I recently acquired a Zuiko 50mm f/1.4 multicoated lens after I noticed that scans of negatives from my Zuiko 50mm f/1.4 single coated lens seemed on the soft side, especially wide open or near wide open. Since I had gotten the new lens, plus also having gotten an Epson 4490 scanner recently and a Bogen 055xb tripod and 486rc2 ball head I decided to do a comparison between my 50mm lenses. I tested my new (to me) Zuiko 50mm f/1.4 multicoated lens (SN 1,050,xxx) and single coated silver nose lens (SN 6xx,xxx) as well as my 50mm f/1.8 made in Japan (mij) and my 50mm f/1.8 single coated silver nose lens. Some day I want to get and test a 50mm f/1.4 1.1m+ SN lens (supposedly the best of the 50/1.4s), a 50/1.2 and a 55/1.2.
The test involved mounting an OM-1n to my tripod with the mirror locked up using a cable release. The film used was Fuji Superia 400 (happened to be in the camera, I probably should have used Reala for finer grain and more resolution). I used a bookshelf in my basement as the test target. I focused on the book “Five little Monkeys sitting in a tree”. I did exposures wide open, f/2.8, f/5.6 and f/8 for each lens to avoid reciprocity issues as the basement isn’t the brightest ever and I didn’t want to use natural light or flash. In truth it might have been a bit more telling to have done it wide open, f/2, f/2.8, f/5.6 and f/11, but could have would have should have. Film isn’t free and my time isn’t unlimited. The scans were done on an Epson 4490 at 3200dpi and processed in Adobe Elements with no noise reduction or USM applied.
The samples are below (click on the image for the full size version). In each set the lenses used were Zuiko 50mm f/1.4 mc, Zuiko 50mm f/1.4 sc, Zuiko 50mm f/1.8 mij, Zuiko 50mm f/1.8 sc in that order from left to right.
Wide open (f/1.4 lens at f/1.4 and f/1.8 lenses at f/1.8 )
@ f/5.6, there appears to be a defect from the ICE dust removal on both of the single coated images at f/5.6 for some reason (you can see it in the red book). They really are from different lenses/negatives despite the similiarity in the defect and location.
My opinion: Wide open the f/1.8 lenses are better then the f/1.4 lens, though they also aren’t at as wide an aperature. The 50/1.4 mc appears a fair amount better then the 50/1.4 sc. The 50/1.8 mij is also noticable sharper then the 50/1.8 sc. Both of the 50/1.4s are soft wide open at larger enlargements (5×7 if you look close, 8×10 without looking to close the 50/1.4 mc being noticably better). At f/2.8 the 50/1.4 mc sharpens up a lot and reaches pretty much parity with the 50/1.8 mij. The 50/1.8 sc is the next sharpest in 3rd place and the 50/1.4 sc rounds out last place. At f/5.6 and f/8 the two multicoated lens are about as sharp as each other still and are a bit sharper then at f/2.8 and from f/5.6-f/8 get just a hair sharper. At these aperatures the 50mm f/1.4 sc and 50mm f/1.8 sc lenses are quite a bit sharper then at f/2.8, but if you look closely they still just aren’t quite as sharp as the multicoated lenses. There is little to chose between the two single coated lenses at these aperatures, they are about as sharp as each other from f/5.6 on.
So the results aren’t to suprising, at least to my thinking with revisions over the years to the lens design resulted in the later versions of the lens being sharper then earlier versions. The 50/1.4 mc reaches parity with the 50/1.8 mij at much wider aperatures then the single coated lenses do with each other. Something else to keep in mind with these images, 3200dpi is a bit beyond what the Epson 4490 can really handle comfortably, better then 2400dpi though. A Nikon Coolscan, drum scan or good optical printing (basically a better scanner) would likely show at least a bit better sharpness/real resolution at 3200dpi. The Epson 4490 can still manage a scan good enough for an 8×10.
My final thoughts are that the 50/1.4 mc is a good lens, if softish wide open and deffinitely better then the 50/1.4 single coated lens. If you need the aperature great, but otherwise a 50mm f/1.8 mij will do just as good a job (of course having done f/2 would show the absolute truth) at the same aperatures that it can achieve for a slightly smaller size and weight. Of course a 50/1.4 isn’t really a size or weight inconvenience. I look forward to some day having a chance to compare a 50mm f/1.4 1.1m+ SN, a 55/1.2 and 50/1.2 to the other lenses.