j'ai pensé que ça pourrait en intéresser au moins deux...

Sigma has confirmed that there is an incompatibility issue between its HSM equipped lenses and the new Nikon D200. Specifically the HSM lenses do not operate when the 'AF-ON' button is pressed on the rear of the camera. This does not affect auto-focus carried out using the shutter release button (half-press). Sigma has stated that this is due to a firmware bug in the lens itself and will soon be introducing a free of charge firmware update for affected lenses.

Press Release:

Notice to end users of Sigma’s HSM equipped lenses with
the Nikon D200 Camera

To our valued customers,

Sigma HSM equipped lenses do not operate when the "AF operation button" on the back of the body of Nikon "D200" digital SLR camera (recently introduced to the market by Nikon) is used. We have determined that this problem is caused by a firmware "bug" in our HSM equipped lenses.

We deeply regret any inconvenience this may cause our customers who own D200 cameras and we are committed to correcting this situation. We will start updating the firmware of these lenses free of charge in the near future.

Please contact your nearest authorized Sigma Service Center for further information

Please also note that if the camera’s shutter button is used for AF operation of HSM equipped lenses, such camera and lens combination functions normally.

This problem occurs with HSM equipped lenses only. Non-HSM models of Sigma lenses function properly with the D200 camera.

Following is a list of HSM equipped lenses which would require an update for the D200 camera:

Fixed Focal Length Lenses
14mm F2.8 EX ASPHERICAL HSM
30mm F1.4 EX DC HSM
APO MACRO 150mm F2.8 EX DG HSM
APO MACRO 180mm F3.5 EX HSM / APO MACRO 180mm F3.5 EX DG HSM
APO 300mm F2.8 EX HSM / APO 300mm F2.8 EX DG HSM
APO 500mm F4.5 EX HSM / APO 500mm F4.5 EX DG HSM
APO 800mm F5.6 EX HSM / APO 800mm F5.6 EX DG HSM
APO 800mm F5.6 EX HSM / APO 800mm F5.6 EX DG HSM

Zoom Lenses
10-20mm F4-5.6 EX DC HSM
12-24mm F4.5-5.6 EX DG ASPHERICAL HSM
17-35mm F2.8-4 EX DG ASPHERICAL HSM
APO 50-500mm F 4-6.3 EX HSM / APO 50-500mm F 4-6.3 EX DG HSM
APO 70-200mm F 2.8 EX HSM / APO 70-200mm F 2.8 EX DG HSM
APO 100-300mm F4 EX HSM / APO 100-300mm F 4 EX DG HSM
APO 120-300mm F 2.8 EX HSM / APO 120-300mm F 2.8 EX DG HSM
APO 300-800mm F 5.6 EX HSM / APO 300-800mm F 5.6 EX DG HSM

merci tchou, j'ai vu...
bon c'est pas grave je n'utilise pas cette fonction, je n'enverrais pas mon objectif au sav pour ça.

J'ai un 70-300, donc j'échappe à quelque chose que je n'ai pas compris.
Ouf ! Bienheureux les simples d'esprits.