Clarification and Correction
You're most welcome.
Just to clarify, some of the numbers I wrote were for Canon APS-C DSLR only. Sony and Nikon APS-C DSLR sensors are a little bit larger than Canon's, so the "crop factor" is different. On a Sony and Nikon, an 18-55mm lens has an equivalent size of 27-82.5mm, and an 18-135mm lens has an equivalent size of 27-202.5mm.