You might think that you’re above this kind of mental lapse, that you always see things objectively and logically, but you’d be wrong.

As details get smaller (represented by a smaller red cone), the bundles in Figure 3a and 3b move closer together. Eventually, increasing the f/# too much causes smaller details to blur due to reaching the lens diffraction limit, since the limiting resolution of the lens is inversely proportional to f/#. This limitation means that while increasing the f/# will always increase the DOF, the minimum resolvable feature size (even at best focus) increases. For more information on the diffraction limit and its relationship to f/#, see The Airy Disk and Diffraction Limit. Using short wavelengths helps to salvage some of this resolution. Learn more about how wavelength affects system performance in MTF Curves and Lens Performance. Note that this diffraction effect is not viewable in Figure 3, but that it is mentioned here as something to mind.

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And it’s not your fault. There are many pre-med myths and misconceptions that are perpetuated by the hivemind, a mob mentality that arises from internet hearsay and a fear of missing out (FOMO, as the kids call it).

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“Does this lens have good DOF?” It is difficult to quantify without specifying an object detail size or image space frequency. The smaller the detail, the higher the spatial frequency needed, and the smaller the DOF the lens can produce. A DOF curve can be used to see how a lens performs over a given depth at a specific detail’s size (Lens Performance Curves). These graphs not only consider theoretical limitations associated with the f/# setting, but also the aberrational effects of the lens design.

In general, when lenses are focused at short WDs, the large cone angles cause the cones to diverge very quickly on either side of best focus, leading to limited DOF. For objects in focus at longer WDs, the transition rate of the bundles decreases and DOF will increase.

For a healthier approach to your application, click here to find out what really separates the typical from stand-out pre-meds.

It was that simple in the book; if you had a ticket, you got to enter. And that’s how the Golden Ticket myth tricks you. It deceives you into believing there’s a secret, hidden method or formula that will guarantee success. If you have X, or if you can get Y position, you’ll be irresistible to every medical school you apply to. It’s at the heart of the easy thinking that plagues all the myths on this list.

What is depth of field microscopeformula

As illustrated in the italics above, a good pre-med example of the False Dichotomy myth is the belief that DO programs will determine your range of future specialties. In essence, it’s MD or bust in some people’s minds when it comes to competitive specialties like surgery. This notion might lead you to believe that DOs exclusively fill primary care specialties, with no grey areas or exceptions in between.

Figure 9 shows the change in MTF performance at the corner of the image for this 35mm lens assuming 25µm of tilt, seen in Figure 8. Figure 9a shows the new performance of the lens at f/2.8; note the decrease in performance from Figure 9a. Figure 9b shows the performance shift at f/5.6, which is minor compared to 9a. Most importantly, the lens at f/5.6 will now outperform the one at f/2.8. The drawback to running systems at f/5.6 is three times less light relative to f/2.8 and this can be problematic in high speed or line scan applications. Finally, if the sensor is tilted about the its center, performance decrease occurs at both the top and bottom of the sensor (and the corresponding points in the FOV), since the ray bundles expand after the best focus. No two camera and lens combinations are identical. When building multiple systems, this fact can manifest at different degrees of magnitude.

Depth offocus in optics

Due to similarity in name and nature, depth of field (DOF) and depth of focus are commonly confused concepts. To simplify the definitions, DOF concerns the image quality of a stationary lens as an object is repositioned, whereas depth of focus concerns a stationary object and a sensor’s ability to maintain focus for different sensor positions, including tilt.

The Golden Ticket myth partly arises from our inability to distinguish the part from the whole (i.e. it was X reason why I did or didn’t get in, rather than a bevy of factors weighed holistically). It also stems from our inability to accept the concepts of luck, chance, and all the small aspects that are out of our control.

Do MDs really have more success than DOs in residency applications? The verdict is that both types of programs can get you into residency programs, no matter their ranking. Sure, MD programs might help you slightly for more competitive specialties, but looking at it in such an all-or-nothing way is reductive.

In an era of fake news and an explosion of opinions on social media, you may have heard the term “confirmation bias” before. If not, it’s pretty simple - it means we tend to seek out and believe information that reinforces our pre-existing opinions.

Sure, that formula of activities worked for your cousin, one person, but there were many other factors at play (his background, GPA, MCAT, overall time commitments and responsibilities, etc.) that affected his success. Attributing it to his volunteer capacity and amount of research alone is a False Cause myth, since you’re creating a correlation that is built on a limited and short-sighted premise.

That’s where the Slippery Slope myth ends for most pre-meds - rejection - not getting in. When voices are telling you that something always or never leads to rejection, speaking in such certain extremes, it’s hard not to listen. The Slippery Slope or Hasty Generalization myth makes a haphazard leap in logic which plays off our fears.

Not exactly. You can’t compensate for iffy stats, limited clinical experience, and typical background by maximizing the amount of applications you submit. If anything, the cumbersome amount of work you’ll be doing to complete the applications will be a detriment to their quality.

It’s usually something relatively minor, like getting a C in freshman biology or taking science courses at a community college. Maybe even choosing a non-science major. But the trolls are hasty in their generalizations, letting small things snowball, claiming others will never get into medical school due to X, Y, or Z reason.

Whether it’s online through forums like Student Doctor Network (SDN) or reddit, you are constantly inundated with advice (both wanted and unwanted), and it’s tempting to take whatever advice sounds good or most convenient for you.

Figure 5 shows the same concept as Figure 4, but the cones represent multiple points in the FOV. Each detail and subsequent space represent one line pair. The overlap in the bundles in Figure 5a shows how the information blends together faster than that of Figure 4b and shows how two different object details can blur together due to a lower f/#. In Figure 5b, this does not occur due to the higher f/# of the lens.

But you won’t even be getting the benefit of the 50/50 coin flip. More likely, you’ll just be eating massive application fees and ending up in the application slush piles.

This myth has us clamoring for a guaranteed solution, perhaps to absurd lengths, but that solution will always remain elusive… because it doesn’t exist.

In some cases, we’ve paraphrased actual comments from these online forums (see the italics below); others are derived from years of working with students who continuously cite these sources as the Gospel Truth of admissions.

Sure, there are stories of pre-meds who have miraculously pulled off this numbers-game approach, but that’s the same as people winning the lotto or beating the house at a casino. They’re the anomaly that helps to feed the myth. You’ll find far more people with crumpled lotto tickets and empty pockets.

That’s how the Sunk Costs myth operates. It tricks you into the idea of feeling “pot-committed” - or obligated to finish something - strictly due to the energy previously spent.

Whathappens to thedepth of fieldas total magnification decreases

In some cases, certain factors will prevent you from getting in, but majoring in anthro is not one of them. Neither is getting a C in freshman bio. Small blips can be compensated for, and many academic paths can lead to pre-med success.

Figure 2 features the same lens as Figure 1a but at a different WD. Note an increase in DOF occurs at longer WDs. Eventually, as the lens focuses on objects infinitely far away, the hyperfocal condition occurs. This condition is reached at the distance in which everything appears in equal focus.

Like wikipedia, these sources are a great place to start when doing research, but they can’t be viewed as the end-all-be-all. Here’s why:

In Figure 1, contrast values (y-axis) are seen over a WD range (x-axis) at a fixed frequency of 20$ \small{\tfrac{\text{lp}}{\text{mm}}} $ (image detail). Note the difference in DOF between Figure 1a, which is set at f/2.8, and Figure 1b, which is set at f/4. Also note that there is more usable DOF beyond the best focus than between the best focus and the lens, due to magnification decreasing. The graphs themselves contain different colored lines denoting different sensor positions. These types of asymmetric DOF curves are common in fixed focal length lenses.

This is NOT to say that disadvantaged candidates don’t face significant challenges, or that emotional and mental health aren’t valid. ‘Do no harm’ includes your own self-care. The point is that there’s a clear line between legitimate disadvantage and fabricated sob story. If you let the facts of your circumstances speak for themselves and don’t editorialize, you can achieve the pathos you want while also maintaining a sound argument. Â

You might follow the same path and wind up miserable and overworked, without much to make you stand out. Do not jump to conclusions about causality or you’ll wind up a casualty.

The red cone in Figure 3 is an angular representation of the system resolution. Where the lines of the red cone and dotted black cone intersect defines the total range of the DOF. The lower the f/#, the faster the black dotted lines expand, and the lower the DOF.

We encourage you to bend conventions and plot your journey in your own distinct way, free of the false dichotomies placed on you.

The Appeal to Authority myth is particularly hard to shake. We’re taught from a young age to listen to our elders and heed the wisdom of those with more experience. As a pre-med, you should recognize how much of a novice you are in the grand scheme, but you shouldn’t blindly follow advice from someone just because they’re on a higher rung of the ladder than you.

Depth of focus is the image-space complement of DOF and is related to how the quality of focus changes on the sensor side of the lens as the sensor is moved, while the object remains in the same position. Depth of focus characterizes how much tip and tilt is tolerated between the lens image plane and the sensor plane itself. As f/# decreases, the depth of focus does as well, which increases the impact that tilt has on achieving best focus across the sensor. Without active alignment, there will always be some degree of variation in the orthogonality between the sensor and the lens that is used; Figure 6 shows how this issue arises. It is generally assumed that problems involving depth of focus only occur with large sensors.

In Charlie and the Chocolate Factory, Willy Wonka prints a handful of golden tickets inside his chocolate bars, dispersed randomly across the globe, giving recipients a once-in-a-lifetime opportunity to tour his factory.

Depth of fieldvsdepth offocusmicroscope

More specifically, let’s say you stick around in a research position that you find unfulfilling, simply from fear of being labeled a “quitter.” Great, you save some element of pride, but you’re unlikely to end up with any inspiring stories, tangible results, or pending publications. Check out our 3 signs it’s time to quit your research position for more insights.

However, this issue is independent of sensor size. As the derivation in Equation 3 shows, depth of focus, $\delta $, is heavily dependent on the number of pixels or pixel count, $ p $, and has little to do with array or pixel size, $ s $. As sensors increase in pixel count, this issue is more evident. Particularly in many line scan applications, the large arrays and low f/#s emphasize the need for careful alignment between the object, lens, and sensor.

Depth offocus definition

The pre-med Appeals to Pity happen most often when students write disadvantaged essays or essays about institutional action.

Think about all those advertisements you see on TV with sad dogs in cages, encouraging you to donate money to such-and-such charity. I’m all about helping dogs, but those nonprofits are clearly pulling at your heartstrings to sell you on their message.

Figure 4a illustrates the ray bundle at the center of an object under inspection at f/2.8 (a) and f/8 (b). The vertical lines represent 2mm increments away from best focus. On each vertical line, a square represents the discrete feature size of single pixel of detail. Figure 4a shows that as the width of the ray bundle spreads out, more rays miss the detail. In Figure 4b, the bundle expands more slowly and the rays all strike the detail which is larger than the bundle diameter for all depths shown.

This monkey-see-monkey-do myth can be useful at times (line dancing, for example), but your medical school application is far too personalized for such a one-size-fits-all approach.

Well, for one thing, the NIH has nothing to do with admissions and no authority over what constitutes good personal non-fiction for your essays. If the supervisor had given you advice on finding research opportunities, then it wouldn’t be a myth - the advice would have legitimate ethos and credibility. Â

Changing the f/# of a lens changes DOF, shown in Figure 3. For each configuration shown in Figure 3 there are two bundles of rays. The bundle represented by dotted black lines shows how well the lens is focused. As an object moves away from the best focus position (where the dotted lines cross), object details move into a wider area of the cone. The wider the spread of the cone, the more the image blurs into the surroundings. The f/# of the lens controls how quickly the cone expands and how much information or detail is blurred together at a given distance. Figure 3a shows a lens with a shallow DOF, where Figure 3b shows a lens with a large DOF.

You won’t find a secret formula for admission, so your best bet is to complete an application that’s authentically the best representation of yourself as an individual. Focus on YOUR strengths, YOUR stand-out experiences, and YOUR potential contributions to the field. They’re your real golden ticket.

Why? It’s because these myths are an easy escape from the truth, a way to avoid deeper and more critical thinking. They often play off our basest fears, instincts, or first impressions. They typically break things down into deceptive black-and-white dichotomies, which are easier for our brain to process and therefore more attractive as ideas.

We make this mistake all the time. When we feel like people are smarter than us, we tend to take their words as objective truth, whether or not they have any specific expertise on the topic. It dates all the way back to agreeing with our parents that babies come from storks, and this tempting mental shortcut never goes away completely.

F. Scott Fitzgerald said that “the test of a first-rate intelligence is the ability to hold two opposed ideas in mind at the same time and still retain the ability to function.” He’s right, but our brains don’t like to operate that way; we like to see things in clear-cut, black-or-white dichotomies because they’re easier to process and seem more reliable.

Figure 8 analyzes the depth of focus for the two cases in Figure 7. In both cases, the far right vertical line is at the best focus for the full image. Each semi-vertical line to the left of best focus represents a position 12.5µm closer to the back of the lens. These simulate the positions of the pixels, assuming a tip/tilt of 12.5µm and 25µm respectively from the center to the corner of the sensor. The blue ray bundle shows the image center and the yellow and red ray bundles show the corners of the image. The yellow and red bundles represent one line pair cycle on the sensor assuming 3.45µm pixels. Notice in Figure 8a, that for f/2.8 there is already bleed-over between the yellow and red ray bundles at the shift to the 12.5µm tilt position. Moving out to 25µm, the red bundle now covers two full pixels and about half the yellow bundle as well. This causes significant blurring. In Figure 8b, for f/5.6, the yellow and red ray bundles stay within one pixel over the full 25µm tilt range. Note that the blue pixel’s position does not change, as the tip/ tilt is centered on this pixel.

Since you’re dealing with such high stakes and steep competition, these forms of mental bargaining all the more alluring. Who doesn’t want an easy formula for success, a quick-fix catch-all solution? Be careful - buying into these myths could have negative effects on your admissions chances.

To overcome these issues, cameras and lenses with tighter tolerances must be used. For sensors, some lenses have tip/tilt control mechanisms to overcome this factor. Note that some line scan sensors can have swale, meaning they are not fully flat; this cannot be mitigated or removed via tip/tilt control.

There is no surefire, foolproof method when it comes to medical school admissions, or life in general. It’s not the “what” of your application that will get you into medical school; it’s the “how.” And how you present your application will depend on your experiences, personality, writing style, school selection, etc.

This myth can rear its ugly head in many scenarios for pre-meds - lingering in impossibly hard classes until it’s too late to drop them without penalty, clinging to countless fringe roles in a slew of half-hearted extracurriculars, settling for a biology major after a year of classes instead of pursuing something more personally stimulating.

Depth of field microscopethreads

Every school gets the same primary application, transcripts, letter of recommendation, etc. from you, and they all receive fairly similar secondaries about your life and experiences. So for the most part, with some exceptions (in-state vs. out-of-state, for example) your odds with each application are relatively the same every time.

Too much thinking in this mindset will cause you to avoid diversification or risk-taking in your application. In turn, this will lead you towards a safe, generic application that comes across rather one-note to admissions committees.

The DOF of a lens is its ability to maintain a desired amount of image quality (spatial frequency at a specified contrast), without refocusing, if the object position is moved closer and farther from the plane of best focus. DOF also applies to objects with complex geometries or features of different height. As an object is placed closer to or farther than the set focus distance of a lens, the object blurs and both resolution and contrast suffer. As such, DOF only makes sense if it is defined with an associated resolution and contrast. Several targets can be used to directly measure and benchmark an imaging system’s DOF; these targets are detailed in Test Target Overview.

No matter where you’re at in the admissions process, make sure to heed this advice and stay clear of the myths that pervade the online forums. Don’t hurt your odds! Keep an open, objective mind and make Fitzgerald proud!

Appeals to Pity (guilt tripping) are ineffective when they stand on their own. That’s why there are three points to the rhetorical triangle. Pathos (emotion) can be very convincing, but it needs logos (logic) and ethos (credibility) for it to be a sound argument.

Moral of the story - take all advice with a grain of salt (even mine) and examine it critically. Consider the sources of information and the expertise behind them, and never lose your healthy sense of skepticism!

Depth offocus formula

Figure 7 shows a 35mm lens using 470nm illumination. Figure 7a is set to f/2.8 and Figure 7b is set to f/5.6. Both graphs go out to 150$ \small{\tfrac{\text{lp}}{\text{mm}}} $—the Nyquist limit of a sensor with 3.45µm pixels. It is easy to see that the performance of Figure 7a is far better than Figure 7b, using this lens at a setting of f/2.8 provides the highest level of imaging quality in a given object plane. However, as discussed in the previous section, sensor tilt will negatively impact the image quality produced, and the higher the number of pixels, the more pronounced the effect.

All work on this site is our own. The content for the Savvy med school search was found on the webpages of the respective medical schools.

In the example above, the candidate is putting a lot of stock into the advice from his superior at the NIH. And why shouldn’t he listen to one of the higher-ups at the National Institute of Health?

We all know this feeling. We’ve invested ourselves into something and we want to see it through. For me, this is my growing collection of stories and poems that have unraveled into the “Outtakes” folder on my computer. Most of the time, it’s good to finish what you’ve started, BUT not at the expense of your long-term success.

Playing the numbers game to the extreme relies on flawed logic. Apply broadly all across the country, cast the widest net possible, and your chances of getting an interview will go up!

We’ve written about how to piss off your medical school admissions reader, and one of the big takeaways from that article is that you shouldn’t make excuses or pull cards that you don’t have. Candidates sometimes take this route when they feel desperate or out of options, but it’s likely to further undermine your chances.

Don’t be fooled into feeling pot-committed - in the end, that’s usually just an excuse to do what’s more passive and comfortable! Â