6D shutter speed changes?????

[SMiller]

Hi everyone, I am new here and if this question has been asked previously please point me to the post. I did browse through the previous questions but did not see this particular problem.

My probles lies with my 6D I shoot automobile racing with a 70-200 2.8 and a 580EXII flash, A couple weeks back during the night I was shooting manual mode and I noticed that my shutter speed kept changing on it's own, so I switched to TV mode and it worked fine for one week, but I noticed last night it started doing the same thing. I am setting my speed at 400 and repeatedly it would change to 200 or even lower, thus making my shots overexposed. Anyone have any ideas as to why this is happening??

[cicopo]

Auto racing at 1/400 seems a bit high to me but I suspect the problem is that a 6D's max sync speed for using a flash is 1/200. Your manual will tell you whether it's 1/200 or some other value but to date I don't think any Canon body goes above 1/250 when working with a flash (in the normal manner).

[SMiller]

I should also add that the shutter speed is changing with or without flash, sync speed is not affecting this at all, It seems if I let the camera hang down then pick it up to go back to shooting it has changed drastically, last night I was shooting without flash, and we had a long caution, I was just standing around with the cameras hanging and when I picked it back up to start shooting the shutter speed and changed all the way down to 1.3 seconds.

[cicopo]

Been there often enough to know the camera is rubbing against you & that's turning the wheel for the shutter speed. Happens to me at radio control events more than I care to count. (I shoot 2 bodies so 1 is usually hanging while the other is in use).

[SMiller]

thanks for the reply, that was one of my first thoughts, I checked to make sure the wheel was away from my body, the first week I noticed the changes, perhaps I did not pay attention to that last night, thatnks I will pay attention to that next week and see if the situation improves. Thanks again!! (Fingers Crossed)

[Skirball]

It has to be rubbing.  Unless you have a very serious software issue you're settings won't automatically change in manual (except auto ISO).

One note though.  You say the "wheel was away from [your] body".  Are you referring to the wheel on the back?  The wheel by the shutter button will change the shutter speed, the wheel on the back aperture.

[SMiller]

Neither wheel is rubbing my body anywhere!!! I have checked that!! It seems to be a problem with the Image Stabilization, turned it off this week and it never changed once. Neither wheel is anywhere near any part of my body to be rubbing, the camera is on my hip, upside down when not in use, Lens pointing to the back. Gonna try to turn the stabilization back on this weekend and see what happens.

[ebiggs1]

I noticed the same thing when I used to have and use a 5D, 5D Mk II and my 7D.  But since I went all 1 series I have not had it happen since.  I still believe it is the knobs moving, rubbing, or something else moving them.

This was a big concern with the pros so Canon changed the way a 5D Mk III works so it can not move accidently.

[RobertTheFat]

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@ebiggs1 wrote:

I noticed the same thing when I used to have and use a 5D, 5D Mk II and my 7D.  But since I went all 1 series I have not had it happen since.  I still believe it is the knobs moving, rubbing, or something else moving them.

This was a big concern with the pros so Canon changed the way a 5D Mk III works so it can not move accidently.

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The shutter wheel doesn't work any differently on a 5D3. It's the mode dial that now can't be turned accidentally.

[ebiggs1]

Oh, yes, I do remember that.  Yes it was the mode dial that kept switching.  Man and it hasn't been all that long since I sold off all my xD cameras.  

But it still can't accidentialy be changed on the 1 D series.  Most controls require two buttons or dials.