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01-01-2013, 05:12 PM   #1
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Sigma 500mm 4.5 ex losing connection

i know i have seen some discussion in the past on other sigma lens...i've had my 500mm for about 3 weeks (love it) and it just started periodically loosing connection to the camera...you get the dreaded f---...if i slightly move the lens i get it back but have lost several pictures opps and really don't expect this to be an issue with a 5k lens...non of my other pentax lens have this issue...i do recall periodically seeing it occur in the past with the 1.4 teleconverter and the sigma 70-200 on my other k5 but i am using the 500mm on my newer camera and not using the teleconverter and it had not been an issue until yesterday...thoughts

01-01-2013, 05:43 PM   #2
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QuoteOriginally posted by pearsaab Quote
i know i have seen some discussion in the past on other sigma lens...i've had my 500mm for about 3 weeks (love it) and it just started periodically loosing connection to the camera...you get the dreaded f---...if i slightly move the lens i get it back but have lost several pictures opps and really don't expect this to be an issue with a 5k lens...non of my other pentax lens have this issue...i do recall periodically seeing it occur in the past with the 1.4 teleconverter and the sigma 70-200 on my other k5 but i am using the 500mm on my newer camera and not using the teleconverter and it had not been an issue until yesterday...thoughts
If that is any help to you, I had something similar happened with my "former" Sigma 100-300/4 and it was worse with the use of the Sigma 1.4X TC !

Now this was with my K20D and my K7 as well back then. Now I have the K5 but no Sigma lens anymore.
With that being said, I would "assume" this could be a lens related problem indeed (contacts?).
One last thing: this always happened ONLY during cold days (winters here ARE cold).

I will follow this thread carefully ... looking forward to see if you have any luck finding exactly what is happening.

JP
01-01-2013, 05:59 PM   #3
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I had this happen the first time I hook hooked my TC to this lens, but as soon as I took it off and tried it again I have not seen it happen again.. Sorry I could not help..
01-01-2013, 06:31 PM   #4
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Tighten your mount screws (both lens and body). The heavier the lens, the more likely the screws will back out due to the weight. Had it happen to my 170-500.
Hope this helps.

01-01-2013, 06:54 PM   #5
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One thought, how are you supporting the lens? Are you hand holding the setup or using a tripod mounted to the lens? If hand holding, there might be too much torque/weight on the mount. Since the camera is so light, if the lens is mounted on a solid tripod, then there shouldn't be an issue.

Since it's new, if tightening the mounts and making sure the contacts are clean doesn't help, I'd send the lens back to Sigma and tell them what's happening.
01-01-2013, 07:39 PM   #6
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I have the same Sigma 500 4.5 lens for over a year (latest production batch) and do have the same occasional issue. I had the issue but a lot worst (30 to 100 times as often) with the bigma 50-500. I thought it was a loss of contrast and the camera couldn't find anything to focus on. I blamed the autofocus system. Seems I could be wrong. The bigma is collecting dust so I won't have the same opportunity to experiment with the problem.
01-01-2013, 08:05 PM   #7
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Bit of foil tape on the mount can usually fix such problems. This seems to happen with Sigma lenses quite a bit.
01-01-2013, 08:33 PM   #8
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I do on occasion get this with my Sigma 300/2.8. but having said that, I have had it happen on some of my older FA* lenses and DFA macro as well, if it does happen, I pop the camera off the lens, and give both the lens contacts and the camera contacts a good clean, also making sure that the contacts are moving in and out and that they are not stuck with dust and then all seems good again.

01-02-2013, 09:09 AM   #9
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thanks all...i did clean it last night but haven't tried shooting anything..i typically shoot with a monopod or on rare occasion handheld...the lens is either supported with the monopod or i carry it with straps connected to the lens so the weight is not on the camera...i will try a few things when i get a chance...unfortunately since it will be dark when i get home it won't be till this weekend but i like the foil idea and will try that first..by the way i don't think i ever saw this with the bigma and now that my husband has it he hasn't had a problem either but do feel it has to do with the sigma lens and maybe due to the colder temperatures (makes sense to me)...thanks and i will keep you posted...amy

by the way what do you use to clean the lens contacts...i heard some use erasers..i just wiped them down last night without using anything
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