| Other possible advantages of the 55-300...
The key advantage of the 55-300 will be that it truly maintains 300mm F/L all the way down to the minimum focus distance whereas the 18-250 is closer to 100mm at the close end. So if you're shooting bugs and you want to keep your distance, the 55-300 will be significantly better (the 50-200 will be significantly better as well in this regard.)
I've also heard the AF speed of the 18-250 is slow. It might be (I don't know) that the 55-300 focuses faster if only because it probably has a simpler focuser which moves less glass when focusing.
Having fewer elements means the 55-300 might be a tad brighter and will have more dynamic range (less scattering between bright and dark areas of the image). And the 55-300 will have a hood that blocks flare better.
Robustness might be another thing. The 18-250 is very complex, perhaps over time it loses some IQ due to gradual misalignment of components. The simpler 55-300 design might be more robust over time.
Yet another consideration is bokah. Have no idea how they might compare here.
Of course none of this would explain anything about price--just considerations on choosing one or the other.
Bart |