Nikon MXA20696 long range comparison with other optics

Planapo · Posted: Wed Apr 18, 2012 2:30 am Post subject:

Craig, thanks for these comparison shots!
Unfortunately, the dropbox link yields me (just me?) an Error 404 with a nice Escher drawing, though.

Hmm... haven't there been some Apo-Gerogons Cool

for sale down the hill there, lately?! Think

--Betty

Craig Gerard · Joined: 01 May 2010 Posts: 2598 Location: Australia

Betty,

The Dropbox files are still in the process of uploading.....
*Looks like they are available now.

Craig Gerard · Joined: 01 May 2010 Posts: 2598 Location: Australia

Another installment....different weather conditions and FOV (too many cars on the road to position a tripod...safely)

This image was taken with the Mitutoyo MT-1 tube lens. I'm still coming to terms with the requirements of this lens.
I need to read the specifications information to find out just where this optic wants to be positioned in relation to the image plane. I'm currently measuring the distance at 215mm.

CA correction is respectable (worse on the foreground light pole as opposed to the distant pole), overall, slightly better than the Nikon MXA, but not as good as the Rodenstock Apo-Gerogon.
However, both of the dedicated tube lenses were designed to work in unison with a microscope objective, so I'm not too concerned with their performance in this exercise.

Here is the first test:
Mitutoyo MT-1 Tube Lens, Canon 50D, focusing helicoid and additional extension tubes.
http://dl.dropbox.com/u/48523277/Mitutoyo_MT-1_1.tif (86MB)

Craig

*edit: Included an additional Dropbox file link for the MT-1
_________________
To use a classic quote from 'Antz' - "I almost know exactly what I'm doing!"

rjlittlefield · Posted: Fri Apr 20, 2012 9:12 pm Post subject:

ChrisR · Joined: 14 Mar 2009 Posts: 3050 Location: Near London, UK

Thanks Craig.
Should the enlarger lenses be set to f/11,22,...45 for a comparison?
If the effective aperture is given by M/(2*NA) (or is it (M+1)/(2*NA)?) then
Mitty apos, (Normal Niks similar):
5/(2 * 0.14) = 18
10/(2 * 0.28 ) = 18
20/(2 * 0.42) = 24
50/(2 * 0.55) = 45
Apo Niks (Mitty HRs similar):
2/(2 * 0.1) = 10
4/(2* 0.2) = 10
10/(2 * 0.45) = 11

NB it would only be fair to be looking inside the designed image circle, which is, um, um....

I checked the performance of a 100 macro versus a (admittedly cheaper) 100 non macro at f/22, as a normal lens focused at infinity. The macro was definitely better. Perhaps not at its best focusing distance, but they do make macro lenses stop down further of course, because it can be useful.
I wonder if there's anything they DO to improve things down there, or at least not make them worse than the physics dictates.

Downloads work only on right-click and Save Target As, by the way.

Craig Gerard · Joined: 01 May 2010 Posts: 2598 Location: Australia

Chris,

Last question first. Choose to 'Save' the file rather than 'Open'.

I did stop down the Gerogon to f/16, could have gone smaller, but basically just wanted to see how it compared to the dedicated tube lenses when used as standalones.

Craig
_________________
To use a classic quote from 'Antz' - "I almost know exactly what I'm doing!"

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