Do i really need an m42 adapter with corrective glass?

mrjayviper · Joined: 21 Jun 2020 Posts: 3 Location: Afghanistan

I have an 55mm f2 takumar. I’m using it on my Nikon FF body using a m42-to-F mount adapter that has no corrective glass for infinity.

I only want to use it for portraits (distance to subject would be 12 feet or less).

Should i get an adapter with the glass for my situation? Thanks!

calvin83 · Joined: 12 Apr 2009 Posts: 7553 Location: Hong Kong

Flange distance for M42 is 45.56mm, for Nikon it's 46.5mm. If the adapter is 1mm thin, there is 2mm extension. You can check how far it will focus with 2mm extension. It will be even better if the there are rooms to adjust the infinity.

D1N0 · Joined: 07 Aug 2012 Posts: 2491

I guess it depends on how much the adapter ads to the flange focal distance. If it sits flush it should focus to around 1.2 meters I guess. Since lens focussing is logarithmic it will not decrease very rapidly from there, but portraits will be pretty close up.

I wonder why there aren't any negative dioptre lenses to screw onto the front. I find that I am getting very good results with close up filters, so why not minus glass. You can get if for your eyes and maybe it will distort the image less than a corrective element behind the lens. I just tested with some glasses and a 50mm lens Infinity is moved to about the 1 meter mark.

visualopsins · Expire: 2025-04-11

Lightshow · Joined: 04 Nov 2011 Posts: 3669 Location: Calgary

Any particular reason you want this lens for portraits? It wouldn't be my 50th choice for that kind of subject,
I like the optics, especially in its 55/1.8 form(I have 3 or 4 versions of it), but I wouldn't go through extra effort to adapt it for infinity if that's not how you intend to use it.
Adding extra optics will degrade the image quality because they didn't optimize the adapter optics for that lens.