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Re: There has to be an M42-Nikon adapter that works
Jan 22, 2011
I suppose you know why there aren't many adaptors for Nikon from other mounts. Nikon has about the largest distance from mount to focal plane (sensor or film) of any camera brand. Infinity is where the lens elements are closest to that focal plane or all the way in. A lens focuses closer to the subject or farther from infinity by moving away from the focal plane. That's why extension tubes work for macro.
Nikon lenses are designed to hit infinity at this distanace from the sensor and no closer. Other brands like Pentax M42 have a closer mount flange to focal plane distance. They are designed to get to infinity at their closest distance.
Now, an M42 would have to go inside the Nikon mount to get close enough, or use glass to bend the light and get to infinity farther away where Nikon's mount is. Get it? A glassless adaptor is going to take up some room and act like a small extension tube. An adaptor with glass is going to act like a small teleconverter. Either way, IQ or infinity suffers.
This is the reason there can be fairly easy adaptors for all these new mirrorless cameras like the Olympus EP1. Their mount to focal plane is very small. Their native lenses are designed to hit infinity at this closer distance. Any adaptor must push the adapted lens out to whereever it is designed to be when mounted on what it was designed to be mounted on. But it's always going to be more than that micro 4/3rd is. With Nikon, all adaptors would have to pull the lens into the camera to work. That would be a problem with the mirror and other things.
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Cheers, Craig
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