It is possible to buy the adapter for...
Porthole Wide-angle in moderate Optic crystal with Flange in aluminum,complete of zoom (Sigma 10/20)
Extension ring in alluminium anodizee with controls zoom
Extension ring in alluminium anodizee of 22mm
Extension ring in alluminium anodizee of 12 mm
Porthole spherical crystal optical.
Temperate lets you put goals Wide Angle Complete with legs for easy placement is a highly valid
Porthole Cases Giosim is produced in anodized aluminum, this for better and reliable precision and quality
GIO-SIM Extension with zoom (SIM)
Porthole in aluminum anodized with anterior fillet 67 mm for objective macro 105 mm
Porthole in aluminum anodized for objective 60 macros with fillet 67 anterior for slow additional