Just Swipe from Right to left on lock screen and you will launch the camera and it is really quick!
Now, coming to why Microsoft needs to bring this to Lumia 530 and Lumia 630 . As you know, new breed of low-end Windows Phone devices or for that matter even some high-end devices like HTC One for Windows are increasingly dropping the dedicated camera button. Now, the fastest way of launching camera on these devices is to swipe down from lock screen and then tap on camera icon, if it is one of the quick-launch buttons in the action center. This is certainly not the best way to do it, neither intuitive nor fast.
So, perhaps there are two ways in which Microsoft can take care of this issue on Windows Phone devices without camera button,
either, implement it like what we just saw on Nokia X2. Lock screen—->swipe,
or, may be a small camera launch Live Tile at the bottom of the Lock Screen.
We have already expressed our disliking of the lack of camera button on Lumia 630 and trust us implementing any of these two methods will make it much better for users.