Wednesday 9 March 2016

Surface Pro 3 Update

My SP3 has seen some upgrades. The launch of the Surface Pro 4 and Surface Book last year saw the release of new peripherals as well. A new type cover for the SP4 and a new pen for both SP4 and Surface Book brought improvements. After a bit of dilly-dallying, I finally gave in an ordered both to replace the SP3 versions.

I had been able to try out the new type cover in-store so I knew that the typing experience has been greatly improved. But I was not able to try out the new pen, especially the new tips that allow the stylus feel to be customized. But I was glad that I did get it as the writing experience is now much more like that of pen and paper, the friction is a lot better leading to less overshoot.

One thing that I am getting used to is the revised button arrangement on the pen. The SP3 pen had two buttons near the tip accessible when holding it to write, and a third button on the top to activate OneNote. The two lower buttons were for erase and right-click respectively. On the SP4 pen, the right click button is still near the writing end, but erase functionality has been moved to the top of the pen (like an old-school eraser pencil) which retains its OneNote activation duties but also can call up Cortana on a long press. The change of the erase functionality is arguably slower and less precise than the old pen. It takes a lot longer to flip the pen, even if I don't change my grip (though it is an awkward rotation on the wrist), than to press a button that is already at one's fingertip. Apart from this, the rest of the pen usage is improved over the old pen.

I'll wait until I've used the type cover a bit more before I come to any definitive conclusions but so far it is a more positive experience than the old one. The SP3 type cover was perfectly usable but I can't say I enjoyed it. The new one feels a lot less flimsy and the key action is more stable. But time will tell how it fares with lots of text. The trackpad seems to be less slippery, it will take a little getting used to, but I won't say it's necessarily better or worse.

But overall, the new typecover and pen have noticeably transformed the Surface Pro 3 to the extent that it feels as if I have a new computer. The upgrade investment is looking to be a good one.

Friday 10 April 2015

Surface Pro 3 Notes

After using the SP3 for 7 months, I can report that it has become an integral part of my teaching, research, and administration work. The pen in conjunction with OneNote has replaced my notebooks, both for calculations and for taking notes in talks and meetings. I can share my notebooks with my students so that they have an instant record of discussions. I can use the SP3 as a virtual blackboard to give lectures and with easy access to the lecture notes as exported PDFs. Marking assignments, commenting on drafts, drawing diagrams and graphs are simple with the pen. The size and mass of the device are advantages when travelling, whether it is to the office on bike, or across the world by plane. The device is fast enough for running Office, Lightroom, and other image processing software. It can do lightweight Mathematica calculations in a pinch.
For the SP4, I would be looking for better battery life (not that the SP3 is bad but more battery life is always good), slightly higher pen hover distance and better palm rejection, better thermal management, improved type cover (incorporating improvements from the Surface 3 version), addition of USB type C ports, and wireless broadband option. But the SP3 is good enough that I may not need to upgrade till the SP5 comes out.

Saturday 24 May 2014

Surface Pro 3 Thoughts

As an educator, I think a lot about how students can best learn. In a technical subject like physics, my main concern is that students learn concepts rather than simply ingest large amounts of information. Part of getting to know physics is being familiar with the equations and formula, knowing how the various variables relate to each other and being able to manipulate them to derive key results. It may sound like a case of, " When I was a lad...", but I think that "chalk & talk" with students taking comprehensive notes, can be more effective for learning quantum physics, for example, than watching a set of Powerpoint slides and relying on printed notes. After all, a student could simply open up a textbook to get all the information they need, what they should try to learn from a lecture is understanding.

New research has suggested that even the act of writing, rather than typing notes leads to better educational outcomes, especially conceptual understanding. I think it is a very important question given the massive changes in education due to technological progress. In the drive for efficiency in a massified higher education system, the presumed advantages of Powerpoint and electronically supplied notes are understandable. However, can we utilise technology to enhance learning quality, not just quantity.

With this background I am very interested in the new Microsoft Surface Pro 3 (SP3), a device touted to be able to replace both a tablet and a laptop. The main features are a 12" high resolution screen, an active pen for notes and drawing, a full PC operating system, and a powerful processor. The basic form factor is a 9.1mm thick slate/tablet, but the addition of a type cover allows laptop functionality together with an integrated kickstand to prop up the screen. Depending on your own usage pattern, this may work as a decent laptop replacement. If I need to do any serious typing on my current laptop, I will sit at a desk so the SP3 form factor won't pose an issue. If you do type a lot with a laptop in your lap, then it may not be as comfortable with the SP3 than a conventional notebook computer, but "your mileage may vary".

What attracts me most to the SP3 is the possibility of having a high resolution, fairly lightweight, powerful slate for reading papers, annotating PDFs, taking notes, and giving handwritten lectures. The SP3 seems to have finally hit the right specifications for a device that can adequately fulfil these functions. I previously had an 8.9" penabled convertible notebook that was slightly heavier, had worse inking capability, and was considerably slower. This showed glimpses of the possibilities enabled by electronic ink but the technology was not at the stage to make me give up paper and pen. At least from initial impressions, the SP3 could be the device to finally fulfil that promise for a large sector, not just for current niche markets.

What many commentators fail to see is that the SP3 represents a new way of using portable electronics. Sure, it tries to accommodate conventional laptop usage patterns but one needs to remove the blinkers and consider new capabilities not available to a separate tablet and laptop. In the educational context, having a large electronic-ink-enabled slate on which to make notes synced to the cloud and made instantly searchable represents an opportunity to combine the advantages of old-school handwritten notes but with the convenience of digital storage and retrieval. There are other penabled tablets and convertible laptops out there but the SP3 is the first to really hit the sweetspot in terms of size, weight, power, and support. It might have taken Microsoft three attempts but I think the SP3 was worth the wait.

Thursday 15 May 2014

Exam Depression

It's that time of the year when students and academics both find themselves in low spirits. The students as they have to take exams, academics because they have to mark said exams. And every year I sit down to a large pile of exam scripts and consider alternate careers where I do not have to deal with the despair of seeing the same desperate attempts encoded in barely comprehensible chicken scratchings.

As an educator I wish to see my students improve, not just in the knowledge they possess but more importantly in the skills needed to make the most of that knowledge. The biggest paradigm shift that students face when progressing from high school to university is the change from simply recalling facts or formulae to being able to understand, reason with, explain, and utilise knowledge, often in situations for which they have not been explicitly shown before. Dealing with the unknown, making judgements, and synthesising new solutions should be critical skills that our students should display.

Unfortunately, even at advanced stages of the undergraduate degree, a large proportion of students are showing that they are still stuck in the old paradigm. Students are thoughtlessly applying formula, they do not understand what the variables represent, use formula in inappropriate contexts, make crucial sign errors that would be obvious if they understood the underlying physical situation. When asked to explain or derive a physical relationship, they just randomly manipulate formula (valid in a regime explicitly not appropriate in the situation presented) without examining the physical basis of the phenomena, leading to entirely erroneous results.

Worrying is also the inability to recognise patently wrong answers that are many orders of magnitude out, e.g. the volume of a Krypton atom being half a cubic metre, or that a buoy requiring a terrawatt of optical power to be visible at a range of 5km. Mistakes happen, especially under exam conditions, but not being able to make physical sense of the numbers calculated speaks to a fundamental lack of understanding of basic concepts.

I do not know what can be done practically. Perhaps 12 or 13 years of prior conditioning through primary and secondary education cannot be undone effectively even in 3 or 4 years. But I'd suggest these general steps:
  • Improve mathematical skills. The maths should be the least of your worries allowing you to concentrate on the physical content
  • Put in the effort. Do lots of examples, without reference to solutions. Do difficult problems, stretch your thinking. Learn from your mistakes.
  • Explain to others, discuss things. The best way of learning is trying to teach it to someone else.
  • Integrate your learning. Make connections between subjects. Use knowledge in one area to help learn another.
For all the government rhetoric about universities supplying skilled workers for the economy, we're failing the basic principles of higher education, that of producing graduates who can think critically and effectively.

Friday 14 June 2013

Overview of Samyang 8mm/2.8 and NEX-7

I'm calling this an overview rather than a review because I haven't taken any test images to give a systematic look at the performance of the lens+camera combination. I am going to give my impressions of using the Samyang 8mm/f.2.8 fisheye lens with the NEX-7 over the last few months. Over that time, I've travelled a bit and taken several panoramas which is my main use of this lens.

The lens itself is small, light, and complements the NEX-7. The aperture and focus rings have a nice feel and damping. The front element is quite a bit smaller than the Samyang 8mm/3.5 fisheye which I have in Alpha mount. The built-in lens hood protects the front element from inadvertent knocks. A clip-on lens hood and pouch completes the package.

The first thing to note is that the lens does have issues with the sensor on the NEX-7. The position of the exit pupil means that the angle of the light rays hitting the sensor is too far from the vertical leading to colour shading in the corners of the image. In this case, it is a magenta cast which can be quite noticeable on images which would otherwise be neutral. In some very strongly coloured circumstances, for instance twilight, you may not see the colour shift. Luckily this colour shading is correctable using software and a reference image. This will require converting your RAW files to DNG first before passing it through corrections tools. CornerFix is a free program which can build a correction profile from a reference image which can then be used to remap the DNG data. A similar process is used by Adobe Lightroom DNG Flat-Field plugin. These can reduce the colour shading to an acceptable level for most applications, panoramas included.

If the colour shading issue doesn't put you off, then the rest of the performance of the lens+camera combination is well worth it. Even at maximum aperture, the image is reasonably sharp, but at f5.6 (optimal for centre sharpness) the lens is stunning giving incredible amount of detail across the frame. One thing to note is that the field of focus is not flat but can be quite irregular especially at the corners. Even with the very wide depth of field inherent with using a fisheye lens, to gain maximum sharpness requires fully magnifying liveview and adjusting the manual focus. However, the effective hyperfocal range is approximately 50cm to infinity at f/5.6 when focussed around the 2m mark, and 20cm to infinity at f/8 when focussed around the 1m mark. I find that although depth of field increases at f/8, diffraction leads to a slight softening compared to f/5.6.

Overall, if you are into panoramic photography this lens should be high on your list of lenses to consider. The price is right, optically it performs very well (colour shading not-withstanding), and it's a compact and light addition to your bag.

Student Evaluations: Campbell's Law in Action

"The more any quantitative social indicator is used for social decision-making, the more subject it will be to corruption pressures and the more apt it will be to distort and corrupt the social processes it is intended to monitor" - Cambell's Law.

I am reminded of this and Goodhart's Law by an article reporting the results of psychology research into how students rated their lecturers and how they performed in their immediate and future exams. A summary of the results is, "We find that less experienced and less qualified professors produce students who perform significantly better in the contemporaneous course being taught, whereas more experienced and highly qualified professors produce students who perform better in the follow-on related curriculum." and "that
student evaluations reward professors who increase achievement in the contemporaneous course being taught, not those who increase deep learning."

One potential explanation mooted was, "the less experienced professors may adhere more strictly to the regimented curriculum being tested, whereas the more experienced professors broaden the curriculum and produce students with a deeper understanding of the material. This deeper understanding results in better achievement in the follow-on courses."

This is a demonstration of the folly of short term drivers and the law of unintended consequences. Teaching to the test becomes the optimum strategy for teachers to satisfy student evaluation scores, yet this is not optimal for long term performance. As a junior lecturer, one does not have the luxury of being idealistic and teaching what you think the students should learn but what will satisfy exam pass rates and evaluation forms.

Unfortunately, these same pressures have been at work throughout various education systems, from primary, secondary and through to tertiary levels. By subjecting schools and universities mercilessly to the drivers of tests scores and league tables, these become ends in themselves. It leads to a "culture of low expectations", where students are not pushed to fulfil their potential.

Education is not about passing exams, nor is it a popularity contest. It is about the betterment of the individual and consequently society.

Monday 14 January 2013

Refreshing Honesty and Integrity

Here's a story which shows that one can retain dignity in failure. Short version is that a paper in Physical Review Letters has flaws pointed out to the author, twice. The first flaw isn't fatal but the second is uncorrectable, "I hereby retract my paper [1] due to a fatal error I explained in [2]. All my attempts to patch the error have failed."

Additionally, the author writes a completely new paper explaining why the approach in the original one fails, "Since the error from the original paper [1]—which makes the proposed setup unfeasible—proved to escape immediate recognition by the physicists who considered the details of the paper I think that it would be of service to the community to comment on the approaches that can and canot be taken in attempts to reach the aforementioned goal or to prove it unreachable."

Everyone makes mistakes, but not everyone has the integrity to properly own up to them and to go the extra mile to help others making the same ones. Science is about being honest, with each other and to oneself, but especially with Nature. Simply wishing something was so does not make it true, something which is lost on denialists and fundamentalists. Admitting you were wrong gracefully is a sign of strength, not one of weakness.

Thursday 12 July 2012

Science vs Libel

A rather peculiar case has just been ruled upon. The editor of the journal, Chaos, Solitons & Fractals (published by Elsevier of course), sued Nature for an unflattering article which called attention to the self-publishing and reviewing practices in the journal. One can read the ruling for a rather bizarre trail of events. It highlights just how out of date the current libel laws in the UK are, that such a costly and censorial suit could be allowed under the current system makes for a chilling effect for reporters, bloggers, and even ordinary scientists publishing papers. If you don't have the legal and finanacial resources of the Guardian or Macmillan, you face ruin even if you are commenting fairly and in the public interest. Reform is sorely needed, free and open exchange of information and ideas is the basis for a vibrant and thriving society. Join the effort to make the law work for the public and not for those few with the resources to squash dissent.

Friday 3 February 2012

Why boycott Elsevier?

Widespread dissatisfaction amongst academic researchers about the state of academic publishing has come to a head with the move to boycott Elsevier. Tim Gowers ignited the move in his blog post here. There are many posts on the web where the misdeeds of Elsevier can be found so I won't repeat their specific sins. I've been holding my own private boycott of Elsevier for several years and it is a relief to see coordinated action on sending a message to exploitative publishers that their free ride is ending. The reasons for my boycott are:
  • We, the researcher (by extension our institution and the public at large), do the research, paid for out of our own grants and funding
  • To publish research we are often charged for the "privilege", and the publishers demand that they receive copyright of the paper, i.e. we pay them to donate our research to them
  • We act as referees of papers, for free, to evaluate the soundness of the research. Editors of the journals also often work for free
  • We, through our libraries, have to then buy back access to the papers, often at outrageous prices. Individuals have to pay ridiculous amounts for per article access
In my field, we produce the majority of the editing and typesetting, there is not much of an "improvement" between the drafts produced solely by the authors and those appearing in print.

No wonder Elsevier has been able to make enormous profits where the authors pay to give them their research, work for free as referees and editors, and then pay massive amounts to get it all back. It doesn't really seem fair to me.

The academic publishing system, whether it is author pays or reader pays, has to be funded somehow so I don't expect everything to be free. However, to "extort" money at both ends does not seem to support assertions that they "expand access in sustainable ways, improve the research experience and enhance knowledge and discovery". I will only donate my time and effort to those organisations which do work towards these goals rather than line their pockets.

Friday 16 December 2011

Electronic First Curtain

One of the nifty features of the A77 (and other cameras like the NEX-5n, A65 and NEX-7) is the option of using Electronic First Curtain (EFC) shutter mode. This eliminates the need to use a mechanical shutter to cover the sensor prior to exposure. In a live view camera, usually the sensor needs to be covered so that the pixels can be reset to zero before the exposure. EFC can accomplish this without requiring the sensor be covered. This has been available in some previous consumer DSLRs but the A77 is the first to really capitalise on its advantages due to the SLT design.

To see how EFC works, we should first understand how a normal shutter works. The purpose of the shutter is to allow light to fall onto the sensor for a specified period of time. In a traditional (non-liveview) camera, the sensor starts off covered by the first curtain, typically a set of interleaved metal blades. As the sensor is not exposed to light in this mode, it is a simple matter to reset it to accept the exposure and record the image. At the beginning of the exposure, the first curtain begins to slide down, exposing one edge of the sensor. As it uncovers the sensor, light falls on the pixels and creates charge. The edge of the first curtain continues to draw across the sensor until the whole sensor is uncovered. After the first exposed pixels have received the proper exposure, the second curtain now starts to move in the same direction as the first curtain to cover the sensor. The charges accumulated in each of the pixels are readout and converted into a digital image. Both first and second curtain then return to their original starting positions keeping the sensor covered, ready for another exposure to be taken.

For even exposure, the first and second curtains should traverse the sensor at the same speed. The delay between the motion of the first and second curtain determines the exposure time. On a professional camera, it take roughly 1/250th of second for the curtains to travel across the height of the sensor. This is called the flash-sync speed as this is the fastest shutter speed you can use for even flash exposure. The whole sensor must be uncovered at the point at which the flash is fired. At higher shutter speeds than flash sync, the region of the sensor which is exposed at any one moment is a slit between the edges of the first and second curtains. Faster sync speeds are difficult as this would require accelerating and decelerating the mechanical blades of the curtains beyond what is easily accomplished given the engineering constraints. Here's a link to a video explaining this.

In a liveview camera, the sensor starts off exposed to light. When the shutter is depressed, normally the first curtain rises from its stowed position to cover the sensor, the sensor is then reset (all the charges in the pixels are drained), and then the sequence as described above is triggered except that at the end, only the second curtain retracts so that the sensor is again exposed for liveview.

EFC eliminates the need for the first curtain to rise to cover the sensor before pixel reset. The pixels are design so that they can be reset without having to be in darkness. When the shutter is depressed and exposure initiated, rows of pixels of the sensor are reset beginning from the top. This line of reset pixels travels down the height of the sensor, just as a first curtain traversing the sensor reveals successive rows. As soon as a pixel is reset, it starts accumulating photocharge. After the proper exposure time, the second (mechanical) curtain then begins its journey across the sensor to shut off light and the image can be read out.The second curtain now returns to the top exposing the sensor for liveview.

The key point is that the start of exposure for any pixel can be electronically and independently controlled, and only the end of the exposure is controlled by a mechanically moving shutter blade. There are particular advantages to this, especially in a pellicle mirror (SLT) camera. Eliminating the moving mirror improves sharpness by avoiding mirror slap, but the first curtain would then be the dominant source of vibration. EFC eliminates this source of unsharpness as well. The sound of the shutter is quieter as there are less moving parts. And the time between the shutter button being depressed and the start of exposure can be shortened as well.

However, there are further potential benefits which could be exploited in future models. Flash sync speed could be effectively halved. EFC could start row initialisation from both sides of the sensor simultaneously, meeting in the middle, at which the whole sensor is exposed and the flash could be triggered. Then both mechanical curtains could move so that they also meet at the middle. Since they have to only travel half as far, the time it takes to cover the sensor is also half leading to a shorter flash sync time. The exposures of the top and bottom halves would have to be matched quite accurately (making sure the traversal speeds were the same), and the overlap region in the centre of the frame would also have to be designed to give even exposure.

A more extensive use of EFC is to do per-pixel exposure control. If each pixel can be reset independently, then the time it accumulates photocharge can be also be controlled individually. Let x be the distance from the top edge of the sensor (where the second curtain starts to cover the sensor) and v be the second curtsin traversal velocity. If at time t_0 the second curtain starts to move, the pixel will be covered at time t_x=t_0 + x/v. To obtain an exposure time of t_e, the pixel needs to be reset at time t_x-t_e. This choice of exposure can be done independently for all pixels.

In a liveview camera, since the camera has a realtime high resolution exposure map of the scene, it can calculate suitable per-pixel exposure times in order to compress the dynamic range of a scene, for instance using a short exposure time to capture the sky and a longer exposure for areas in shadow. This will require specific pixel reset capabilities of the sensor, current ones may only be able to reset pixels on a row by row basis. However, even row by row exposure compensation could give you an in-camera neutral grad filter (albeit only for landscape orientation).