Index: camlibs/ptp2/config.c
===================================================================
--- camlibs/ptp2/config.c	(Revision 13194)
+++ camlibs/ptp2/config.c	(Revision 13195)
@@ -3497,7 +3497,7 @@
 			gp_log (GP_LOG_DEBUG, "ptp2/canon_eos_mfdrive", "Could not parse %s", val);
 			return GP_ERROR;
 		} else {
-			xval = (-xval) | 0x8000;
+			xval |= 0x8000;
 		}
 	}
 	ret = ptp_canon_eos_drivelens (params, xval);