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02-10-2020, 03:33 PM   #16
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QuoteOriginally posted by mlt Quote
Or just try cleaning the contacts first, particularly if the lens is stopping down to the correct aperture for exposures in all modes.
OP can't tell because they are getting F--. It appears they have already cleaned the contacts.


Steve

02-10-2020, 06:25 PM   #17
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Yes, I have already cleaned the contacts with lens cleaning solution. Did not help.
QuoteOriginally posted by stevebrot Quote
OP can't tell because they are getting F--. It appears they have already cleaned the contacts.


Steve
02-11-2020, 11:32 AM   #18
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Hi, Any chance you have another Pentax DSLR or know someone that does and you can check to see if the lens registers on other than a K-1

also, and this may be a dumb question but does the Tamron 70-200 2.8 even work on Full frame with complete functionality? I know the lens database says it does, but I haven't tried my Tammy 70-200 2.8 on a K1 as I don't have a K1. Any chance the Issue is the K-1 not the lens?

al
02-11-2020, 12:08 PM   #19
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I have a k-x somewhere in my closet with the aperture control problem where the aperture gets stuck and all pictures come out dark. I have not bothered to fix it after I got my K-1. I could try to put the Tamron 70-200mm on it and see if it even reads the aperture. Thanks for the tip.

The Tamron 70-200mm has functioned fully and wonderfully on my K-1 for over a year now. It is one of my favorite lenses. I don't see any issue with my other lenses with the K-1. Only this Tamron has a problem.

QuoteOriginally posted by brewmaster15 Quote
Hi, Any chance you have another Pentax DSLR or know someone that does and you can check to see if the lens registers on other than a K-1

also, and this may be a dumb question but does the Tamron 70-200 2.8 even work on Full frame with complete functionality? I know the lens database says it does, but I haven't tried my Tammy 70-200 2.8 on a K1 as I don't have a K1. Any chance the Issue is the K-1 not the lens?

al


02-12-2020, 11:12 AM   #20
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Last night I tried the Tamron 70-200mm on my K-30. This camera did not have a problem reading the aperture value or changing
the aperture value. Though, the K-30 has the problem with aperture getting stuck and all pictures come out dark.

Now, this is confusing. I have no issue with any of my other lenses on the K-1 except the Tamron 70-200. I do feel there is some play in the mount of this lens when attached to the K-1. When twisted and held in place the K-1 is able to read the aperture value. I don't feel this kind of play in any other lenses. Do I need to be concerned if there is a problem with the mount on the K-1? The Tamron 70-200 is a heavy lens. I mostly hang the camera attached with this lens by the neck strap. Would that stress the mount?

Should I try to tighten the screws on the mount for both the lens and the camera? I don't want to mess with anything without knowing what I am doing.

Thanks for your help.


QuoteOriginally posted by brewmaster15 Quote
Hi, Any chance you have another Pentax DSLR or know someone that does and you can check to see if the lens registers on other than a K-1

also, and this may be a dumb question but does the Tamron 70-200 2.8 even work on Full frame with complete functionality? I know the lens database says it does, but I haven't tried my Tammy 70-200 2.8 on a K1 as I don't have a K1. Any chance the Issue is the K-1 not the lens?

al
02-12-2020, 12:39 PM - 1 Like   #21
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I don't have the K-1 but
QuoteQuote:
When twisted and held in place the K-1 is able to read the aperture value
does not sound good especially since you haven't had a problem before with the lens on it and the lens works fine on other bodies..


If the K-1's mount goes into plastic like the K-3's it may be pulling out by the weight of the lens. Is the K-1 under warranty? It really may be safer to assume its the K-1 and have the mount checked out.


al





02-12-2020, 01:09 PM   #22
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QuoteOriginally posted by muraliy Quote
I do feel there is some play in the mount of this lens when attached to the K-1. When twisted and held in place the K-1 is able to read the aperture value. I don't feel this kind of play in any other lenses.
Some play on twist is not unusual, even with Pentax-brand lenses. It has to do with the width of the retention slot on the lens and the diameter of the retention pin on the body. There is also some potential for the lens to flex very slightly on the mount, given that the body side tangs are spring-loaded. Much depends on lens tang thickness and ramp. I would not expect that with any name-brand lens.

QuoteOriginally posted by muraliy Quote
Do I need to be concerned if there is a problem with the mount on the K-1?
Unless you start having similar problems with other lenses, I would think not.

QuoteOriginally posted by muraliy Quote
The Tamron 70-200 is a heavy lens. I mostly hang the camera attached with this lens by the neck strap. Would that stress the mount?
It might, on both lens and camera. It might also stress the strap lugs. People that I know with heavier lenses typically don't let the combo hang like that. Instead, they will simply carry the lens/camera combo, often upside-down by the tripod foot.

QuoteOriginally posted by muraliy Quote
Should I try to tighten the screws on the mount for both the lens and the camera? I don't want to mess with anything without knowing what I am doing.
Unless you have the proper JIS head screwdriver, I suggest not. There is potential to strip the heads if one uses a Phillips head driver.


Steve
02-12-2020, 01:13 PM   #23
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QuoteOriginally posted by brewmaster15 Quote
this may be a dumb question but does the Tamron 70-200 2.8 even work on Full frame with complete functionality?
Yes, it is a FF lens and there is no difference in the way the mounts function between the APS-C and 24x36mm format cameras.

02-12-2020, 01:26 PM   #24
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QuoteOriginally posted by brewmaster15 Quote
If the K-1's mount goes into plastic like the K-3's it may be pulling out by the weight of the lens. Is the K-1 under warranty? It really may be safer to assume its the K-1 and have the mount checked out.
The K-1 is not under warranty. Where can I get the mount checked? Are there any simple tests that I can do myself before getting checked professionally. As I said before, I see no issues with other lenses.

---------- Post added 02-12-20 at 02:35 PM ----------

QuoteOriginally posted by stevebrot Quote
Some play on twist is not unusual, even with Pentax-brand lenses. It has to do with the width of the retention slot on the lens and the diameter of the retention pin on the body. There is also some potential for the lens to flex very slightly on the mount, given that the body side tangs are spring-loaded. Much depends on lens tang thickness and ramp. I would not expect that with any name-brand lens.
Thanks for explaining this to me.



QuoteOriginally posted by stevebrot Quote
Unless you start having similar problems with other lenses, I would think not.
How would I then decide if the problem is with the lens or the camera? Do I need to get both checked? Both are not under warranty. Where would be a good place to go?



QuoteOriginally posted by stevebrot Quote
It might, on both lens and camera. It might also stress the strap lugs. People that I know with heavier lenses typically don't let the combo hang like that. Instead, they will simply carry the lens/camera combo, often upside-down by the tripod foot.
I also tend to hold the lens by the tripod foot as it is not comfortable to hang the camera by the neck strap for too long with such a heavy lens.



QuoteOriginally posted by stevebrot Quote
Unless you have the proper JIS head screwdriver, I suggest not. There is potential to strip the heads if one uses a Phillips head driver.
Steve
I do have JIS head screwdriver set. Maybe, I will carefully try to tighten the mounts and see if it helps.

Thanks for the help.
02-12-2020, 01:46 PM   #25
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QuoteOriginally posted by muraliy Quote
Should I try to tighten the screws on the mount for both the lens and the camera? I don't want to mess with anything without knowing what I am doing.
Looking at the base of your lens, it appears that its screw heads are not the same as those on brewmaster15's lens further down. Is there any chance your lens has been taken apart at some point and the lens mount screws replaced?


Steve
02-12-2020, 03:31 PM   #26
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QuoteOriginally posted by stevebrot Quote
Looking at the base of your lens, it appears that its screw heads are not the same as those on brewmaster15's lens further down. Is there any chance your lens has been taken apart at some point and the lens mount screws replaced?


Steve
That is a good observation. I have never touched the screws since i bought the lens. The lens when I got from adorama though sold as "used" looked brand new to me. I would say the the screws were never replaced.
02-13-2020, 10:49 AM   #27
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QuoteOriginally posted by stevebrot Quote
Looking at the base of your lens, it appears that its screw heads are not the same as those on brewmaster15's lens further down. Is there any chance your lens has been taken apart at some point and the lens mount screws replaced?


Steve
I checked the screws on both the Tamron 70-200 and K1. They were not loose. What I found was if I point the camera towards the ceiling with this lens attached, it can communicate the aperture value and I can even change it. As soon as I point the lens anywhere else, I lose communication.

To check if the weight of the lens is causing the mounts to not touch properly causing the issue, I tried an even heavier lens, the Sigma 50-500mm which did not have any issue.
02-15-2020, 06:19 AM   #28
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QuoteOriginally posted by muraliy Quote
Steve, Thank you for your reply. The metal conductor ("button") is missing in that position. You can see that in the attached photo.
Missing that pin is fine, my 28-75 F2.8 XR Di. Is also missing that pin, it tells MF cameras the lens is F2.8 wide open

Try taking the lens in and out of the A position on the aperture ring
02-15-2020, 07:06 PM   #29
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QuoteOriginally posted by Lowell Goudge Quote
Missing that pin is fine, my 28-75 F2.8 XR Di. Is also missing that pin, it tells MF cameras the lens is F2.8 wide open

Try taking the lens in and out of the A position on the aperture ring
It is not a pin. There should be a nylon insulator in that position. Additional posts by the OP indicates that there may be a problem on the lens side that is positional (by gravity) and not present with other lenses.


Steve
02-15-2020, 07:20 PM   #30
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maybe the spring (or whatever) for the 'a' contact on the lens is bad since upwards makes contact and elsewhere does not.....seems that would indicate movement of some sort making the contact faulty......is the ring locking into place in the 'a' position? maybe rotate the ring from 'a' and then return it?
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