Last two lenses/objectives Filip has sent me for MTF testing are Nikon Plan 10x 0.30 160/0.17 and Reichert aus Austria 10x 0.25 160/-. In order to get the absolute feeling of their performance I decided to test them side by side to currently my only 10x objective, infinite Nikon Plan 10x 0.30 oo/0.
Two finite objectives were extended on plain tubes for exact 10x magnification. Shorter tubes were tried for lower magnification/higher resolution but the edge performance suffered considerably along with pronounced vignetting. My infinite Nikon objective was stacked to Nikkor 200mm f4 AiS stopped down to f/5.6. This tube lens is not the best I own overall but somehow it gets the best out of this objective.
For starters let me mention slim Reichert objective. Simply put, this vintage piece of optics performs at level not worth mentioning. I've seen cheap Chinese 10x objectives performing better than this so European quality & performance is not always a universal rule
On the other hand, Nikon objectives performed much better, except for one well known drawback of excessive CA. Although I usually suggest CA is easy to treat contrary to lack of resolution, when over certain amount blue and red tinted object edges are simply uncurable. This was true for both Nikon objectives, more so for the newer infinity model. This one had equal edge to edge resolution with just slightly curved focusing plane. Filip's finite variety had worse edge resolution but higher center resolution which is more important. One peculiar thing about this lens (generally rarely seen) is reversely (outwards) curved focusing plane. Curvature is mild (those are both „plan“ objectives) and no big deal anyway since we are always stacking at this magnification level.
This test concluded this series of lens testing and now I announce short brake for my free lens testing service offer. This is because my own lens/objective newcommers have piled up in the last couple of months (18 of them and couple more on the way), waiting for MTF testing. I have a strong feeling some of those might provide pleasant surprise. Test results will follow....