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Has anyone experienced problems when combining Sigma lenses with Dynax/Maxxum 7?

I have a Sigma 28-70 f2,8 EX, and sometimes the camera doesn't shut down the display when I turn it of, and when I turn the button to "On" again the camera is "numb", it doesn't react to anything.
When I dismount the lens everything goes back to normal.

I also have a problem with a Sigma 24-70 f3,5-5,6.
The AF doesn't function, unless I "fiddle" with the lens when it's mounted. I guess this is due to bad connection in the mount. This is a very cheap lens wich I don't use anymore, so this problem isn't a big deal for me.

Can anyone help me with this problem?



New Member

I have an earlier version (non EX) of your 28-70, and had to return it to Sigma to get it re-chipped for Dynax 5/7/9 compatibility. Once done, it worked perfectly (still does!).

I had a really old Sigma 90mm which they said didn't need re-chipping, however the camera ended up breaking the AF mechanism by mashing the gears inside.



I had an older Sigma 75-300 which worked fine on my 7000 and a friends QTsi and STsi, however, on my 5, 7 and 7D, it would lock up and fail to focus.

I contacted Sigma in Canada and they wanted $95 + shipping to re-chip it. I decided not to bother as it was a poor lens anyway, replaced it with a Minolta lens.

Sigma is the only manufacturer that seems to have major compatibility problems, at least as far as I know. I now stay clear of Sigma lenses and buy Minolta or Tamron. I've heard that some Tokina's are good.


> I had compatibility problems with a Minolta original (expensive) 1-3x macro zoom. It has taken months to find the cause of the problem (long story that I will not bother you with). The zoom is now in Japan to be "upgraded". This lens worked excellently with my Dynax 9 and 7000i, but not with the 7D. For magnifications over 2 and apertures smaller (higher number) than 27 the camera would freeze. Minolta's view is that this is a problem of the lens: wear in the lens makes the aperture mechanism "too slow" and locks up the camera. The problem is caused by the differences in aperture control mechanisms (electronic in the 7D instead of mechanical in the older cameras). My view is that this is a compatibility problem, as it never showed up with the older analog Minolta's. There may be more lenses that could have this problem. It is difficult to recognize and the first thing to think is the camera is broken. As so often it is a combination of things. Hope this helps some of you if you expreicne similar