[62mm]

Hi...
Not sure where to post this. I have had a 'Sears AUTO 2X TELE CONVERTER 4E/MC KR 271.8100' fall into my lap and was thinking about driving it around the block once.
I might be looking right at it in the databases but I do not see it.
Is it safe to mount to my K5II, Kx and etc as-is... and is it safe for all of my K mount lenses of various generations?
Is there a link to data or reviews?
Thanks!

---------- Post added 03-05-17 at 06:18 PM ----------

Hi...
Not sure where to post this. I have had a 'Sears AUTO 2X TELE CONVERTER 4E/MC KR 271.8100' fall into my lap and was thinking about driving it around the block once.
I might be looking right at it in the databases but I do not see it.
Is it safe to mount to my K5II, Kx and etc as-is... and is it safe for all of my K mount lenses of various generations?
Is there a link to data or reviews?
Thanks!

Forgot Made in Japan

[MarkJerling]

It may or may not be, depending on whether it has the "Ricoh pin". I believe those may have a "Ricoh pin" in which case they're not safe to mount. Lots of threads about the infamous "Ricoh pin" See for instance: Ricoh pin - what is it and why the need to remove? - PentaxForums.com

[marcusBMG]

There is more than one vintage MC4 tc listed: soligor, vivitar, focal, prinzflex... Sears is just a seller brand so it is probably the same as one of them, study the pics. Yours sounds like it's PKM, the PKA ones usually have pka written on them.

In general the MC7 ie 7 element tc's are better - better corrected anyway if not necessarily sharper. There's a number of threads discussing whether tc's, esp 2x tc's, are worth using..

[62mm]

It may or may not be, depending on whether it has the "Ricoh pin". I believe those may have a "Ricoh pin" in which case they're not safe to mount. Lots of threads about the infamous "Ricoh pin" See for instance: Ricoh pin - what is it and why the need to remove? - PentaxForums.com

Thanks.
I knew that I had read about some forms of older k's not working out but have had no issues with any of mine. Good to know that the KR is what to look for.
I read around about it after your reply and see some references to a 'spring-like ball style' (which mine would appear to have) but saw no pics of such critter. Is the bad guy flat on the end and not round and springy? Should I also take out this one?

Thanks again...

[MarkJerling]

Here's a picture of one: Lens question... - PentaxForums.com
Some say the round ones are OK. I've not tried one on any of my cameras.

[marcusBMG]

Quoting from that linked thread:

The infamous Ricoh pin, if exists, is on lens with pK-A mount. In most cases, the marking is something like "PK-A/R-PK." Note that Ricoh pin does not necessarily mean bad. The one in this photo is harmless because it's a ball, not actually a pin.

I can confirm these are no problem.
The designation PK/A-R is usual on mounts that are intended for both pentax and ricoh, and which will have a rcoh pin..

[62mm]

Quoting from that linked thread:



I can confirm these are no problem.
The designation PK/A-R is usual on mounts that are intended for both pentax and ricoh, and which will have a rcoh pin..

OK, Thanks...
Not sure what to think... saw one report that one of these was OK on a Kx but not on a K5II, but outside of that I don't think I saw any other bad experiences. I am not wild about opening that puppy up and possibly letting dust in or by leaving a hole remaining as I will be playing with this in some less than ideal conditions.

Thanks for the replies.