Spotmatic F/A3000 lens switching

**Tonytee** · 08-27-2013, 10:53 PM

Greetings again,

I have an Asahi Pentax Spotmatic F with the M42 screw mount. I have an adapter that allows me to use the Takumar lenses on any Pentax K mount. I want to know of any caveats to be aware of before I use my Asahi Takumar 135 mm lens on my Pentax A3000. The lens fits perfectly, and I hope to be using it very soon. Thanks in advance for any assistance. My concerns are the added focal length's affect on the light meter and if I will still have free travel with the f/stop ring.

Tony

Adam · 08-27-2013, 11:10 PM

As long as you set the lens diaphragm to manual, you should still be able to use the lens in Av mode. Because it's a screwdrive lens, the viewfinder will get darker as you stop down.

**wirrah** · 08-28-2013, 01:34 AM

Is it an early Takumar or a later Super Takumar? If it is the earlier type it will have 2 aperture rings and no auto switch. When I use mine I set the click stop ring to minimum aperture and then use the other ring to effect stop down metering. Effectively what happens if you set the switch to manual on later lenses.

Greg

**Tonytee** · 08-28-2013, 02:38 PM

Originally posted by wirrah

Is it an early Takumar or a later Super Takumar? If it is the earlier type it will have 2 aperture rings and no auto switch. When I use mine I set the click stop ring to minimum aperture and then use the other ring to effect stop down metering. Effectively what happens if you set the switch to manual on later lenses.

Greg

Hello Greg,

It is a Super-Takumar 1:3.5/135 lens. It does have the Manual/Auto switch. Now I understand why the viewfinder goes dark when I stop down. Thanks very much.

Tony

08-27-2013, 10:53 PM	#1
Tonytee Loyal Site Supporter Join Date: Jul 2012 Photos: Gallery \| Albums Posts: 21,530	Spotmatic F/A3000 lens switching Greetings again, I have an Asahi Pentax Spotmatic F with the M42 screw mount. I have an adapter that allows me to use the Takumar lenses on any Pentax K mount. I want to know of any caveats to be aware of before I use my Asahi Takumar 135 mm lens on my Pentax A3000. The lens fits perfectly, and I hope to be using it very soon. Thanks in advance for any assistance. My concerns are the added focal length's affect on the light meter and if I will still have free travel with the f/stop ring. Tony

08-27-2013, 11:10 PM	#2
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 51,608	As long as you set the lens diaphragm to manual, you should still be able to use the lens in Av mode. Because it's a screwdrive lens, the viewfinder will get darker as you stop down. Adam PentaxForums.com Webmaster (Site Usage Guide \| Site Help \| My Photography) PentaxForums.com server and development costs are user-supported. You can help cover these costs by donating or purchasing one of our Pentax eBooks. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, KEH, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

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08-28-2013, 01:34 AM	#3
wirrah Site Supporter Join Date: Sep 2006 Location: Lower Hunter, NSW Photos: Gallery Posts: 527	Is it an early Takumar or a later Super Takumar? If it is the earlier type it will have 2 aperture rings and no auto switch. When I use mine I set the click stop ring to minimum aperture and then use the other ring to effect stop down metering. Effectively what happens if you set the switch to manual on later lenses. Greg

08-28-2013, 02:38 PM	#4
Tonytee Loyal Site Supporter Join Date: Jul 2012 Photos: Gallery \| Albums Posts: 21,530 Original Poster	Originally posted by wirrah Is it an early Takumar or a later Super Takumar? If it is the earlier type it will have 2 aperture rings and no auto switch. When I use mine I set the click stop ring to minimum aperture and then use the other ring to effect stop down metering. Effectively what happens if you set the switch to manual on later lenses. Greg Hello Greg, It is a Super-Takumar 1:3.5/135 lens. It does have the Manual/Auto switch. Now I understand why the viewfinder goes dark when I stop down. Thanks very much. Tony