The Bausch & Lomb Model R part: II

It’s time to see how the optics of the original B&L Model R perform. To begin with a few common test objects, beginning in this instance with the wing of a fly, will be evaluated visually. Then, the next visual test will be the scales of a Podura springtail followed by the more finely striated Pleurosigma angulatum. The ability to resolve the features of these objects once served the same descriptive needs that the numerical aperture measure serves now.

It’s worth mentioning that no special effort will be made to ensure perfectly clean elements, so although this microscope is in exceptional condition for a stand of its age one could expect to see a not insignificant improvement in resolution should the effort be made. All photomicrographs taken will be made with a ring-stand supported iPhone camera. To avoid putting up an over abundance of images that will will only be given a cursory place only two images of each test object will be provided. The lowest power is that marked on the Model R microscope as 75 while the highest power is that marked as 300. It’s worth noting that to configure the Model R to provide the lowest power one must remove the front element of the objective lens and set the draw tube to its shortest length. To achieve the highest power one must use both elements of the objective and set the draw tube to its greatest length. Lighting is provided by a high variable intensity condensed B&L illuminator.

In the low power photomicrograph we can see that there is some indication of markings on the various cells of the wing and make out a pattern of hairs on the costa. At the high power end of things we can clearly see the individual hairs of the costa, they are not the toothy spikes represented on the first photomicrograph. The pattern of hairs on the marginal cell is clear but the individual definition is somewhat obscure. It is not immediately clear that they are in fact raised hairs, easy enough to determine with a bit of back and forth of the focusing knob. All things considered the imaging abilities of the microscope are surprising. The axial third of the field of view is surprisingly clear and sharp, even when viewing so comparatively thick a specimen as a fly wing. Except at the lowest power, without the complete objective in place, there is very little evidence of chromatic aberration.

In the low power image of the podura scales we are able to discern some implied texture on the surface of the scale, it’s obvious it is not simply a color gradient. Again it is clear that there is some chromatic aberration, more in evidence due to the slight misalignment of the illumination source, but one should expect that when using a divisible objective. Turning to the high power photomicrograph the texture becomes a clear pattern of lines although, one could certainly not make any secure judgment as to the nature of the texture in cross section. It should perhaps not be surprising that the Model R can make no clear statement on that count, there was in fact profound disagreement on the form a podura scales texture would have that was unsettled until the rise of electron microscopy. As a side note, these scales are not intact lined but rather feature a pattern of lines composed of fine hairs.

Although the Model R did not provide the performance of a professional stand on any of the test objects thus far it certainly stood tallest on the fly wing. It’s then somewhat pointless to set it against the Pleurosigma angulatum as there’s little reason to expect it to resolve the finer points of the diatoms test. Fortunately, one would hardly expect someone to put such a difficult object before the Model R. It is gratifying though to note that if hard pressed one could certainly enjoying viewing diatoms with the stand, clearly it’s not the ideal object one might chose to observe but it certainly performs far better than one might expect. The red and blue fringes of an achromatic objective are obvious on the photomicrographs of the diatoms; they are by no means reason to disregard the Model R. It would be a great thing if a microscope of this quality were put before every elementary school student rather than the sort of needlessly complicated and overly ambitious toy one can find at any of the “science” themed stores that exist in shopping malls and digital marketplaces.

In part III, a few simple tests one can perform to find the powers of the optical elements. -K

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Large Format Photomicrography part: IV

Photography Basics / Darkrooms

Not having a darkroom doesn’t mean giving up on large format photography; there is a darkroom solution for every problem out there, ranging from fully equipped professional quality spaces all the way to under a comforter, with the lights out, at night. One could run over to a site like localdarkroom.com to see the spaces available in ones area and, if fate is kind, find out a nearby space can be had for a nominal fee. If everything is hopelessly far away or self reliance is more ones style it’s just a question of expense. Free solutions can be as simple as waiting for nightfall and putting towels over every bit of light in evidence in a darkened bathroom, or cleaning out a little space in a closet.

Buying a photographic changing bag or darkroom tent is certainly an option. A changing bag is essentially a darkroom, for ones hands. A fairly large changing bag may be found in the $25.00-$40.00 USD range on any of the countless “we have everything” web-stores, just search for “changing bag.” If going that route don’t try and save a little cash by purchasing an undersized bag that’s really only useful for 35mm work, unless of course that’s ones ambition. Except in cases where every penny must be pinched it’s generally good advice to buy the largest changing bag one can afford; something about darkness turns a meter into a millimeter.

Photography Basics / Holders for 4×5

With some sort of perfectly dark place, a box of film, and a film holder one’s all set to load some film. The assumption here is that one will be loading up 4×5 film into a 4×5 holder.

If working in an improvised dark room take a moment to lay everything out that will be needed in an orderly way. It’s imperative that the box of film be fully reassembled as the final step; it’s no fun at all to have the lid of a box go missing as a result of a cluttered workspace. Where at all possible bring everything that is needed and only what is needed into the darkroom, whether that darkroom is a closet or a changing bag. It’s a good habit to open up the dark slides of the film holders as shown before going dark; closing the holders then only after film has been loaded. In this way one avoids both failing to load film and wasting time trying to load a sheet in a full holder.

Before the actual business of loading a few notes on film holders and loading 4×5 film. Holders usually have two sorts of indicators to avoid loading film incorrectly and double exposures. The first indicator is less universal and is based on two colors, white and black. One side of the dark slides handle is apt to be painted white or molded from white plastic. By convention this side is placed facing out when the film is un-exposed; it’s ready to see the light. After exposure the dark slide is placed back with the opposite (black) side facing outwards, indicating that the film has been exposed and should only be removed in the blackness of the darkroom.

Vintage or antique film holders are liable to have plain metal dark slide handles (or to have had all their paint worn off). Moreover, one can hardly observe the color on the dark slide when working in a darkroom or changing bag. All film holders thankfully have a second indicator which most commonly takes the form of  one or more raised or recessed dots on the upper right hand corner of the dark slide when viewing the un-exposed indicating side.

In addition to indicating the exposed or un-exposed state of a loaded film holder the raised dots serve as a reminder of how to properly load film. Every sheet of film has two sides, the emulsion side and the back. The emulsion side is the side which has been coated with light sensitive material and is the side which should be exposed to the light from ones camera lens. Unlike 35mm film which can only be loaded in one direction (as a result of the cartridge construction) 4×5 film can easily be loaded backwards. To address this issue every manufacturer includes a small indicator on each sheet of 4×5 film.

The indicator takes the form of one or a series of shaped notches in on corner of the film. Different patterns of notches indicate different types of film, speeds, manufacturers, and emulsions. Explanations of the notches is beyond the scope of this post, see the film makers documentation for details. Just as the raised dots of the dark slide should be in the top right when the film is un-exposed so too should the notches in the film be in the top right when loaded. If the notches are loaded such that they are in the top right, whether one loads the film by sliding it up from the bottom of the holder or down from the top, it is not possible to face the emulsion side away from the lens. Thank goodness for chirality.

Photography Basics / Loading 4×5

One should prepare for loading 4×5 film holders by giving them a good clean up. Take a clean, 2″ paintbrush, just the sort one would use for painting trim or moulding, and brush out the film holders. In a similar vein it’s frequently recommended that one use some sort of air duster for the task. The thought of so powerfully propelling dust into the air at a time when it would rather be settled seems enough to proscribe that practice. Pull all the dark slides out only so far as to expose the channels into which the film will be slid. Don’t pull the dark slides out all the way, doing so only serves to clutter up the work-space. At the same time do not think to simplify the task by only pulling out the dark slides a very minimal amount; one should be able to bend the partially loaded film slightly upwards to tell that each side is uniformly slid into its channel, a task that’s impossible if the dark slide itself is holding down the film.

If a picture is worth a thousand words I own at least one now.

Well there it is, enough to get anyone loading 4×5 in no time at all.

Large Format Photomicrography part: III

The Homemade Camera

At this point I’ve got everything I need to shoot some 4×5 film. I could load some film into a holder, and start shooting without any delay. I wonder though, what about everyone else? What if I didn’t have a trinocular BalPlan, a working System II shutter assembly, the proper camera body, and the right adapter? What if all I had was was a basic monocular microscope and dreams of shooting 4×5? Could I get away with something simple and homemade or would that be too impractical. Thinking about the preceding one is apt to consider the old standby of shoe-string photography: the pinhole camera. Such a camera need be nothing more complex than an opaque box with a pinhole at one side. It should then be entirely possible to use the same principles in the task at hand; replacing the pin-hole with a microscope wouldn’t do though. One would need some way of determining focus. Depending on what’s to hand it may prove more or less feasible to solve the problem of focus by building two cameras; the one for focusing only a screen of some sort in place of a sheet of film. Two identical carers could be easy (perhaps two identical shoe boxes) or nearly impossible at a moments notice (the recycling picked up yesterday). In any case I have a ground glass and a film holder so a single camera seems easier. A student should be able to borrow both from the art department or one could buy a holder second hand and make their own screen easily enough.The question now becomes how to attach the box that will be our camera to the microscope. With a basic monocular microscope with inclination joint, using it in a fully horizontal arrangement seems ideal. One needn’t bother with standing on a chair to view the screen or precariously balancing the “camera”. So far, no consideration has been paid to the question of a shutter. The simplest option would be to ignore a shutter in the traditional sense and merely block out the light source with a bit of light opaque material, tin foil, for example. Then we need only consider the need to ensure that the only way light may enter the camera is through the microscope. Easy enough, a hole only just the size of the ocular tube is made in the camera and the connection masked with a bit of gaffer tape. All that remains is to consider how the film holder will be held to the box. This being the most complicated aspect of construction it has been left for last. One need cut away enough of one end of the box so that the light may reach the film. This hole may be made large enough to utilize the entire film or it may be masked so as to provide a circular photomicrograph. With the hole cut one should then glue a few layers of soft dense material to the area the film holder will press against. This material will serve as a light seal. A few layers of dark colored fleece or soft foam insulation will do nicely. To hold the film holder in place one has a number of options, the first that occurs to me is to poke four holes through the box and insert through the same a pair of dowels or pencils, mask the ends with tape for a tight fit, and then stretch rubber bands from end to end to hold the film holder tight against the light seal.

1. Place the specimen on the microscope stage and position the “camera” at the ocular.

2. Affix the focusing screen to the camera.

3. Turn out the room lights, turn on the illuminator, and focus the microscope.

4. Taking care not to move anything, remove the screen.

5. Place the loaded film holder in position.

6. Block the light of the Illuminator with foil.

7. Pull out the film holders dark slide.

8. Briefly remove and replace the foil in the illuminators path to control for exposure.

9. Replace the dark slide with the exposed film indicator facing out.

10. Process exposed film as per developer instructions and enjoy!

Large Format Photomicrography part: II

Preparation of a Ground Glass

Using the integrated camera system II means that one will be correcting for parfocality between the camera and oculars with the shutter assembly optics not the cameras tube length. The process is the same for any of the Bausch & Lomb integrated camera systems and the effect is functionally identical to increasing the cameras tube length. This may not be immediately clear to anyone using the device because on a number of models the adjustment is marked with an “x”. Rest assured that focusing the knob to “15x,” is not going to provide an increase in magnifying power of 15 times over the obdective magnification. Provided this little endeavour is successful, I’ll look into calculating the power of the lens system when in focus. Unfortunately, before any of that a method of obtaining clear focus in the plane of the film will be required. An ideal method of obtaining focus would be inserting a ground glass in place of the film holder. The ground glass would need to be in some type of frame so as to keep the ground surface at the same position the film would occupy. It would at first seen expedient to place a piece of waxed (or oiled) paper onto the camera back and this would work in a pinch. A far better opption would be to cut a sheet of glass to size. If one hasn’t got a sheet of glass to hand a quick trip to the nearest second hand shop or discount store (where a picture frame can be had very economically) will provide the needed material. If one hasn’t got a glass cutter or is not confident in their use of one, a stiff sheet of lexan or transparent acrylic that may be cut with a hand saw will do. If one intends to use glass a finely ground surface may be quickly achieved with a bit of carborundum powder. One must take care to cut the glass to size before grinding. For determining size I have considered two methods. First one may trace out and cut the glass to match the outside dimension, of the plate holder. Alternatively, one may trace the dimensions of a sheet of film and cut to that size. The former is likely the easier option, but if one is careful and has a spare or broken film older the later may prove a more secure and attractive option. In the first case, one will later be supporting the glass with shins to bring it into the film plane. It may be easier in the sense that one may make alterations with little trouble if initial results are not all that one could hope for. Another option would be deconstructing a film holder so that it provides an empty frame into which one may fit the ground glass. Originally sold with a frame supported ground glass, I have never seen a 4×5 body for the Integrated Camera System on the market together with the glass back and feel it likely that most were either broken or lost track of over the years since the apparatus was in active production. It may be worth noting a few points concerning focusing with a ground glass. Focus is limited in sharpness by the fineness to which the glass in question is ground. To obtain an area for perfect focus, one should then cement a cover slip in the center of the ground glass or leave a small area unground. When the clear area is observed using a hand lens or small focusing magnifier one may observe the quality of image that will be captured on film. To leave an area unground one may mask it with a layer of heavy tape (or even a cemented cover slip) which must then be removed after grinding. To grind the glass one need only introduce a little carborundum grit in water to one side of the glass. A second piece of glass (a plain slip works well) is then sanded over the grit under light pressure.

The gallery below demonstrates the process.

Above may be seen my poor abilities in cutting glass, and two ways to go about creating a ground glass for focusing. First a 4×5 piece of glass salvaged from a broken window is inserted into a film holder that had irreparably damaged dark slides. The solid film holders were removed and the glass is supported by the top and bottom of the holder rather than the sides. As an alternative I cut a piece of 1/8th inch acrylic to the size of the film holder. Rather than grind it I simply left in place the frosted protective film on one side. It should be noted that in each case the frosted surface is the one which should be held in the film plane. This means that the in the wooden holder the frosted surface is facing down and in the case of the acrylic it is facing up.

B&L Photomicrographic Apparatus VI: AX-1

The final development, before the microscope camera went from still-chemical photography to motion/still digital photography is equal parts groundbreaking and re-purposing. Like the System II the new version maintained the same basic layout and universality, it was made compatible with all the camera backs of the System II. It retained the focusing knob (to date all those known are marked at 3x, 5x, 7.5x, and 10x) but departed from the consumer camera style shutter speed selector and remote shutter release; the new camera was automated.

Since the earliest days of photomicrography it was just assumed the the microscopist would be the darkroom technician as well. Those seeking to record images of their work were expected to practice and understand the skills needed not only for obtaining a clear, useful image at the eyepiece, but at the imaging surface of their camera, and final media as well. Books from the golden age are filled with detailed information on how to properly compose and sequentially expose test images. Entire chapters in books on general microscopy are devoted to the proper taking of photomicrographs. In detailed texts on photomicrography extensive chapters describe the best way to salvage (and in future avoid) over or under-exposed films. The AX-1 changed all that.

 

For a generation that grew up (or like the author, grew complacent) with the automatic exposure and aperture cameras of the “Kodak Moment” era, the AX-1 no doubt seems unduly complex. A two variable analog meter, no less than six buttons-two thirds of which light, two additional indicator lights, four tumbler set values, all run off of a grounded AC plug in a package the size of a lunch box and weight of a bag of sugar is understandably daunting. The space-hogging controller is only half the unit and like it’s counterpart is entirely useless without the automatic shutter assembly camera. As previously mentioned it is superficially like the System II but in place of a release bears a nine pin cable and connector that conducts light data from its integrated sensor to the control box and carries the exposure signals back. A small electromagnet actuates the simple shutter, and the photo-sensor is positioned to one side of a right angle partially silvered reflector.

To allow for the proper calculation of required exposure one must set a few parameters on the controller before beginning. Film speed is dialed in using A.S.A. units and it’s worth noting that the controller uses the 1960 revision (from what I can tell in use, I’ve not been able to locate anything in the documentation). One must also select the desired reciprocity, which is best left set to “OFF” for most uses. Setting the level of magnification to the nearest value marked on the shutter informs the photo-sensor of the general range of light intensity and is vital for achieving accurate exposure times and light levels. One may also set the desired exposure to a fixed value darker or lighter than the calculated exposure which may be useful for those who want to avoid pushing or pulling during processing.

Once properly set up the user is ready to set the focus of the shutter assembly, load film, power up and begin taking pictures at the push of a button! Imagine, no need to shoot and develop costly trial exposures or to calculate required shutter speeds/exposure times by hand with based on light meter readings. The device can serve as a light meter only and exposure may be done manually at the press of a button. The controller can be put on a separate table and the only source of vibration limited to the movement of the shutter itself. That’s probably the chief point in the AX-1’s favor these days, but it may still be worth while for those more willing to give it the space than to learn about shutter speeds.

-K

B&L Photomicrographic Apparatus V: System II

A Re-design

The System II represents a fundamental change in B&L integrated photomicrographic cameras. Sleeker than the early DynaZoom camera but far more substantial than the later versions, the System II is a step back to the design principles that required a focusing system. It was necessary for the System II to feature a focusing lens system because the unit was intended to be a new universal device for all (camera ready) professional B&L lines, including the earlier DynaZoom/DynOptic lines. Despite maintaining the compatibility of the system with earlier stands, once more the camera backs required are not compatible with previous versions (although they do come in all previous formats).

New Features

The opticians behind the System II seemingly asked themselves ‘how can we make this the last camera a microscopist will need?’ and set about answering it. The systems chief major departure is the coupler, specifically its diameter. At 7/8ths it’s a full quarter inch larger than the previous model DynaZoom camera, and a return to the large size used with focusing DynaZoom cameras. Care was also taken in the design of the coupler, it was made to be removed and a number of versions of the coupler were made, some making allowance for the use of a manual exposure meter.

Once more the camera back attachment point was redesigned. The new male dovetail fitting was made a bit smaller than those used previously and unlike previous models did not feature an alignment screw that required the female dovetail camera back be fixed in relation to the camera. Additionally, where earlier camera backs used two thumb screws the new versions used only one; making it a simple thing to orient the photosensitive surface however one wished without being forced to suffer an inconvenient shutter release or winder position.

Couplers and Camera Backs

Three couplers are known of: the silver Bal-Coated male dovetail, the black lens-less male dovetail, and the eyepiece mount. The silver dovetail makes good use of a Bal-Coated lens to eliminate errant reflection which can prove frustrating with uncoated optics and both it and the black dovetail carry a small slot in the dovetail that mates with the camera. This slot may be turned to align with a similar slot in the System II or turned so as to exclude all light. The purpose of the slot is to permit the insertion of the B&L Cat. # 421240 exposure meters sensor.

Versions

The versions are discrete rather than explicit, which is to say there is not any particular model number to distinguish them that is official but they are readily identifiable. One sort is focusable from below 3x to over 10x. On these models only four magnifications are marked: 3x, 5x, 7.5x, and 10x. Two versions of this sort are known, one having an all black shutter speed selector and the other having a silver ring. An additional version, and perhaps more desirable (if less common) one has the same range but is marked in one unit increments from 0-25x with every fifth mark being numbered.

Accessories

Apart from the previously mentioned camera backs a number of accessories were produced. Special viewfinder adapter plates and eyepieces were available for the various camera backs. It should be noted that these eyepieces were not the film area viewfinder eyepieces that would show the field that would be covered by various popular film sizes. Extension tubes were also available that would extend the distance between the final lens element of the shutter assembly and the camera back. Tubes were made in 2.5x and 5x lengths were produced and could be used in various combinations where special needs required.

Notes:

∗It should be noted that the connection to the shutter in all cases is a male dovetail and the designation here refers to the connection to the microscope photo-port.

†I’ve seen one in use during the course of a museum visit although I’d be hard pressed to say if it were an actually B&L item or the product of a machinist and a tight budget.

B&L Photomicrographic Apparatus III: Integrated Cameras

Microscope Stand Design

Around the halfway point of the last century (1940 or so) microscope design began to change drastically. Modern manufacturing and engineering, together with the proliferation of compact, bright, electric lamps contributed to an opticians ability to design microscopes which provided a new option for the photomicrographer. Contemporarily advertised as tri-nocoular (but more properly referred to as photomicrographic) microscopes began to become available with specialized camera ports that did not require interchanging a binocular body for a monocular body, or the occupation of a standard eyepiece tube by a cumbersome attachment camera.

At the time this was a considerable advance and as photographic process became more accessible and streamlined so too did the process of making ones microscope ready to capture an image. In many cases a microscope could be used visually as normal and simultaneously outfitted with appropriate apparatus capture images on a variety of media. Ones microscope could stand ready for either photomicrography or visual use and a great many sights that were only previously fleeting could be captured.

Regrettably, while some mechanical aspects such as the Royal Microscopical Society (RMS) thread, or 23.2mm eyepiece have become standard, the same can not be said of photomicrographic apparatus. For obvious reasons apparatus from one manufacture may not be compatible with another. Infuriatingly, apparatus from a given manufacturer may not be immediately compatible with a different line or generation of microscopes.

The Systems

It can be impossibly difficult to find information on the integrated camera systems of Bausch & Lomb, so forgive any inaccuracies and permit the establishment of two broad categories; the DynOptic/DynaZoom (hereafter DynaZoom camera) and the Integrated Camera System II (hereafter System II). Each was available with a range of formats and in a variety of styles with various interchangeable or permanently fixed accessories.

The DynaZoom camera was created specifically for the so named line of microscopes and was available throughout the life of that line. When the black finish stands were replaced by the slate finish models the cameras followed suit but maintained the established standards and are interchangeable with the earlier versions and vice versa.

The System II was in simultaneous production with the DynaZoom but was created so as to be compatible with a wide range of microscope lines and to offer improved options and forward compatibility. While still compatible with both the black and slate DynaZoom microscopes it could also be fitted to StereoZoom, and BalPlan microscopes as well as Bausch & Lomb Bench Metallographs, and inverted microscopes. System II also saw the introduction of automatic shutter control with electronic light metering.

One may immediately identify the camera system because in the DynaZoom cameras of every sort there is no independent magnification (focus) control. System II cameras of every sort feature a vertically oriented magnification (focus) control which may be marked from 0 too 25 or from 3x too 10x.

Sorry for the long silence, computer failure and a new job have eaten up a great deal of my time lately. I promise the next post wont be so far away. -K

B&L Photomicrographic Apparatus II: Attachment Camera

The Attachment Camera

The attachment camera as designed by Bausch & Lomb remained primarily the same over its production life. Changes to the apparatus itself were minor and all components have proven interchangeable if one is faced with assembling a complete working device from multiple units purchased separately for parts. The shutter features the following speed settings: 1/10, 1/25. 1/50, 1/100, 1/200, B, and T, and uses a standard cable release. There is no prism release as may be found on attachment cameras from other manufactures. This is a bit of a trade off, as without the prism release one can not direct 100% of available light to the camera. Fortunately, absence of a prism does eliminate its motion as a source of vibration during exposure. In place of a swing out prism a preferential beam splitter is fitted which directs 85-90% of available light to the camera and from 10-15% to the viewer. Aside from the camera itself (see below) the part most likely to be missing is the ocular sleeve which is a metal collar that slips over the tube of the microscope prior to the fitting of an ocular. The sleeve holds the shutter assembly in alignment with the optical axis of the microscope and holds the beam splitter at the exit pupil of the ocular.

This design requires a vertically oriented microscope tube. If used with a classic style B&L Dynoptic binocular microscope one will need to obtain the interchangeable monocular body. When attached the viewfinder projects horizontally towards a seated microscopist. There are two varieties of viewfinder both projecting significantly from the axis of the microscope so that the microscopist need not lean in uncomfortably when using the camera. Each sort makes use of a ground glass screen which the older version views through a large fixed focus condenser. The newer variety uses a spiral focus condenser that improves the clarity which one obtains to a certain extent, but does require that the user lean in towards the lens for proper viewing. Focus is entirely via the controls of the microscope.

Cameras

The camera bellows and bodies that are available for the unit run the gamut. Most common of the camera attachments is the 35mm camera body. The camera itself is often quite diverse and might be any of a half dozen different models. As of this writing the author has found the following 35mm camera bodies: Argus (stripped down, unknown model), Kodak Pony (without view finder), Kodak ColorSnap (complete with permanent lens mount). There are two lengths of bellows tube for the 35mm camera, one providing a 5x enlargement, the other 10x. Each tube is equipped with a dark slide.

Less common is the 2¼ x 3¼ cut film holder which is not equipped with a dark slide. The fixed enlargement factor metal bellows cone is felt lined internally and is confirmed as compatible with Kodak film holders and plates. There may or may not have been a ground glass focusing screen but considering the standard size of the film holder it is simple enough to obtain one from a third party source. Thankfully, a ground grass screen is not necessary as the film plane is parfocal with the fixed focus ground glass viewer. Film is only infrequently available from a limited number of suppliers but may be desirable if one has access to a dark room and a willingness to cut down more commonly available film stock. It is not compatible with the common 120 roll film Graflex camera backs without modification to the camera back or a homemade light seal.

The 2¼ x 3¼ Polaroid instant film pack camera backs may be found and makes use of the 10 exposure peel apart film now produced by Fuji. Although the images obtained are very nice, and provide an easy introduction to medium format photomicrography, the difficulty of pulling film from the camera (so that the chemistry is applied to the film) will require verification of alignment between exposures. The commonly available backs compatible with Graflex cameras are not compatible with the above described bellows. An additional model permanent camera is fitted to a plastic fixed enlargement factor bellows cone and is not outfitted with a dark slide. Unless one has a Polaroid back that is known to be interchangeable with a Kodak film holder it is advisable to obtain the permanent Polaroid version if one is set upon using that format.

The 4 x 5 camera bellows is infrequently seen but provides the best option for those interested in medium or large format photomicrography. A scaled up version of the 2¼ x 3¼ camera, it is metal and felt lined and like it’s smaller counterpart, also does not have a dark slide. The cone is compatible with 4 x 5 camera backs, of all sorts including cut film, film pack, and plate holders. Off the shelf 120 roll film backs from Graflex are compatible and the ease of using such a system can be an economical way for the beginner to get involved with large and medium format chemical photomicrography. Depending on the winder it may be necessary to remove the metal spring that holds cut film plates in place. Ground glass focusing screens are simple to find or make with a bit of glass and a dab or carborundum grit, but the original screen features a thick rubber frame.

Use

No doubt everyone can picture the attachment camera in use on a classic monocular microscope. In the interest of displaying something one might not have considered, below is an image of the attachment camera (with Polaroid back and spiral focus viewfinder) in service on a Phase Contrast DynaZoom as well as two detail images of the difficult to find ocular sleeve.

 

Notes:

∗Images in reference works term the apparatus the “Model N” attachment camera but I have not been able to locate the appropriate B&L catalog or manual to confirm the proper name.

†The camera back is slightly too wide and thick. A few minutes with a hobby grinder or similar tool is all that is needed to permanently adapt a roll film back. If one is unwilling to dedicate a camera back, a thick felt gasket may be glued to the back and cut so that it projects slightly into the bellows cone to prevent it from being jostled while in use.

‡The hardest part is cutting the glass to the right size and it isn’t even that hard if one has ever cut glass.

On Photomicrographic Apparatus

Modern Variety

There is a staggering amount of digital photomicrographic equipment. Modern student or college level microscopes outfitted for photomicrography have moved away from the previous standard of the tri-nocular head with detachable camera, and are now frequently found with dedicated integral digital cameras. The downside of such cameras aside from the added initial expense (which may double the cost of a comparable binocular microscope) is the inability to upgrade to a superior camera as advances are made or funds become available, and the software requirements. The upside is the possession of a tailored optical system that (ostensibly) has been designed with a knowledge of the microscopes optical system.

The contemporary alternative is the digital eyepiece camera or the eyepiece relay adapter. Despite the versatility of such things their occupation of an eyepiece may greatly complicate the normal use of the microscope. Such secondary optics might just as easily result in inferior image quality depending on the optical system of the microscope. Various artifacts and aberrations may be unavoidable and not immediately apparent.

Classic Variety

Putting aside the issue of format for a moment, classic photomicrographic equipment falls into the same two broad categories as modern digital photomicrographic gear. The traditional attachment camera was designed for use with monocular microscopes and many binocular microscopes were available with an interchangeable monocular body to be used with the photomicrographic outfit. Such apparatus was generally designed so as to use an ocular which could be varied depending on the objectives employed or magnification desired. Unlike modern equivalents most used a beam splitter to provide a viewing port for focusing, those which did not made use of a ground glass screen which could be interchanged with the film or plate holder.

The second category relied upon specialized microscope viewing heads which were designed with a beam splitter which would send a portion of the light into a photomicrographic camera system. Nearly all lines of microscopes by the major houses were available with photomicrographic heads of different sorts encompassing the solely photomicrographic (without provision for visual use) to the monocular and binocular photomicrographic (trinocular). Such microscopes relied on the use of compatible photomicrographic systems generally provided by the manufacturer.

Hazards

An off-the-shelf microscope equipped for digital photomicrography will undoubtedly function but one risks being tied to an overly simplistic microscope that does not meet the requirements of the microscopist as they grow in their ability. The same might be said of a modern or classic microscope outfitted with a digital camera and an eyepiece adapter, with the added difficulty of uncertainty of the suitability of the system. For modern photomicrographic equipment then the chief hazards is inferior equipment and the easy of excessive digital image modification.

Classic photomicrographic gear is only very infrequently available as a complete system in good working order. Obtaining results that do it justice is often heavily reliant on the ability of the user to locate and properly employ gear which was originally designed for use with a given microscope line. Such efforts are often complicated by the lack of relevant documentation or informed sellers§ who greatly increase the difficulty of locating equipment by selling it under some other designation. Recognizing compatible equipment on sight is inherently difficult. Attachment cameras using chemical photographic formats provide resolution that well exceeds consumer grade digital cameras, but one suffers for the time and expense of development and processing of significant numbers of test photomicrographs while getting the equipment in working order.

Recommendations

One can obtain a perfectly suitable modern microscope and outfit it for digital photomicrography at a reasonable cost, assuming of course the images are not required to be used for serious work. A student microscope designed for entry level photomicrography might easily run $500.00 US and one suitable for college level work could exceed $1000.00 without batting an eye. Regrettably, such microscopes are generally inferior to used professional microscopes of similar cost, but for assurance of capacity one could not be faulted for going that route.

A used professional grade trinocular microscope (such as the B&L DynaZoom, DynOptic, BalPlan, AO Spencer 10, Microstar, or 2/4) from any of the major houses may generally be found for far less than all but the cheapest modern student microscopes. Many microscopists have no interest in chemical photomicrography, however, what is seldom considered is that such microscopes as mentioned above existed at a time when the C-mount video camera was in wide use. After obtaining a trinocular microscope one should endeavor to find the c-mount photo-tube sold by the original manufacturer. This author is personally aware that such tubes exist for Bausch & Lomb and AO Spencer, an is told it is true of Olympus, Ziess, and Nikon as well.

One may just as well go the above route and in place of a difficult to find c-mount tube purchase a widely available Polaroid instant camera system designed for the microscope. Film remains available for the more common formats and one has all the benefits of chemical photography without the need of expensive darkrooms or tedious developing processes.

Notes:

∗As distinct from antique photomicrographic equipment which should be taken to include the bellows outfitted horizontal and vertical cameras.

†Alternatively the microscope head might be equipped with a control which would direct 100% of available light to either the ocular(s) or the photomicrographic outfit.

‡By this is meant the difficulty of using a system that can not be tested before hand—most equipment must be purchased on the internet—and the difficulty of recognizing unforgivable visual artifacts and aberrations as a beginner.

§Most of the authors photomicrographic equipment was obtained from dealers who incorrectly identified it as projection or aerial photography gear.