Digital Photography in Available Light

essential skills: digital photography in available light

Left to right adjustment - The lens and tripod should be

viewed from the front and the lens position adjusted from

left to right until it sits vertically above the tripod’s pivot

point.

You can check your positioning skills by turning the camera

90 degrees down (so that the lens faces the tripod pivot)

and confi rming that the pivot point is located centrally in

the LCD preview screen. This is the easy part

Why all this bother with specialized equipment? The stitching software’s main task is to seamlessly

blend the edges of overlapping images. This is best achieved when the edge details and perspective

of the two pictures are as similar as possible. Slight changes in the relationship of the objects in

the scene will cause problems when stitching, often resulting in ‘ghosting’ of the objects in the fi nal

panorama. Now, for the occasional panoramic photographer this is not too big a deal as a little

deft work with your Photoshop editing tools and the picture is repaired, but frequent panorama

producers will want to use a technique that produces better results faster. Using a special VR or

panoramic tripod head produces such results by positioning the ‘nodal point’ of the lens over the

pivot point of the tripod. Images shot with this set up will have edges that match more evenly, which

means that Photomerge can blend these overlapping images more successfully and accurately.

Finding the nodal point

If you have a VR head designed specifi cally for your camera and lens then the hard work is already

complete. Simply set up the equipment according to the manufacturer’s instruction and you will

be taking ‘nodal point correct’ pictures in no time. If, however, you are using a fully adjustable VR

head or you just want to fi nd the nodal point for a specifi c camera and lens combination you can

use the following techniques as a guide.

Back to front adjustment - Move the camera back and

forward to fi nd the nodal point of the lens. Set camera and

tripod up so that there is a vertical object such as a lamp

post or sign very near the camera and a similar vertical

object in the distance. The closer the foreground object the

more accurate the results of the test will be.

Watching the LCD preview screen (or looking through the

viewfi nder in an SLR camera) rotate the camera. If the gap

between the near and distant verticals increases as the

camera is rotated move the camera either forwards or

backwards and try again until the gap remains constant