Deciding on a mid range zoom for the Fuji s5 is not an easy task, not because there is a lack of good lenses to choose from.
The problem for me was to choose the right lens that would compliment my future lens choices and to obtain a "seamless" focal range from wide angle to telephoto for the camera. Cost and image quality were both considered.
Can "one" have his cake, and eat it too?
My goal for the camera is to end up with a focal range of 28mm to around 400mm equivalent, when compared to a 35mm film camera.
As the s5 uses the Nikon F-mount there are many great Nikor lenses to choose from.
The Fuji also uses a sub 35mm APS-C sized photo sensor and runs at a crop factor of 1.5X.
So a lens marked as a 100mm is the equivalent of a 150mm, when mounted to the s5.
Third party lenses are also an option with very capable lenses being produced by companies such as Sigma, Tamron, Tokina and a few offerings from noted glass manufacturer Zeiss.
I could have made the process even easier by choosing one of the "super zoom" lenses that would give me the focal range of 18-200mm, 18-250mm or 18-270mm all in one piece of glass. These I view as a bit of a compromise as far as image quality goes so I figured that I would look for one lens that would offer 18-55mm or 18-70mm and then cover the higher range in the telephoto capabilities with a dedicated telephoto zoom lens.
My initial choice for my mid range zoom lens was the Nikon 18-70mm f/3.5-4.5 DX ED G IF, and this is a good lens, But I thought that the lens was a bit slow on the wide end of the zoom with an open aperture of only f/3.5.
I looked at the 18-55mm lenses but they would not offer me the ability of obtaining a telephoto zoom lens that would cover the 55-300mm range that I would need for the price that I was willing to spend on the combination.
The Sigma 17-70mm f/2.8-4.5 DC HSM checks all of the boxes on my "wish list". Offering a fairly quick f/2.8 at 17mm, the lens is a bit faster than the Nikon lens. Although the lens is not offered with image stabilization, I feel that this feature is not really needed on a lens of this type.
The lens is also advertised as a macro lens and although this label is a bit misleading, this lens will focus very close and the results are in fact, quite "macro like".
I have been very impressed with the Sigma. Image quality is great, with little distortion and very sharp in detail. The lens is well built and the focus is very quiet, quick and accurate.
This is the lens that will probably be hanging on the front end of my Fuji s5 most of the time, as it is both capable and covers the most common focal ranges that I tend to use on a day to day basis.