Understanding Microscope Objectives - objective of microscope

 2024-08-02 03:30:51

Now, to be fair, Target Test Prep does offer a digital eBook, but really this doesn’t even compare to Kaplan since they provide their students with a bundle of comprehensive prep books packed with substantive instruction, test taking strategies, practice problems, and more.

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Lastly, Kaplan beats Target Test Prep when it comes to practice tests. Kaplan offers six (6) full-length simulated exams, whereas Target Test Prep only offers two (2). Not to mention, the Kaplan exams are official exams from past administrations of the GMAT Focus.

🚨🚨 Update: When we reference Kaplan in this post, we are also referring to Manhattan Prep, as the two companies merged their GMAT prep courses last year under the “Manhattan Prep Powered By Kaplan” brand.

Now there is some fine print behind this guarantee, so you’ll definitely want to read up on that before purchasing, but with that said, it’s still a nice insurance policy, especially considering Kaplan does not offer the same type of guarantee with their GMAT courses.

Axial chromatic aberration correction is divided into three levels of achromat, semiapochromat (fluorite), and apochromat according to the degree of correction. The objective lineup is divided into the popular class to high class with a gradual difference in price. An objective lens for which axial chromatic aberration correction for two colors of C ray (red: 656,3nm) and F ray (blue: 486.1nm) has been made is known as Achromat or achromatic objective. In the case of Achromat, a ray except for the above two colors (generally violet g-ray: 435.8nm) comes into focus on a plane away from the focal plane. This g ray is called a secondary spectrum. An objective lens for which chromatic aberration up to this secondary spectrum has satisfactorily been corrected is known as Apochromat or apochromatic objective. In other words, Apochromat is an objective for which the axial chromatic aberration of three colors (C, F, and g rays) has been corrected. The following figure shows the difference in chromatic aberration correction between Achromat and Apochromat by using the wavefront aberration. This figure proves that Apochromat is corrected for chromatic aberration in wider wavelength range than Achromat is.

Low powerobjective microscope function

Yes, their courses are more expensive, but all in all, I just think that their program is far more comprehensive and effective. Kaplan pretty much beats Target Test Prep in every category that truly matters: video lessons, practice tests, live classes, prep books, and more.

Photography or image pickup with a video camera has been common in microscopy and thus a clear, sharp image over the entire field of view is increasingly required. Consequently, Plan objective lenses corrected satisfactorily for field curvature aberration are being used as the mainstream. To correct for field curvature aberration, optical design is performed so that Petzval sum becomes 0. However, this aberration correction is more difficult especially for higher-magnification objectives. (This correction is difficult to be compatible with other aberration corrections) An objective lens in which such correction is made features in general powerful concave optical components in the front-end lens group and powerful concave ones in the back-end group.

Lastly, Target Test Prep does a really good job with performance data and analytics. I was very impressed with the level of detail included in their reports.

At $229/month, this is a killer value. Given that it only takes 60-90 days to effectively prep for the GMAT Focus (when you can dedicate the time), your all-in cost will be somewhere between $460 and $690. This is a great value.

Kaplan has been one of the biggest names in GMAT prep for decades, but recently combined their GMAT prep program with sister company Manhattan Prep’s to form a new, more powerful GMAT Focus prep course. In this post, we explore how this new combined GMAT course compares against one the other most popular courses out there—Target Test Prep.

The videos from Kaplan, on the other hand, are actual lessons, not just short problem explanations. The Kaplan lessons are in-depth, engaging and offer tons of useful content review.

After testing and evaluating the GMAT study materials from both companies, our team believes Kaplan offers the more complete and effective GMAT Focus course from top to bottom.

Function ofcondenser inmicroscope

An optical microscope is used with multiple objectives attached to a part called revolving nosepiece. Commonly, multiple combined objectives with a different magnification are attached to this revolving nosepiece so as to smoothly change magnification from low to high only by revolving the nosepiece. Consequently, a common combination lineup is comprised from among objectives of low magnification (5x, 10x), intermediate magnification (20x, 50x), and high magnification (100x). To obtain a high resolving power particularly at high magnification among these objectives, an immersion objective for observation with a dedicated liquid with a high refractive index such as immersion oil or water charged between the lens end and a specimen is available. Ultra low magnification (1.25x, 2.5x) and ultra high magnification (150x) objectives are also available for the special use.

In the optical design of microscope objectives, commonly the larger is an N.A. and the higher is a magnification, the more difficult to correct the axial chromatic aberration of a secondary spectrum. In addition to axis chromatic aberration, various aberrations and sine condition must be sufficiently corrected and therefore the correction of the secondary spectrum is far more difficult to be implemented. As the result, a higher-magnification apochromatic objective requires more pieces of lenses for aberration correction. Some objectives consist of more than 15 pieces of lenses. To correct the secondary spectrum satisfactorily, it is effective to use "anomalous dispersion glass" with less chromatic dispersion up to the secondary spectrum for the powerful convex lens among constituting lenses. The typical material of this anomalous dispersion glass is fluorite (CaF2) and has been adopted for apochromatic objectives since a long time ago, irrespective of imperfection in workability. Recently, optical glass with a property very close to the anomalous dispersion of fluorite has been developed and is being used as the mainstream in place of fluorite.

I was personally very impressed by the Kaplan GMAT instructors. They are some of the best in the business. Not only do they know their stuff inside and out, but they also do a really good job of keeping the live sessions engaging and fun too.

Both companies offer live GMAT classes. After using both courses, we found the Kaplan/Manhattan Prep classes to be more insightful and useful.

The second win for Target Test Prep is their score improvement guarantee. Essentially, after completing the Target Test Prep course, if your GMAT score does not improve by at least 130 points, the company will issue you a refund.

The content in the Kaplan videos is on point and the production quality is first rate. Thus, if you’re more of a visual learner, take note.

Target Test Prep takes a streamlined, digital approach to GMAT prep that revolves around practice problems and a heavy focus on quant, while the Kaplan GMAT courses are more comprehensive in terms of features and study materials (e.g. live classes, prep books, video lessons).

What isobjective lensinmicroscope

Now that you have a better understanding of what Kaplan has to offer, let’s discuss Target Test Prep. I have the company beating Kaplan in three categories.

Objective lenses are roughly classified basically according to the intended purpose, microscopy method, magnification, and performance (aberration correction). Classification according to the concept of aberration correction among those items is a characteristic way of classification of microscope objectives.

Meanwhile, an objective lens for which the degree of chromatic aberration correction to the secondary spectrum (g ray) is set to medium between Achromat and Apochromat is known as Semiapochromat (or Flulorite).

High powerobjective microscope function

In my opinion, these prep books together make for a very powerful prep resource, especially if you’re more of an old-school type of learner like me that likes to read through actual physical books, highlight key points, and dog-ear pages to revisit later.

Target Test Prep offers several different plans, ranging from just $229 per month to $1,600. However, the one I most want to discuss is their month-to-month recurring subscription.

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The purposes of optical microscopes are broadly classified into two; "biological-use" and "industrial-use". Using this classification method, objective lenses are classified into "biological-use" objectives and "industrial-use" objectives. A common specimen in a biological use is fixed in place on the slide glass, sealing it with the cover glass from top. Since a biological-use objective lens is used for observation through this cover glass, optical design is performed in consideration of the cover glass thickness (commonly 0.17mm). Meanwhile, in an industrial use a specimen such as a metallography specimen, semiconductor wafer, and an electronic component is usually observed with nothing covered on it. An industrial-use objective lens is optically designed so as to be optimal for observation without any cover glass between the lens end and a specimen.

An objective lens is the most important optical unit that determines the basic performance/function of an optical microscope To provide an optical performance/function optimal for various needs and applications (i.e. the most important performance/function for an optical microscope), a wide variety of objective lenses are available according to the purpose.

Function ofstage inmicroscope

Therefore, Kaplan effectively offers 3x as much opportunity to practice under exam-like conditions, and considering the fact that students often make the biggest gains by taking and reviewing practice tests, this is pretty big advantage for Kaplan.

Objective lensmagnification

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The company’s tech is able to identify your behavioral tendencies, answer habits, and subject area weaknesses so that you know what topic areas to focus on and how to tweak your test taking strategies moving forward in order to keep improving.

Kaplan also beats Target Test Prep when it comes to prep books. Frankly, this is another easy win for Kaplan as Target Test Prep does not offer its students any hardcopy prep books whatsoever.

In the video above, John from the Test Prep Insight team compares the GMAT prep courses from Kaplan and Target Test Prep. For more detail, be sure to continue reading our full written review below.

Typesof objectivelenses

In this post I am going to focus on the key areas where I see each company having an advantage over the other (as opposed to a broad overview of each GMAT course). So with that in mind, let’s start with Kaplan. I have them winning in four key categories.

A variety of microscopy methods have been developed for optical microscopes according to intended purposes. The dedicated objective lenses to each microscopy method have been developed and are classified according to such a method. For example, "reflected darkfield objective (a circular-zone light path is applied to the periphery of an inner lens)", "Differential Interference Contrast (DIC) objective (the combination of optical properties with a DIC( Nomarski）prism is optimized by reducing lens distortions)", "fluorescence objective (the transmittance in the near-ultraviolet region is improved)", "polarization objective (lens distortions are drastically reduced)", and "phase difference objective (a phase plate is built in) are available.

Although there’s a lot to like about the GMAT course from Target Test Prep (namely its affordable price, score improvement guarantee, and performance insights), I ultimately have to give the win to Kaplan and Manhattan Prep here.

The greatest highlight of the Kaplan course is the video lessons. To put it simply, they’re just better than the video lessons from Target Test Prep. I know Target Test Prep likes to make a big deal about the number and quality of their “video lessons,” but in reality, these videos are just practice problem explanations.