500mm pinhole camera "lens"

The focal length or projection length is determined by how far the pinhole is from the negative. In this case I have built a "tube" to have  the pinhole at 500mm from the negative.


The photographs are of Kingsnorth Power station taken from the shore line 3kms away the other side of the river.

As with pinhole camera the focus is soft but the depth of field is from in front of the camera to infinity.

A different view with closer foreground

The exposure was 6 minutes with a pinhole of 0.89mm giving an aperture of f/561.

The Calculation

I established the size of lens needed by measuring the width of the power station and the distance away on an Ordnance Survey map.  Then by the use of simple trigonometry I established the Tangent of the angle for half the width of the station. Knowing the half width of the image and now the Tangent of the angle I calculated the distance of  the lens to negative and made the necessary tube accordingly.  It created a photo exactly as expected.

A macro picture

On another web site, see link below, I have given a description as to how I make my pinholes. 
To make the size repeatable I have pushed the needle into a section of pencil rubber and the size required is the diameter of the needle at the surface of the rubber as measured by digital callipers.

The Nikon lens to take this photo was kindly loaned to me by Mike as it will be a rare thing that I need to take such close-ups.  The diameter of the needle poking through the rubber is only 0.28mm, the piece of rubber is about 5mm x 5mm  !!!

The needle is prepared ready to make the new pinhole "lens" for the film camera.

I am also building a monster 500mm "lens" for the 5x4" paper negative camera in an attempt to take telephoto photographs using a pinhole camera. The pinhole diameter for that will need to be 0.89mm quite the largest hole I have made.

LINK
http://www.darleys.pwp.blueyonder.co.uk/photography/

35mm Film pinhole camera tests

I decided not to give up so I prepared some photographic paper and popped it in the camera and closed over the eye piece .

 

The paper was exposed for 45minutes and then developed, scanned  at 1200dpi, mirror image and negative conversion and this is the result. 

I cannot see any fogging which I had previously experienced. The image is much sharper than when I tried to enlarge the previous negatives photographically. 

I have now stripped the camera apart again and  further improved the light prevention measures and a further test will be carried out ASAP.

Oh what a steep learning curve

Well the day has not been a complete waste of time on the pinhole 35mm film camera photo shoot as I have learned a great deal ...

1. All the negatives were fogged identically and thus  if using a camera on a tripod blank off the eye piece as that was where the light is getting in and fogging the negatives ( I found that out by exposing pieces of paper negative in the camera proving that is the route of the photons.)

2. Whilst 35mm film can be used to make pinhole negatives making even half reasonable prints is for me impossible because the negative has no critical focus is amazingly difficult to achieve a near correct focus in the enlarger  trying to enlarge more would in my opinion make it even worse ... ALSO  having a 100mm lens made it to much telephoto !!!  (May be if I placed a good negative in the enlarger, set the focus) and then tried enlarging the pinhole negatives I would obtain better results ??)

3. The new to me enlarger will be great to use when using film in the normal lensed camera, which I have and I have several films left so my walk round Rochester today has shown me some great locations - so before the film developing chemicals go out of date  I must go out and take normal film camera pictures ....

So it is back to the 5x4 and the contact prints which I have enjoyed doing for pinhole and using the enlarger as a light source and colour head which is working well now with the timer and transformer with a 35W 12V bulb ...

So what is next ...  I need to make up a sort of view finder so that I have a much better idea what is in the field of view on my pinhole camera  ...  That could take awhile to perfect ...


I have been asked to place examples of the photos here which previously I had not thought good enough but at least now you can make your own judgement. 

Photo in Rochester Castle gardens - oops drying spots on negative 

another in Rochester Castle gardens

Durst M305 colour enlarger

Well well well Father Christmas called me to his grotto the other day and said that there was a load of photographic equipment that was now taking up space and he wanted it out.


So I went to his grotto and loaded up the car with all manor of things including a Durst M305  enlarger for 35mm film.  Instruction manual found on the web is in French but old school boy French and the pictures helped a great deal.


I have changed the bulb for a 20W 12V ( which should last 4000 hours) from 75W 12V (which would last only 100 hours) and have made some B & W prints using the contact printing frame.


I have also started to understand the use of Multigrade IV Ilford paper and the filters to control contrast.  I can of course replace the original bulb if I go for colour prints.


Photos to follows when scanned !!!