I'm told that the BIGMA lenses don't autofocus on teleconverters - at least the Nikon mount versions don't. I only have an ancient fully manual TC, so when I put my BIMGA on it I lose any aperture control, since the BIMGA has no manual aperture ring. Of course, with a TC, I'd probably want to shoot wide open anyway. I never even try it - I just use the lens alone and then crop the shot. Also, they are sharpest at 400mm but acceptably sharp at 500. ________________________________ From: Larry Pace <larrypace64@xxxxxxxxx> To: "missbirdphotos@xxxxxxxxxxxxx" <missbirdphotos@xxxxxxxxxxxxx> Sent: Thursday, March 8, 2012 8:49 AM Subject: [missbirdphotos] Re: Birding on Saturday Several of you have mentioned the Bigma. What are your thoughts on pros and cons for this lens. I think part of my problems have to do with lack of reach with the 100-400. particularly on the smallest subjects. I have to crop way too much. I am aware that most problems related to quality photos are related to poor technique but equipment does matter especially in NATURE photography. Does the Bigma allow autofocus when using tele-converters? Larry ________________________________ From: Frank Hensley <dr_frank_hensley@xxxxxxxxx> To: "missbirdphotos@xxxxxxxxxxxxx" <missbirdphotos@xxxxxxxxxxxxx> Sent: Thursday, March 8, 2012 6:49 AM Subject: [missbirdphotos] Re: Birding on Saturday I plan to go! First day of Spring Break so I asked for time off at home. Look for a tall guy with a gray goatee and a BIGMA. ________________________________ From: "Dance, Gayla" <dancegf@xxxxxxxxxxxx> To: "missbirdphotos@xxxxxxxxxxxxx" <missbirdphotos@xxxxxxxxxxxxx> Sent: Thursday, March 8, 2012 6:22 AM Subject: [missbirdphotos] Birding on Saturday I believe there is a birding event on Sat. near Turcotte Labs and Highway 43. Weather permitting, I wondered if any of the MissBird Photographers were planning on attending. gayla