Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
03-28-2010, 04:51 PM   #1
Site Supporter
dawsonjm's Avatar

Join Date: Sep 2007
Location: Boardman, Oregon
Photos: Gallery
Posts: 106
K mount lens to M42

Here's the deal. I am getting a genuine Pentax bellows with a slide copier attachment for it. I want to use a K mount macro lens, but the bellows is M42 (I think!). If the bellows is not a M42 thread, then there must be another adapter for my lens, but if it is M42, how can I mount a K mount lens on it? I have a M42 to K mount adapter to mount the bellows to the camera, just not sure about the rest of the way.

Any help will be appreciated.

03-28-2010, 05:06 PM   #2
Veteran Member
RioRico's Avatar

Join Date: Jun 2008
Location: Limbo, California
Posts: 11,264
Here's one way to kluge it:

I bought some el-cheapo PK macro tubes on eBay. (I think they were two sets for US$10 a couple years ago. I ordered two sets, they sent me four. What a deal!) They come as thin rings that are front and back PK mounts, with various tubes to insert between.

The mounts and tubes have 61mm threads. So, you get a 42(M)-->61(F) step-up (SU) ring, if possible. Assemble: mount, SU ring, bellows. Voila! Or if you can't find the SU ring, use Liquid Metal to bond the mount ring to the front of the bellows. But that's kind of permanent. Hmmm...

Better yet, the same vendors of the PK tubes probably sell them with different mounts, including M42. So you get one set each of PK and M42 tubes, then mix-n-match the mounts. Voila! And it's all modular and reversible. Yes, that's better. Whew.
03-28-2010, 05:36 PM   #3
Site Supporter
dawsonjm's Avatar

Join Date: Sep 2007
Location: Boardman, Oregon
Photos: Gallery
Posts: 106
Original Poster
That sounds a lot like I thought I might have to do to accomplish this backwards compatability issue. Maybe just find a junker K1000 and JB weld the lens mount to the bellows?

I'm sure there must be an elegant solution to this.
03-28-2010, 05:51 PM   #4
Banned




Join Date: Oct 2007
Location: Savannah, U.S./Baguio City, P.H.
Posts: 5,979
QuoteOriginally posted by dawsonjm Quote
That sounds a lot like I thought I might have to do to accomplish this backwards compatability issue. Maybe just find a junker K1000 and JB weld the lens mount to the bellows?

I'm sure there must be an elegant solution to this.

sell the kmount lens and get an m42 lens. why do you need a macro lens for use on a bellows anyway? a good old 50mm lens will give you more magnification than you would likely need anyway at full extension. I see no need to use a macro lens on a bellows. messing with the bellows just seems like a backwards approach, when just using a different lens would be so much easier. besides the dedicated 100mm bellows takumar (and later bellows pentax) lens, the bellows was always intended to be used with the standard 50 or 55mm lenses. you have an m42 standard lens? thats all you need to achieve excellent results. you want even more magnification? get yourself a cheap set of m42 extension tubes and add them between the bellows and the lens. it doesn't get any more elegant than that.

03-28-2010, 06:06 PM   #5
Veteran Member
RioRico's Avatar

Join Date: Jun 2008
Location: Limbo, California
Posts: 11,264
QuoteOriginally posted by séamuis Quote
why do you need a macro lens for use on a bellows anyway? a good old 50mm lens will give you more magnification than you would likely need anyway at full extension. I see no need to use a macro lens on a bellows.
You're exactly right. A PK macro lens belongs on a PK camera. A M42 bellows can take any M42 (or adapted M32 enlarger) lens and deliver bookoo magnification. A bellows has infinite flexibility, but it also may make it hard to get close enough with the wrong lens. Tubes allow extreme closeness, limited only by how far the objective is recessed. I've gone tubular. I rarely use my bellows (PK and M42) anymore, except to mount weird optical substances to see what happens (Yow!) or to hold tubes to give a long lens far enough extension.
03-29-2010, 06:33 AM   #6
Ira
Inactive Account




Join Date: Mar 2009
Location: Coral Springs, FL
Photos: Gallery | Albums
Posts: 5,218
I would scan instead.
03-29-2010, 09:49 AM   #7
Site Supporter
dawsonjm's Avatar

Join Date: Sep 2007
Location: Boardman, Oregon
Photos: Gallery
Posts: 106
Original Poster
I have two Super Taks, a 35 3.5 and a 55 1.8. Never having used a bellows unit before, I didn't know what the best lens for slide reproduction would be. I will be using my K20D, and I want to get the best digital copy that I can. Would either of these lenses be the best, or should I try to find a M42 50mm Macro or a dedicated bellows lens?

If anybody has a suggestion for the light source behind the slide holder, I would like to hear about that too.

Thanks for everyones help so far!
03-29-2010, 10:32 AM   #8
Banned




Join Date: Oct 2007
Location: Savannah, U.S./Baguio City, P.H.
Posts: 5,979
QuoteOriginally posted by dawsonjm Quote
I have two Super Taks, a 35 3.5 and a 55 1.8. Never having used a bellows unit before, I didn't know what the best lens for slide reproduction would be. I will be using my K20D, and I want to get the best digital copy that I can. Would either of these lenses be the best, or should I try to find a M42 50mm Macro or a dedicated bellows lens?

If anybody has a suggestion for the light source behind the slide holder, I would like to hear about that too.

Thanks for everyones help so far!
you will be using the lens stopped down, so pretty much any lens you mount is going to perform well. a macro lens, such as the macro takumar 50 f4 1:2 will certainly be sharper throughout the aperture range, but not enough to be worth the extra cost, at least in my opinion. getting ahold of a bellows takumar will be difficult and expensive, and since its use would likely be relegated to just the bellows, it would also not be worth the higher cost. if you can find the 100mm f4 1:2, it is optically identical to the bellows version (also 100mm) but both of the macro takumars would be adding extra cost that really wouldn't be needed. if your 55mm 1.8 is a good performer, honestly you have what you need already. getting ahold of a macro-takumar is going to cost you north of 150 USD or higher. of course you could explore macro lenses in m42 mount from other manufacturers, but I cant help you there. if you want a macro lens, I would personally suggest the 100mm f4, only because, as a telephoto it has a flatter field of view.

im not sure how crop factor may affect magnification scales with the bellows but you might want to give these a look over. password for both is 'Pentax'

m42 bellows manual
http://www.pentax-manuals.com/manuals/m42/close_up_m42_s.pdf

auto bellows M manual
http://www.pentax-manuals.com/manuals/accessories/bellows_ii_s.pdf

03-29-2010, 11:09 AM   #9
Veteran Member




Join Date: Dec 2009
Location: Deep Forest
Posts: 630
QuoteOriginally posted by dawsonjm Quote
If anybody has a suggestion for the light source behind the slide holder, I would like to hear about that too.

Thanks for everyones help so far!
Slide projector with lens removed works well. I disassembled (minor, reversable) a tiny Minolta Mini II to extract the lamp/condenser unit (with tripod mount!) to use with my bellows for slide copying.
03-29-2010, 11:10 AM   #10
Veteran Member
RioRico's Avatar

Join Date: Jun 2008
Location: Limbo, California
Posts: 11,264
Sensor (frame) size has absolutely nothing to do with magnification; a 50mm lens with 50mm of extension produces 1:1 magnification no matter the frame size. A smaller sensor just sees a smaller slice of the subject, that's all. Try this: take a magazine picture. Draw a 3x2" horizontal rectangle on it. Inside that, draw a 2x1.5" horizontal rectangle, centered. The big rectangle represents a full-frame view. The smaller rectangle represents a halk-frame view. Both contain a 1:1 image of the picture, just different-sized slices of it.

With your screwmount bellows, you can use any screwmount lens. An extremely popular and cheap lens for bellows use is the Russian apochromatic Industar-50. But as séamuis said, almost any 50-55mm M42 lens will be fine when stopped down. Just be sure the objective isn't deeply recessed.

Other possibilities, if you insist on (or can't resist) buying more lenses, include enlarger-projector lenses. These are often M39, same diameter as Leica Thread Mount (LTM, L39) and require a M39-M42 adapter ring. Such rings are very cheap, but beware the cheapest. For some bellows work, I use enlarger lenses of 50-75-90-105-140mm depending on subject, lighting, and how the hell I feel at the moment. Such are necessarily flatfield lenses, great for extreme edge-to-edge sharpness.

(Uh oh, I'd better not mention my Schneider Betavaron enlarger zoom lens...)
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!
adapter, k-mount, lens, m42, pentax lens, slr lens
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
K mount lens on M42 Camera Legend Pentax Camera and Field Accessories 2 08-24-2010 05:19 PM
[Afraid] Can't get my M42 screw mount lens off my K-x! tiny Pentax DSLR Discussion 11 10-28-2009 10:25 PM
New to M42 mount lens okitoki Pentax SLR Lens Discussion 23 12-27-2008 05:48 PM
M42 mount lens database? Gooshin Pentax SLR Lens Discussion 4 11-30-2007 09:37 AM



All times are GMT -7. The time now is 09:42 PM. | 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