HI,
I have a Nikon F3 that I use for the majority of my photography and was curious about using auto-extension tubes and bellows attachments. I honestly have no idea how these work with a normal lens and was wanting to just know the basics. Thanks
They work by moving the lens farther away from the camera which allows for closer focusing. Also remember that this requires compensation for the loss of light. More loss the further out you go.
As far as focusing do you need to compensate anything or will it be as normal with just the lens? thanks. Sorry for the dumb questions. Does anyone recommend or not recommend using them?
You may find it easier to focus by moving the whole camera nearer or farther from the object. But...no there is nothing magic about extension tubes. They're simply an empty tube that moves the optic farther from the film. This is what the focusing helicoid in the lens does...it just has limited range of motion. That range covers from infinity to something reasonably close.
When using extension tubes the lens focus ring only changes the focus about a foot for the shortest tube to a few inches for the longest tube. Focusing is accomplished by varying the distance to the subject. The shorter the lens focal length the closer you have to be to the subject. Extreme wide angle lens won't work as the point of focus occurs behind the lens and its impossible to put the subject there. I use a 35-135 zoom on a F4 with a 20mm tube and a zoom setting of 40mm to 70mm depending on subject. Bees don't like you too close to them.
No, I haven't been stung but they move away.
Depth of field also decreases significantly even at small apertures.
I believe the extension tube has the meter coupling and aperture coupling so metering would be normal but if you use the bellow the lens will always stop down and the meter coupling doesn't work.
Extension tubes if listed as Auto will work with the camera meter system and lens aperture to give the correct exposure. Non auto tubes and bellows require one to calculate the exposure compensation.
For metering with non-coupled extension tube you use the stop-down metering procedure. No compensation is needed if you're using the camera's through-the-lens meter.