Problem with SMC PENTAX-F 50mm f/1.4

ttabps · 03-24-2016, 02:30 AM

Hi

I have recently purchased one of these, hoping to make it my go to Pentax 50mm. The example I bought has beautiful optics and is cosmetically near mint. But unexpectedly it has two issues...

1) The 'A' contact does not raise up when the ring is set to 'A' and

2) The AF screw drive slot does work when you turn it manually with a screwdriver but it does not appear to make contact with the AF SLRs I have tried it with (K-3 and MZ-5n)

Are these two issues connected? I expect that they probably are but what would be the reason for both the 'A' contact and AF drive slot not raising up higher? The other four mount face contacts can be pushed down a bit with the tip of a small screwdriver but the 'A' contact pin does not give at all.

Any advice would be hugely appreciated!

Simon

Wild Mark · 03-24-2016, 03:15 AM

Sounds like the lens has been pulled apart and not re-assembled correctly. You might want to send it to Eric for a CLA if you do not feel confident in making your own investigations. Worthy lens to resurrect.

pathdoc · 03-24-2016, 03:57 AM

Originally posted by Wild Mark

You might want to send it to Eric for a CLA

Check his profile; he's listed as being in the UK. Eric's a bit far.

OP, look here and scroll down; UK service centres are listed near the bottom.

ttabps · 03-24-2016, 04:13 AM

Thanks for the replies.

I once sent a K-2 to Eric in the distant past but yes, there are alternative options available over here in the UK. I have already mentioned it to Robin at Harrow Technical (UK) and he said he was happy to take a look for me but, If I can get some advice from the forum then I would a) understand what has happened (and be able to tell Robin) and/or b) be able to hopefully fix it myself. I have fixed a fair few Pentax lenses in the past but never an 'F' series 50mm. When I carefully removed the mount last week I could not visually identify where the problem lay and it did not appear that anything was obviously missing. I can remove the mount again, take a picture and post it in this thread if it helps.

**BCtoad** · 03-24-2016, 09:27 AM

When you select a on your aperture ring all it does is make a ground on the a contact in the lens. The drive slot should be flush with the lens flange not lower or higher, it should also turn freely with a small screwdriver, clean the contacts on your camera and lens with microfiber cloth no cleaning solutions other than 99% alcohol. If that doesn't get it going there is probably a problem in the lens itself.

ttabps · 03-24-2016, 11:53 AM

I have cleaned the contacts with alcohol. I have tried it on my K-3 and also an MZ-5n and it makes no difference unfortunately - the problem is with the lens. I have a spares/repairs F70-210 so I will see if I can swap the mount over and let you know if that fixes the issue. In the meantime I would still welcome any other suggestions.

ttabps · 03-24-2016, 12:15 PM

Thanks dcshooter... I will be very wary of those springs!

6BQ5 · 03-24-2016, 12:25 PM

The FA 50mm f/1.4 seems to be a fragile lens. Mine basically wobbled itself apart. The screws and attachments holding the cams, gears, arms, and brackets loosened up and would jam against each other. It was impossible for lens to focus and set the aperture. I sent mine to Eric for rebuilding and it came back in perfect working order. One of my favorite lenses!! :-D

pathdoc · 03-24-2016, 12:27 PM

Originally posted by 6BQ5

The FA 50mm f/1.4

OP is talking about the F, not the FA. While we're on the topic, though, my FA50, secondhand, seems to be holding up very well; you might have been unlucky.

6BQ5 · 03-24-2016, 12:37 PM

Ooops! Sorry about that!

03-24-2016, 02:30 AM	#1
ttabps New Member Join Date: Oct 2011 Posts: 8	Problem with SMC PENTAX-F 50mm f/1.4 Hi I have recently purchased one of these, hoping to make it my go to Pentax 50mm. The example I bought has beautiful optics and is cosmetically near mint. But unexpectedly it has two issues... 1) The 'A' contact does not raise up when the ring is set to 'A' and 2) The AF screw drive slot does work when you turn it manually with a screwdriver but it does not appear to make contact with the AF SLRs I have tried it with (K-3 and MZ-5n) Are these two issues connected? I expect that they probably are but what would be the reason for both the 'A' contact and AF drive slot not raising up higher? The other four mount face contacts can be pushed down a bit with the tip of a small screwdriver but the 'A' contact pin does not give at all. Any advice would be hugely appreciated! Simon

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03-24-2016, 03:15 AM	#2
Wild Mark Veteran Member Join Date: Jun 2013 Location: Newcastle Photos: Gallery \| Albums Posts: 1,954	Sounds like the lens has been pulled apart and not re-assembled correctly. You might want to send it to Eric for a CLA if you do not feel confident in making your own investigations. Worthy lens to resurrect.

03-24-2016, 03:57 AM	#3
pathdoc Pentaxian Join Date: Mar 2015 Photos: Gallery \| Albums Posts: 6,381	Originally posted by Wild Mark You might want to send it to Eric for a CLA Check his profile; he's listed as being in the UK. Eric's a bit far. OP, look here and scroll down; UK service centres are listed near the bottom.

03-24-2016, 04:13 AM	#4
ttabps New Member Join Date: Oct 2011 Posts: 8 Original Poster	Thanks for the replies. I once sent a K-2 to Eric in the distant past but yes, there are alternative options available over here in the UK. I have already mentioned it to Robin at Harrow Technical (UK) and he said he was happy to take a look for me but, If I can get some advice from the forum then I would a) understand what has happened (and be able to tell Robin) and/or b) be able to hopefully fix it myself. I have fixed a fair few Pentax lenses in the past but never an 'F' series 50mm. When I carefully removed the mount last week I could not visually identify where the problem lay and it did not appear that anything was obviously missing. I can remove the mount again, take a picture and post it in this thread if it helps.

03-24-2016, 09:27 AM	#5
BCtoad Site Supporter Join Date: Oct 2008 Location: Prince George, British Columbia, Canada. Posts: 135	When you select a on your aperture ring all it does is make a ground on the a contact in the lens. The drive slot should be flush with the lens flange not lower or higher, it should also turn freely with a small screwdriver, clean the contacts on your camera and lens with microfiber cloth no cleaning solutions other than 99% alcohol. If that doesn't get it going there is probably a problem in the lens itself.

03-24-2016, 11:53 AM	#6
ttabps New Member Join Date: Oct 2011 Posts: 8 Original Poster	I have cleaned the contacts with alcohol. I have tried it on my K-3 and also an MZ-5n and it makes no difference unfortunately - the problem is with the lens. I have a spares/repairs F70-210 so I will see if I can swap the mount over and let you know if that fixes the issue. In the meantime I would still welcome any other suggestions.

03-24-2016, 12:15 PM	#7
ttabps New Member Join Date: Oct 2011 Posts: 8 Original Poster	Thanks dcshooter... I will be very wary of those springs!

03-24-2016, 12:25 PM	#8
6BQ5 Veteran Member Join Date: Jun 2013 Location: Nevada, USA Photos: Albums Posts: 3,348	The FA 50mm f/1.4 seems to be a fragile lens. Mine basically wobbled itself apart. The screws and attachments holding the cams, gears, arms, and brackets loosened up and would jam against each other. It was impossible for lens to focus and set the aperture. I sent mine to Eric for rebuilding and it came back in perfect working order. One of my favorite lenses!! :-D

03-24-2016, 12:27 PM	#9
pathdoc Pentaxian Join Date: Mar 2015 Photos: Gallery \| Albums Posts: 6,381	Originally posted by 6BQ5 The FA 50mm f/1.4 OP is talking about the F, not the FA. While we're on the topic, though, my FA50, secondhand, seems to be holding up very well; you might have been unlucky.

03-24-2016, 12:37 PM	#10
6BQ5 Veteran Member Join Date: Jun 2013 Location: Nevada, USA Photos: Albums Posts: 3,348	Ooops! Sorry about that!