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08-30-2012, 11:54 AM   #1
Pedrodelta
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Help with Vivitar s1 105mm f2.5 macro lens

Hello folks,
I wonder if any of you talented people can throw a light on my problem. I have a Vivitar Series 1 f2.5 macro lens which when mounted on either my K5 or Samsung GX10 and placed in the 'A' mode, neither camera will let me set an aperture wider than f4.5 but will go 5.6 6.7 8.0 9.5 11 13 16 19 22 27 & 32 no problem.
There does not appear to be any physical defects with the aperture linkage which opens an shuts quite freely, no obvious sticking aperture blades and the aperture appears to open as wide as it possibly can.
There is no problem either as far as my eyes can detect with infinity focus. I've cleaned both sides of the contacts on mount and so far I'm stumped!

Anyone any thoughts? Grateful thanks in advance...Pedro

08-30-2012, 12:02 PM   #2
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QuoteOriginally posted by Pedrodelta Quote
Hello folks,
I wonder if any of you talented people can throw a light on my problem. I have a Vivitar Series 1 f2.5 macro lens which when mounted on either my K5 or Samsung GX10 and placed in the 'A' mode, neither camera will let me set an aperture wider than f4.5 but will go 5.6 6.7 8.0 9.5 11 13 16 19 22 27 & 32 no problem.
There does not appear to be any physical defects with the aperture linkage which opens an shuts quite freely, no obvious sticking aperture blades and the aperture appears to open as wide as it possibly can.
There is no problem either as far as my eyes can detect with infinity focus. I've cleaned both sides of the contacts on mount and so far I'm stumped!

Anyone any thoughts? Grateful thanks in advance...Pedro
I have the exact same lens and have no issue controlling the aperture on the camera via A mode.

Try this.

Set the DSLR to M mode then on the lens manually set it to f2.5, press green button to stop down, note the f speed then take a shot, now set the lens to f4.5 then press green button, note the fspeed, take a shot.

Does the camera change drastically the fspeed? check the two images does the prior look like it was shot open and the latter shot at 4.5? If yes then your A contact might have a problem communicating with your DSLR.

Do you you have another lens with A mode so you can test with your DSLR and see if it's not the contact on the camera?

I suspect your lens has problem with the A pin.
08-30-2012, 12:53 PM   #3
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Thank you Ducdao for your quick response. I have done as you suggested and the results appear consistent with a camera & lens working as they should.
I have many Pentax 'A' lenses and don't have issues with any other than this Vivitar, which previously worked OK! It appears to still work as it should from F4.5 down to F32, The camera will not however
display any f/stops wider than F4.5. i suspect as you suggested that there is an issue with the 'A' pin or contacts but at the moment I'm at a loss as to what that issue is.

Pedro.


PS Sorry it's taken me so long to reply but I've had to take time to register as my reply attempt was being flagged as spam.....
08-31-2012, 09:53 AM   #4
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Anyone else experienced similar problems or have any off-the-cuff thoughts that they are willing to share???

08-31-2012, 10:04 AM   #5
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Pedro: Welcome to the forum!

In order to help you get more responses to your problem, I have moved your question to the General Technical Troubleshooting section.
08-31-2012, 10:24 AM   #6
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QuoteOriginally posted by Tom S. Quote
Pedro: Welcome to the forum!

In order to help you get more responses to your problem, I have moved your question to the General Technical Troubleshooting section.
Thank you very much for that Tom S it.s much appreciated and it's a pleasure to join the forum at long last, having been a stalker here for several months..... Pedro....
08-31-2012, 11:10 AM   #7
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Have you tried cleaning the lens and camera contacts with alcohol?
08-31-2012, 11:17 AM   #8
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I have an 'A' lens that is max 2.8, but on hot days becomes f4, at least according to the camera. Cool it down, and 2.8 comes back.

08-31-2012, 11:26 AM   #9
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QuoteOriginally posted by macTak Quote
Have you tried cleaning the lens and camera contacts with alcohol?
Cleaned it thoroughly but made no difference and the problem is the same on both Samsung GX10 and K5. The k5 is brand new... Pedro
08-31-2012, 11:28 AM   #10
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QuoteOriginally posted by vonBaloney Quote
I have an 'A' lens that is max 2.8, but on hot days becomes f4, at least according to the camera. Cool it down, and 2.8 comes back.
Now that.s something new! A long-shot maybe but worth a try. Thanks... Pedro...
08-31-2012, 11:39 AM   #11
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QuoteOriginally posted by Pedrodelta Quote
Now that.s something new! A long-shot maybe but worth a try. Thanks... Pedro...
That same lens last winter suddenly had its apertures get all out of whack (wouldn't stop down until past f4) due to a metal linkage connected to aperture lever spontaneously becoming bent -- my theory is because of the cold. The fact that now it started messing up in hot weather is evidence of same. I think one of the materials used is just too sensitive to hot/cold and warps like a cookie sheet in the oven (and doesn't always return to original shape/position). (My lens is a Sigma 24/2.8 Super-Wide II.)
08-31-2012, 02:54 PM   #12
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QuoteOriginally posted by vonBaloney Quote
That same lens last winter suddenly had its apertures get all out of whack (wouldn't stop down until past f4) due to a metal linkage connected to aperture lever spontaneously becoming bent -- my theory is because of the cold. The fact that now it started messing up in hot weather is evidence of same. I think one of the materials used is just too sensitive to hot/cold and warps like a cookie sheet in the oven (and doesn't always return to original shape/position). (My lens is a Sigma 24/2.8 Super-Wide II.)
That's interesting because my lens had issues several weeks ago with the focus ring locking up when the lens was racked out for max magnification. A regular problem I gather with this model
and caused by the aperture linkage jamming internally on retraction. The answer is to apply a slight bend to the linkage to keep it out of harms way. Following this mod the lens has worked flawlessly until last weekend. I've now had chance to try the cooling suggestion but to no avail. I'm certain that the lens is actually opening to it's widest aperture, even though the camera will only display f4.5 but not beyond.
It's just so damn vexing!!!! Pedro....
08-31-2012, 03:44 PM   #13
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The lens has a pair of really long arms that control the aperture blades. Because it's a 1:1 macro, the blades can change their distance from the mount considerably. Those arms might cause your focus jam. Here's the arms from the Kiron version:



You can remove the four screws above the aperture ring and this whole part comes off on the Kiron version.

Back to the original point, If you look at the chart on this page, you can see that changing only one contact from 0 to 1 tells the camera the difference between an aperture range of f2.5-f32 or f4.5-f32. So I suspect that contact.
08-31-2012, 04:26 PM   #14
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Thank you just1moredave for your input.
Mine is the Kiron version (serial number beginning 22....) and it is the top most armature as depicted in your photo which is the offender for causing the lockup.
This was accessed by the method you described and adjusted slightly to avoid impeding with the forward lens carriage on it's return. It's a relatively easy fix
though admittedly not for the faint hearted. Doing this had no effect on the aperture though which actually registered as f2.4 at it's widest. I've looked at
Dimitrov's page several times already but must confess to not being able to quite get my head around how the relationship with the contacts & aperture work
exactly and hence determining which contact on the lens has possibly gone awry. But I agree it's defo looking like a contact issue. More study on 'Dr Dimitrov'
is required me thinks.... Pedro....
09-02-2012, 04:50 AM   #15
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Well, I stared at Dimitrov's K-mount page for a while and then the penny dropped. Initially I was thinking the chart was dynamic and reflected the change in the contacts as you cycled through the apertures but couldn't grasp how they could change their state from conducting to insulating until it dawned on me that each set of contacts reflects an aperture range doh.... Talk about can't see the wood for the trees! Anyway, now that I have a clear understanding of how the lens communicates with the camera (simplicity itself) I can easily identify the erring contact as 'r1' according to 'Dimitrov'. What I still can't fathom though is why this appears to be insulating and not conducting as it should. I've examined it with a loupe and can't see anything obviously wrong with it. I've removed the mount from the lens and cleaned it front and back but to no avail!!!

So now I venture the question, does anyone know how or why a conducting contact should fail to conduct? Am I missing something?? Pedro... severely vexed...
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