Asahi Pentax Auto extension tubes on a modern lens question

Michael Piziak · 08-03-2021, 11:53 AM

Is there any situation where Asahi Pentax Auto extension tubes, or using 1 of the 3 tubes, could be used with a DA or DA L lens, or is the facts that there are no aperture rings on the lens and the tubes lacking modern electrical contacts on the tubes a no go for any situation - ?

https://www.pentaxforums.com/articles/influential-gear/asahi-pentax-auto-extension-tubes.html

stevebrot · 08-03-2021, 12:09 PM - **2 Likes**

If you are happy with full stop-down for every shot, go ahead.

Steve

Not a Number · 08-03-2021, 12:17 PM - **1 Like**

In manual mode the lens will fully stop down for green button reading and exposure.

Not sure what happens in Av mode. Meters wide open but not sure if it closes down fully or stays wide openfor the exposure. Would behave the same as a K series lens set to minimum aperture.

vonBaloney · 08-03-2021, 12:21 PM - **1 Like**

So that's basically a no -- need one with contacts to control the aperture.

**othar** · 08-03-2021, 02:07 PM - **1 Like**

Originally posted by vonBaloney

So that's basically a no -- need one with contacts to control the aperture.

If you plan to use them with only 1 special lens, then there is the theoretical possibility to simulate the aperture contacts of the lens by painting the conductive/non-conductive pattern on the extension tubes, but this solution isn't very practical in general

**clickclick** · 08-03-2021, 04:27 PM - **1 Like**

Keep an eye on eBay for some extension tubes by Jessops with contacts. Every now and then a set will appear. I had a saved search set to email me when they showed up. It's not often, but they do appear.

Michael Piziak · 08-03-2021, 05:00 PM

Thanks all. I gave everyone a thumbs up.

**UncleVanya** · 08-04-2021, 06:21 AM - **1 Like**

Originally posted by clickclick

Keep an eye on eBay for some extension tubes by Jessops with contacts. Every now and then a set will appear. I had a saved search set to email me when they showed up. It's not often, but they do appear.

Hansa tubes also work but are rare as hens teeth.

Another option is to reverse Mount the da lens using the appropriate adapter. This already gives a larger “macro” image (perhaps not 1:1) and then add a mirrorless adapter for DA lenses, these typically have a ring that can be used to open the aperture in a stepless way and they are hollow and without glass. The adapter also acts as a small hood protecting the rear of the lens.

Wheatfield · 08-04-2021, 07:17 AM - **1 Like**

Originally posted by Michael Piziak

Is there any situation where Asahi Pentax Auto extension tubes, or using 1 of the 3 tubes, could be used with a DA or DA L lens, or is the facts that there are no aperture rings on the lens and the tubes lacking modern electrical contacts on the tubes a no go for any situation - ?

Asahi Pentax Auto Extension Tubes - Influential Photo Gear | PentaxForums.com

The lack of an aperture ring makes this a non starter for practical use.

**i_trax** · 08-04-2021, 08:32 AM - **1 Like**

Originally posted by clickclick

Keep an eye on eBay for some extension tubes by Jessops with contacts. Every now and then a set will appear. I had a saved search set to email me when they showed up. It's not often, but they do appear.

...or buy 2x converter with contacts and remove the glass,

there are many of them on eBay and very cheap.
I have 5 , some still with glass waiting to be converted

**UncleVanya** · 08-04-2021, 10:51 AM - **1 Like**

Originally posted by Wheatfield

The lack of an aperture ring makes this a non starter for practical use.

I’ve used them reversed as described. Not complicated to do. But more complicated than my Hansa tubes or deglassed teleconverters. Beware that the deglassed teleconverters are a bit restricted in their openings and might reduce the aperture even more than the extension predicts.

08-03-2021, 11:53 AM	#1
Michael Piziak Closed Account Join Date: Dec 2013 Location: West Virginia Posts: 2,815	Asahi Pentax Auto extension tubes on a modern lens question Is there any situation where Asahi Pentax Auto extension tubes, or using 1 of the 3 tubes, could be used with a DA or DA L lens, or is the facts that there are no aperture rings on the lens and the tubes lacking modern electrical contacts on the tubes a no go for any situation - ? https://www.pentaxforums.com/articles/influential-gear/asahi-pentax-auto-extension-tubes.html

08-04-2021, 08:32 AM - 1 Like	#10
i_trax Loyal Site Supporter Join Date: Jan 2011 Location: Perth Western Australia Photos: Gallery \| Albums Posts: 2,621	modify old converters Originally posted by clickclick Keep an eye on eBay for some extension tubes by Jessops with contacts. Every now and then a set will appear. I had a saved search set to email me when they showed up. It's not often, but they do appear. ...or buy 2x converter with contacts and remove the glass, there are many of them on eBay and very cheap. I have 5 , some still with glass waiting to be converted

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08-03-2021, 12:09 PM - 2 Likes	#2
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	If you are happy with full stop-down for every shot, go ahead. Steve

08-03-2021, 12:17 PM - 1 Like	#3
Not a Number Moderator Join Date: Mar 2012 Location: Venice, CA Posts: 10,526	In manual mode the lens will fully stop down for green button reading and exposure. Not sure what happens in Av mode. Meters wide open but not sure if it closes down fully or stays wide openfor the exposure. Would behave the same as a K series lens set to minimum aperture.

08-03-2021, 12:21 PM - 1 Like	#4
vonBaloney Pentaxian Join Date: Oct 2011 Location: Albuquerque, NM Posts: 6,029	So that's basically a no -- need one with contacts to control the aperture.

08-03-2021, 02:07 PM - 1 Like	#5
othar Site Supporter Join Date: May 2014 Location: Linz Photos: Albums Posts: 3,098	Originally posted by vonBaloney So that's basically a no -- need one with contacts to control the aperture. If you plan to use them with only 1 special lens, then there is the theoretical possibility to simulate the aperture contacts of the lens by painting the conductive/non-conductive pattern on the extension tubes, but this solution isn't very practical in general

08-03-2021, 04:27 PM - 1 Like	#6
clickclick Loyal Site Supporter Join Date: May 2016 Location: East Coast Posts: 2,903	Keep an eye on eBay for some extension tubes by Jessops with contacts. Every now and then a set will appear. I had a saved search set to email me when they showed up. It's not often, but they do appear.

08-03-2021, 05:00 PM	#7
Michael Piziak Closed Account Join Date: Dec 2013 Location: West Virginia Posts: 2,815 Original Poster	Thanks all. I gave everyone a thumbs up.

08-04-2021, 06:21 AM - 1 Like	#8
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,407	Originally posted by clickclick Keep an eye on eBay for some extension tubes by Jessops with contacts. Every now and then a set will appear. I had a saved search set to email me when they showed up. It's not often, but they do appear. Hansa tubes also work but are rare as hens teeth. Another option is to reverse Mount the da lens using the appropriate adapter. This already gives a larger “macro” image (perhaps not 1:1) and then add a mirrorless adapter for DA lenses, these typically have a ring that can be used to open the aperture in a stepless way and they are hollow and without glass. The adapter also acts as a small hood protecting the rear of the lens.

08-04-2021, 07:17 AM - 1 Like	#9
Wheatfield Moderator Join Date: Apr 2008 Location: The wheatfields of Canada Posts: 15,981	Originally posted by Michael Piziak Is there any situation where Asahi Pentax Auto extension tubes, or using 1 of the 3 tubes, could be used with a DA or DA L lens, or is the facts that there are no aperture rings on the lens and the tubes lacking modern electrical contacts on the tubes a no go for any situation - ? Asahi Pentax Auto Extension Tubes - Influential Photo Gear \| PentaxForums.com The lack of an aperture ring makes this a non starter for practical use.

08-04-2021, 10:51 AM - 1 Like	#11
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,407	Originally posted by Wheatfield The lack of an aperture ring makes this a non starter for practical use. I’ve used them reversed as described. Not complicated to do. But more complicated than my Hansa tubes or deglassed teleconverters. Beware that the deglassed teleconverters are a bit restricted in their openings and might reduce the aperture even more than the extension predicts.