This camera is available either with a (stock) starter lens, or just as the camera body. Initially I thought I'd buy the camera with the inexpensive starter lens and decide what lens I really wanted after playing with the camera for a bit. I quickly realized that wasn't the right answer for me - so I bought the camera body along with not one, but two lenses.
Part of my initial thought was driven by looking at the price of Canon lenses. Luckily I work with two folks who have been into photography for years and years and years; both of them have 35mm cameras with lots of lenses. They both recommended lenses from Sigma and Tamron as good quality with both manufacturers having some reasonably priced options (in addition to their top end choices).
Once I mentally made the leap to looking at lenses in addition to the camera, I knew that I wanted a decent zoom lens - one that I am capable of using without a tripod. And I knew that I wanted to be able to take close-up shots too - mainly of plants & flowers.
Starting with the zoom
A little background Because of the smaller size of the sensor in a digital SLR as compared to 35mm film, a focal length modifier of 1.5 is used to identify the equivlent lenses on a digital SLR and a 35mm SLR. That is, a 200mm lens on a digital SLR is the equivalent of 200 * 1.5, or a 300mm lens on a 35mm camera. The sales rep at the camera store treated me to this explanation, and I later found an explanation along with supporting photographs at http://www.dpreview.com/learn//key=focal+length+multiplier
I played with two Sigma lenses, both of which were designed for use with digital cameras.
A lens that was designed for a 35mm camera can be used on a digital camera, but the reverse is not true; a lens designed for use on a digital camera can only be used on a digital camera.I started with the longer of the two, the 18-200mm F3.5-6.3 DC. This lens has a zoom ratio of 11:1. That would be nice, but I was unable to hold the camera steady with the lens fully extended. I would have needed to carry and use a tripod with this lens, so I quickly ruled it out. The other lens I tried was the 18-125mm F3.5-5.6 DC. This lens has a zoom ratio of 6.9:1, still not bad from a zoom standpoint - especially considering that my S400 has only a 3x zoom. And, most important, I was able to take pictures with the lens fully 'zoomed' with no shake. Another option would have been to go with a lens with built-in image stabilization - but remember, I was trying to keep my purchase within a somewhat reasonable price range. (OK, OK, buying a digital SLR and two lenses really doesn't fall within reasonable, but still )
First lens decision made: the Sigma 18-125mm F3.5-5.6 DC was my choice for my everyday lens. Using the focal length modifier, that's the equivalent of a 187mm lens, not a bad zoom.
On to the macro lens
I really enjoy taking pictures of flowers - and not just flowers in a group, but details of the petals, or the leaves, or a bee happily feeding within a flower.
My S400 has a macro setting that supports taking pictures of objects 5cm (just under 2 inches) from the camera. The closest the zoom lens I bought can get is 1.6 feet (48 cm). That's not going to make me happy.
Since I'm likely to take both the S400 and my new camera when I'm cycling, I could use the S400 for all macro shots. But then again, I still want the abiilty to focus manually - which means I would be happier with a macro lens.
I ended up buying a Canon macro lens; that lens was very close in price to the non-Canon options for my camera, and from a quality standpoint the two lenses were equal. But this time price did come into the picture; at the time I bought my camera there was a very good Canon rebate program running. It was a little wacky in that each item covered by the macro had a rebate price associated with it. But - if you bought 2 (rebate items), the rebate for each was doubled. That made it an easy decision to go with the Canon macro lens!
