It is not so difficult to say what the best portrait lens is. You want a medium telephoto lens from 85 mm through 105mm and 135mm. You pick the widest aperture you can afford and that may mean 85/1.2 at great expense. The background could be so well blurred that you do not need a studio back drop. My favourite is of course the 180/2.8.
with 180/2.8 Taken in France.
© Am Ang Zhang 2005
Now, when it comes to landscape, I am going to go against the grain (in true Cockroach Catcher style) and suggest something different.
So you are not recommending the 18 mm superwide then.
What? That is a telephoto lens! I thought that should be for birds and safari.
May well be.
But because of the better resolution, you have situations where you can make use of it.
But such a narrow angle of view?
Ah! But you can take a number of photos and stitch them together. You can use either Photoshop or there are free softwares including one from Microsoft that can be used for panoramic merging.
Here are 4 photos I took on my recent cruise. We reached Panama at dawn.
Four straight shots with 250mm lens © Am Ang Zhang 2011
Oooops here is a nice boat © Am Ang Zhang 2011
Put them through Photoshop© Am Ang Zhang 2011
Move the boat up© Am Ang Zhang 2011
Some minor photoshopping
Panama © Am Ang Zhang 2011