sink out of PVC.  It provided the basic instructions and importantly they key parts.  With that information, and the inventory of wood I had available, I created my own plan (pdf). 



Added on by Bill.

The hydrangea are in bloom.  

Tachihara Field Camera 4x5, Nikkor-W 150mm 1:5.6, Kodak TMAX, f/64, 5 sec, ISO 100, D76

Hydrangea are an interesting subject; globes of small-petalled flowers on a background of large-leafed stems.   Compositionally this offers a natural contrast.  However, now my attention is directed towards the Zone System to ensure proper capture and development.

In the digital world results are immediate and each shot can be used to iteratively hone in on the right exposure and composition. There is really no cost to taking another shot.  In the film world results come only later after development and processing and each shot costs about $2.00.  It takes me between 5 and 10 minutes to set up and complete a shot. Mistakes are costly in terms of time and money. Attention to detail and a consistent process is important.  Therefore, planning the shot and ensuring proper exposure are important. As I get better at this, I expect this to increase; and then may be at some point it will decrease.  

My attention right now is on getting the tones right and understanding what constitutes right.


Added on by Bill.

I've been upgrading my darkroom.  My entry into large format photography has placed demands which Darkroom 1.0 was unable to support. I've separated the wet and dry areas according to traditional darkroom design practices.  The wet side is where one does the development. As I follow a hybrid analogue-digital model, the dry side hosts my computer, scanner, printer and work area for framing pictures. Same capabilities as a traditional darkroom, just different technologies.  The dry area is set up, the wet side remains in progress. 

To complete the wet side will require plumbing and a darkroom sink. This being more complicated extended timelines result.  Finding a sink being on the critical path.  So until this is complete I will use the framing area as the wet zone. Yet even with this interim state, Darkroom 1.5 improves the level of maturity of the core capabilities.  

View of the darkroom in action. 

Ithaca Series: Wrap-up

Added on by Bill.

This belated post provides a wrap-up of my learnings from the Ithaca Series of waterfall shots.  In that series I explored my [tending negative] feeling towards "silky" waterfall shots with a view to finding a root cause and thus whether there was anything I could do about it.  

In the end it is simply one of preference.  It's not that all silky-water-fall shots are bad; it's just my tolerance of them exists within a very narrow band.  Yet there are some things which I can do to widen that band of tolerance: 

  • Black & white makes things better.
    Why?  Black and white  tends to simply (which can already be a complicated composition). By removing the colour it removes one variable of distraction from the picture. This results in tending to emphasize the texture of the shot which in turn can be used to manage the overwhelmingly sickly silkiness of a composition if managed properly.  What this means is that converting to black and white is not necessarily a single solution; other techniques may need to be applied (see below).
  • Contrasting hard and soft
    The silkiness of the waterfall can overwhelm a shot with its softness; it's just too smooth.  I found it important to balance this with hardness, of rock, or some texture. 
  • Proportion
    This is about finding the right proportion of soft and hard.  I'm not sure there is a set ratio; it is likely related to the composition and mood. 
  • Light and Sparkle
     These shot, like all other, benefit from good light.  I found those that let out the sparkle of water or did not blow out the silk were more satisfying. Backlighting helped as well and could provide an etherial sense.