Bigma Problem

[ozzie]

Hi All
I have been a bit concerned with the amount of play on my e3 and e5 with a lens attached . The 50-200 has about the same amount of play (lens moving in the twisting plane) as the Bigma but I have noticed that the Bigma will lose AF function when the camera is twisted . This happens when attached to a tri/monopod and holding the camera body. All comes good when the lens is locked again and the camera turned off and then back on. It looks like the lens can turn enough to lose contact with the body any one else having this problem or any suggestions.
The lens works fine and takes great images but this is becoming a bit a pain.
Thanks
John

[David Morison]

Re: Bigma Problem

There is a small amount of rotational play on both my E30 and E5 which has been there since new and I guess is standard. It was more noticeable with the E30 and Bigma I had, but never affected any functions. It is also more noticeable with the 300mm f2.8 so I guess this is just because of the weight and size of these lenses. It does seem strange to have this amount of play, about 0.3mm, in a precision instrument but I imagine there is a good reason for it. Anyhow as I say it doesn't seem to affect function in my case.

David

[Ian]

Re: Bigma Problem

The lens is locked in place by a groove in the mount. If there is play there might be wear or a bent pin. If the paly is worse with a particular lens, it might be worth getting the lens inspected. Sigma's service here in the UK is very good. It might be well worth giving them a call.

Ian

[Chevvyf1]

Re: Bigma Problem

Hi All
I have been a bit concerned with the amount of play on my e3 and e5 with a lens attached . The 50-200 has about the same amount of play (lens moving in the twisting plane) as the Bigma but I have noticed that the Bigma will lose AF function when the camera is twisted . This happens when attached to a tri/monopod and holding the camera body. All comes good when the lens is locked again and the camera turned off and then back on. It looks like the lens can turn enough to lose contact with the body any one else having this problem or any suggestions.
The lens works fine and takes great images but this is becoming a bit a pain.
Thanks
John

Ossie at Popham, I just caught my BIGMA ! Now reading this experience of your reminds me! I thought I must have inadvertantly pushed the little release button on the front of the camera ... but I am pretty sure I did not ! so I am interested to see what others say here ... Peter Drury is the most regular BIGMA user I know, so I hope he sees this, or maybe pm him!

[ozzie]

Re: Bigma Problem

Thanks David Ian and Chevvy
The play is more like 1mm and maybe more on the E5 the 50-200 is about half.
Strange I have just spent some time with the E3 twisting and trying to get the problem to occur but couldnt get it to happen. I will now take notice if somehow my grip is touching the release button (thanks Chevvy)

[Ross the fiddler]

Re: Bigma Problem

When I first got my E30 I inadvertently bumped the release button & a twist of the lens would reset the pin again. I had to change my hold to avoid it. Sometimes a twist of a lens can interrupt the lens contacts briefly even now.

As far as warranty for Ozzie goes, CR Kennedy in Melbourne is the importing agent here for Sigma & Ozzie is in Queensland. I would suggest checking the locking pin hole on the Sigma lens to make sure it still has sharp edges & the pin on the camera is also not rounded or bent looking & operates freely. Also check the screws on the lens mount are not loosening at all (both lens & camera). If anything looks worn, a decision about the course of action can be taken then.

[ozzie]

Re: Bigma Problem

Thanks Ross
Well you found the problem this lens has at some time in its life had a fall
and I can only presume camera first as the front shows no signs of injury however the attach plate on the lock side is pushed in slightly which allows the lens to release when the body is twisted a certain way.
I might see how much a replacement plate is however the lens appears to be working perfectly and could be put up with now I know the problem.
This has also sorted out another area I have been concerned with , the movement in an attached lens ,the locating holes on the lens are of a size that they allow the lens to rotate slightly on the locating pin when attached . It would appear that some lenses have a slightly larger hole alowing more movement.
Thanks again Ross never thought to look there .
Cheers
John

[Ross the fiddler]

Re: Bigma Problem

Thanks Ross
Well you found the problem this lens has at some time in its life had a fall
and I can only presume camera first as the front shows no signs of injury however the attach plate on the lock side is pushed in slightly which allows the lens to release when the body is twisted a certain way.
I might see how much a replacement plate is however the lens appears to be working perfectly and could be put up with now I know the problem.
This has also sorted out another area I have been concerned with , the movement in an attached lens ,the locating holes on the lens are of a size that they allow the lens to rotate slightly on the locating pin when attached . It would appear that some lenses have a slightly larger hole alowing more movement.
Thanks again Ross never thought to look there .
Cheers
John

Thanks John.
I'm glad my ramblings actually helped.

[PeterD]

Re: Bigma Problem

Good evening all,

Sorry I have not been on here for some time but I am buried in work and not much time for anything.

I read this thread with interest - thanks Chevvy for pointing it out.

I have noticed the small rotational movement everyone has mentioned and it is present on all my lenses - ZD and Sigma. I also had the problem of the lens (Bigma) unlocking itself. I leave the tripod mount attached to the lens and found the potential unlock condition was caused by the way I carried the camera/lens combination. I rest the combination across my body. If the tripod mount is close to the body with the end of the lens across my elbow, I found that, as I moved, the lens would try to rotate in the unlock direction. I now carry the lens in the same way but with the tripod mount away from my body. No problems since adopting the new way of carrying the combination. Hope this makes sense.

[ozzie]

Re: Bigma Problem

Hello Peter
Just out of interest could you look at the locking plate on your bigma to see if there is any dishing near the locking hole. I ask this because I thought my lens had had a fall with a previous owner causing my problem (probebly is still the case) but on close inspection a fall to cause this dishing would I think do major damage to the lens which is not the case.
Thanks in advance
John

[Ross the fiddler]

Re: Bigma Problem

Hello Peter
Just out of interest could you look at the locking plate on your bigma to see if there is any dishing near the locking hole. I ask this because I thought my lens had had a fall with a previous owner causing my problem (probebly is still the case) but on close inspection a fall to cause this dishing would I think do major damage to the lens which is not the case.
Thanks in advance
John

If you are confident in replacing the plate yourself, it might be OK to remove (using good quality jeweller's screw drivers) the existing one & by putting the concaved face down on a steel plate (sometimes on the back of an engineer's vice or the base of a drill press), use a hammer & punch to gently return it to shape, but I would use a sheet of paper between ring & plate & maybe under the punch too to avoid unnecessary scratch marks. I don't suggest doing it unless you are totally sure of yourself with this as things can go horribly wrong if done incorrectly.

[ozzie]

Re: Bigma Problem

Well Thanks again Ross
With Jewlery kit at hand I dissembled the plate from electronics etc. and with heart in mouth and wooden mallet tapped the plate back into nearly level.
Some filing had to be done as the fit is very exact . After much mucking about to get the three washers lined up all is back together and working as it should.
I now cant get the lens to release unless I press the release button Mission complete.
What are you like on aircraft engines I have an annoying little miss at 4000 rpm?
Thanks agian
John

[Chevvyf1]

Re: Bigma Problem

WOW ! Ozzie ... so glad to hear the operation was successful Your very BRAVE !

[Ross the fiddler]

Re: Bigma Problem

Well Thanks again Ross
With Jewlery kit at hand I dissembled the plate from electronics etc. and with heart in mouth and wooden mallet tapped the plate back into nearly level.
Some filing had to be done as the fit is very exact . After much mucking about to get the three washers lined up all is back together and working as it should.
I now cant get the lens to release unless I press the release button Mission complete.
What are you like on aircraft engines I have an annoying little miss at 4000 rpm?
Thanks agian
John

My father was an aircraft fitter with the RAF (during WWII), but I ain't going anywhere near that.

I've done up a Corolla engine years ago & now I pay motor mechanics to do my dirty work on all my cars (well, most of it). I stick to repairing & setting up new violin family of instruments (& a bit of others, including making a few Celtic styled whistles for myself).

I'm really pleased you had success with the lens, but I got scared when you mentioned filing it.

Now for some more photos with it from you.



PS I probably should have said to use a large pin punch. I new what I meant but that doesn't mean others can see what's in my mind.

[PeterD]

Re: Bigma Problem

Hello Peter
Just out of interest could you look at the locking plate on your bigma to see if there is any dishing near the locking hole. I ask this because I thought my lens had had a fall with a previous owner causing my problem (probebly is still the case) but on close inspection a fall to cause this dishing would I think do major damage to the lens which is not the case.
Thanks in advance
John

Hi ozzie

I checked the locating hole on my lens and p[hotographed it (will post shortly when I download the image). the hole itself is prety well OK but there is some wear on the surface at each side.