[pathdoc]

I just fitted my Pentax original M42/K adapter to the front of my deglassed Kalimar 2X PK-A/R teleconverter, to use with the Industar 50/3.5 lens.

This worked well enough, but then to my horror I simply COULD NOT get the adapter off again.

I had to resort to taking the front ring off the T/C, at which point all the pass-through A contacts SPROINGED out like rabid snakes, so it took a JIS screwdriver, some tweezers, and strings of four-letter words that would get me a lifetime ban before I got the adapter off and things back together again.

I therefore submit this cautionary tale. Don't do it, people; just don't do it.

[Not a Number]

The adapter won't even fit in my Vivitar 2x macro focusing TC. It seems the third parties take great liberty with the design of the mount on TCs.

[D1N0]

Or just take of the locking spring, before using the adapter, then you do not even need an original.

[UncleVanya]

I've never tried but I am curious what could be different enough to cause this?

[marcusBMG]

Not for the first time I shall remark that the flanged adapters are more reliable, more stable, more secure and prevent possible light leaks, and the presence of the flange with its effect on infinity focus distance is inconsequential in this case since you were "macro'ing" anyway.

[pacerr]

Often inconvenient depressions in mating surfaces can be 'exorcised' with a drop of 5-minute epoxy shaved smooth when set -- presuming you notice the need.

Don't forget to de-grease the depression.

[stevebrot]

I just fitted my Pentax original M42/K adapter to the front of my deglassed Kalimar 2X PK-A/R teleconverter, to use with the Industar 50/3.5 lens.

This worked well enough, but then to my horror I simply COULD NOT get the adapter off again.

I had to resort to taking the front ring off the T/C, at which point all the pass-through A contacts SPROINGED out like rabid snakes, so it took a JIS screwdriver, some tweezers, and strings of four-letter words that would get me a lifetime ban before I got the adapter off and things back together again.

I therefore submit this cautionary tale. Don't do it, people; just don't do it.

Let me get this straight...your M42 adapter became stuck on your Kalimar T/C? What is it that I am just not supposed to do?

Did the retention mechanism on the T/C fail or did did the adapter get munged somehow during mounting? As Marcus noted, this is one case where a flanged adapter might have been the better choice given that infinity focus was not an issue.


Steve

[pathdoc]

What is it that I am just not supposed to do?

You're advised not to put the adapter on a teleconverter, lest the same happen to you.

Not for the first time I shall remark that the flanged adapters are more reliable, more stable, more secure and prevent possible light leaks, and the presence of the flange with its effect on infinity focus distance is inconsequential in this case since you were "macro'ing" anyway.

That doesn't help when you want to use the lens throughout its full range.

Or just take of the locking spring, before using the adapter, then you do not even need an original.

There's always a first time for everything, and this was the first time. Experience is a valuable teacher, but you have to have the experience first. I was just letting you all know about mine.

The adapter won't even fit in my Vivitar 2x macro focusing TC. It seems the third parties take great liberty with the design of the mount on TCs.

Now that IS interesting to know.

[marcusBMG]

That doesn't help when you want to use the lens throughout its full range [of focus?].

I still recommend having one in your kit bag. They're only cheap - an essential bit of kit if you're using M42 lenses IMO.