Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
01-29-2013, 03:42 PM   #1
Site Supporter




Join Date: May 2010
Location: melbourne
Posts: 934
"A" Series 28/135 Zoom on a Spotmatic?

As I've previously mentioned on the forum, many years ago I was right into LX, I had all the accessories etc, & one of the lenses I used, was the A28/135 zoom, a really big piece of glass, quite heavy, but it suited most of my needs, & was the lens I was able to use covering most situations. I sold all of my LX stuff/lenses years ago, but kept my mint SP11, & then I bought a ES11.
If I ever see a M42 45/125 zoom, mint with all access, case etc, I may purchase it, but another alternative would be the A28/135?
So, I was just wondering that if I bought the genuine Pentax M42 to K Mount "converter" (which one should I get?), how would the 28/135 work on my two Spotmatics.....would the exposure/focussing systems etc work the same with this lens as with M42 items?
Thanks, Pickles.

01-29-2013, 03:57 PM   #2
Loyal Site Supporter
paulh's Avatar

Join Date: Sep 2010
Location: DFW Texas
Photos: Gallery | Albums
Posts: 12,458
That would be very cool, but I don't think it's possible. You can adapt a screwmount lens to fit a K-mount camera, but not the other way around, AFAIK.
01-29-2013, 03:59 PM   #3
Pentaxian
Just1MoreDave's Avatar

Join Date: Feb 2007
Location: Aurora, CO
Photos: Gallery | Albums
Posts: 4,814
You can't really go the other way (K to M42) without some surgery. The first K mount cameras are pretty closely related to the late Spotmatics, so maybe an extremely clever parts swapper could make a K-mount Spotmatic, or change the lens mount, but it would be a lot easier to get something like a KM and use that.
01-29-2013, 04:30 PM   #4
Site Supporter
boriscleto's Avatar

Join Date: Dec 2009
Location: Liverpool, NY
Photos: Gallery
Posts: 12,297
Just get a KX or MX. Even a K2 should be less than $150 (plus a likely necessary CLA). M42 lenses are easily adapted to a K-mount camera but the reverse isn't possible, the mouth opening isn't wide enough. The adapter would have to be outside the body, and that makes the flange focal distance too long.

01-29-2013, 07:40 PM   #5
Pentaxian
Just1MoreDave's Avatar

Join Date: Feb 2007
Location: Aurora, CO
Photos: Gallery | Albums
Posts: 4,814
You can save some on the A28-135, though, once you find one. Despite your recommendation, mine didn't sell for a lot, and I believe one went pretty cheap here recently. How many Pentax lenses can you buy for only 16.4 grams per dollar? That's would be $10 for an A28/2.8
01-29-2013, 09:00 PM   #6
Loyal Site Supporter




Join Date: Jun 2009
Location: Tumbleweed, Arizona
Photos: Gallery | Albums
Posts: 5,001
The diameter of the K mount is slightly larger than the diameter of the M42 lens. It was purposely designed in this way, so that the K to M42 adapter could fit inside of the camera's K mount bayonet opening, thereby allowing the M42 lens to screw into the adapter. In this way the M42 fits flush with the K mount adapter and the camera's K mount. This design ensures that the M42 lens maintains the proper reregistration distance and thus will be able to achieve infinity focus.

Some (non original Pentax) adapters have a flange that sits on top (or outside) of the camera's mount and these are the adapters that interfere with the M42 lenses ability to focus to infinity, since the registration distance is artificially lengthened (by the width of the adapter's flange).

Unfortunately, this design does not support the reverse, since the K lens would be too wide for the M42 mount opening of the Spotmatic.

Hope that helps.

01-29-2013, 10:05 PM   #7
Site Supporter




Join Date: May 2010
Location: melbourne
Posts: 934
Original Poster
Thanks so much, all of you, for your replies. I now understand very well, that it CANNOT, happen!
Cheers, Pickles.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
k-mount, lens, lx, m42, mint, pentax lens, slr lens
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Don't say Pentax "Q" in French ... "Q" = "cul" = "A--" Jean Poitiers Pentax Q 52 11-10-2013 06:25 AM
Thought on manual lenses: The "A" function has a little use on digitals minahasa Pentax SLR Lens Discussion 49 05-04-2012 11:20 AM
Picked up a 50 1.4 today. Is this a "M" series??? CEWren Pentax SLR Lens Discussion 27 09-25-2011 04:47 PM
Pentax "A" lens and "F" 1.7X converter on K10d yyyzzz Pentax SLR Lens Discussion 4 07-09-2009 05:04 AM
"Hunger for a DA*50-135?" or "The DA*50-135 as a bird lens!" or "Iron age birds?" Douglas_of_Sweden Post Your Photos! 4 08-13-2008 06:09 AM



All times are GMT -7. The time now is 05:51 AM. | See also: NikonForums.com, part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top