I think I bought the wrong adapter

[ongakublue]

I recently ordered an M42 adapter for Nikon with a glass part for infinity focus. Doesn't this mean the iq will be significantly poorer? Also could someone please explain why I need infinity focus? Sorry for novice Question. Can I do without it?

 

[Ricardo Miranda]

Why don't you use a M42 body like a Pentax Spotmatic?

Doesn't this mean the iq will be significantly poorer?

Yes.
You need the glass to provide infinity focus. Without it you can only focus to close distances.

 

[Luckless]

How important infinity focus is for photography will depend on what you are photographing, and just how much of your focus range is lost.

If you're doing portrait or relatively near focus activities, then losing a bit on the longest end of your focus range isn't a huge loss. - You'll probably never notice it is gone if you're never focusing in that range anyway.

However, if it loses too much of your focus range, then you may find yourself getting deep into "extension tube" territory in how the lens is functioning for you, and using the setup for anything other than macro like work becomes impossible in that case. - But if you're using it for macro work anyway, then you're golden really.

 

[michr]

The distance from the lens mount to the film (called the flange-focal distance) on a Nikon is significantly further than almost every 35mm camera mount. This additional distance puts the lens further from the film than would be case if the lens were attached to its native m42 body. Since the lens is further from the film on the Nikon, you cannot focus the lens at infinity (the closest distance), but rather the lens will focus at some feet away from the lens and no further. The adapter you bought is necessary to restore infinity focus, but at some cost to the image quality (usually dependent on the quality and price of the adapter) and by extending the focal length a bit (e.g. wide angle lenses won't be as wide). The lens in the adapter is essential unless you are using the adapted camera lens for macro photography.

 

[Dan Fromm]

Why do you need an adapter with glass? Because the Nikon F flange-to-film distance (register) is 46.5 mm and is 45.5 mm. With an adapter of zero (0) thickness, an M42 less will be extended 1 mm when held to an F-mount body. With a real world adapter that has positive thickness, the extension from the infinity position will be the adapter's thickness + 1 mm.

 

[michr]

I also add that unless your Nikon camera is especially nice (like an F6), where you'd prefer to use it over any other camera, you can pick up a fully functional screw mount Pentax or Mamiya for not much money. If you like a bit more automation, there are focus confirmation Canon EF to m42 adapters out there for cheap, and older Canon EOS bodies are not expensive either. Since m42 is a longer flange distance than Canon EF, you can retain infinity focus without a correction lens in the adapter.

 

[GarageBoy]

It'll adapt to canon fd and ef without glass

 

[RichardJack]

Take the advise about buying a second hand Canon DSLR. You can buy an adapter for M42 mount lenses that will allow you to focus to infinity for about $10. The adapters with optics are crap, don't waste your time. If you own a serious amount of M42 glass and want to get the most out of it in digital, a mirrorless camera like a Sony is the way to go. But you just might be disappointed that your lenses don't work as well with a digital sensor as they did with film.
just my 2 cents

 

[ongakublue]

Thanks for the help and the info