Search found 1311 matches

by enricosavazzi
Thu May 27, 2010 8:41 pm
Forum: Equipment Discussions
Topic: JML lens Q&D unstacked images
Replies: 12
Views: 2974

Hi Rik, the reason I am asking is that I have a lens of shorter focal length in a similar barrel, which can be used on a microscope with the hollow barrel end toward a subject (with about 3-4 mm of working distance) but cannot be focused onto a subject the other way around (pupil too deep within the...
by enricosavazzi
Thu May 27, 2010 12:18 pm
Forum: Equipment Discussions
Topic: JML lens Q&D unstacked images
Replies: 12
Views: 2974

Hi, your results are quite consistent with mine. It seems the JML lens is a uniformly good performer. We have yet to see any bad specimens of this lens. By the way, what bellows are those? I don't recognize the make/model. I do recognize the Manfrotto fine focuser at the bottom. Edit: Never mind, I ...
by enricosavazzi
Mon May 24, 2010 7:10 am
Forum: Equipment Discussions
Topic: Advice on 50mm or 60mm lens for Canon
Replies: 13
Views: 3045

Hi Brian, I have no direct experience with any of these lenses, but the data you mention suggest to me two possibilities (or a combination of both factors): 1 - The angle of view of these different lenses could be specified at different magnifications (infinity? 1:1?). This could account for the app...
by enricosavazzi
Sat May 22, 2010 11:49 am
Forum: Macro and Micro Technique and Technical Discussions
Topic: Resolution at (rather) high magnification
Replies: 6
Views: 2255

Can you measure it without the camera? I'd try inserting a 250mm dowel down the tube (taking precautions not to damage the objective), then measure the length of the dowel that's inside the tube. Hi Elf, yes, that is pretty much what I did (actually with a length of plastic-clad copper wire, not to...
by enricosavazzi
Sat May 22, 2010 2:52 am
Forum: Macro and Micro Technique and Technical Discussions
Topic: Resolution at (rather) high magnification
Replies: 6
Views: 2255

Hi Charles, I re-did the measurements after finding out that the distance was actually well over 210 mm and shortening the tube length. With the new setup, the distance between sensor plane and mounting flange of the objective is quite close to 210 mm, but I still cannot measure it exactly because o...
by enricosavazzi
Tue May 18, 2010 11:33 pm
Forum: Macro and Micro Technique and Technical Discussions
Topic: 25mm vs 12.5mm vs 8mm for 10x magnification
Replies: 18
Views: 4890

That makes me think of an old PZO stereomicroscope (actually almost identical to old Zeiss models, but branded PZO) that made its way to me several years ago. The image seen through the eyepieces was clear but distinctly yellowish, and there were no obvious filters anywhere. I sold it years ago. So ...
by enricosavazzi
Tue May 18, 2010 11:35 am
Forum: Equipment Discussions
Topic: Viewer
Replies: 12
Views: 2656

The only "down-side" to the HD connection is that there is a lag time of a second or two when the camera establishes the connection. The plain video connection is very fast, just like viewing on the camera back. Hi Charles, is the delay you are talking about a constant lag of the HD signal, or only...
by enricosavazzi
Tue May 18, 2010 11:28 am
Forum: Equipment Discussions
Topic: Leitz/Leica/other microscope stand for photomacrography?
Replies: 11
Views: 13743

As a third review of a focusing rack, here are my impressions of an Olympus BX30MF. This is not a complete stand, but what one could call a "focusing rack on a stick" plus nosepiece. It has a built-in revolving nosepiece of generous size, with space for five RMS objectives. The right-angle bracket o...
by enricosavazzi
Mon May 17, 2010 9:09 am
Forum: Macro and Micro Technique and Technical Discussions
Topic: Dornblüth wristwatch ... with a 3 element Minolta 100mm lens
Replies: 24
Views: 8503

Oh i wont be getting any more cameras, certainly not film, but I just love mechanical things! I wish I'd been born earlier and been growing up when these cameras were all the rage. The problem is, at that time these cameras were too expensive for most people. I was around at that time, and the most...
by enricosavazzi
Mon May 17, 2010 6:08 am
Forum: Equipment Discussions
Topic: 25mm f/2 Photar data required
Replies: 3
Views: 2018

Hi pkg, according to my notes, this lens is said by Leitz/Leica to be optimised for 6.3x to 20x. I am not sure where I got this information, but it should be reliable. I have one, and depending on the magnification you should stop it down up to 2 stops below 5x, 1 stop between 5x and 7.5x and use it...
by enricosavazzi
Sun May 16, 2010 8:59 pm
Forum: Macro and Micro Technique and Technical Discussions
Topic: Dornblüth wristwatch ... with a 3 element Minolta 100mm lens
Replies: 24
Views: 8503

Some time ago I tested another Minolta 100 mm f/4 bellows lens, and it also performed quite well at slightly more than 1x. I don't know if the optical formula is the same. My test was with a large white background, to verify both resolution and flare sensitivity/contrast. My results are here: http:/...
by enricosavazzi
Sun May 16, 2010 9:06 am
Forum: Macro and Micro Technique and Technical Discussions
Topic: Resolution at (rather) high magnification
Replies: 6
Views: 2255

Resolution at (rather) high magnification

These are a few tests I run on fossil foraminifers. The setup is: Leica Galen III stand, LED illumination for focusing and framing, electronic flash (Nikon SB-800) for exposure in iTTL mode, Nikon D200 camera. The distance between sensor plane and mounting flange of the objectives is about 210 mm. T...
by enricosavazzi
Sun May 16, 2010 4:10 am
Forum: Macro and Micro Technique and Technical Discussions
Topic: Extra! Extra! Read all about it!!!!
Replies: 19
Views: 8821

Enrico, I like your analysis but I am having trouble putting part of it together in my head. Let's presume that the angled plates sit in an "infinity" part of the system, so in each bundle all the rays are parallel. Then at each wavelength the effect of each plate is only to shift each bundle sidew...
by enricosavazzi
Sat May 15, 2010 2:44 am
Forum: Macro and Micro Technique and Technical Discussions
Topic: Extra! Extra! Read all about it!!!!
Replies: 19
Views: 8821

Looking at the lens diagram, my attention was caught by the use of two oblique plates to cancel out each other's aberrations. Am I correct to believe that this is feasible only if the light beams in this part of the equipment should be parallel to each other? It does seem so from the ray trace, so p...
by enricosavazzi
Sat May 15, 2010 12:03 am
Forum: Macro and Micro Technique and Technical Discussions
Topic: Case study: "Portable" stacking set-up.
Replies: 44
Views: 28560

like most mechanical problems, it could be solved by an appropriate combination of tinkering and brute force. Yes indeed! :wink: ... but I do have a few little plastic bags holding the pieces from the projects where the solution was not what I had intended! :shock: :cry: I prefer to regard it as a ...