Thursday, November 12, 2009

[3D Tutorial] – Stereo Photography - Part 3

Part 3 – Refining the technique

Selecting the right themes


Some themes work better for 3D than others. Especially where the stereo-pair of pictures are not taken at the same instant but in sequence (e.g. cha cha). Generally, themes that work well are static and don't change between the two shots. Animals, people, waves and windy trees are a disaster. Scenery, bridges and still life, work much better.

Also, try to select themes that have a strong dimensional character or perspective. Leading lines such as walk paths or bridges work very well. Pictures with multiple depth levels (foreground, mid-ground, background) also work well. Pictures that are by their nature two-dimentional (a wall, a painting, a far away mountain range) don't lend themselves to 3D work.

Tripods & supports

One of the fundamental principles in creating anaglyphs, is that the pictures are taken from the same vertical plane. so ideally, the two shots should be taken with the camera at the same hight and pointing in the same direction and only shifting horizontally.

There are third-party "slide bars" that allow you to mount your camera on a dripod and shoft it horizontally. If you are interested in buying one, just click on the picture:



However, here are some other ways you can achieve the same effect. If your tripod allows you to move the central column to a horizontal position, you can usually shift the camera along horizontally:



If you are lucky enough to have a set of bellows (or can get hold of one!) with a separate focus rail, then mounting the camera sideways gives you the identical functionality of a slide bar, with a lot of control. (The one shown here is from a Minolta series II bellows):



If you are a crafty DIY man or woman, then you can always make your own of course... Click on the picture to see how.



Keeping it consistent

Last tip: consistency between the pictures in the stereo-pair is important! To get the best results you should have the same focus and the same exposure between the two shots. Once you have mounted your camera on your tripod and slide bar, take a test shot and make sure your camera has focused correctly. If your camera allows you, switch at that point to manual focus (MF) and you should retain the same focus point.

Similarly with exposure: take a few test shots to determine the correct exposure for your shot. Then make a note of the reading, and set your camera manually to the same setting for the two pictures. This is especially important when shooting outside where the light is changing constantly. It's better to have a pair that is consistently over/under-exposed, than one of each! (hint: If the sun is playing hide and seek in and out of the clouds, wait for a few minutes to let it stabilise one way or the other, between taking the pictures!)

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