Olympus 17mm 2.8 "decoration ring"

There is no decorative ring for the 17mm f2.8. (At least mine doesn't have one).

My lens has a blue line instead of a blue front "nose" as seen in your photo.

You can google on how other 17mm look and i would recommend you following up with the shop / person you bought this lens from.

Cheers.

 

I may be wrong here, as I do not own this lens.

But it appears that this is a part that's not actually supposed to come off (unlike the "decoration" rings on the 45, which conceal the hood bayonet mount and are designed to come off and be put back on). As far as I can tell, on this lens, the only option for mounting a hood would be to screw it onto the filter thread, therefore there's no reason why that ring should ever come off.

It looks like the part you're missing snapped off (ie: it's not meant to come off...ever), and thus you'd likely have to contact Olympus about a replacement part, as it wouldn't be a readily available part.

 

I hate the blue rings as well! Ironically enough, the ring is missing BECAUSE of the blue haha, they could have made it all one piece, had they not try to spice things up with that silly blue ring...if you're feeling adventurous, you could always try painting it semi-gloss or matte black or silver to match the rest of the lens.  

 

That lens looks like it took quite a beating. Do those scratches on the coating show up in the images?