The Olympus Zuiko 100mm f/2.8 lens is cosmetically almost identical to the Zuiko 85mm f/2. The front lens element is a hair smaller and of course the labeling of the lens is different, but the focus grip, lens barrel length and diameter as well as filter ring are all the same size. The 100/2.8 is also just a few grams lighter. The lens measures 48mm in length and 60mm in diameter and tips the scales at 230g. The lens uses the Zuiko standard of 49mm filters, has a 6 bladed aperture and is 5 elements in 5 groups. The lens has a minimum focal distance of 1m and an aperture range of f/2.8 to f/22.
There are 4 “versions” of the lens, all optically identical as near as I have been able to find out. The first is single coated, has a silver filter ring and is labeled “E. Zuiko” Serial number 100,000-~140,000. The next is single coated, has a black filter ring and is labeled “E. Zuiko” Serial number ~140,000-~180,000. The multicoated lenses are marked “MC Zuiko) with serial number ~180,000-190,000. Finally the last series were mulitcoated with Zuikos “NMC”* coating and are labeled just “Zuiko” with serial numbers greater than 190,000. The serial number ranges are approximate as I used a listing of about 40 Zuiko 100mm f/2.8 lenses on Ebay and their various pictures to come up with the ranges.
*NMC coating apparently is listed in several Zuiko lens brochures and appears to simply be a better multicoating than the “earlier” multicoatings in use on the MC marked lenses and some of the high-end Zuiko lenses (such as the 35/2 and 28/2) which appear to be multicoated from early on, but are not marked as it or have a silver ring, but are obviously multicoated. Most/all late versions of Zuiko lenses marked only “Zuiko” appear to have this coating. Cosmetically it is basically identical to MC marked lenses’ coating.
The lens I have is a very sharp, even wide open and is of the later “Zuiko” multicoated variety. I haven’t been able to use the lens too extensively yet, but the use I have gotten in shows the lens to be small, smooth and sharp. As you’ll see from the test results below, the lens is very sharp, even on an E-PL1 where the defects would be magnified it is very sharp. The corners on a 4/3rds are a little soft wide open (I’d give them a B), but sharpen up immediately on stepping down. On 35mm film, granting not using the best scanner ever, things are very good even out in the corners at 100% and f/2.8 and don’t get noticeably better on stopping down. Note with the test shots below, the f/11 image was shot at around 5 seconds exposure time because of the dim room, so it was mental timing and an attempt to compensate for mild reciprocity failure without the cheat sheet, so the contrast/exposure is slightly different. Don’t read anything in to that when it comes to f/11 and contrast.
Here is a lens test on my wife’s E-PL1 (200mm EFL), tripod mounted and 2 second shutter delay.
Here are the test results of the lens mounted on my OM-1 on a tripod and mirror lockup.
left of center
Upper right corner
I’ll have more real world samples up soon, I just have to finish scanning my pictures from my backpacking trip. Till then, here is one sample (click for full size 600×400).