People love fast things. Fast cars, fast guns, fast internet. When it comes to lenses, it is the fast primes that often garner attention from the slower zooms that sit on many a DSLR. Unfortunately, the 135mm f/2.8 Series-E (for a history of the Series-E lenses, see here) is not one of those lenses. Despite its fast f/2.8 aperture, good reach (200mm FOV equiv on APS-C, 270mm on m4/3), and compact size, the 135mm–and other Series-E lenses–were largely considered dinky and consumerish. Due mostly to their sub-par build quality (at the time, compared to the AI-s counterparts), they never gained popularity with the masses. Good news for you and me, most of these lenses used the same (or similar) optical formulas as the AI-s lenses, and can be had at a bargain at your favorite online auction house. For instance, this lens goes for about $90/€71, while its AI-s counterpart regularly sells for at least twice the price. Though I do not have the AI-s version (yet), I have my doubts that it is twice-as-good as the Series-E version. Time will tell.