Search found 30 matches

by michael_r
Tue Aug 23, 2016 6:16 am
Forum: Equipment Discussions
Topic: how do you find entrance pupil on Mitutoyo objectives?
Replies: 15
Views: 3463

Rik, Really interesting indeed. If i look into my MTTY5 i can see your point, but the 10x behaves somewhat different and i can see a sharp circular boundary over a wide range of distances to the eye that i considered to be the entrance pupil. I made a quick image (just placed the objective on a piec...
by michael_r
Mon Aug 22, 2016 10:58 am
Forum: Equipment Discussions
Topic: how do you find entrance pupil on Mitutoyo objectives?
Replies: 15
Views: 3463

Hi Rik, i used the method with a macro objective with shallow dof and made sharp images of the entrance and the exit pupil using a white background to determine the pupilary magnification. That is to my knowledge a standard procedure. Your question makes me thinking. Making the lens telecentric mean...
by michael_r
Sat Aug 20, 2016 9:56 am
Forum: Equipment Discussions
Topic: how do you find entrance pupil on Mitutoyo objectives?
Replies: 15
Views: 3463

The entrance pupil should be separated from the front focal plane by f/m_p, where m_p is the pupilary magnification of the objective. With f = 20 mm (=200 mm/10) and m_p = 0.67 (determined from the ratio of the two pupilary diameters) the entrance pupil should be shifted by 29.8 mm with respect to t...
by michael_r
Sat Oct 03, 2015 10:13 am
Forum: Macro and Micro Technique and Technical Discussions
Topic: Setup of Ploum
Replies: 92
Views: 35493

Frederic, thank you for confirming this number. If this is the case you have probably built a two-sided telecentric system in your first stage, as the distance between the two elements appears to equal the some of the focal lengths. Placing the diaphragm in the common focal plane makes the system tw...
by michael_r
Fri Oct 02, 2015 11:59 pm
Forum: Macro and Micro Technique and Technical Discussions
Topic: Setup of Ploum
Replies: 92
Views: 35493

Frederic, i can't believe it: is 25 cm really the distance between the 200 mm lens (lentille de focale de 200 mm) and the microscope objective (objectif) in your drawing?

Michael
by michael_r
Fri Oct 02, 2015 9:15 am
Forum: Macro and Micro Technique and Technical Discussions
Topic: Setup of Ploum
Replies: 92
Views: 35493

Frederic - thank you for the answer. In 2. i would be interested to learn the distance between the 200 mm lens and the objective (that is the length of the white rings (including diaphragm) in your drawing, between the 200 mm lens and the microscope objective)

Michael
by michael_r
Fri Oct 02, 2015 7:08 am
Forum: Macro and Micro Technique and Technical Discussions
Topic: Setup of Ploum
Replies: 92
Views: 35493

Frederic did i get this right: 1. Distance between the Raynox and the 200 mm lens is 18 cm on the average? You change this distance for stacking by 2 cm, so it varies from 17 cm to 19 cm? 2. What is the distance between the 200 mm lens and the microsocope objective (or enlarger lens) In your drawing...
by michael_r
Wed Sep 30, 2015 7:49 am
Forum: Macro and Micro Technique and Technical Discussions
Topic: Setup of Ploum
Replies: 92
Views: 35493

In my first contribution to this thread is gave some formulas that describe a lens combo if the distance between the two stages is smaller than the sum of the focal lengths. I consider these still to be correct. In the analysis given i assumed however that the second stage taken alone produces a rea...
by michael_r
Wed Sep 30, 2015 7:44 am
Forum: Macro and Micro Technique and Technical Discussions
Topic: What happens when e > f1 + f2
Replies: 11
Views: 4607

Thank you for the information Frederic - a distance of 8 cm between Raynox and sensor cannot give a real image of the second stage. In my investigation in the original thread (Ploums setup) i assumed that the second stage alone produces a real image. In order to keep up with the new information conc...
by michael_r
Tue Sep 29, 2015 12:38 pm
Forum: Macro and Micro Technique and Technical Discussions
Topic: What happens when e > f1 + f2
Replies: 11
Views: 4607

Hello Frederic,

i'm still curious: what is the distance (accurcay +/- 1 cm would be sufficient to me) between Raynox and sensor if you make images with the 20x nikon [i assume together with the "tube lens" (which can be combined with the nikon to L1 in the discussion)]?
by michael_r
Tue Sep 29, 2015 8:39 am
Forum: Macro and Micro Technique and Technical Discussions
Topic: What happens when e > f1 + f2
Replies: 11
Views: 4607

Hello Frederic, i like your mineral images very much - they are really beautiful. I have to admit that i did not understand the first of your sketches, explaining your setup. I think i understand the second case - with a separation e of the two lenses that is smaller than the sum of the two focal le...
by michael_r
Mon Aug 10, 2015 12:10 am
Forum: Macro and Micro Technique and Technical Discussions
Topic: Setup of Ploum
Replies: 92
Views: 35493

Hello Rik, i do completely agree - the problem with Frederics setup is, that you cannot make m2 small if you want large magnification m AND reasonable step sizes for the stacking procedure. Large values of m2 requires the MTTY to be operated far from m2=0 - the point it has been designed for. So: no...
by michael_r
Sun Aug 09, 2015 11:52 pm
Forum: Macro and Micro Technique and Technical Discussions
Topic: What happens when e > f1 + f2
Replies: 11
Views: 4607

Very interesting Rik - i know the (afocal) case f1+f2=e which is widely employed in two-sided telecentric optics used for measuring purposes (Schneider-Kreuznach e.g. produces a series of such lenses - and has published a nice tutorial on telecentric optics, that might be of interest to others). I o...
by michael_r
Sat Aug 08, 2015 8:02 am
Forum: Macro and Micro Technique and Technical Discussions
Topic: Setup of Ploum
Replies: 92
Views: 35493

Rik - i think there are several restrictions to the accessible range of e - but if e gets larger than f1+f2 then total f becomes negative - i'm not sure that my calculations apply to that case (to my knowledge imaging with f1+f2 < e is usually described as a succession of two imaging processes with ...
by michael_r
Thu Aug 06, 2015 3:24 am
Forum: Macro and Micro Technique and Technical Discussions
Topic: Setup of Ploum
Replies: 92
Views: 35493

Rik - thank you for your excellent demonstration, i’m glad to here that the formulas worked. I completely agree with your conclusions, and just cite from an email that i sent to John (dolmadis) yesterday in the afternonn. „You get really small shifts of the object plane even from a shift of the two ...