Good fun lens

I have made close-up photos with Nikon 60mm f/2.8 and Pentax 100 f/2.8. In comparison, the Nikon 60mm has better resolution. However, I much prefer the 100mm in real life. The Pentax 100mm and other 90mm and 105mm macro lenses allow me to be much further away from the insect so that it doesn't get frightened and move away. The Pentax 100mm is small and light for a macro lens. Given the long working distance and the small lens diameter, I can actually use the built-in flash for a 1:1 macro photo, which is impossible with a 60mm or 50mm macro lens. The 100mm also makes a very decent portrait lens. However, this Pentax lens has two weaknesses. First it is not the sharpest lens I own; the Pentax 50mm f/1.4 is. Second, auto-focus is slow and unreliable, except near infinity. Manual focus is required for close-ups; but the focusing ring is slightly loose and could be more precise.

A Gem!

There are several nice things I like about this lens:

1) Maximum aperature of 2.8 means this lens is suitable for portraits where you'd like the background to be out-of-focus.

2) A focus-clamp system means you can preset the focus, say at infinity for an airshow, and shoot without worrying that your focus setting will "creep".

3) A quick-change system from auto-focus to manual focus means you can let the camera pre-focus for you, yet simply by turning the manual focus ring, you can "tweak" the focus without feeling for a switch or moving your eye from the viewfinder.

4) The 1:1 macro-focus lets you get life-size images with no filters to attach and no settings to change.

5) This lens is very compact and light-weight. It won't wear you out to carry this lens on your camera all day.

6) The images produced are Pentax-quality, tack-sharp and with plenty of contrast.

So, save your nickels and dimes, and go buy this lens. You won't regret it!