https://community.usa.canon.com/t5/EF-RF-Lenses/Lens-cap-help-please/m-p/72934#M16865 <P>100-400 is 77mm and 18-135 is 67mm. They're the same with filter size. You can get the knock off pinch cap from ebay for $5 each.</P> Wed, 05 Mar 2014 16:28:48 GMT hsbn 2014-03-05T16:28:48Z https://community.usa.canon.com/t5/EF-RF-Lenses/Lens-cap-help-please/m-p/72930#M16864 <P>I lost my lens to my 100-400mm on a trip and I am in need of a new one. What size lens cap fits this lens? Also, what size lens cap fits the 18-135mm?</P> Wed, 05 Mar 2014 16:21:13 GMT https://community.usa.canon.com/t5/EF-RF-Lenses/Lens-cap-help-please/m-p/72930#M16864 Jbcarrere 2014-03-05T16:21:13Z https://community.usa.canon.com/t5/EF-RF-Lenses/Lens-cap-help-please/m-p/72934#M16865 <P>100-400 is 77mm and 18-135 is 67mm. They're the same with filter size. You can get the knock off pinch cap from ebay for $5 each.</P> Wed, 05 Mar 2014 16:28:48 GMT https://community.usa.canon.com/t5/EF-RF-Lenses/Lens-cap-help-please/m-p/72934#M16865 hsbn 2014-03-05T16:28:48Z https://community.usa.canon.com/t5/EF-RF-Lenses/Lens-cap-help-please/m-p/72938#M16866 <P>THANK YOU SO MUCH!</P> Wed, 05 Mar 2014 16:37:45 GMT https://community.usa.canon.com/t5/EF-RF-Lenses/Lens-cap-help-please/m-p/72938#M16866 Jbcarrere 2014-03-05T16:37:45Z