Maximum Extension: Schneider Kreuznach APO Componon 40/2.8 Hm

I was under the impression that you can't disable automatic updates anymore in Windows 10, unless you have some professional or enterprise edition (or something like that).

At least the anniversary update will give us something: bash and Ubuntu binary support, which could be interesting. Maybe gcc will work, which will give us an alternative to Visual Studio (which is actually pretty good nowadays, in terms of C++11/14/17 support).

Ahh, only version I've used is Enterprise or Professional version at work, which I have turned updates off. I don't know why my IT guy doesn't do this, as it breaks my laptop every time an update happens. Maybe he allows it for job security. I did not know that the home version kept you from turning off updates. I still have WinXP on all my computers except for one, which I keep current for compatibility purposes.

austrokiwi schneider kreuzach APO-Componon HM MC 4,0/45mm I mounted this lens on a nikon PB-6 bellows . I lengthen the bellows to maximum lenght. the lens is of course reversed. the camera is a sony A7R mark II. here is my images this lens preforms very well. the full image an crop no editing

Its possible that the Nikon objective labelled "MUE10100 LU Plan Fluor Epi OFN25 10X/0.30 A oo/0 WD 17.5" might slightly outresolve the Mitutoyo M Plan APO (378-803-3, new version) at the center. It's hard to be sure due to the limitations of my tests:

- I used a 2X teleconverter to magnify the image from the objectives, and not another microscope objective (4X might be good here).

- Apparent chromatic aberration? from the all the objectives other than the Mitutoyo made if hard to tell where the best focus really was. So, I did a stack with 1um increments around the apparent best focus point and let Zerene Stacker PMAX mode pick the image with most luminance? contrast.

- The AF test chart I used only goes down to element 9-3 (645 Line pairs per millimeter), and this is not really small enough to test 10x objectives. All objectives could outresolve the test chart, even the cheapest ones.

Anyway, it looked like the Nikon might possible outresolve the Mitutoyo, but it's not clear. I suppose, to eliminate the effects of chromatic aberration, it might be best to do tests like these using a narrowband filter (O-III, for example). That way, you'd be measuring the resolution with a known wavelength. With my Jansjo white light source, it's possible that I'm comparing the Mitutoyo using some weighted average of wavelengths, against the Nikon using subset of these wavelengths (the best Nikon images selected by Zerene Stacker are red/purple, not the dark gray of the Mitutoyo images).

Note: I compared only my infinity-corrected objectives using a Thorlabs 200mm ITL200 tube lens, and a Canon T6s using a Canon EF 2x teleconverter. These include the two good ones already mentioned, plus a bunch of cheaper Nikon ones that are highly regarded over at PhotoMacrography.net.

Overall, I'd say the Mitutoyo was the best, given its good working distance, and low CA, even though it doesn't clearly outresolve the Nikon.

Edited to add a list of the ones I compared:

Mitutoyo 378-803-3 ---- M Plan APO f=200 10X/0.28 oo/0

Nikon MUE10100 ---- LU Plan Fluor Epi OFN25 10X/0.30 A oo/0 WD 17.5

Nikon MRL00102 ---- Plan 0X/0.25 oo/- WD 10.5

Nikon MRP70105 ---- MTB C20 Plan 10X/0.25 oo/- WD 7.0

Nikon MRP70100 ---- MTB CFI E Plan Achromat OFN20 0X/0.25 oo/- WD 7.0

Nikon MRN70100 ---- BE Plan OFN18 10X/0.25 oo/- WD 6.7

In the next few days, I'll test the Mitutoyo again against the Nikons. To get the APSC corners, I won't use the teleconverter, so unless there is a big difference in sharpness, it'll be hard to draw any conclusions (because the camera pixels and AA filter get in the way).

To eliminate problems with CA (we already know that the Mituoyo is way better than any of the Nikons), I'll probably shoot through a green filter. This means I won't have to let Zerene Stacker pick the sharpest frame. Since I can't do live wiew focusing at the corners, I'll still have to take a bunch of pics, and then pick the sharpest one after they've been uploaded.

Note: the image circle required to cover the T6s sensor is 26.8mm, which exceeds the image circle of all the Nikons (18mm, 20mm, or 25mm). I don't know what the field number is for the Mitutoyo. However, 26.8mm also exceeds the 25mm "diffraction-limited" image circle for the Thorlabs ITL200 tube lens. I suppose a full-frame 200mm camera lens would get around this problem, but there's the problem of mounting it solidly enough to eliminate vibration
problems.

What method, other than doing a 3D shot with Helicon Focus, is good for measuring field curvature? It needs to correct for non-flatness of the AF test target (assuming the target is not optically flat), and also for any tilt of the target (I doubt that my setup is exactly level down to the micron level).

Please elaborate. How is that distance going to indicate curvature? How accurately do you have to measure that distance?




At high magnification how do you know which is the highest corner and which is the lowest corner? To my old eyes I just see that part of the image is out of focus I can't tell if it is high or low( at high magnification)


I understand the need for a flat field lens. The 10X microscope objective that I use is a shocker... it takes well over 150 shots to create a sharp stacked image. The SK this thread is about takes only 50-60 shots. (Note this relates to a 14th century coin. A US cent, being a much more 2 dimensional design, would need considerably less shots)

I find I can assess field curvature using focus peaking. It isn't accurate but it assists as I can actually see the shape of the area in focus and by moving the focus I can observe how it shifts on the subject. Edit: this is the only way my old eyes can tell if part of the subject is high or low.

Sounds like the LU Plan Fluor has a very flat field. My experiments showed that my best 3 objectives were within ~13um (2x 6.5um steps).

I think the working distance for the Mitutoyo M Plan APO 10X/0.28 is supposed to be 33.5 mm.

How does this method of testing field curvature distinguish between tilting of the top surface of the test target and actual field curvature (and any increased aberrations away from the center)?