Has anyone compared Chinese objectives to similar objectives from the Big Four?

[Scoper]

Has anyone one done side by side comparisons of Zeiss/Leitz/Nikon/Olympus objectives versus the Chinese offerings of today (both 160mm and infinity)?

If so, where would those comparisons be to be viewed?

Thanks

[Phill Brown]

More than anything if the slide clamp is up to holding a slide and the plastic mechanical parts hold up.
There's the yellow and blue fringing from the pretend Kohler and LED to deal with.
The objective can only do so much.

[apochronaut]

I don't think anyone has done any extensive 1 on 1 comparisons. Cheaper Chinese made objectives suffer from a lack of precision in the barrels, so parcentering can be poor. This leads to frustration in use and uneven optical performance between examples. Quality control in production is going to be lower for more basic objectives due to the low selling price and better as the price of the objective goes up.
I obtained several examples of a 40X .75N.A. inf. PlanF 180mm design from both China and India several years ago and tested them against each other and a Reichert 40X .70 Planfluor of known performance levels. These were higher end objectives which retail for around the 300.00 mark, which is still very inexpensive for what they are. The Reichert, were it made today would be in excess of 2,000.00 retail.
I ended up with 3 different designs ; one made in China and 2 made in India but all originating from the same source. Parcentering and parfocal distance were o.k. but using the Reichert nosepiece with 6 objectives in it as a bench mark, none were as accurate as the Reicherts, which were factory centered.

Using an Olympus type optical system, the 3 performed optically o.k. as well. In descending order of preference and why. This is all from memory.
1) Reichert 40X .70 planfluor. Almost planapo colour correction performance with more working distance. Perfect planarity with high resolution.Very centered. High contrast. grade out of 100 : 100
2) India made. Noticeably better colour correction than a 40X .65 planachro, with typical fluorite characteristics.Tighter working distance than the Reichert. Excellent planarity with slightly lower resolution than the above. Finish of barrels a little rough but engraved. Slightly lower contrast than the benchmark. 3 examples tested. I had to reshim the second lens cell of one in order to improve it's spherical aberration level up to the other 2.grade out of 100 : 92
3) China made. Slightly poorer colour correction than #2. Similar working distance. Planarity good. Resolution a little lower yet but still better than a 40X .65 planachro.Barrel nicely finished and polished but painted instead of engraved. Similar contrast to #2. one example tested. grade out of 100 : 87
4) " New" India production. These were about the same as the original India production with just very slightly poorer colour correction and resolution when viewing cellular inclusions in B.F. The colour correction is somewhere between an achromat and what I would expect of a fluorite. Working distance a bit longer than above. Planarity good. Barrel a bit rough with lighter, cheaper engraving. Similar contrast level to # 2 and 3. 3 examples tested. grade out of 100 : 85

I also included a Reichert 40X .66 planachro in the comparison as a low bench mark and a good tested generic Chinese 180mm 40X .65 planachro . They would score about 82 and 75 repectively,

[Scarodactyl]

Not nearly as relevant as Apo's, but I've done a few head to heads between Mitutoyo objectives and Chinese clones. Mitutoyo isn't one of the traditional big four but they're the big dog in their niche of long working distsnce metallurgical objectives (to the point Nikon has copied their standard for their own engineering objectives and Leica has offered adapters to use them on their macroscopes). The Chinese objectives vary from almost equivalent to much inferior, particularly on field coverage and especially color correction in higher mag objectives. Some excellent stuff is being made in China though and getting better.