Filter thread sizes.

[Bionic eye]

Hello there. I'm having trouble with my pentax SMC 50mm F 2 and helios 44-2 58mm F2.
Does anyone know what filter size these lenses take?

[ameerat42]

For the Helios, scroll down here (http://vintage-camera-lenses.com/helios-44-2-58mm-f2/) to filter size (and pitch).

For the Pentax lens, both these lots of people talk about filter size:
http://www.pentaxforums.com/forums/58-troubleshooting-beginner-help/68740-filter-size-smc-pentax-m-50mm-f2.html
and
http://www.velocityreviews.com/threads/filter-size-pentax-m-smc-50mm-f2-lens-asahi-optical-co.432995/

It would seem to be 49mm.

Am(m).

[ricktas]

Look inside the lens cap. Some brands (Nikon do) print the filter size on the inside of the lens cap