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05-19-2017, 08:10 AM - 1 Like   #1
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K-1 with DFA*70-200 or DFA150-450 Bad connection

Hi!

I have hade some bad connection between my kamera and the new tele lenses. More when colder weather than when inside.

Watch the video to see what I mean with bda connection.

It goes to Manual Focus and/or loses the F-number going to F--

Is it only my combo doing this?

p.s Due to the problem the bayonett on the K-1 has been changed and I have gotten a new DFA150-450. d.s

The camera and lenses are at the workshop right now and have been for a couple of weeks but they have problem finding a solution. They were about to give me a new camera but that one also showed the same problem.


So my question is: Any one else?

Please refer from coming with speculations.


The video is in Swedish but the video should be self explanatory.

/T





05-19-2017, 08:23 AM   #2
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QuoteOriginally posted by Tjompen1968 Quote
K-1 with DFA*70-200 or DFA150-450 Bad connection
I've had the issue when using the 150-450 lens in the cold and after moving the lens / camera in/out of the car because moving from cold to hot create condensation on the lens mount. After mounting the lens and drying, it never happened again.
05-19-2017, 08:32 AM   #3
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Hi,
Unfortunately, I don't speak Swedish. So, my understanding of the issue is that the camera could be moved when the lens is on the tripod.
I had similar problem (I have 70-200). Turns out that when you loose the collar to turn camera to portrait or landscape orientation and don't go all the way in you get this motion.
Now, I make sure that when I change the orientation that it "clicks" in.
Hope it helps.

AK
05-19-2017, 08:40 AM   #4
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The problem is not that the camera can be moved when on a tripod. It is there for ease of making the video. Normaly the camera is in on hand and the tripod collar in the other or hand on lens itself. Due to more movement possible in these bayonetts and the heavier construction the lens and camera will move in the bayonet when handled. If it looses connection it will try to focus again or will not fire if not in focus etc. Also exposure will suffer. So...


Anyone else finding that these lens-camera combos sometimes has these problems?

Note that it is not just one K-1 but two, one from the first batch and one much newer that has this problem. ALSO that it is both lenses AND a second version of the DFA150-450.

Also they have tested with all other Pentax DSLRs and only the K-1 gives this problem.

---------- Post added 05-19-17 at 05:42 PM ----------

The problem may not occur directly but after a few hours in the wild it suddenly starts. In the beginning it only did like that but lately it was all the time.

05-19-2017, 09:17 AM   #5
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Hypothetical....

As a one off guess, the larger air volume of the mirror box on the K-1, if warmed, could be depositing the condensation on the colder mount, which is exposed to the cold air at the outer edge (and has a higher metallic specific heat). Any gap at the mount (from not supporting BOTH the body and heavy lens weight) would allow the vapor to escape the mirror box and condense on the contacts... Reason I mention this: We were in the Yukon recently in wind and tundra sand (which is very fine), and we saw deposits on the mounts which got on the flats, with heavier lenses (Siggy 150-500 and DFA 150-450), on 2 separate K-3s. Just a thought....
05-19-2017, 09:29 AM   #6
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It occurs when dry, when moist, when cold and when warm. It also occurs when it has been in the same environment for hours, it occurs even if cleaning the contacts.


As I stated in the original post, PLEASE refer from speculations on why or how.

Please ONLY respond if you have the same problem/symptoms.
05-19-2017, 06:57 PM   #7
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Thanks for posting this, Tjompen! I'm not alone!

I've been having the same issue with my K-1 and some Sigma lenses for a long time. All these lenses work perfect on my K-5 and *ist DS. Handheld or tripod, cold weather or hot weather, it always happens.
It rarely happened with a Sigma 105mm f/2.8 Macro lens I used to own, sometimes with a Sigma 24-60mm f/2.8 I sold, and frequently occurs with my Sigma 400mm f/5.6 APO Tele-Macro.

I really like this 400mm, but I have been considering replacing it with the D-FA 150-450 because of this issue. Any Pentax-label lens has worked perfectly, just Sigma giving me trouble. So, I'm very concerned when you write about the 150-450 having this issue too!
I've also tried mating that Sigma 400mm with a Kenko 1.4x teleconverter. The problem still exists with the TC attached, but not as frequently.

The camera loses connection to the lens in exactly the way you describe in the text, camera loses aperture value (F-- in viewfinder), AF stops working (camera shows MF) and whatever exposure I had ready to go is overridden by a different one (like 1/800s f/8 becoming 1/100s f--). I am shooting TAV mode for the most part, so the exposure is usually saved by the ISO switching. I end up with lots of blurry chickadees at ISO 100.

One partial solution I have discovered is this: If I hold down the lens release button very lightly, the lens will become fully functional as the locking pin is no longer making contact with the lens mount.. If you hold the button too hard, the camera AF screw (for screw drive lenses) will disengage from the lens completely.
Maybe you can try this too, you shouldn't lose AF because your lens is not screw-drive.

I think there may be some kind of intermittent electrical short involving the lens locking pin somewhere near the lens mount in the camera, or perhaps the lens draws too much power/camera can't supply enough power and it shuts down. You don't want any speculation, but from my testing I think one of these might be the case.

I won't send it in for repair because I've only encountered the problem with 3rd party lenses (Pentax will simply blame Sigma). If you're able to get yours repaired, please come back here and let me know what service to ask for!

Last edited by Mock; 05-19-2017 at 07:42 PM.
05-20-2017, 06:05 AM   #8
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QuoteOriginally posted by Mock Quote
Thanks for posting this, Tjompen! I'm not alone!

I've been having the same issue with my K-1 and some Sigma lenses for a long time. All these lenses work perfect on my K-5 and *ist DS. Handheld or tripod, cold weather or hot weather, it always happens.
It rarely happened with a Sigma 105mm f/2.8 Macro lens I used to own, sometimes with a Sigma 24-60mm f/2.8 I sold, and frequently occurs with my Sigma 400mm f/5.6 APO Tele-Macro.

I really like this 400mm, but I have been considering replacing it with the D-FA 150-450 because of this issue. Any Pentax-label lens has worked perfectly, just Sigma giving me trouble. So, I'm very concerned when you write about the 150-450 having this issue too!
I've also tried mating that Sigma 400mm with a Kenko 1.4x teleconverter. The problem still exists with the TC attached, but not as frequently.

The camera loses connection to the lens in exactly the way you describe in the text, camera loses aperture value (F-- in viewfinder), AF stops working (camera shows MF) and whatever exposure I had ready to go is overridden by a different one (like 1/800s f/8 becoming 1/100s f--). I am shooting TAV mode for the most part, so the exposure is usually saved by the ISO switching. I end up with lots of blurry chickadees at ISO 100.

One partial solution I have discovered is this: If I hold down the lens release button very lightly, the lens will become fully functional as the locking pin is no longer making contact with the lens mount.. If you hold the button too hard, the camera AF screw (for screw drive lenses) will disengage from the lens completely.
Maybe you can try this too, you shouldn't lose AF because your lens is not screw-drive.

I think there may be some kind of intermittent electrical short involving the lens locking pin somewhere near the lens mount in the camera, or perhaps the lens draws too much power/camera can't supply enough power and it shuts down. You don't want any speculation, but from my testing I think one of these might be the case.

I won't send it in for repair because I've only encountered the problem with 3rd party lenses (Pentax will simply blame Sigma). If you're able to get yours repaired, please come back here and let me know what service to ask for!
I will keep this issue updated when I know something more.

05-28-2017, 02:59 PM   #9
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Talked to the workshop the other day and they were about to send me a new camera when the problem suddenly appeared in that combo aswell. They now have had the camera for a month so tomorrow I will call them for a game plan because I wan't my gear back.


And... Only three units with the problem sounds really strange...
05-29-2017, 08:22 AM   #10
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Me too

I believe I had the exact same problem with my newly acquired Irix 15mm lens. This lens had be sitting on my camera for some months when I went ill (and in hospital).
The camera with lens on it, was safely stored in "household"conditions in a waterproof case. When I started photographing again, the K-1 had F - - and no photo's could be taken with this lens.
I put it on my backup K30 and it failed also (cannot remember the symptoms on the k30). The K-1 with my other lenses was ok at that time.
As this was a new lens, I went back to the shop for guarantee service. (I showed It andit failed in the shop also).
The lens was sent the the Irix service center, where it stayed for over a month.
The camera shop was well aware of the delay and was putting some presure on the repair center (in Poland I believe).
At last I received a replacement copy (other serial number), which worked.
05-29-2017, 08:31 AM   #11
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The problem in this case is the camera, not the lenses.
06-03-2017, 03:12 PM   #12
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So I got a new camera yesterday and so far it seems to work fine. Tomorrow I will take it out for a whole day of shooting and after that I know if I can trust it or not.
06-05-2017, 05:18 AM   #13
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QuoteOriginally posted by Tjompen1968 Quote
So I got a new camera yesterday and so far it seems to work fine. Tomorrow I will take it out for a whole day of shooting and after that I know if I can trust it or not.
Did they give a a cause (Pins, mount, lock), or any info? THX
06-05-2017, 06:02 AM   #14
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QuoteOriginally posted by GlassJunkie Quote
Did they give a a cause (Pins, mount, lock), or any info? THX
They do not know why it does not work. All the pins, bayonet, electronics has been exchanged...
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