Where is this? (a macro setup)


pinholecam

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Jul 23, 2007
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#1
Been trying to find a way to get an auto aperture macro setup, as my current 'dummy' extension tube will mean that the aperture closes down as I stop down the aperture. Auto extension tubes for Pentax seem to be rare and the ones that I can find are expensive.

I got a 2x teleconverter from ebay with auto aperture and removed the lens element. This becomes a ~25mm auto extension tube. Next I taped up the rear that touches the k-mount contact pins with metal tape to allow stop down metering. Combining this with the Pentax 1.7x AF teleconverter, I managed to get a "near point" auto focus, auto aperture, setup.

Here is a sample 50mm+extension tube+1.7x AF teleconverter

Guess where is this? :)
 

nik34

Senior Member
Aug 30, 2007
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AMK Singapore
#2
Been trying to find a way to get an auto aperture macro setup, as my current 'dummy' extension tube will mean that the aperture closes down as I stop down the aperture. Auto extension tubes for Pentax seem to be rare and the ones that I can find are expensive.

I got a 2x teleconverter from ebay with auto aperture and removed the lens element. This becomes a ~25mm auto extension tube. Next I taped up the rear that touches the k-mount contact pins with metal tape to allow stop down metering. Combining this with the Pentax 1.7x AF teleconverter, I managed to get a "near point" auto focus, auto aperture, setup.

Here is a sample 50mm+extension tube+1.7x AF teleconverter

Guess where is this? :)
Hmm! i smell notes..;p
 

Dec 22, 2009
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#7
Wow you guys are good!

I thought it's a page from my "Hao Gong Ming" textbook
 

Moonlightsg

Senior Member
Jan 28, 2010
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#8
post the step with pic... then we can learn from you...
I like to DIY item! haha
 

pinholecam

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Jul 23, 2007
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#10
Here is the setup :




The taped up area to short k-mount contact pins to enable auto aperture.
The black area can be sanded off to reveal the aluminum as well, but taping is better to me as it destroys nothing and is cleaner.
 

pinholecam

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Jul 23, 2007
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#11
2 sample shots using a 50/1.4 at f8.

This one is only slightly cropped



Cropped off about 20-25%




I think the next step is to see if I can couple the setup with something longer like an 85mm or even better a 135mm for better working distance. At the cost of magnification.
 

creampuff

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Jul 11, 2006
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Dover
#12
Dusting off of some old gear... so some test shots hand held. All shots uncropped.

K-7 with Sigma 50mm f/2.8 Macro at 1x magnification


K-7 with Sigma 50mm f/2.8 Macro with Pentax Bellows Unit K (approx 2.5x magnification)


Pentax Bellows Unit K
 

creampuff

Senior Member
Jul 11, 2006
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#16
can i borrow the bellow & focussing rail? :bsmilie:
Sure, no problem.
Just so long as the got no damage to the expanding section. Do you need a macro focusing rail to go with it?
 

pinholecam

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Jul 23, 2007
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#17
Pentax Bellows Unit K
This is very nice and pristine looking.
I presume its necessary to maintain the bellow (ie. the black folding part)?


Have you tried with the Vivitar 2X Macro Focusing Teleconverter setup?
Sorry, man!
I did not even know it exists :D
After doing a google, it does seem interesting (seems to be the same thing I am doing but macro option can be taken out). My gripes would be the 2x teleconverter portion, which is sure to degrade image quality.
I think I see this even with my setup which is only 1.7x coupled with a K135/2.5. I tried that indoors at night, so I'm uncertain of my results atm.

I'm not a serious macro shooter. The thing I wanted was an auto extension tube that I can keep in my camera bag to give a close-up option. So since the AF1.7x was with me, I just stacked them together to see if it was any good. :)
 

creampuff

Senior Member
Jul 11, 2006
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Dover
#18
This is very nice and pristine looking.
I presume its necessary to maintain the bellow (ie. the black folding part)?
Like all bellows, the material is either reinforced paper, cloth or some other synthetic material, so some care needs to be considered when handling to avoid damage or light leaks.
Yeah, mine is pristine. Weight is actually pretty light.
 

pinholecam

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Jul 23, 2007
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#19
Like all bellows, the material is either reinforced paper, cloth or some other synthetic material, so some care needs to be considered when handling to avoid damage or light leaks.
Yeah, mine is pristine. Weight is actually pretty light.
Thanks for the info.
I've never seen one up close, and before this had thought the material was leather and maybe needed oiling :D
 

Nikkornos

Senior Member
Oct 31, 2008
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Singapore/Asia
#20
Like all bellows, the material is either reinforced paper, cloth or some other synthetic material, so some care needs to be considered when handling to avoid damage or light leaks.
Yeah, mine is pristine. Weight is actually pretty light.
Dennis, saw your beautiful flowers shot in your blog using the Sigma 50mm F2.8 macro. Nice work.

I have the same bellows for Nikon. I used it for slides copying in old days. Now practically in cold storage....
 

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