I'd like to get into photomicroscopy.
Specifically, 10X to 20X magnification (but up to 100X) of abstract subjects,
printed large on fine art paper and canvas.
- Image Gallery page
- My current system
- My target system
- I'd like to use this as a learning exercise. Both in the fundamentals of photomicroscopy.
And in 3D printing to close tolerances and implementing fine control when necessary.
- I hope that using high quality components will let me cook up a system capable of high quality images.
- I want to be able to make large prints. Thus, "stack & stitch" capability using
the Stackshot rails for X, Y and Z.
- I hope to find and adapt older, slightly used, high quality components from eBay, etc.
- Speed up my whole image creation process by employing faster hardware and pipelining the process.
My current system (a work in progress)
Lake Placid, 7 Jun 2019
Here is my current system.
Left to right: a new PC and monitor (for post processing), the old PC and monitor (for capture),
Regarding the camera (left to right):
- Sony a7RIII (w/ Pixel Shift). The a7RIII's USB-C port is connected to Sony Imaging Edge Remote
running on a PC, allowing tethered remote control of the camera. The a7RIII's Multi-terminal port is
connected to the Stackshot controller which
actuates the shutter under the control of Zerene running on the PC. You can setup Zerene to move the
Stackshot rail to a desired start position, take a certain number of shots, moving the
camera forward by a certain distance between each shot. The tethered connection
(over the USB-C cable) streams each image from the camera to the PC. With Pixel Shift set on, after the 4th image has been
streamed to the PC, Sony Imaging View automatically combines the 4 images together to create the pixel-shifted result
- Thorlabs SM2 tubes and
attached with Arca-Swiss clamps to an Arca-Swiss rail
- Thorlabs ITL200 tube lens
all mounted in 3D-printed holders allowing rotation
- Mitutoyo 10X & 20X Apo objectives
(my other objectives and tube lenses are listed here)
- A cheap but effective
mounted on a 3D-printed rotating disc
- A 3D-printed holder for the Polarizer and filters. Again, all rotatable.
- Allowances for a condenser and collimeter
- A 3D-printed holder for an LED light source
- The X-Y stage, filters and light source are mounted on an Arca-Swiss rail to a pair of
rails arranged to move in the X-Y axes (up-down and left-right to support stitching, ie. panoramas)
- a Stackshot rail in the Z axis (forward and back for focus stacking)
Thorlabs optical breadboard,
resting on Sorbothane feet
on a fairly solid IKEA dresser on thick carpet on a concrete slab
The X-Y rotating stage makes it easy to move the sample up & down and left & right.
Then to rotate the subject to pose it.
The optical breadboard is
isolated from my tabletop on the left on which my monitors and keyboards rest. Still, I leave the room
when I'm taking a series of photos (which can be a couple hundred) of say a butterfly wing
for focus stacking.
I will update this section periodically as I develop the system.
Lake Placid, 14 Aug 2019
At the 42MP resolution of the a7R III (7952 x 5304px) and
61MP resolution of the a7R IV (9504 x 6336px), the images would print at resolutions of:
|Print Size ||a7R III |
|a7R IV |
|13" x 20" ||400 ||475 ||Canvas: utilizing the full width of my 24" canvas for the width, with a 2" border for staples to the frame |
|18" x 27" ||300 ||352 ||The often quoted, 300dpi |
|20" x 30" ||265 ||317 ||Canvas: utilizing the full width of my 24" canvas for the height, with a 2" border for staples to the frame |
|22" x 33" ||241 ||288 ||Paper: utilizing the full width of my 24" paper for the height, with a 1" border for handling and framing |
- 52MM STUDIO SETUP
(after which I modelled my setup)
- Matching Camera to Microscope Resolution
which I've plotted here -->
The dotted horizontal line (at Pixel Size = 4.5 µm) corresponds to my a7RIII (not counting the presumed
benefits of Pixel Shift). My Mitutoyo objectives are marked.
The Mitutoyos have a decreasing cost-performance benefit to resolution at higher magnifications.
It is possible that the benefits of these objectives at the higher magnifications are increased Working
Distance and reduced Chromatic Aberation (due to them being APO).
I think this plot shows that my a7RIII is capable of out-resolving my Mitutoyo objectives
(but not by
much for the 10X.. not counting the benefit of Pixel Shift).
Note, this plot is based on traditional microscope design (the text refers to aligning the
condenser and matching the condenser's NA to the objective's NA), so I may be
mixing apples and oranges.
Lake Placid, 13 Jul 2019
I have a Sony a7RIII.
Here is a look at the a7RIII image quality from
Digital Camera Review's website
compared with the Pentax K-1 Mark II (which also has pixel shift) and
leading Canon and Nikon cameras.
Click on the image to enlarge it or on the link above to use the tool.
Lake Placid, 21 Jul 2019
I have an
ordered - scheduled to ship Sep 12...
- Sensor resolution has been increased from 42MP to 61MP.
- Pixel pitch has decreased from 4.56 µm to 3.76 µm.
- Pixel Shift has increased from full pixel to half pixel - with resolution of combined image increasing from 42MP to 240MP.
I suspect this may outresolve my microscope objectives.
But, I hope to see benefits at macro scale - say, 1:1 of my Sony 90mm Macro.
is an early comparison from Tony Northrup, using an 85mm f/1.4 GM.
Lake Placid, 20 Aug 2019
"To correctly reconstruct an image, it must be sampled at at least twice the highest spatial
frequency contained within the image. Sampling it at a lower spatial frequency will result in
ambiguity which will cause artifacts in the reconstructed image. Making the Pitch finer raises
the sampling frequency. Making the pitch coarser lowers the sampling frequency."
Lake Placid, 20 Aug 2019
"Lot of handwringing over the R4 "outresolving" unworthy lenses.... any examples of this
on cameras like the R2-3 or the 5DSR? What does sensor outresolving look like on photos?"
A DPR poster posed an interesting question: “What does sensor outresolving look like in photos?”
In order to deal with this, I needed to define what “sensor outresolving” means. I’m taking it
to mean that the sensor samples the projected image from the lens not just at, but more finely
than the Nyquist frequency.
|Lens outresolving sensor
||Sensor outresolving lens
Settings: Lightroom with a few contrast, white balance and exposure tweaks, and sharpening to strength = 20,
radius = 1 and detail = 0.
--Sensors outresolving lenses
Lake Placid, 2 Aug 2019
"Just about any modern FF E-mount prime, on axis, can benefit from the transitions from 42 to 61 to 100 to 125
to 168 MP. 168 MP is only twice the resolution of 42 MP."
Lake Placid, 24 Jul 2019
To have a look at diffraction at these high resolutions for say, my Sony 90mm Macro lens, I ran several scenarios
MACRO DIFFRACTION CALULATOR at photopills.com
with the following results:
|Camera ||MP ||Focal Length (mm) ||Aperture (f/) ||Focal Distance (cm) ||Magnification ||Effective Aperture (f/) ||Dia. Airy Disk (um) ||100% Crop ||Print |
|Pixel Size (um) ||Diffraction Limited for f/2.8 ||Diffraction May Become Visible (f/) ||Circle of Confusion (CoC) (um) ||Diffraction Limited for f/2.8 ||Diffraction May Become Visible (f/) |
|a7RIII ||42 ||90 ||2.8 ||36 ||1X ||5.7 ||7.53 ||4.54 ||No ||4.5 ||30.00 ||No ||11 |
|a7RIII-PS4 ||84 ||90 ||2.8 ||36 ||1X ||5.7 ||7.53 ||3.21 ||No ||3.2 ||30.00 ||No ||11 |
|a7RIV ||61 ||90 ||2.8 ||36 ||1X ||5.7 ||7.53 ||3.76 ||No ||3.5 ||30.00 ||No ||11 |
|a7RIV-PS4 ||122 ||90 ||2.8 ||36 ||1X ||5.7 ||7.53 ||2.66 ||Yes ||2.5 ||30.00 ||No ||11 |
|a7RIV-PS16 ||240 ||90 ||2.8 ||36 ||1X ||5.7 ||7.53 ||1.90 ||Yes ||1.8 ||30.00 ||No ||11 |
So, even my 90mm Macro lens may become diffraction limited with 240MP Pixel Shift. Ie. the sensor outresolves the lens.
I wonder though if the other benefits of pixel shift - reduced moiré, reduced noise and improved color accuracy -
will be evident in that combination.
Lake Placid, 1 Aug 2019
Recently, I have read some commentaries on whether 61MP is warranted.
- I need to make the measurements (as best I can) and see for myself.
- This may make me want to delve into techniques and subjects that will push the boundaries in ways I
don't appreciate now. Nothing wrong with that.
Lake Placid, 22 Aug 2019
Some reasons why the a7R IV and Pixel Shift make sense for me (yes, this is my rationalization for
buying it, although it has a number or other
- Shooting with microscope objectives limits cropping when composing the shot.
There is only one distance at which the subject is in focus - it's not like you can recompose the
shot by taking a few steps forward or back.
It's like having a manual focus lens and not being able to rotate the focus ring (there is no
So, I will want to do some
cropping in post processing, maybe much of the time. Having more megapixels helps.
- I want to print large so high resolution and image quality are desireable.
See The TRUTH: High Megapixels + BIG Prints are a WASTE? .
- My rig is very stable. Thus, I should not have problems with shake-induced blur possible
- My subjects are not moving. They are microscope slides or mounted specemins in a studio.
Movement (people walking, wind in the trees) messes up pixel-shift.
- People talk about image resolution being limited by lens resolution.
I have two cases:
- For microscope magnifications (greater than 1:1):
I think my microscope lenses are pretty good.
My Mitutoyo microscope objectives are well regarded on the
that I follow.
The lens that I'll likely use as my "tube lens", the Thorlabs ITL200,
is also well regarded in tests. For example, in
this test of 18 lenses,
it was rated the best. And again, in
- For macro 1:1 magnification:
I think my macro lens is pretty good.
My macro lens (a Sony 90mm Macro)
is the 2nd sharpest lens ranked on
DXOMark (scroll down to the start of the list of lenses,
then click on the top of the Sharpness column (on where it says, "Sharpness") to sort
the sharpest to the top).
More PhotoGeekery: Finite Conjugate MTF Bench Tests for Macro Lenses
Roger Cicala compared MTF curves for the Sony 90mm Macro and Canon 100mm f/2.8L Macro. I've sumarized
his results here.
It shows the Sony besting the Canon when focussed at 1:2 magnification. It shows
the Canon besting the Sony when focussed at infinity (which applies if I were to use
it as a "tube lens" with a microscope objective).
But, from what I've seen so far, my Thorlabs
ITL200 appears to perform better
as a tube lens. It sort of makes sense that the macro lenses that I've tested do not perform
well as a tube lens compared to the ITL200. The ITL200 was designed to operate focussed at infinity.
- People point out that this high-MP and Pixel Shift are demanding of compute resources. I have
been gearing up for that - a new 5GHz 8-core PC, a future high capacity NAS, upgrading to Cat 8 (40 Gbps)
ethernet, a future 48-node Multiprocessor, plans to automate the process between the point of composing the shot
(which is done manually, of course) to post-processing (again, done manually).
- A number of reviews point out that Pixel Shift has benefits besides increasing resolution
(reduced moiré, reduced noise and improved color accuracy). For example, see
240 MEGAPIXELS BLEW MY MIND.
- It's fun to push the limits. I hope it will challenge me in any number of ways that I don't
even know about now.
Here is a look at the a7RIII dynamic range from the
Photons to Photos website.
It is the black line. The Phase One IQ4 (blue line) bests it but that is a medium format $52,000 camera.
The Pentax K-1 Mark II beats it but at higher ISOs. I am able to control the lighting and exposure and am shooting at
the lowest ISO (where many of the cameras converge in any case - about 11½ stops).
has ranked the a7RIII favorably since the camera first came out - now virtually tied in the top three full frame
It is reported
that Sony's post processing
tool, Imaging Edge, when used on the a7RIII sharpens the result when it creates the combined image.
But when I've just eyeballed it at 100%, I think I've seen detail in the combined
image that is not simply the result of sharpening (it could be I'm looking at it wrong).
In any case, I will look at using other tools (e.g. SonyPixelShift2DNG, Raw Therapee) as noted in
There do appear to be benefits using pixel shift of reduced moiré, reduced noise and improved color accuracy.
I realize this all has very little, if any, effect at "web page image sizes". My hope is that its
benefits will come into play at large format print sizes.
Armenia, 7 Apr 2019
I want to make polarized photos like the crystals on my gallery page.
It looks like that calls for 2 polarizing filters,
a "retardation or wave plate"
(mica, scotch tape or I'm going to try
this retarder film)
and a holder for the microscope slide.
I'm planning to 3D-print a holder for them. Click on the animation ->
The light panel in this animation is an LED light source such as
There are numerous descriptions of how crossed polarizers work online.
This one by Olympus
is particularly good.
The graphic on the left (borrowed from
at Georgia State University) seems to me a good illustration of 2 polarizers
The graphic on the right shows the effect of a birefringent sample. It splits the polarized lightwaves
that enter the sample into two new lightwaves which are able to pass through the second polarizer (called the
Analyzer). Retardation/wave plates enhance the color.
Here is a description of retardation or wave plates from
this Facebook post:
Optical waveplates (also called wave plates or retarder plates) are transparent plates with a carefully
chosen amount of birefringence. They are mostly used for manipulating the polarization state of light
Two common types of waveplates are the half-wave plate, which shifts the polarization direction of linearly
polarized light, and the quarter-wave plate, which converts linearly polarized light into circularly
polarized light and vice versa. Addition of plates between the polarizers of a petrographic microscope makes
it easier to identify optically minerals in thin sections of rocks. Or people use them to get pretty images.
One polarizer (called the Analyzer) and the Retardation Plate would be located in the tube between the
tube lens and the objective. The Slide and other Polarizer would be held in the 3D-printed holder.
I am able to insert multiple retardation plates in the holders, resulting in more varied colors reaching the
camera. Each of the retardation plates can be rotated to vary the colors.
- The Art & Science of Photomicrography with Polarized Light, Dr. Robert Berdan, June 22, 2017
- Crystals Photographed with Polarization Microscopy: Water, Beer, Caffeine, Vitamins, Amino Acids and Human Tears, Dr. Robert Berdan, March 17, 2019
- Cool demo : Polarized Microscopy With A Retardation Plate
- Polarized Light Microscopy - Microscope Configuration
- Convert Any 2D Image to a 3D Object Using OpenSCAD
Lake Placid, 13 Jul 2019
Here is the printer I'm using - a
It is capable of printing on 44" wide media.
I expect to mainly make 20" x 30" prints on canvas and fine art paper.
But have the ability to print much larger.
Paper and Canvas
Lake Placid, 21 Jul 2019
Here's what I have:
|Type ||Brand ||Name ||Wt. |
|Size ||Cost |
|Canvas ||Breathing Color ||17M Satin Canvas ||350 ||24" x 75' ||$1.88 ||"industry-leading Dmax and color gamut. No Varnish Required. Use Photo Black." -Src |
|Lyve Matte Canvas ||450 ||24" x 40' ||$1.25 || |
|Epson ||Glossy Exhibition Canvas Archival ||420 ||24" x 40' ||$1.90 || |
|PremierArt ||Museum Bright Satin Canvas ||350 ||24" x 40' ||$1.74 || |
|P&L Art ||A cheap polyester canvas ||290 ||24" x 100' ||$0.50 || |
|Glossy ||Canon ||Glossy Photo ||170 ||24" x 100' ||$0.42 || |
|Semi/ Smooth Glossy ||Canon ||Premium Semi-Glossy Paper 2 ||280 ||24" x 100' ||$0.75 || |
|Canson ||Infinity Baryta Prestige ||340 ||24" x 50' ||$1.94 ||"richness and depth in tonal values and hues. Inks seem to blend in with the surface rather than sit on top, a very pleasing look. It is a “smooth gloss” paper, which means that it has the look and sharpness of traditional glossy paper while lacking the distracting sheen of a “hard” surface gloss." -Src |
|Epson ||Legacy Platine ||314 ||24" x 50' ||$1.90 ||"On the luster side, the Legacy Platine has a particularly pleasing feel and it gives the photos a bit of a distinctive richness that I believe will make this paper a favorite in the fine art photographic community." -Src |
|Metalic ||Red River ||#1771 Polar Gloss Metallic 255 (formerly 66lb. Polar Pearl Metallic) ||255 ||24" x 100' ||$1.00 ||"closely matches the look of photo lab metallic prints" -Src |
|#1848 Polar Luster Metallic 255 ||255 ||24" x 50' ||$1.11 ||"related to Polar Gloss Metallic 255. The difference is that this paper has a luster texture similar to Arctic Polar Luster. Your images will take on a brilliant, almost luminescent quality. Everything from airplanes to flowers will look bold, more saturated, more intense." -Src |
|Satin ||Hahnemuhle ||Fine Art Baryta Satin ||300 ||24" x 39' ||$1.91 ||"a satin-gloss surface on a bright white base. The barium sulfate in the coating works in conjunction with a microporous ink receiving layer to deliver vivid prints from subtle to intense color images: monochrome prints express deep, rich blacks as well as a wide gamut of grayscale values." -Src |
|Red River ||#5129 68lb. UltraPro Satin 4.0 ||270 ||24" x 100' ||$0.47 ||"looks and feels just like traditional photo lab paper. The surface is textured to a medium depth. Bright white papers are particularly good at reproducing deep blacks and higher contrast." -Src |
|#1278 San Gabriel Baryta SG 2.0 ||315 ||24" x 50' ||$1.30 ||"tonality, depth, and feel of a traditional darkroom print. The paper has a lightly textured surface, similar to a fine satin." -Src |
Choosing paper and canvas:
Always go for a paper that has a TAPPI rating of around 90.
|Paper ||Comments |
|RC Photo Papers || |
|Metallic Papers || |
|Fiber-Based Baryta Papers ||baryta papers have set the gold standard for fine photographic papers with incredibly rich blacks, wide gamuts, great contrast and sharpness, and smooth tonal transitions. These papers are perfect for black and white prints. |
|Cotton Fiber Papers || |
|Alpha-Cellulose Papers || |
|Hot and Cold Press Papers || |
|Canvas Papers || |
|Specialty Papers || |
|What ||Process ||Why We Love It ||Great For ||Not As Great For |
|GLOSSY ||Inkjet ||Delivers colors that are saturated and bold and shows plenty of detail ||Competition prints, framed work and owners of high-resolution camera bodies ||Clients—cast-coated glossy papers can look and feel more like plain paper |
|SATIN and LUSTER ||Its textured surface reflects less light and can smooth skin tones ||Portraits ||Images where very fine details are critical |
|MATTE ||Matte’s smooth and non-reflective finish and variety of weights make it a beautiful choice for fine-art prints ||Landscapes, black-and-white prints, lower-contrast photos and portfolio images ||Prints that will be handled often. Pigment inks can sit on the surface of matte papers, making them prone to scratching |
|COTTON and RAG ||Cotton papers usually deliver a warm white and a premium feel ||Portraits, fine art, nature scenes ||High-volume prints, as it can be pricey |
|BARYTA ||Delivers colors that are saturated and bold and shows plenty of detail ||Competition prints, framed work and owners of high-resolution camera bodies ||Prints that will be handled often as the surface is typically delicate |
|CANVAS ||The classic fine-art media, canvas can be stretched and hung for beautiful wall art with its no-glare surface ||Wall art, gallery wraps ||Prints that will be handled often as ink can be scratched off the surface (coating it helps) |
|METAL PRINTS ||Dye-sub transfers or direct-to-metal printing using UV printers ||The metal resists damage from humidity, fading and is scratch-proof ||Images with silver, high-contrast, high-resolution and metallic subjects like cars, skyscrapers and robots ||Portraits, since skin tones don’t always translate well on brushed aluminum |
|SILVER HALIDE ||Digital photographic ||This versatile material has a wide color gamut and continuous tone ||Mid-gloss photographic papers (between a matte and full glossy) are particularly suited for portraits ||Long-term archiving as silver halide prints don’t resist fading as well as some inkjet paper or ink combinations |
|Use ||Paper ||Notes ||Have |
|Monochrome ||Canson Infinity Baryta Prestige 340gsm ||The baryta nomenclature tags it as having the look and feel of silver-halide prints. Inks seem to blend in
with the surface rather than sit on top, a very pleasing look. ||1 |
|Rich Color with a Satin Surface ||Hahnemühle FineArt Baryta Satin ||a satin-gloss surface on a bright white base. The barium sulfate in the coating works in conjunction with a
microporous ink receiving layer to deliver vivid prints from subtle to intense color images: monochrome
prints express deep, rich blacks as well as a wide gamut of grayscale values. ||1 |
|Art Prints and More ||Moab Entrada Rag Textured || ||0 |
|Color Richness ||Epson Legacy Platine ||smooth yet not so shiny that it reflects back like “harder” glossy papers are apt to do. . On the other
hand, it has the print “snap” and contrast edge enhancement we’ve come to associate with a glossy surface. ||1 |
|The “Profiled” Print and the Case for Printer-Branded Papers ||Canon and Epson ||Canon Glossy ||1 |
|Multimedia ||Red River Paper 88lb. Polar Matte Magna || ||0 |
Cotton/poly is the most common. The reason I've heard from manufacturers is that it is the
best compromise between durability, lack of shrinkage and flexibility. 100% cotton is usually more flexible and easier to stretch
but at the expense of possibly having to restretch it again later.
Besides composition, the other variables are thickness, surface texture and whether it contains OBAs.
From what I gather from the various printing forums, the most commonly used canvas is Breathing Color's Lyve (no OBAs). It
is a matte canvas that offers a good combination of price, a relatively smooth texture, and a high quality image. It is also one
of the few canvases that can be used with either PK or MK ink and still look good (I use it with PK).
The smoothest surface is provided by Canson's Museum ProCanvas, which is 100% cotton and OBA free. It comes in either matte
or satin and is very soft and easy to stretch.
The canvas with the whitest background (without OBAs) is Premier Art's Museum Bright Satin canvas.
Supposedly the whiter the coating the better the colors, but I haven't seen much difference compared to either Lyve or Museum
ProCanvas. It's also slightly more expensive than the others.
For your best images, consider satin luster photo paper if your content has a high level of contrast or is highly saturated.
The textured surface yields brilliant color saturation and deep black density.
A fast PC (PC2)
Armenia, 5 Apr 2019
Post processing and Stacking
Lake Placid, 22 Aug 2019
Armenia, 25 Apr 2019
Lake Placid, 14 Aug 2019
Optically, this is the sort of system (left) I'd like to initally emulate using my components (right).
That is, add to my current system the linear polarizers, retardation
material, a light source and
whatever bits of 3D-printed holders I need to glue it all together (the grey and yellow parts in the animation).
This is the process I plan to use to develop the rig for photographing crystals:
My Mitutoyo 10X has an NA of 0.28 for a computed resolution of 0.98 µm
(0.5 x lambda / NA; lambda = .550 µm, an average wavelength of light).
My Mitutoyo 20X has an NA of 0.42 for a computed resolution of 0.65 µm.
The a7RIV (at 61MP) has a sensor pixel pitch of 3.76 µm - 3.8 pixels on the 10X objective and
5.8 pixels on the 20X.
Status: My new MP monitor based on my old Raspi Monitor is coming along.
I feel it takes a long time to process a large stack - converting the Raw Pixel Shift images from the camera to TIFFs
for Zerene being much of it.
It requires several manual steps - easy drag-and-drop operations, but I have to be there to do it.
I'd like to speed up the process by souping up my computer system and removing the manual steps.
Computationally, this is the system I'd like to build. My goal is to automate the end-to-end process.
And convert and stack the images as they come off the camera. To accomplish that, I am putting together
a Multi-processor (MP) from single board computers (Raspberry Pi's)
and planning to
build a fast PC (PC2) to do the stacking and post processing.|
I'm planning to locate the
MP, NAS and Ethernet switch in a separate room to avoid their cooling fans from affecting the image capture.
Everything is connected together by Gigabit Ethernet. There is also a Wifi connection from the Controller on PC1
to a web server-based monitor so I can check on status using my laptop, tablet or phone.
- Old Microscopes
|Leitz Dialux, Early 1970s
||many parts and accessories are available on the market
|American Optical Series 110, Mid-1980s
||[a so-so review]
|Zeiss Standard, Late 1970s
||higher level are the Universal or Photomic models
|Nikon Labophot, Mid-1980s
||an "entry level" benchtop scope, less expensive than the Optiphot line (which are rare in POL),
unsurpassed optics, large controls
|Wild Heerbrugg M21, Early 1970s
||considered by some experts to be the best microscope ever made
|Olympus BH-2 BHTP, Late 1980s
||"the microscope I prefer over all others"
- New Microscopes
- Research Microscopes
4X mag, NA 0.47, field size 6mm, WD 3mm, resolution 0.7 µm lateral, 7 µm axial
In which they claim, "For more than 100 years, the ratio of magnification to NA has been held at
approximately 40:1 for all microscope objectives." I've plotted Magnification vs NA
for the objectives I'm interested in (infinity focus, non-oil). ...
Polychromatic polarization microscope:
- DIY Microscopes
New Bertrand Lens on Ebay
Tungsten halogen vs white LED
Optiphot modular light source
FAQ:How (and why) to use electronic flash at the microscope?
Microscope Conversion to LED-Light
HOW BRIGHT IS YOUR LIGHT PART III: LED CONVERSION
Making Rheinberg illumination discs
How to Make Rheinberg Filters
Rheinberg Filters for Photomicrography
A Practical Guide to Creating Superresolution Photos with Photoshop
Raspberry Pi MP
I'd like to build this Multiprocessor out of the latest version of the Raspberry Pi
(Raspberry Pi 3 Model B+). The Pi 3 B+ is clocked at 1.4 GHz, has 1 TB of RAM and
supports Gigabit Ethernet at 300 Mbps.
I will model mine after Joshua Kiepert's
He has documented his system well, including Eagle files for his power distribution cards.
At the end of that article, it says his 32-node system (using an older version of Raspberry Pi)
does 10.13 GFlops, where "the first Cray-2 supercomputer
did 1.9 GFlops". I look forward to benchmarking mine. Let's see, Summit did 200,795 TFlops in the latest
Nov 2018 Top500 List. How close will I be?
- Build your own supercomputer out of Raspberry Pi boards, Steven J. Vaughan-Nichols, May 23, 2013
- Creating a Raspberry Pi-Based Beowulf Cluster, Joshua Kiepert, May 23, 2013
- RPiCluster Repository, Joshua Kiepert, 8-13-2013
- Creating a Raspberry Pi-based Beowulf Cluster, Bleeker, 2017
- Projections made for Summit back in 2014
Armenia, 12 Apr 2019
I'd like to be able to support up to 48 Raspberry Pi's. Add a port for the Master Node,
two for the NAS, one for the PC1+PC2 (that I'll bring in from a separate switch where they're located at
my desk). Making 52 ports all together.
This 52 port switch
looks good. Gigabit speed at a reasonable price.
Lake Placid, 1 May 2019
I read that Ethernet Switches are vulnerable to power glitches. I see many refurbished switches for sale.
At first, I thought I should get a battery backup, ie. an Uninteruptable Power Supply (UPS).
So, I estimated the power requirement of a UPS as follows:
The total of 360W+ led me to this
450W CyberPower CP800AVR
(which was highly rated in
- 46W max
for the switch.
- 5.7W x 48 = 274W for the Raspberry Pi's.
(using the max. of
0.980 x 5.1V = 5.0W (400% busy, no attached devices)).
- 40W for the NAS (source). Although that doesn't include
the optional DX517 expansion unit.
Great, but then I saw that that review also said,
"Unfortunately, most affordable UPS units don’t offer much protection compared with a
dedicated surge protector. In previous tests, electrical engineer Lee Johnson took apart our UPS samples to examine
their guts. Based on his assessment, we found that our picks should protect your equipment about as well, if not
for as long, as basic surge protectors we’ve tested before."
is their most recent review of surge protectors. It has a pretty glowing review of the
Furman Powerstation 8.
A little pricey (for me) but hopefully worth it.
I've ordered four. One for the ethernet switch and NAS, one for the printer and two for other electronics.
Network Attached Storage (NAS)
Armenia, 25 Apr 2019
looks good. Five bays plus an optional 5-bay add-on.
140 TB (70 TB + 14 TB drive x 5) capacity. Two Ethernet ports. Good reviews. At a reasonable price.