Originally posted by Jorgario 12 blades ! That's the funny thing. There is one on Ebay for only 50$ approximately and in fact a preset one. Maybe the same as yours. Is there a difference between t-mount and M 42 ? Because on the picture we can not see any difference.
Nice picture anyway !
turns out it was sold as a m42 lens......but recently realized that it is a t-mount that had a m42 adapter on it.....I had an extra t-mount to k-mount and put that on it.....it doesn't seems to perform as well this way...that's why I wonder about the registration distance.....
t-mount and m42 are very very similar but quite different....unless expressly stated what mount it is....it is difficult to tell the difference from pictures or even looking at it directly....an m42 to k adapter will not thread properly on a t-mount.....which will certainly be felt trying to screw it on