Discussion in 'Native Lenses' started by Superstriker#8, Dec 25, 2013.
What (wider than 35mm actual fl) native lenses work best with extension tubes?
hate to answer a question with a question but -
1. work (best) at what?
2.(work) best in which way?
if you are taking in terms of simple magnification, the answer is simple - pick the one that has the highest magnification factor in the first place!
Work as in autofocus correctly, still maintain optical quality, and such.
I'm only aware of the Kenko extension tubes still able to AF correctly. As for optical quality, extension tubes have no optics, so the optical quality depends on the lens you put on the front. Extension tubes enlarge the image circle, so they have 2 effects:
- Only the centre part of the image thrown by the lens is visible to the sensor, so the lines per mm resolution is reduced. So you need a lens that is rated highly for this in the first place.
- the light from the lens is more "spread out" so the area that falls on the sensor gets less light. This has implications for exposure.
The Kenko tube set is a 10mm and 16mm. If you use both stacked, then you'd get about 1:1 magnification at minimum focus distance with the Sigma 30mm, and more than 1:1 with the Panny 25mm. However, the subject would be so close to the front of the lens (around 3-5cm) that you would have problems lighting it.
optical quality is unaffected by extension tubes
auto focus is more complex, involving the camera body rather than the lens and, of course, requiring the extension tubes themselves to have the appropriate electronics?
you will need a good lens though
edit - Andy has put it better while I was typing!
Good points from Andy. There are Chinese extension tubes with the electrical contacts available for about 1/2-1/4 the price of Kenko, so they should also do AF. I have a set on order.
The shorter the focal length, the bigger magnification is possible, but like mentioned above, the closer you have to place the camera to the subject. This can make it more tricky to get the lighting you desire, but not impossible. Experiment.
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