Although I have a Canon TS-E 24mm ( http://www.canon.co.uk/lenses/ts-e-24mm-f-3-5l-ii-lens/ ), I don’t use it very often; despite being one of the best lenses I have from a quality, distortion and CA perspective. So my Easter treat has been re-acquainting myself with one of my most expensive lenses: some GBP1700 on Amazon (https://www.amazon.co.uk/Canon-focal-length-12mm-Shift/dp/B001TDM7DA).
First I decided to reread a few articles on the Scheimpflug principle and the hinge rule, which can be read about here: http://www.trenholm.org/hmmerk/
Thanks to Harold Merklinger we also have this diagram:
Having read about the ‘maths’, I thought I would do some virtual experimentation first. Having tried various Apps I can recommend three that really allow you to play around with all the Tilt variables.
The first is a web page with an interactive interpretation of shift: http://www.cambridgeincolour.com/tutorials/tilt-shift-lenses2.htm
The second is an online App and a great visulisation tool by Tim Parkin at http://static.timparkin.co.uk/static/dslr-tilt-shift/
Finally, as far as iOS Apps are concerned, I think the best and most powerful, for both normal depth of field and tilted DoF calculation and visualisation is LumariverDoF: http://www.lumariver.com/#LumariverDoF
For me, although the LumariverDoF interface is a bit intimidating at first, once you ‘work it out’, this App allows you to experiment with tilting, all from the comfort of your own sofa!
Once I had re-acquainted myself with the theory, I put it all to the test with a simple table top example.
From experience I knew that a ball head was not the ideal tool to use for tilt & shift work, as it is exacting work and ball heads don’t come with vernier control. So I turned to my Manfrotto geared head ( https://www.amazon.co.uk/Manfrotto-410-Junior-Geared-Head/dp/B000JLI4Q2 )
As for focusing the tilt-shift lens, the ‘secret’ is to use Liveview and iterate to a focus solution.
For the test case, I simply placed a magazine on the dinning room table, with the desire to have the cover of the magazine in focus at an aperture of F/3.5! Normally (no tilt) such an aperture would result in a very narrow depth of field, eg focusing at about 50cm on the bottom of the book, meant, at the CoC I was using, the near and far DoFs were 46cm and 54cm: not enough to get all the magazine in focus.
The tilt-focusing approach I use with LV is to iterate by ‘focusing on the foreground and bending (tilting) for the background. That is focus on the edge of the book closest to the camera using the Canon 10x zoom, then reposition the zoom box and tilt (bend) until the background comes into focus. This will throw out the foreground focus, so move the zoom box back to this point and refocus and repeat/refine the background bend/tilt; until both foreground and background areas of interest are both in focus.
The resultant test image looks like this:
Bottom line: once you understand the basic principles of the tilt/shift lens and played around with the visualisation apps, using this incredible piece of glass technology is both rewarding and fun.