Canon focus problem

[Sparts99]

I hope someone can help with this. I have a Canon 300D which has performed 100% reliably over the years. Recently I bought a 2nd hand Sigma 28 - 300 and experienced no problems other than a few instances of the lens hunting for focus when the battery was running down. Yesterday the autofocus failed, the lens would hunt from one end to the other, then settle at a point just out of focus (I only use the centre point). I changed over to both a Canon lens and a Tokina, they now exhibit the same problem, any suggestions ? I have heard that there are software issues with newer Canon fit lenses on old bodies, could the newer lens have affected the body in some way ?

[awacsfan]

Hmmm... hard to tell but does the camera display any error code such as the all familiar and often dread "Error 99"? It most certainly sounds like the AF system is not working properly. Have you tried using other AF setting than just the centre point only? Are the batteries fully charged? Just some ideas that might or might not work. If you have a photographer friend who also uses Canon nearby, try your lenses on his/her camera to see if the results are similar or not. This could narrow it down to either the lense or the body. Do you have the latest firmware on your camera?
Good luck

Andy

[Sparts99]

Thanks for the reply. I am going to check my lenses with another Canon body, hopefully tomorrow, and yes I tried with fully charged batteries. What is the dreaded Error 99 ? I've tried changing the AF points but that has no effect, firmware is 1.1.1 which I assume isn't the latest, how do I download and/or install firmware ?

[The Phantom]

Thanks for the reply. I am going to check my lenses with another Canon body, hopefully tomorrow, and yes I tried with fully charged batteries. What is the dreaded Error 99 ? I've tried changing the AF points but that has no effect, firmware is 1.1.1 which I assume isn't the latest, how do I download and/or install firmware ?

You'll know the dreaded "Error 99" when it happens! It locks the camera up and displays a message on the screen - and it makes you shout very loudly!

[Wallace]

This is the best place to start downloading Canon software
http://www.usa.canon.com/consumer/contr ... adIndexAct" onclick="window.open(this.href);return false;

For some reason the USA site always works better than the UK site.

[Richard B]

Try cleaning the contacts on the Lens and the Camerea, it does look like the 2nd hand sigma may have had some dirty contacts and this as rubbed off too the body for it to also effect your other lens. give them a clean and polish.

[Sparts99]

Thanks everyone, I've fixed it now. I did suspect the Sigma of being the cause but that was a red herring. I trawled the web and found a site where a very similar fault was described due to the secondary mirror sticking. I lifted the main mirror and the secondary was visible, so I errr.... wiggled it a bit and now all is good but it does suggest to me that the camera is getting past it. Anyone got a 450D they want to sell, 20D maybe ?

[Richard B]

Good to know you have for the time being sorted the problem. and a nice new soloution learnt. that could help others in the future.

[Sparts99]

Well I had to get a result. Hopefully I'll be able to get (up) into a very good position for the Spitfire & Typhoon flypast over London next week (see the NOTAMS thread), if I do and get any good shots I'll post them up.

[aviationandy]

Theres a 20D in the for sale section...

[tinmansr22]

Hi have the same problem with my Canon 17-85mm lense was told some sensor in the lense has gone cost around £80-90 to fix, so i just switched it over to Manual focus and the results are better, will get it done when I can afford to