The system uses fairly large swatches of Velcro on the 'clip'. Even the water bottle holder has overkill in this regard. As long as you are buying an accessory bag that is appropriate for the item concerned (in this case a 1+ kg lens), there shouldn't be a problem. My experience with the Lowepro system has been extremely positive and that it would easily handle a lens of that weight. If you have any doubts, contact Lowepro directly. Their tech rep (Maury I believe) responds within 24 hours and knows their products inside and out.