As Pronoy rightly said, CPR is not useful for lenses with rotating focus. it can only be used for lenses which do not rotate while focusing. I have a HOYA CPR which is not that useful as all the lenses I have rotate while focusing. I will however use it future when I have such a lens. Secondly, If you are a serious photographer, you must invest in a sturdy tripod and it is a must. Don't get fooled by those cheaply made tripods. Tripods are very essential in still photography, irrespective of whether you have shaky hands or not, Tripod will save your day, especially when shooting with low shutter speeds or if you are in to low light photography. I would also recommend everyone to invest in a lens pen. It is a handy little piece which will save you from fingerprints, smudges and is very easy to carry and use. - - - Merged Post - - - Moreover, people who possess a canon DSLR with an EF mount, should have the Canon 50mm 1.8 prime lens, in their collection. You can never go wrong with this lens. It is not extremely fast at focusing, but does the job perfectly. It is very cheap and is arguably one of the sharpest lens from Canon. I bought it two years ago for approx 6500/- rupees and I never ever regretted my decision even for a moment. It will definitely be one of your best investments, especially if you are in to portrait photography.