Dear Friends,  My Nikon digital SLR has a 1.5 "crop" or in other words, a 30mm lens will read about like a 45mm on the camera.  This is due to the "crop factor" of the camera.   We go by film camera "mm" of focus but the digital works according to the sensor size.  

I want a good prime lens of about 50mm.  It seems one way to do that is get a prime lens of about 30mm, giving an "effective" focal of 45mm.     Seems sensible as to fl...but , do I inherit with this sort of choice all the problems sometimes associated with a wider angle lens?   Will this be an "efffective 45mm" that behaves like a 30mm?

The above example is just from a random look at lenses available.  Sigma has a new 30mm f/1.4 I saw and use this as an example lens to get effective fl of close to 50mm. Am I barking up the wrong tree or going down the wrong rabbit trail in this thinking?

Any input will be greatly appreciated.           TomDart.