Article

Using a Pinhole to Simulate
the Rising Front on a camera

We have an article on Pinhole cameras   and another a pinhole for your DSLR please read these first or this article may not make sense to you.

Simulating the rising front on a camera

Most plate and many folding cameras had rising fronts, something that we have lost with our later cameras. The effect of raising the front is to take a higher section of the images without needing to lean the camera, so images of buildings remain upright instead of leaning back. There are special perspective control lenses that can do this, that we can fit to a DSLR, but these are expensive, a picture of one is shown at the end of this article.

If we move our pinhole up from the centre (see a pinhole for your DSLR ) towards the top, we can produce the same effect.

We have another article on perspective and perspective control, Making Buildings Stand Up Straight. Overcoming the problem of buildings sloping backwards, this also shows a perspective control lens that does the same task as we are undertaking here.

To demonstrate this I have carried out another experiment, using similar items to the one in a pinhole for your DSLR.

In this case I made two holes on the card, one in the centre and one above, put on the foil and made two holes in this, I then cut a piece of card to form two doors, cellotaped this in place and rolled two pieces of cellotape to produce double sided tape, so I could hold either of the doors open or closed.

Image shows top pinhole in use, central one has door closed

This allows me to put the pinhole on the camera with the central hole only open and take a photo, then without moving the camera close one door and open the other, allowing me to take another photo with the top door only open.

In practice no two pin holes are the same size so I need to also change the exposure time to get this to work.

The other way that I could have done this, with a single pinhole would have been to have had a slot that allowed me to move the pinhole up and down, with a slot in the card for the pinhole to line up with. If you did this with an exchangeable slide, with one piece having a larger pinhole in, then you would be able to use liveview to see the effect, and then replace it with the smaller hole to take the photo.

The Results

Taken through a ground floor window, so having flair from the glass, they are not the best pinhole pictures I could have got, but illustrate the point quite well.

The two images below were taken without moving the camera, the one on the left with the central pinhole, while the one on the right uses the top pinhole. The camera was pointing level, straight ahead all the time.

 

Central pinhole	Top pinhole

Remember I have not moved or moved the camera, the image on the right has no converging verticals, as you would have got with an ordinary lens when pointing upwards, and is probably the same image as I would have got with the central pinhole or an ordinary lens if I was to go two floors up, in my case into the loft and took off a tile or two.

This was taken with 3 tube elements, repeated with one small one, the view was wider so you had an overlap of the image but I had the same effect.

The article using a pinhole to Get a zoom/wide angle effect  shows two images, to demonstrate the effect of removing or adding tubes, and by changing the distance between the pinhole and sensor, the image can be changed from wide angle to telephoto, but as the hole was not exactly central in the card, and it was put back in a different position after a tube element was removed,  we have another rising front like effect, like we have above, but as the movement between hole position was less it is not as great a change in height.

Now imagine we could arrange for our lens to slide up and down, perhaps one day I will find a camera attachment that allows for this, but it would require some lenses to allow the increase in distance. I have been told one was made in the USA, but I haven't found it yet.