Who says you can't shoot bugs with the DA35mm ltd macro?
It is just a bit more difficult! (both are shot with the DA35/2.8 ltd macro hand held on the K20D, backgrounds are my left arm and my car window
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Also, someone claimed you cannot use this lens with extension tubes because it has no aperture ring. That is only true if you buy manual tubes that lack the A connection. With tubes with KA mount the 35mm macro works very well. It even does so on film since you get rid of the bad corners.
In the long run you will want two lenses, one normal macro lens (the 35mm macro is near normal on APS-C) and one tele macro. There are many good options if you buy new mentioned in this thread. Cheap used alternatives are a Pentax 100mm/f4 1:2 macro, or the Tamron adaptall 2 SP 90/2.5 1:2 macro (gives you 1:1 with an extension tube or converter).
As someone mentioned another option if you have a good prime lens is to put tubes on it. I'd like to add that the 2xmacro converters are also a good a relatively cheap start if you put it on a prime lens that you already have.
135mm lens on a Kenko (aka Vivitar) 2xmacro converter => 270mm/f3.6 1:2.7 gives good working distance (sorry for the dust on the sensor)...now this lens is not cheap, but the macro converter does not cost that much and can be used on any other lens with good results
2xmacro converter on the cheap A50/1.7 => 100mm/f3.4 1:1, cropped a bit
Most normal macro lenses will serve as sharp but slightly slowish normal lenses as well (including the 35ltd) and many tele macros (like the 70, 90, 100, 105 options) will serve as good portrait lenses, especially those a little bit faster like the Tamron 90/2.5 or 2.8.