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05-08-2008, 08:17 PM   #1
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Adapting

Hello form a newbee
I am Jim

I am writing to you in regards to digital cameras. My inquiry is about adapting screw mount lenses to Pantex digital camera bodies.

My present camera is a “Pantex Spotmatic II”, screw mount (yes an oldie). My questions are regarding weather on not my lenses would be able to be adapted to a new digital body, I am thinking of a “K110D or K100D” system. The cost is one consideration if it could be done. I would like to get into digital, if it is with my lenses and a new body or just a point and shot.

Inquiry
- Is it possible to adapt screw mount to bayonet mount bodies.
- Would the aperture setting work with the Digital body.
- Would the metering system of the Digital body work with my lenses.

Thank you
jim form Ontario
jimrodman@sympatico.ca

05-08-2008, 09:13 PM   #2
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Yes, a screwmount to K-mount adapter is available. This one is only $14. (Can anyone vouch for its quality?)
By default, the lens's aperture setting is ignored, but you can change this behavior.
Pressing the green button will stop down to the selected aperture and auto-set the shutter and ISO. (Though there seem to be issues with exposure accuracy with this method.)
05-09-2008, 05:34 AM   #3
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QuoteOriginally posted by jimrodman Quote
Hello form a newbee
I am Jim

I am writing to you in regards to digital cameras. My inquiry is about adapting screw mount lenses to Pantex digital camera bodies.

My present camera is a “Pantex Spotmatic II”, screw mount (yes an oldie). My questions are regarding weather on not my lenses would be able to be adapted to a new digital body, I am thinking of a “K110D or K100D” system. The cost is one consideration if it could be done. I would like to get into digital, if it is with my lenses and a new body or just a point and shot.

Inquiry
- Is it possible to adapt screw mount to bayonet mount bodies.
- Would the aperture setting work with the Digital body.
- Would the metering system of the Digital body work with my lenses.

Thank you
jim form Ontario
jimrodman@sympatico.ca
It would be interesting to know what your lenses and picture taking preferences are.

One thing you need to consider going from film to digital is that the pentax DSLRs have a sensor that is smaller than the frame of a 35mm camera.

your film camera has a 36mm wide by 24mm high frame. The DSLR has a frame 24mm wide by 16mm high

therefore your shots will be "cropped" or have a narrower field of view. This will cause you to perhaps purchase one additional lens (i.e. a wider lens than yoou presently own).

You can probably get by with a Kit lens in the 18-55 mm range.

Also note that with your screw mount lenses, the easiest way for you to shoot is in Av mode, and you would focus and compose with the apature wide open, and then manually stop down the lenses for the exposure you want.

Also note, while you hear people on the forum talking about the magical "green button" it only exists on the *istD, K10D and K20D, and is really more practical for K mount lenses not as much for screw mount. Screw mount, as I said work just fine in Av mode, because when you turn the apature ring you stop the lens down. This is because there is no automatic apature functionality on M42 lenses with the K mount adaptor.
05-09-2008, 05:43 AM   #4
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QuoteOriginally posted by joefru Quote
Yes, a screwmount to K-mount adapter is available. This one is only $14. (Can anyone vouch for its quality?)
By default, the lens's aperture setting is ignored, but you can change this behavior.
Pressing the green button will stop down to the selected aperture and auto-set the shutter and ISO. (Though there seem to be issues with exposure accuracy with this method.)
This adapter has a flange that will push the lens to far forward, therefore making it impossible for the lens to focus to infinity, The adapters that allow full focusing throw don't have a flange on the lens side of the adapter.

05-09-2008, 06:24 AM   #5
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Screw mount to K-mount adapters

QuoteOriginally posted by flyer Quote
This adapter has a flange that will push the lens to far forward, therefore making it impossible for the lens to focus to infinity, The adapters that allow full focusing throw don't have a flange on the lens side of the adapter.
Not so. The one in his link to B & H is a proper adapter without the flange. It will fit flush in the opening and allow full infinity focus.

Here is one that has the flange: 10x Pentax K to Pentax Screw M42 Lens Adapter PK PX NEW - eBay (item 190220225458 end time May-12-08 15:39:46 PDT)

Note how much wider the flange is than on the one at B & H. This one will definitely affect infinity focus. I really don't know why they even make these.

Since the OP is accustomed to using a Spotmatic II, stop-down metering shouldn't be an issue. It works essentially just like his Sp-II did, except that, in Av mode, the camera will actually set the shutter speed. In M mode, it is almost identical. The lightmeter indicator (not a match needle) in the viewfinder will tell him if he is over or underexposing.

I, too, have a Spotmatic and a few M42 lenses. I particularly like using my Super-Takumar 50mm, f/1.4 on the K10D. I just set the lens to manual mode, so that the aperture ring stops the lens down when I turn it. Remember, the dslr has no meter switch to stop the lens down, the way the Sp II did.

AFAIK, just about all the Pentax lenses had the auto-manual switch. I few third party lenses did not have such a switch. Such lenses can only be used wide open on a Pentax (or any other) dslr.
05-09-2008, 08:32 AM   #6
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QuoteOriginally posted by noblepa Quote
I really don't know why they even make these..
The adapter with the flange in much cheaper and of equal quality. They won't do infinity, but are useful for other applications, such as bellows mounts, converting non-Pentax lenses to PK,and for general shooting where infinity isn't required. I use them for many of my conversion projects.

Dave
05-09-2008, 08:50 AM   #7
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One thing I love about the old Takumar lenses is that thet work great in Av mode. You just have to turn the aperture ring to the desired aperture, focus, and shoot. No need to meter, although they usually require a bump in EV.
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