Photography thread

[lyman]

glad to see you back,

tell me more about extension tubes,

not that I would ever use one,,,just not heard of them

[Doc Sharptail]

There's a look at a modern (and quite well made) 3rd party extension tube set.



12mm tube is on top of the stack, and is the smallest.
This set sends electronic data for aperture to the camera, and automatically calculates exposure factors so a correctly exposed image is made with an appropriately chipped lens. Other wise, exposure is determined by the modern camera's metering system.

They work by increasing the focal length by moving the rear of the lens further away from the image plane. In most all cases, ability to focus to infinity is lost, which we don't need for quality macro photography anyways. The band of usable focus becomes pretty narrow using any of these. Close focus becomes fairly easy up to about 135mm lenses, at least in my hands. Prime lenses seem to work better than zooms, mostly on account of their fast minimum apertures.



There's an image made with a fast 50mm on the 12mm tube. Curvature in the image is the curl of the old dried out Gun Digest catalog the image was made from. The use of flash is a pretty good idea with this system. Bright summer daylight works well too, but shutter speeds need to be watched.

I think there is a tutorial on using these at camera-pedia.
The set pictured was purchased in excellent used condition.
A new set for DSLR's would run in the low $100.00 range for 3rd party systems. OEM versions can get a bit on the steep side price-wise, but I think they are still being made. If one knows about proper exposure, the old manual extension tube sets are fine, and can be had for very cheap from various sources. I've got a Vivitar manual set around here somewhere that I got from Good-will for ten bucks, and a N.P.S. manual set that came as part of a package deal with one of the older cameras I bought.

Regards,

Doc Sharptail