Lens OK when used 50-85mm, use 17-35 willl go to

Hum, error 99 eh? Canon's catch all error code, there is a ton of little entities that can cause error 99 from using third party lenses, batteries and even grips but, it all comes back to an electric contact fault. By using a good clean new pencil one with the red rubber eraser most of the error 99 problems can be quickly for lack of words erased. The most obvious problem area if you camera is not fitted with a battery grip is the lens contacts between it and the body of the camera.
Remove the lens, put the body cap on the camera when you are doing this part and while holding the lens as vertical as possible with the contacts down lightly rub the cold contacts. You can use a lens tissue and blow bulb/puffer to remove loose rubber. While you are at it clean all your lenses and put the rear lens cap on while not in use.
Okay the body, it's not as easy but doable, remove the body cap keeping the lens mount and open cavity pointing downward. Lightly rub the body contacts well but also gently, clean any rubber away from the contacts using a lens tissue. Don't use the bulb/puffer as it will blow eraser dust into the camera and possibly cause flecks of dirt to adhere to the sensor.
Once clean reinstall your lens and go do some photography.
Other things that cause this annoying error 99 are grip contacts, battery and recently I got into an error problem and my fix was updating to new camera firmware. That problem took me while on an assignment and would have been embarrassing except my back up was a "Rebel". Winding down the shoot the Rebel started with this error 99. Once back to the studio I did the updates and cleaned every lens I had. Cheers Happy New Year have fun make lots of pictures.

Hi,

Can you replicate this fault on other lenses? Is it is only on the 17-85 lens try cleaning the lens contacts with a pencil eraser and see if it helps.

error 99 may be the only error that the camera can identify with the problem. Generally this is dirty contacts in the camera and on the lens. The fix is to rub them with a pencil eraser and ensure no rubber swarf gets inside the camera. ( Hold upside down and use a blower and brush for cameras after doing it. Do the same to the lens contacts and re position turn on camera and see if it works ok now.
Please rate my help++++Thanks for using FIXYA

'Error 99' indicates some problem with the AF contacts. This is a common error in Canon lenses. It could indicate a very simple problem like dirty contacts or a much serious one like the breakage of USM cable.
As a first step, you can try cleaning the lens and body contacts (the metal contacts between the lens and body) using a pencil eraser. Be careful to hold the body facing down so that no dust falls inside. After cleaning both the lens and the body contacts, re-attach the lens and try shooting. If the AF does not work still, you need to take the lens to an authorized service center.

What wide angle lens is it need f number it may be to old to work on eos 400d

try cleaning the lens contacts of your lens and camera.

You will get that error when using some lenses other than Canon. A lot of the older Sigma lenses have that issue. Do you get this error when using newer Canon EOS lenses?

Hi all
On most lenses the way to test if your old lens works on a cannon digital to set the camera to AV then set the iris to the small setting ie F16/F22 then use the stopdown button.
Things that might happen
1 The lens will close down OK
2 The error 99 will show,will need are rechip if avaliable
3 Nothing happens, will need a rechip

Q.Why will it work inside but not outside.
A. Inside the camera needs light so the iris is full open, outside the lens needs to close down and if not compatible it is unable to close down. will need a rechip

Your camera performs a quick 'integrity' check before each shot and goes into error 99 mode if the lens in incompatible or has a diaphragm problem. ( it will also display e99 if the shutter or flash unit is not ok but this does not apply here ). This is how you can check whether the diaphragm mechanism is ok : attach lens to your old camera and set camera to AV and set F stop to 16 . open back and release shutter and look through the back to see if your lens is closing to F 16. If it is closing fine then the lens is ok but is not compatible with your D400.

Assuming that other lenses function normally on the camera, the "Err 99" can be caused by a failure of the aperture component in the lens. Error 99 is a generic error, so unfortunately it does not indicate exactly what is wrong. There are other factors that can cause the failure, but there is a good chance that the aperture is not functioning correctly. You can try cleaning the electrical contacts on the lens, if this does not work you may need to get the lens serviced. Check with Canon, or check the web for other repair service providers. David Millier Advance Camera Repair