Thank you all who showed interest in my offer for free MTF testing. After doing Filip's lens selection, the next batch in row was Christian's (partial) lens collection of no less than 28 pieces. As shown before, there were all sorts and origins; from scanner lenses to enlarger, industrial and video camera lenses. More than 2400 shots were done and 80 sets of data processed and put together in one large spreadsheet. Christian started to convert data into attractive charts which he'll present here but since it requires lot of his spare time, I wanted to show a quick & dirty review of best five lenses that were heads and shoulders above all the others. I believe all five were already mentioned, discussed or reviewed here but now we got some firm MTF figures to compare to other good lenses I've tested before.
First in a testing row were scanner lenses made by Reflecta and Nikon. Lens from Reflecta 7200 scanner performed best when stacked to a tube lens so I thought two Nikon scanner lenses migh behave the same. However, their performance when stacked was terrible so I retested just extended in couple of magnification steps from 1x to 2x. The sweet spot for both was at 1.4x where CoolScan 4000/5000 lens produced one of the best figures I ever measured at that magnification along with very low CA. Smaller CoolScan III lens was equally good at center but dropped more at the edge with CA twice as high as CC4000/5000. However, total score is similar due to 75/25% weighting towards center resolution. Unfortunately, resolution drops fast when you move to both sides away from 1.4x and is not worth publishing.
Next nice surprise was Rodenstock Rodagon WA 4/40. This is version with fixed internal aperture. It was tested stacked at both 2x and 3x magnification, the later one giving just average results. At 2x Rodenstock Rodagon 4/80 was used as the tube lens, stopped down to f/4.7 sweet spot. Resolution is one of the best ever at 2x so as this lens is easy to find and get on Ebay in multiple versions, it is must have if 2x is your thing.
At this same magnification there was another lens that outshined Rodagon WA and it is vintage Schneider Kreuznach Xenon 2/35 producing 3449/2986 LW/PH and nice 0.17 CA. Measuring only 40mm dia and 29mm long, this tiny lens performed better than anything else in Christian's collection at 2x. I've stacked it to FNNL 5.3/72 (Filip's No Name Lens) for 2x and Agfa 4/107 for 3x. Exceptional performance extended actually all the way to 3x where 2954/2839 LW/PH was measured. Not the best ever but still very high and usable for 3x.
But Christian probably won't use it at 3x since he's got another miracle lens that outperformed anything else I've measured at that magnification: Schneider Kreuznach Xenoplan 1.4/23. This C-mount CCTV camera lens already mentioned on this forum as the excelent Ebay buy at $38 has fixed internal aperture at f/4. When stacked to FNNL 5.3/72 lens produces 3340/2977 LW/PH and negligible chromatic abberation. This outstanding performance made me wonder how far this performance could go so I retested using Ysaron 4.5/90 tube lens. This test returned another set of great results: 2556/2360 LW/PH. For comparison, another best seller, Lomo 3.7x when stacked gives 2136/1988 LW/PH at the same magnification, while way more expensive Nikon LU Plan 5x NA 0.15 objective short focused to 3.8x produces 2317/2276 LW/PH. At this magnification Xenoplan has much worse CA than Lomo (0.40 vs 0.06) but it's still better than Nikon at 0.64.
Since Xenoplan didn't give up at 4x, I've raised the bar to 5x using Tominon E90C 115mm as the tube lens. I expected total fail since 5x is way into objective playground. To my surprise, it kept going strong, delivering 2219/2036 LW/PH. This is 7% better at center and 3% at the edge than Nikon LU Plan 5x/0.15 objective at nominal magnification. What a performance from tiny inexpensive lens!
BTW, exactly equal data at 3x as Rodagon WA 4/40 at 2x is not a mess up, I've checked it. It's just a one in a million coincidence!
