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Do Aspherons Cause Light Loss


M Joel W

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I've read that wide angle converters (that maintain focus distance) neither increase nor decrease the f stop (coatings and t stop aside) of a lens.

But aspherons require a lens be focused in macro to hit infinity. Is there light loss from this (similar to a lens being in macro mode suffering from light loss)? I calculated it at about a stop for a 24mm lens to be in macro mode for an attachment I want to use. But the adapter also is 0.7x. Would that cancel out somehow? Or would I lose a stop of light light because the effective aperture is shrunk by the asperhon too?

What if I used a 250D filter rather than a macro tube? 

Does a 24mm lens lose less light when focused as a macro lens than a 180mm focusing at the same distance? 

The 10mm Zeiss standard speed, 18mm K35, and 17mm Moviecam lens are just 16mm standard speeds, 24mm K35s, and 21mm Olympus lenses with an aspheron, right? 

I need to spend less time online lol.

 

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