Pentax K20D & Sigma Mini-wide II 28mm 1:2.8

pedro730 · 10-13-2013, 08:01 PM

it just seems easier to put the lens aside and purchase another one that I hope to not have problems with. Thanks everyone for your help in the matter. It is greatly appreciated!!!

stevebrot · 10-14-2013, 07:57 AM

Originally posted by interested_observer

I do not have a clue as to why you are having problems mounting the lens.

It is probably the Ricoh pin. I currently have and have in the past had other lenses with the ball style pin that mount rough. This is not true on every body, so it might be a matter of tolerances and/or the positioning of the screw holes on the mount that the pin must pass over and clear.

Steve

jjdgti · 10-14-2013, 01:38 PM

This may be your problem. What I notice, the flange guard is to big. As a result is stop in the middle. Since Pentax DSLRs support the SDM contacts, the large flange guard interferes with it. If you mount it in a Film camera such as K1000 or ME it will fit without a problem.

Compare the flange from other lens and check. You may have to remove the flange and shave the extra part.

Let us know if that was the problem.

stevebrot · 10-14-2013, 04:49 PM

Originally posted by jjdgti

What I notice, the flange guard is to big.

Good catch. The Sigma Mini-wide 28mm is pretty common on this forum and I don't remember any complaints about the flange, but that lens was made in several variants and there may well be an issue with the lens in question on the K20D.

Steve

jjdgti · 10-22-2013, 11:01 AM

Pedro any updates? Is it really K mount or not? Was the size of the lever the problem?

stevebrot · 10-22-2013, 06:52 PM

Originally posted by jjdgti

Pedro any updates? Is it really K mount or not? Was the size of the lever the problem?

It is definitely a Ricoh/Pentax-A combo K-mount.

Steve

pedro730 · 10-28-2013, 01:01 PM

I shaved down the flange, even got a file and filed down some of the edges in hopes that maybe a small piece of metal might be getting stuck along the edges....and it still doesn't fit.

**marcusBMG** · 10-28-2013, 05:36 PM

Originally posted by pedro730

I shaved down the flange, even got a file and filed down some of the edges in hopes that maybe a small piece of metal might be getting stuck along the edges....and it still doesn't fit.

Can you post a better pic or two and more precise info - pic of the lens at the point its stuck. If its the ricoh pin, that hooks into the AF hole when the white orientation cue button is pretty much at the quarter-to position as you look at the lens on the camera from the front.

**k0og** · 10-29-2013, 06:41 AM

Try this: Before you try to mount the lens, slide the MF/AF switch on your K20D to MF. This will retract the AF drive mechanism into the mount flange. Now try to mount your lens. Is it any better?

-Joe-

pedro730 · 10-29-2013, 07:08 AM

K0og, its been on MF the entire time and unfortunately it didn't work either. I tried all three settings: MF, APS-C and AF. The lens is on the A position on the aperature ring as well.

Im including the picture that someone suggested about the lens with the shaved down flange. Also including a picture of my current setup...a K20D with a SMC PENTAX-A 50 mm

**k0og** · 10-29-2013, 07:26 AM

Pedro,

That's strange!

Try this: Take a series of pictures of the Pentax-A 50mm along side the Sigma so we can see the two mounts side-by-side (make sure the aperture levers are in the same positions). The back end of your Sigma looks a little strange to me, but maybe it is just the perspective.

-Joe-

**marcusBMG** · 11-06-2013, 01:30 PM

I have had another thought: I had a similar issue a year ago, actually with a tamron adapter. The cause was a slightly bent aperture lever. Have a close look at the lens, comparing to the lens that does mount, and see if this might be the case.

Daniellah · 02-05-2014, 10:11 AM

I was wondering if anybody has arrived at any conclusions about this... I have recently bought the above lens to use with my two Pentax - K-5 and film SLR - as well as with my CSC (I have an adaptor for this). The lens fitted my adaptor and my Pentax SLR fine, but it doesn't want to talk to my K-5 mount. Comparing to other k-mount lenses I have the aperture lever seems a bit different, however it is not stuck or seems broke or loose. I have checked the pictures here and it even looks different from the examples of PK and CY mounts so I am a very puzzled. Had it not fitted my other Pentax I would probably see what was wrong with it. Any ideas please?
Thank you.

**Lowell Goudge** · 02-05-2014, 11:35 AM

The flange is not located correctly remove it and all will be fine.

You will note the flange is actually rotated about 20 degrees from the aperture lever this was common. It hits the two power pins of the KAF2/3 mount. It will mount unmodified on any camera prior to the K100Super in digital, or on any film body except the PZ series.

To use on a PZ camera or a digital body K100super or later with HSM support the flange must be removed.

Sigma, and also vivitar lenses have this issue frequently.

10-14-2013, 01:38 PM	#18
jjdgti Veteran Member Join Date: Jun 2008 Location: NJ Posts: 1,824	Sigma Mini-wide not mounting in the K20D This may be your problem. What I notice, the flange guard is to big. As a result is stop in the middle. Since Pentax DSLRs support the SDM contacts, the large flange guard interferes with it. If you mount it in a Film camera such as K1000 or ME it will fit without a problem. Compare the flange from other lens and check. You may have to remove the flange and shave the extra part. Let us know if that was the problem.

11-06-2013, 01:30 PM	#27
marcusBMG Site Supporter Join Date: Nov 2012 Location: North Wales Photos: Gallery \| Albums Posts: 2,870	aperture lever bent?? I have had another thought: I had a similar issue a year ago, actually with a tamron adapter. The cause was a slightly bent aperture lever. Have a close look at the lens, comparing to the lens that does mount, and see if this might be the case.

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10-13-2013, 08:01 PM	#16
pedro730 New Member Join Date: Oct 2013 Posts: 10 Original Poster	it just seems easier to put the lens aside and purchase another one that I hope to not have problems with. Thanks everyone for your help in the matter. It is greatly appreciated!!!

10-14-2013, 07:57 AM	#17
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by interested_observer I do not have a clue as to why you are having problems mounting the lens. It is probably the Ricoh pin. I currently have and have in the past had other lenses with the ball style pin that mount rough. This is not true on every body, so it might be a matter of tolerances and/or the positioning of the screw holes on the mount that the pin must pass over and clear. Steve

10-14-2013, 04:49 PM	#19
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by jjdgti What I notice, the flange guard is to big. Good catch. The Sigma Mini-wide 28mm is pretty common on this forum and I don't remember any complaints about the flange, but that lens was made in several variants and there may well be an issue with the lens in question on the K20D. Steve

10-22-2013, 11:01 AM	#20
jjdgti Veteran Member Join Date: Jun 2008 Location: NJ Posts: 1,824	Pedro any updates? Is it really K mount or not? Was the size of the lever the problem?

10-22-2013, 06:52 PM	#21
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by jjdgti Pedro any updates? Is it really K mount or not? Was the size of the lever the problem? It is definitely a Ricoh/Pentax-A combo K-mount. Steve

10-28-2013, 01:01 PM	#22
pedro730 New Member Join Date: Oct 2013 Posts: 10 Original Poster	I shaved down the flange, even got a file and filed down some of the edges in hopes that maybe a small piece of metal might be getting stuck along the edges....and it still doesn't fit.

10-28-2013, 05:36 PM	#23
marcusBMG Site Supporter Join Date: Nov 2012 Location: North Wales Photos: Gallery \| Albums Posts: 2,870	Originally posted by pedro730 I shaved down the flange, even got a file and filed down some of the edges in hopes that maybe a small piece of metal might be getting stuck along the edges....and it still doesn't fit. Can you post a better pic or two and more precise info - pic of the lens at the point its stuck. If its the ricoh pin, that hooks into the AF hole when the white orientation cue button is pretty much at the quarter-to position as you look at the lens on the camera from the front.

10-29-2013, 06:41 AM	#24
k0og Site Supporter Join Date: Nov 2008 Location: Rolla, Missouri Photos: Gallery \| Albums Posts: 699	Try this: Before you try to mount the lens, slide the MF/AF switch on your K20D to MF. This will retract the AF drive mechanism into the mount flange. Now try to mount your lens. Is it any better? -Joe-

10-29-2013, 07:26 AM	#26
k0og Site Supporter Join Date: Nov 2008 Location: Rolla, Missouri Photos: Gallery \| Albums Posts: 699	Pedro, That's strange! Try this: Take a series of pictures of the Pentax-A 50mm along side the Sigma so we can see the two mounts side-by-side (make sure the aperture levers are in the same positions). The back end of your Sigma looks a little strange to me, but maybe it is just the perspective. -Joe-

02-05-2014, 11:35 AM	#29
Lowell Goudge Site Supporter Join Date: Jan 2007 Location: Toronto Photos: Gallery \| Albums Posts: 17,892	The flange is not located correctly remove it and all will be fine. You will note the flange is actually rotated about 20 degrees from the aperture lever this was common. It hits the two power pins of the KAF2/3 mount. It will mount unmodified on any camera prior to the K100Super in digital, or on any film body except the PZ series. To use on a PZ camera or a digital body K100super or later with HSM support the flange must be removed. Sigma, and also vivitar lenses have this issue frequently.