Lens won't allow me to change aperture & several other functions on camera

The flat printed cables inside the lens that connects to the aperture diaphragm unfortunately develops small cracks over the years and this causes the lens to fail.

The repair is NOT easy, you have to tear down the lens all the way to it's base components and replace the flex cable on the aperture diaphragm. The cable and the diaphragm are available online, but again it's not a simple repair and most people should not attempt it themselves.

Thomas Drayton
Owner Darntoothysam com

Check this article which will lead you through diagnosing the problem and a possible fix.

http://www.richardsnotes.org/archives/2005/04/29/50mm-lens-contact-points/

Aperture flex needs to be replaced inside of the lens. They wear out from zooming a lot. Very common problem,

I offer you to buy Canon EF 24-105mm f/4 L IS USM Lens. This gives very good performance for your studio work and specially for portre. It has Image Stabilization and Ultrasonic Motor. Other professional lens are very expensive. It has red ring.
Please check the link below.
http://www.the-digital-picture.com/Reviews/Canon-EF-24-105mm-f-4-L-IS-USM-Lens-Review.aspx

Regards

I hate to re-invent the wheel (and I don't want to cut 'n paste someone else's hard work to present as my own) so please click here for a likely practical solution which usually works and for Canon's own suggestions on the error 99 fault.

If this has assisted you then please rate my answer; if not then add a comment to provide feedback and I'll attempt to provide an alternative solution.

There are several things it could be. Send it in for service is your best bet.

You are correct in thinking that it should be possible to set the aperture wider than f/5.6 at the wide end of the zoom range.  My best guess is that the lens is defective.  I'd suggest returning it for a replacement.

Have a look here http://www.cameraspareparts.co.uk/

something sounds strange about this. aperture 00 is an invalid aperture value. stands to reason if that is the case the camera would complain about it. via error code. being that its only six mos. old i would give canon a ring.

Have you tried this same lens with other cameras? Do you have another camera body you can try? or perhaps a friend with a Canon EOS Camera? Also try the following please: Remove the lens. Look at the lens mount contacts, take a Cotton swap with some rubbing Alchol & clean the contacts very well, both on the lens and the camera body. Is your camera reading the lens aperture range correctly (at least most of the time)? Also since you replaced the PCB on the lens, isn't it under warranty? Let me know if this works. Thank you, AJ.