I like to experiment with photography and I
also like the idea of being able to take tilt/shift style photos. I decide to
combine those two things and experiment with creating my own budget tilt/shift
lens.
There are a few guides online features the various
ways in which such a lens can be assembled but I went with the simple bicycle
inner tube ‘free-lens’ type. It is cheap, effective and does not require a
degree in engineering to build.
Parts required:
- · A section of bicycle inner tube
- · Some long cable ties
- · A lens body cap
- · A suitable donor lens
That’s everything required. You’ll also
need some fairly standard tools like scissors, a sharp knife and screwdrivers
then you’re good to go. So far, so cheap!
Step 1 – The Body Cap
In order to mount the lens to your camera
body you’re going to need to obtain a body cap in the correct mount for your
brand of camera. Being a Pentax user I purchased a generic hard plastic ‘K’
mount cap from eBay for the grand sum of £1.99.
Once you have your lens cap you need to
carve out the centre hole leaving just the outer ring mount. I found the
easiest way to do this was to melt/cut it with a soldering iron but a heated
sharp knife should have the same effect. Once the hole was made I used a sharp
craft knife to cut away any sharp pointy bits.
Step 2 – The Inner Tube
You need a wide inner tube to act as the
flexible part of the lens. A typical 26” MTB inner tube should suffice with a
minimum width of 1.95” but ideally the wider the better. Once you have your tube
cut approximately 5cm of length from it stretch it around the modified body
cap. Once in place secure with a cable tie.
Step 3 – The Lens
Lens choice is going to be important here.
On an APS-C sized sensor camera you’re going to need at least a 35mm full-frame lens. To allow an even greater freedom of movement when you tilt and
shift the lens bigger is also going to be better. I used an old full-frame 28mm f2.8 lens simply because I already had it at home but a lens designed for
medium format would be even better and not all that expensive from eBay.
To begin with start from the rear of the
lens and strip away the mount and any superfluous body parts. The idea is to
strip enough of the lens away that you can freely move the lens around without
being restricted by the lens coming into contact with the camera body.
The next image shows how much of the lens I
stripped away but in hindsight I wish I’d have taken it even further to allow
more movement. Also with the focus ring still attached be sure to set (and then
leave) the focus at infinity.
With the lens stripped down and the
aperture ring removed I had to use some fixing putty to hold the aperture
blades open at their widest setting. Without this the aperture would close down.
This behaviour can vary depending on lens manufacturer so this step may be
optional for some.
With the lens stripped and the aperture
open you can now stretch the inner tube from step 2 over the body and secure it
with a cable tie or two. The end result should look something like the lens I
made in the next image and is ready for use.
Demonstration
To demonstrate the lens working I mounted the camera on a tripod, set aperture priority and took the first image with the focal point as close to 'normal' as I could reasonably get it of the rug in my lounge. The resulting image looked like this:
Then without moving the camera or tripod I moved the lens to the left and right and took more images to show how the focal point moves along with some changes in perspective. This is further exaggerated the more you are able to move the lens.
As stated earlier in the post if you are able to use a lens with a bigger image circle then greater movements will be allowed so on a typical APS-C camera a full-frame lens is useable but a medium format lens would be preferable. If, like me, you use a full-frame lens on an APS-C camera then keeping movements small is key as you will quickly find none of the image in focus otherwise.
Overall it's a fun lens to use and due to it being flexible and imprecise no two images will likely be the same. Have fun experimenting!
Revision
I made a slight revision to my version of the lens as when moving it around I found the focus ring of the lens would hit the body of the camera and restrict movements too much. I made a quick modification by removing the focus ring and reattaching the inner tube and now have a greater freedom of movement.
