Archive for the ‘Compound Microscope’ Category

HardCORR Optics

Choosing a correction collar objective upfront will save you a hassle in the future

“Clayton, I need you to get down to the lab. There’s a problem with the 40x objective.”

I get to the lab after looking over the original quote. My eyes race down the line-by-line configuration to “Objective HI PLAN 40x/0.65.” The numerical aperture, 0.65, says it all. Coverslips only.

I put a slide down on my customer’s Leica DMi1 microscope and visualize it easily for them through the digital camera.

“All good?” I blankly ask, suspecting there is more.

“Now put on a well plate and tell me what happens,” asks my customer.

I grab her flask with a confluent layer of kidney cells in it and place it on the stage. My heart beats faster knowing what’s going to happen next. I’m able to visualize the cells in phase contrast at 20x. Check.

Switch to the 40X objective lens and then, “SHING-CHUNK!” As the 40x objective slides into place, the surface of the lens housing grinds against the stage insert and crashes into the plastic flask.

“Ohhh that is bad,” the PI says to me, “is there a way to fix this?”

Sure enough, the objective bumped into the bottom of the 2 mm thick flask due to the short working distance of the lens. This 40X lens is designed for the 0.17 thickness of standard microscope coverslips and has a free working distance of 0.36 mm. Plastic dishes vary in thickness, but most are 1mm thick. Too thick for the plastic flask the PI is attempting to use with the 40X objective lens. I explain the optical limitations of the lens and we agree that the 20x will get the job done for this flask.

Coverslips or plastic dishes, an impossible choice!

Right about now, the PI is wishing he had chosen the long working distance version of the 40x objective lens. The long working distance version is designed to focus through plastic cell culture dishes and flasks. This objective has a lower numerical aperture than the objective he currently has (0.50 vs. 0.65), but enough working distance to focus through thicker flasks and well plates. These lenses, although ideal for cell culture vessels, are not ideal for slides. When this microscope was purchased the PI prioritized slides over plastic dishes at 40X. It’s clear now that he needs an objective lens for both plastic vessels and slides.

If only there were a lens that could adjust for coverslips and plastic…

The product managers at Leica recognized that users need a lens for both plastic and glass, which provides an adjustment for either application. Leica offers an option for mid-range magnifications on inverted microscopes called a “correction collar objective” (CORR). The CORR brings flexibility and savings to imaging. A twistable, ribbed ring encompasses the circumference of the objective, marked by the numbers “0, 1, and 2.” These numbers stand for the thickness of the vessel (mm) that light must go through in order to properly focus on the sample. For slides, the correction collar can be adjusted to the “0” position to compensate for the thin coverglass. For well plates and petri dishes, the objective can be adjusted to the “1” position for optimal focus. Lastly, for vessels that utilize thick 3D matrix media, the lens can be adjusted closer to the “2” position for optimal focus and contrast.

So much value in CORR lenses

The CORR method saves users headache, space, and the cost of purchasing two objective lenses. Alternatively, choosing one lens design will limit the types of compatible vessels ultimately causing frustration and limitations to the types of experiments that can be completed. The investigator could go out and buy a revolving microscope, but the user is still limited by the lens that is being switched!

The use of two 40x lenses, with clear tradeoffs of numerical aperture/working distance, takes up an extra objective lens position. Depending on the number of objective lens positions on the microscope, two lenses may force researchers to have to put another magnification on the shelf. Lastly, purchasing a CORR objective in the beginning means the lab won’t have to duplicate spending. Users won’t be forced to purchase a second 40x lens when it becomes apparent that current experiments require long plastic or glass.

Seeing is believing

Fast forward two weeks, my fingers clench a test slide and a CORR 40X lens rests safely in my jacket pocket. I take off the existing non-CORR 40x from the DMi1 and slip on the new one. The ribbed ring marking rests under “0”, and my slide sits on the stage.







“Very good, Clayton. Now my flask.”

The plastic flask full of a neon red liquid comes out of the incubator and is placed on top of the DMi1. I twist that CORR to “1,” and go back to my 20x lens.



Fingers crossed now. My memory is vivid. I can hear the “SHING-CHUNK” of it grazing the harsh metal stage and crashing into the unforgiving plastic.


Silence. No sound. Only a clear layer of phase cells after a tad of focusing. “Nailed it,” I quietly said to myself.

Trust W. Nuhsbaum

Be hardCORR and choose Leica’s specialized CORR lens when imaging at 20X and 40X for glass and plastic. Don’t be limited to the types of vessels that can be used on your microscope – be limitless! When it comes to CORR, always better to have it and not need it than to need it and not have it.

Trust the microscope specialsts and imaging specialists at W Nuhsbaum to learn about your application and recommend the CORRect lens for the application.

Leica is MAD about LIBS

Leica LIBS is a verb

To LIBS or not to LIBS? That is the question. When analyzing material from ISO16232 cleanliness testing, users normally don’t care whether Laser-Induced Breakdown Spectroscopy (LIBS) is a noun, adjective or verb; they just want to know whether the large metallic particle is normal machining debris, or something more insidious, such as a bearing failure, hydraulic fitting failure, or a completely foreign object. Users know that they need to “LIBS the object” in question to acquire the elemental analysis needed to move to the next step of the manufacturing process.

Technology built into NASA’s Mars Rover means LIBS is out of this world

Although LIBS technology has been around since at least the 1960’s, it’s application did not garner mainstream understanding until, most notably, NASA’s Mars “Curiosity” Rover implemented the technology with its ChemCam in 2012. Since that mission, the technology has been implemented into all kinds of products with varying degrees of power, sensitivity, and resolution.

For all of it’s applications, LIBS has not been integrated into a microscope, until now. The Leica LIBS system focuses a columnated Nitrogen laser (337nm) to a 15 micron spot on the material. The laser then near-instantaneously heats the material to melting point, which converts it to a plasma. The energy from this process elevates electrons to a higher energy state and, upon return to the electrons’ resting state, release photons. The released photons travel through the microscope optics to a prism where they are spectrally detected within seconds.

The visible light spectrum created from the rapidly cooling plasma is unique to pure elements and/or alloys. In principle, the Leica LIBS system is able to produce a spectral fingerprint for the material – which can be referenced back to a known material from a user-created database.

Leica LIBS is a time machine

Until recently, materials laboratories completed elemental analysis exclusively on scanning electron microscopes (SEM) with Energy Dispersive X-Ray Spectroscopy (EDS). This technology has the advantage of being able to quantitatively analyze a particle’s chemical makeup. However, what SEM provides in quantitative analysis, it lacks in speed. On most SEM systems, scans that include elemental analysis can take minutes to hours – which can be a serious problem in a time-sensitive production environment.

Leica LIBS is different from SEM because if the user can see a metallic material, she can click a button to analyze the material – on the spot. No need to transfer the cleanliness filter paper or failed part to an SEM – just center the digital cross hair over the area of interest, click a button, and have an elemental fingerprint within seconds. This allows average users to provide quality managers qualitative information at Ludicrous Speed.

Leica LIBS is a decision machine

Leica LIBS is not SEM, nor does it replace SEM. Leica LIBS is a unique technology that provides quality managers with decision-making information quickly and easily.

  • Is the large particle a material that will grind parts in the field? Yes or no.
  • Is the particle from a failing washing system? Yes or no.
  • Is the particle cross-contamination from an adjacent workstation or line? Yes or no.
  • LIBS provides this information with a fingerprint reference from a standard and user-created library assembled from materials that occur within the facility.

    Leica LIBS is a promotion machine

    You don’t need to stay at a Holiday Inn Express to look really smart when you’re using Leica LIBS. Quality managers, engineers, and executives all look brilliant when they can solve a mechanical problem on the line within minutes. The failing element is the third bearing from the top. You can prove it – so don’t waste time looking anywhere else.

    The obvious and only logical next step is that you are labeled a genius by the CEO and promoted to the Board of Directors. Anyone that looks this good must go straight to the top!

    Trust W. Nuhsbaum

    Navigating the world of materials analysis doesn’t have to be slow or unnecessarily detailed. Materials engineers need actionable information fast to keep processes running at the quality that their customers expect.

    Trust the sales representatives and imaging specialists at W. Nuhsbaum to provide you with the tools and knowledge put the decision making information in your hands – fast.

    Look like a Cleanliness Expert

    You’re not fully clean until you’re ISO 16232 – fully clean!

    Manufacturing is just catching on to what bath soap companies have known for years – cleanliness sells product! In a never-ending quest for superior product and reliability, manufacturers, particularly in the automotive industry, are turning to the ISO 16232 standard to hold manufacturing practices to the same quality of engineering.

    Cleanliness standards are being applied to everything from drive train components to suspension and steering. Manufacturers have discovered that infrequently occurring metal objects can lead to component failure, costly repairs, and recalls.

    Increasingly, major automotive companies have been requiring suppliers to provide cleanliness information. Now, in order to maintain or earn new contracts, suppliers need to meet or exceed cleanliness standards set by the manufacturer.

    Although there are plenty of systems claiming to provide suppliers with cleanliness data, Leica has several easy to use and cost effective Cleanliness Expert systems that provide suppliers with ISO 16232 cleanliness results.

    Rinse, Baby, Rinse!

    Standard cleanliness procedure includes rinsing a part with a solvent and filtering the fluid through a 47mm diameter filter patch. The filter will catch inorganic material such as organic fiber, but it will also capture metallic debris. The metallic debris are concerning, depending on size they can either be insignificant or lead to component failure in a final product.

    Scanning the filter paper with a microscope can identify the difference between organic and metallic objects using a polarizer. Since metallic objects are highly reflective, the software compares the polarized and non-polarized images to identify objects that are reflective (metallic) and non-reflective (organic).

    Reduce User Errors with Leica

    Automation and routine save time, but they also significantly reduce user error. The Leica Cleanliness Expert system automates both hardware and software to make acquiring consistent conditions as simple as a few mouse clicks. With Leica systems, engineers can configure the image acquisition conditions and set the limits for cleanliness.

    Once the system has been configured, users can log into the system with restricted access to settings and quickly work through the guided acquisition procedure. Generating consistent and accurate results has never been easier!

    Reporting is also made easy and consistent with standard report templates – providing engineers and decision makers with the information they need in a familiar format.

    High Content Cleanliness Data

    In addition to providing engineers with XY size information, Leica also offers users the ability to provide Z data for the most detailed contaminant data. If a metal shaving is taller than it is wide, the motorized focus motor can capture an “extended depth of focus” image to calculate volume!

    This feature could be the difference between failure in the quality lab or failure in the product. Measuring contaminants in 2D only provides half the information; 3D is required for the full picture.

    Time Equals Money

    One unique feature of the Leica Cleanliness Expert system is speed. The software will acquire both brightfield and polarized light images rapidly with a filter wheel and provide analysis results during acquisition. Therefore, if there are too many contaminants detected at 25% complete, the user can cancel the acquisition and report the results.

    The high-speed filter wheel also means that the cleanliness scan happens more quickly. Other systems require manual polarizer switching leading to lost time and possible error. In a setting where results have to happen quickly and accurately for a shipment to leave the building, time equals money!

    Money Equals Money

    Leica offers a variety of configurations for Cleanliness Expert systems to meet just about any budget. The fully automated system, which is the pinnacle of speed, accuracy, and quality, may fit into the manufacturer’s budget, but it may not fit into the supplier’s budget.

    However, the suppliers need to meet cleanliness to maintain and win new contracts – so Leica offers fully configurable semi-automated systems and manual systems to meet budget. At the entry level, a system can be configured with one of Leica’s digital microscopes!

    Along with affordable Cleanliness Systems from Leica Microsystems, for a limited time, W. Nuhsbaum, Inc. is offering up to $2,500 savings with any Leica Cleanliness Expert system purchased before June 30th, 2016. There has never been a better time to have the experts at W. Nuhsbaum, Inc. provide you with a system that meets your needs and your budget!

    Trust W. Nuhsbaum, Inc.

    With 35 years of experience in microscopy and a track record of delivering results for customers with cleanliness systems across the Midwest, the sales representatives and imaging specialists at W. Nuhsbaum, Inc. are qualified and prepared to deliver results for your company.

    Contact your representative to learn more about the Leica Cleanliness Expert system and how much you could save!

    Leica DMi8 C: Work faster with the 0.7X lens

    Microscope Marco Polo: Why the 0.7X lens on your DMi8 C helps you find what you are looking for

    For years metallurgists have preferred inverted microscopes for sample leveling simplicity and the ability to accommodate large materials. However, one of the major sources of frustration with inverted microscopes is the inability of the user to quickly scan a sample before switching lenses for increased magnification and inspection.

    On an upright microscope, the user simply needs to look down at the sample on the stage to get a quick perspective on the sample location, but on an inverted, the user needs to do handstands to see the sample under the stage and around the objective lenses.

    Short of enrolling in gymnastic classes, there is no convenient way to look under the microscope stage. This inconvenience persists on modern inverted microscopes. That is, until recently when Leica introduced the DMi8 with a new tube lens and a 0.7X macro lens. The improvements in the microscope optics and objective lens provide an incredible 36mm field of view, which rivals the perspective provided by stereo microscopes!

    Provide Perspective for Reports

    The benefits of a 0.7X lens are simple: scan samples for defects, features, and areas of interest faster and more efficiently, thus saving you time and the company money. An added benefit is that you will look like a genius when users can provide engineers and executives with concise reports they can see and understand.

    The cliché of “a picture is worth 1,000 words” applies when the 0.7X lens is used to provide perspective for reports. When combined with Leica Application Suite (LAS) software, the 0.7X lens can provide a large overview image to go with a high magnification image that highlight subtle details. Combining the two images is made easy with LAS Analysis Suite which includes LAS Extended Annotation. With LAS Extended Annotation, users can easily overlay a high magnification image onto the large low magnification image acquired with the 0.7X lens. With easy to interpret information from LAS Analysis, engineers and executives can make decisions quickly and easily.

    Make Big Measurements

    With the Leica DMi8 C, 0.7X lens, and LAS Analysis software, users can make measurements on a macro scale. Is the feature of interest larger than the field of view? Is the measurement made at higher magnification missing the perspective of a related feature?

    Make big measurements with the 0.7X lens and the Leica DMi8 C inverted microscope. Since the Leica DMi8 C comes in two configurations with digital coding, lens calibration updates automatically depending on the position of the microscope. Therefore, regardless of whether measurements are made with the 100X lens or 0.7X lens, scale bars and measurements will be mistake-free.

    Save Big with Leica Promotions

    With the introduction of the Leica DMi8 C, Leica is offering the analysis package for Leica Application Suite free of charge. This allows users to make 2D measurements to manually measure distance, area, and points with a simplified reporting process at the end. Users can also create threshold profiles and with the use of filters, automatically count features in one or 100 images!

    Since the images have embedded calibration data from the microscope objective lens, users can make measurements without calibrating images. Engineers can trust the accuracy because Leica’s intelligent automation has eliminated user error.

    Trust W. Nuhsbaum, Inc.

    Through years of customer feedback, Leica Microsystems has developed an inverted microscope that addresses the needs of metallurgists in the Leica DMi8 C. With the power of the 0.7X lens, users have unprecedented perspective of their samples, and with the current Analysis promotion, users have never had a better opportunity to invest in a new digital inverted microscope.

    Of course, the best microscope, camera and software in the world would be useless without the knowledge, training services, and expertise of the sales representatives and imaging specialists at W. Nuhsbaum, Inc. Contact your local representative to learn more about the Leica DMi8 C, 0.7X lens, and the current Analysis promotion that will save you more than $3,100.

    Color Infidelity: Why Choosing the Wrong Lens is Like Cheating on your Data

    The Microscope Objective Lens is a Critical Decision

    When choosing a microscope and the associated lenses, many microscope users understand that the objective lens is a critical component to producing an excellent image. However, many people, when faced with the ultimate decision of what objective lens to select, do not have all the information to make an informed decision.

    Simple and easily digestible information provided by lens manufacturers include immersion and numerical aperture. This information is in large print on the lens and makes it into the lens description on every quote. Aspects that are less obvious are levels of planar correction, registration in Z, lens coatings, and correction collars. These items are less obvious on a quote but critical to an excellent image that produces equally excellent data.

    The objective class you choose, such as an Achromat, Semi-Apochromat, or Apochromat, will affect the final image. The ability of a lens to efficiently pass light and have the respective wavelength reach an identical focal plane is what the user observes in every image. When light is passed inefficiently at different points in the light spectrum or when wavelengths of light reach different focal planes, the final image is degraded which influences resolution, contrast, and color reproduction.

    Correcting Lenses for Color in Brightfield

    Dominant sources of distortion change with magnification, however, as a general rule correction is more critical at higher magnification. The simple answer is that imperfections are, well, magnified. However, regardless of magnification there are critical distortions that need to be corrected for an ideal image. Although not a complete list, these include field curvature (flatness of field), spherical aberration, image distortion, and axial color.

    Without proper correction images appear out of focus on the edges (field curvature), blurry (spherical aberration), oddly shaped (distortion), and color fringes (axial color). Many of these corrections are addressed in every objective lens, however, the degree to which they are corrected depends on the name of the lens. For instance, although imperfect, Plan Apochromat has a higher degree of correction than Plan Achromat. Both are corrected, just at different levels.

    In addition, although there are industry standards for lens correction, there is variance between manufacturers. In other words, just because two companies are presenting Plan Apochromat lenses does not mean they are identical in the quality of their correction.

    All of the sources of a degraded image come down to contrast. Assuming the microscope has been aligned for Kohler illumination, the contrast provided by the lens provides the clean edges, crisp and vibrant color in a final image.

    Correcting Lenses for Color in Fluorescence

    Fluorescence presents its own set of challenges because of the nature of single wavelength excitation and emission and low light. Since glass passes light at different speeds depending on the wavelength being used, correcting for spherical aberration is a critical component particularly in multi-channel fluorescence applications.

    Without correcting for spherical aberration, features in different fluorescence channels will appear in different focal planes. This is most noticeable in achromat lenses, but it can be detected in Plan Apochromat lenses in applications such as confocal microscopy.

    In addition to Z registration of each wavelength, the objective lens will also pass light more or less efficiently based on wavelength. For instance, assuming the light source is providing an equal number of photons at each wavelength of light, an objective lens will pass the 500nm wavelength more efficiently than 400nm. This mean that labels that emit at the 500nm wavelength will appear brighter simply because of the objective lens being used!

    Brightness variability is present throughout the visible light range, however, it can be corrected – albeit differently by each manufacturer. A general rule of thumb is that an Apochromat will be superior, however, without the transmission data for each lens, or a spectrophotometer, it is impossible to know.

    Immersion matters

    Whether you are imaging histology slides, observing adherent cells on a live cell imaging system, or focusing deep into brain tissue, there is a lens that is specific for the application. One of the most important, and often overlooked features of the lens is immersion and numerical aperture (NA). Similar to camera megapixels, many assume the higher the NA the better the resolution. Not true! The better the contrast the better the resolution!

    As explained earlier, eliminating aberrations and distortions improve contrast which in turn improve resolution. So although NA is an important feature to resolution, it is not the only feature.

    When selecting an immersion lens it is important to consider the medium that will be used. Will there be an aqueous medium as with live cells, dehydrated and mounted tissue section, or fresh brain tissue in solution? Each medium will dictate whether oil, glycerol, or water immersion is required. Without the immersion medium matched to the mounting medium distortions will degrade the resolution. One is much better selecting a lens with a lower NA that matches the mounting medium!

    Trust W. Nuhsbaum, Inc

    When evaluating lenses and microscope systems having a person to guide you through the decision making process is critical. The ability to offer information and expertise will ensure that you, the user, will end up with a system that is optimized for your experiments.

    The microscope and imaging specialists at W. Nuhsbaum, Inc. have the expertise and resources available to make proper recommendations that go beyond megapixels and numerical aperture. Trust W. Nuhsbaum, Inc. to guide you through the microscope configuration process.

    Using Köhler every day

    Using Köhler every day: Tips you will not want to flush down the toilet

    Although most people are familiar with the word “Köhler” because of the brands world class bathroom fixtures, the global brand does not define the people with the last name Köhler. That is certainly the case for August Köhler who changed microscopy in 1893 by developing a method of transmitted light illumination that produced even illumination across the field of view. Prior to August Köhler’s innovation, the predominant method for aligning the lenses required for optimal light was critical illumination. The most significant shortcoming of critical illumination was that the bulb filament is visible in the resulting image. Insert August Köhler and the bulb filament disappears in the final image.

    What is Köhler Illumination?

    Köhler Illumination is a perfectly aligned optical path relative to the sample and objective focal plane. Put simply, it’s when every lens is in the correct position to provide perfectly even light across the field of view with optimal brightness, color, contrast, and resolution.

    Why Köhler Illumination is Important for everyone

    Many upright microscope users overlook the bottom half of their microscope, or top half for inverted users. This is the unexciting portion of the microscope because it’s lacking eyepieces, camera mount, and the exciting objective lenses. However, the ignored half of the microscope is critical because it contains optics that determine the success or failure of your imaging work.

    When a microscope is aligned with proper Köhler Illumination, the condenser is at the correct height relative to the sample, the field diaphragm is adjusted to eliminate reflections and glare, and the aperture is moved to an optimal position to provide contrast without producing shading artifacts. This benefits the user in many ways with a bright and clean image – but also a dirt free image! When a microscope is in Köhler, the hidden dust and smudges in an optical system disappear! This is the genius of August Köhler, lens surfaces, which are home to dust and debris, are placed in an intermediate focal plane and invisible to the microscope detector (your eyeballs or the camera).

    Without proper microscope alignment, the image will look washed out, dirty, fuzzy, or it could look dim, too much contrast and produce halos in the image.

    Only upside to Köhler Illumination

    Aligning your microscope is easy and it will only make your images, and the resulting data, better and more convincing. So how do you accomplish this task? Excellent question, I’m glad you asked.

    Step 1: Focus the microscope to the sample.

    Step 2: Adjust the field diaphragm until you see an octagon in the field. No octagon? No problem, move to step 3.

    Step 3: Adjust the condenser height until the edges of the octagon are in focus. This is the smaller focus knob directly below the stage. You know, the one you always grab to focus the microscope before you realize you are not focusing the microscope? That one. If all you see is a shadow in the background, or a general darkening of the image, your condenser is too far away from the sample. Move it closer to the surface of the slide and keep an eye out for the octagon!

    Step 4: Using the knurled knobs that stick out of the front of the condenser base, those knobs that you always grab when you want to “fiddle” with the image, align the octagon until it is in the center of the field of view. When complete, adjust the field diaphragm just outside of the field of view.

    Step 5: Perhaps the most critical and most often overlooked step, adjust the aperture. This is often the slider that is built into the condenser, you know, the one you slide back and forth in the hopes of creating a better image? Well, this time you will remove an eyepiece and look through the optical tube without an eyepiece. Now, slide the aperture back and forth, just like old times. Then, once you see the octagon position it so that it covers 1/3 of the field of view. Put the eyepiece back in and you have a perfectly aligned microscope!

    Impress your friends!

    If you want to impress your friends or pretend to be a microscope snob, teach everyone in the lab your new found knowledge. You can also visit Leica Science Lab for an interactive tutorial.

    If you are tired of constantly correcting the lighting, field diaphragm, aperture, and other optical components, check out the fully automated DM4, DM6, and DMi8 to simplify routine microscope tasks through intelligent automation. If you would like to learn more about intelligent automation, you can contact us anytime to see what an automated Leica microscope can do for you.

    My microscope stinks! The misunderstood 40X correction collar lens.

    When consulting on an inverted microscope purchase, one question I always ask is whether the lab intends to use coverslip bottom dishes or plastic vessels. In approximately 9 of the 10 conversations the investigator says, “both.” How silly of me to ask.

    Many companies would simply provide a long working distance lens that was designed for plastic, but worked just fine for glass as well. However, many years ago, Leica designed a lens with a correction collar that would allow the user to account for the different properties of glass or plastic – particularly thickness. The user simply needs to twist the lens housing to adjust internal lenses up and down. Whether the lenses are “up” or “down” will align the lenses to provide the sharpest image possible for the vessel being used. Thankfully there are even handy little markings on the lens that give the user reference points for lens adjustment.

    Inevitably I will visit the lab months, or in many cases years, later and users complain that the 40X lens is bad. Other users say, “We don’t use the Leica because the 40X lens doesn’t produce the images we need.” Comments like this leave the 40X microscope lens feeling sad and forlorn. Fear not, the 40X lens has great resolve-ing power. If you listen closely, you can hear it whispering, “What you perceive as my biggest weakness is actually my greatest strength.”

    I certainly hear the whisper when I walk into the lab, which is why I stand up in support for the 40X correction collar lens: “You Sir, were designed for a greater purpose!” Once the new users are educated on the virtues of adjusting the 40X lens, they see the difference in a properly adjusted lens in all lighting techniques – even low-resolution techniques such as phase contrast. Among the many benefits the user will notice are increased resolution, improved flatness correction, and increased brightness. In fact, once the lens is correctly adjusted, many people can’t help but say, “WOW!” This is uplifting for the lens and motivates it to perform at its best!

    The difference is critical for techniques such as Differential Interference Contrast (DIC) and fluorescence. DIC depends on correct optical adjustment because of the light sheer that takes place in the prisms and polarizers, which are required for the technique. If the lenses are out of alignment, the angle of the light sheer is not optimal; the image looks fuzzy, and lacks contrast.

    For fluorescence microscopy, light is at a premium and lenses that are out of alignment do not transfer light efficiently. They also take the single points of light that are generated by fluorescent labels and turn them into giant fuzz balls – great for stuffed animals, not so great for your eight hour experiment.

    Making the correction collar adjustment is simple: adjust the correction collar clockwise, focus the microscope on your sample, adjust the correction collar counter clockwise slightly and refocus the microscope. Repeat this process until you are satisfied with the image. There is no “focus indicator” with this process, simply trust your eyes. They are one of nature’s best detectors! If you use the same vessels for your experiments you may consider making a small mark on the lens housing to make adjusting the lens faster. It will also help you show your less technically inclined colleagues how to adjust the lens properly.

    So before you blame your Leica microscope for behaving badly, double check the correction collar on your 40X lens for proper adjustment. And if it’s the 20X lens that you are mad at, check that lens too. Leica makes both 20X and 40X long working distance lenses with correction collars. So don’t get mad, just get smart and look under your microscope stage to see if you have a correction collar on your rig.

    Before starting your next experiment or snapping your next picture, do not forget to adjust your lens, it could be the difference you were looking for in your experimental data. Only then will thank Leica for making a lens that gives you the flexibility you need in your lab.