Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
12-25-2011, 10:21 PM   #1
Forum Member
LightSpeed's Avatar

Join Date: Dec 2011
Posts: 96
I'm looking for Extension tubes for the k5

I would like some recommendations on extension tubes.
What I'm looking for is something that has contacts where the cameras light meter still works and I can set Fstops.
Auto focus would be nice, but not really needed.

I do not know how one would set the aperture on the lens (100mm wr macro) without contacts that allow communication from the camera to the lens.

12-25-2011, 10:40 PM   #2
Veteran Member




Join Date: Jan 2010
Location: Vancouver, BC
Posts: 1,421
QuoteOriginally posted by LightSpeed Quote
I would like some recommendations on extension tubes.
What I'm looking for is something that has contacts where the cameras light meter still works and I can set Fstops.
Auto focus would be nice, but not really needed.

I do not know how one would set the aperture on the lens (100mm wr macro) without contacts that allow communication from the camera to the lens.
If the tubes have contacts then the body sets the aperture values. What you are looking for is something like Vivitar AT-23 extension tube set but they are rare and expensive. Another option is to buy some Teleconverters with contacts, remove the glass and use them as extension tubes. If you can locate a 2x, 7 element TC and a 4 element TC then you can have some variation in lengths of the extension tubes. 1.4x TC would also work but they retain their value better as a Teleconverter than a glassless extension tubes.

Hope this helps,
12-25-2011, 10:43 PM   #3
Pentaxian
jeffshaddix's Avatar

Join Date: Jun 2010
Location: Albuquerque, NM
Posts: 1,371
I just got a Vivitar AT-23 extension tube set (12mm, 20mm, 36mm). It has all the contacts including AF. Unfortunately these things are rare to be sure, on ebay they usually go for $100+. I found mine in a local camera shop, it had been sitting there for many years. I got it for $75, which in their mind I'm sure was a big win for them. Of course they think Pentax died with Hoya and don't bother to read up on photography on the newfangled interwebs...but I digress...

Anyway, look for a Vivitar set that has P/Z listed on the box. The "Z" refers to the old auto-focus Pentax camera line. It may also be listed as KR, which is the Pentax/Ricoh combo mount also from the film era.
12-25-2011, 10:45 PM - 3 Likes   #4
Veteran Member
RioRico's Avatar

Join Date: Jun 2008
Location: Limbo, California
Posts: 11,264
AF tubes are rare and costly. A-type tubes, with the aperture contacts but no AF, aren't real cheap and available either. I've found the cost-effective approach is to get old A-type TCs and remove the glass from them. My 2x TCs averaged US$15 each (shipped). These are both about 25mm thick; I've seen M-types as much as 30mm thick. If a 100mm macro will reach 1:1 magnification by itself, then with four such deglassed TCs, each 25mm thick, you can reach 2:1. And four TCs will probably cost rather less than 100mm of A-type extension tubes.

EDIT: Clarification highlighted above. But I just checked the DFA100WR specs and it DOES go to 1:1, right? So the numbers are correct.

If you're handy with a soldering iron, there's another trick: Get just one A-type TC, and almost any used bayonet bellows. Doesn't matter if the bellows are for Pentax, Nikon, Exakta, OM, whatever, as long as the mounting plates are held on by screws. Remove the mounts from the TC. Pull the mounts from the bellows and replace them with the PK-TC mounts. Solder wires to connect the contacts of the front and rear mounts. Now you have an A-type bellows!


Last edited by RioRico; 12-26-2011 at 11:26 AM.
12-25-2011, 11:34 PM   #5
Pentaxian
ivoire's Avatar

Join Date: Mar 2007
Location: chicago burbs
Photos: Gallery
Posts: 3,368
https://www.pentaxforums.com/forums/photographic-equipment-sale/167877-sale-k...sion-tube.html

The Kenko 25mm Uniplus Tube DG (extension ring) is an accessory exclusively designed for use with standard AF lenses to shoot subjects at closer distance with higher magnification. Magnification ratio for the Uniplus Tube 25 is about 1/2 when used with a 50mm standard lens.

Provides perfect coupling with automatic aperture, TTL metering and AE mechanism. AF support is dependent on your lens' maximum aperture. As a rule, the lens has to be set to f/5.6 or brighter in order for the camera's AF system to work.

This DG Extension tube has upgraded "Gate-Array IC" circuitry to work better with digital SLR's and some of the digital SLR lenses.
12-26-2011, 12:06 AM   #6
Forum Member
LightSpeed's Avatar

Join Date: Dec 2011
Posts: 96
Original Poster
PM SENT.
This will be for my K5 by the way
12-26-2011, 12:13 AM   #7
Veteran Member
Bruce's Avatar

Join Date: Oct 2009
Location: Sydney
Photos: Gallery | Albums
Posts: 448
QuoteOriginally posted by RioRico Quote
If you're handy with a soldering iron, there's another trick: Get just one A-type TC, and almost any used bayonet bellows. Doesn't matter if the bellows are for Pentax, Nikon, Exakta, OM, whatever, as long as the mounting plates are held on by screws. Remove the mounts from the TC. Pull the mounts from the bellows and replace them with the PK-TC mounts. Solder wires to connect the contacts of the front and rear mounts. Now you have an A-type bellows!
One vote for the MacGyver Award for Rico!
12-26-2011, 08:57 AM   #8
Site Supporter
mattt's Avatar

Join Date: Feb 2011
Location: Niagara
Photos: Gallery | Albums
Posts: 2,794
QuoteOriginally posted by Bruce Quote
One vote for the MacGyver Award for Rico!
+1 to that!

12-26-2011, 09:31 AM   #9
Pentaxian
bluestringer's Avatar

Join Date: Nov 2011
Location: Cotton fields of South Georgia
Photos: Gallery | Albums
Posts: 2,435
Question for RioRico

With a Pentax 100mm F4 Macro, which does 1:2 on it's own, how much tube do I need to get 1:1? Thanks.
12-26-2011, 09:36 AM   #10
Veteran Member
creampuff's Avatar

Join Date: May 2007
Location: Singapore
Photos: Gallery
Posts: 3,955
QuoteOriginally posted by bluestringer Quote
With a Pentax 100mm F4 Macro, which does 1:2 on it's own, how much tube do I need to get 1:1? Thanks.
You'll need another 50mm extension.
12-26-2011, 11:35 AM   #11
Veteran Member
RioRico's Avatar

Join Date: Jun 2008
Location: Limbo, California
Posts: 11,264
QuoteOriginally posted by bluestringer Quote
With a Pentax 100mm F4 Macro, which does 1:2 on it's own, how much tube do I need to get 1:1? Thanks.
QuoteOriginally posted by creampuff Quote
You'll need another 50mm extension.
Quite right. Be aware that adding extension means the lens will not focus to infinity. (That *should* be obvious, right?) Far-focus drops to about 31cm / 12in.
12-26-2011, 12:23 PM   #12
Pentaxian
bluestringer's Avatar

Join Date: Nov 2011
Location: Cotton fields of South Georgia
Photos: Gallery | Albums
Posts: 2,435
Ok. Thanks. I've found a 3x TC that may be just about right after removing the glass.
12-26-2011, 02:04 PM   #13
Veteran Member
RioRico's Avatar

Join Date: Jun 2008
Location: Limbo, California
Posts: 11,264
QuoteOriginally posted by bluestringer Quote
Ok. Thanks. I've found a 3x TC that may be just about right after removing the glass.
You'll want to measure the thickness. The 3x TCs I've seen are about 40mm thick. The closer you get to 50mm thickness, the closer you'll get to 1:1 magnification.
12-29-2011, 02:12 AM   #14
Site Supporter




Join Date: Jul 2011
Posts: 1,028
QuoteOriginally posted by bluestringer Quote
Ok. Thanks. I've found a 3x TC that may be just about right after removing the glass.
There may also be some mechanical parts in the way...

Anyways, I can see a need for macro tubes and extensio tube from PENTAX.
01-01-2012, 02:04 AM   #15
Pentaxian
philbaum's Avatar

Join Date: Oct 2007
Location: Port Townsend, Washington State, USA
Posts: 3,659
How do i remove the lens element?

I've got a Promaster 1.7x TC. I want to turn it into a permanent extension tube because my camera has a hard time locking a focus through the 1.7x.

I'm, able to remove the 3 philips screws that hold the Px contacts ring easily enough with a #000 philips screwdriver but that uncovers a threaded castellated cylinder with 2 180 deg apart slots that seems to thread onto the lens module and hold it in place. The castellated slots are less than 1/16" width and i'm not sure how to get a grip on the cylinder to unscrew it from the lens mount???

Any help much appreciated, i can send a photo if needed.

Phil
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!
camera, contacts, dslr, extension, extension tubes, k-5, k-5 ii, k-5 iis, k5, lens, pentax k-5, tubes
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
How to use extension tubes? chinotenshi Troubleshooting and Beginner Help 15 12-18-2010 06:26 AM
Extension tubes Gary G Pentax DSLR Discussion 2 04-14-2010 06:28 PM
Extension Tubes audio.mann Pentax SLR Lens Discussion 7 04-08-2010 05:34 PM
Extension tubes anyone? max889 Pentax SLR Lens Discussion 13 03-01-2010 01:38 PM
extension tubes keithbaran Troubleshooting and Beginner Help 15 02-25-2010 10:48 PM



All times are GMT -7. The time now is 11:50 PM. | See also: NikonForums.com, CanonForums.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