Month: August 2024

Roger Cheng

Scratching The Surface Of Autofocus

A camera’s auto-focus algorithm is a bit of black box magic where I have a passing interest. I was disappointed to learn while Adafruit’s Memento camera module exposes programmable control over its focus mechanism, the auto-focus algorithm remains opaque hiding inside its own black box. A brief survey of custom Canon camera firmware found that they’re not likely to have any details, either, as they call into existing Canon code to handle that kind of thing. A bit of web search found that I could dig up research papers on the topic, but I don’t foresee how this interest could grow beyond idle curiosity.

With commercial offerings at a dead end, I started looking at the venerable OpenCV library and how it might enable research and experimentation in auto-focus algorithms. It turns out Adafruit Memento is not the only camera to expose control over focus mechanism or triggering an auto-focus black box. Some cameras expose similar things in their OpenCV capture driver in the form of capture capabilities. I suppose it would be possible to connect an Adafruit Memento in the same way and use it with OpenCV. I will file that away as a potential future project.

Beyond OpenCV drivers, I did find some research papers about auto-focus. This is great, because research papers usually include an overview section that describes prior work in the field. This helps anyone who wants to get up to speed. If they can find a few papers in the field, they can look over the citations list. Any common citations are likely to point to foundational work and a good place to start. I skimmed through my first two hits: Robust Automatic Focus Algorithm for Low Contrast Images Using a New Contrast Measure (2011) and a more recent paper Learning to Autofocus (2020) applying some machine learning to the problem. My comprehension was pretty low, I can tell I have a lot to learn before I can really follow these papers.

So there’s a lot of work… what about the reward side of the equation? Right now my Adafruit Memento is the only camera where I could even try to do anything hands-on. Running autofocus in my own software is going to be far slower than the existing hardware component. And what might I be able to do with such a thing that’s interesting and different from existing autofocus? Right now I don’t have any ideas, which means not much motivation, resulting in a poor work-to-reward ratio. Until a suitable idea arises to motivate me to dive in to the field, autofocus will remain a passing curiosity sitting at a low priority in my project to-do list.

Roger Cheng

Window Shopping Plex Alternative Jellyfin

I’ve been using Plex for a few years to run my home local network media server, with vast majority of usage centered around my music CD collection in the form of MP3 files. It’s a fairly simplistic usage pattern so I haven’t encountered any problems. Most of the problems I had with running Plex server was my own fault, because I also used Plex as a test case to explore various home server technologies. That’s not Plex’s fault unless you want to say “Plex makes so many different deployment methods available” is a fault. At the moment I am not motivated to move off Plex. But if I ever do, I recently learned of Jellyfin as an alternative.

I used Plex at its free tier for a while before choosing to pay the one-time lifetime subscription fee to unlock a few features that looked interesting. I ended not using most of those features, but that was fine. A company needs revenue to operate and I paid the company for a product I found useful so the current situation is fine. But like most businesses, Plex is constantly trying to expand its revenue stream. So far that’s been in the form of paid features like video rentals but it does make me a bit suspicious. Tech industry history has many tales of companies alienating their existing customers in pursuit of money. I would be disappointed (but not surprised) if one day Plex decide my one-time lifetime subscription should become more than one-time or less than lifetime.

I have my media on my TrueNAS server, and I am running Plex Media Server software on a virtual machine of my Proxmox server. All capability is on my home local network, but I have to periodically sign in to my Plex account to verify my subscription status. If something happens to be offline at this critical time I would be locked out of my own Plex server. This has actually happened a few times, but not (yet) often enough to motivate me to ditch Plex.

Jellyfin improves on both of those problems. It is a free software project so as long as it stays on that ethos, I shouldn’t fear my account status changing and getting charged more money. In fact, I should be able to run everything on my home network server and never have to authenticate against an account server on the internet. Jellyfin is a less mature project with fewer features than Plex, but it has the “keeping MP3 collection organized” feature already and that’s most of what I need. If Plex (either the business or the software) gives me enough grief, I will likely migrate to Jellyfin for my home local network media server needs.

Jellyfin logo is from their UX repository https://github.com/jellyfin/jellyfin-ux

Roger Cheng

Internet Search: Nonsensical Plagiarists

Out of curiosity, I took a look at some tools provided by search engines to help sites drive traffic. I’m very glad site traffic isn’t important to https://newscrewdriver.com because search engines ask for some weird things. On the other hand I appreciate that making a good internet search engine is a constant battle against unscrupulous people trying to game the system. There are some legitimate things sites can do under the umbrella of “search engine optimization” but there’s a lot of deceptive SEO techniques out there as well.

This site is my personal project notebook. I write things down as I go, and it’s all searchable whenever I want to look back on something. It’s publicly visible in case someone is willing to sift through a lot of my ramblings to find a nugget of gold useful to them. Unfortunately it also means it’s publicly available for others to copy for less noble purposes. There’s a lot of those! When I want to search my own project notebook, I have to restrict it to my own site or I’ll get a lot of mangled junk copies.

Here’s one example: several years ago I was playing around with PIC microcontrollers and using Microchip’s MPLAB development tools. When I moved from browser-based MPLAB Xpress to desktop MPLAB X IDE, I wrote down a few thoughts about how the move affected my ability to use git source control: MPLAB Xpress vs. MPLAB X: Git Source Control. Recently I started using another tool that wouldn’t necessarily work with git (more on that in a future post) and searched for my old post.

My default search engine is DuckDuckGo, which subcontracts out to Microsoft’s Bing. I repeated my search on both sites to confirm this observation: If I search on the title of my blog post, both of those search sites’ first page of results include at least two hits from sites that copied my content. And there are more copycats in second page, third page, etc. You know what’s not on the first few pages of search results? My original page.

I blurred the URLs out of my screenshot above because I am not going to help drive traffic to those sites and I’m certainly not going to click on those links. But preview snippet shown by DuckDuckGo/Bing is enough to show me they’ve changed a few words in order to avoid being an exact copy. There’s a Roman numeral obsession where “MPLAB X” became “MPLAB ten” (uhhhh I guess it might be?) and “C source code” became “century source code” (no, absolutely not.) There was a misguided attempt to spell check when “git source control” became “get source control”. But the most puzzling changes involved things like taking my “and” and replaced it with “or” (or vice versa) which drastically changes the meaning of my original sentence. Their search/replace algorithm is not just ignorant of technical terminology, it’s just plain dumb at English syntax. I don’t know how those sites became ranked higher than my original text, and I’m not sure what purpose they aim to serve. I’m just sad at the possibility someone would be led astray in their own project because they found a mangled version of my project notebook.

Roger Cheng

Internet Search: Google Always Knows Best

One advantage of having my own domain like https://newscrewdriver.com is that I can subscribe to search engine services that provide feedback on how they process a site. Microsoft has Bing Webmaster Tools, Google has Google Search Console, etc. These are products focused on helping websites improve their chances of showing up in internet search results. An important objective for many sites, but not this one because I’m not trying to maximize revenue or anything here. I set up my dashboards because I was curious what information was available and what search giants expect site owners to do about it. Not that I can, for the most part, because majority of site implementation details here are handled by WordPress and out of my direct control.

Every once in a while I would receive a notification that some problem prevented a part of my site from search indexing. Most of these were caused by a change in WordPress and are quickly fixed with no action on my part. Sometimes the notification reflect a big attitude change in how Google thinks about the web and want sites to follow along. For example, a few years back Google decided a site’s treatment of mobile devices is more important than desktop, so sites are encouraged to have a good mobile experience or else their Google search ranking would take a hit. This was a change I agree with: making sites usable on small screens with slow processors and low bandwidth makes the web more accessible to all, and wielding Google search ranking as a stick to encourage adoption is one way to use Google power for good.

But then there are times that make me… less fond… of Google. I just received an error notification: “Duplicate, Google chose different canonical than user” with a link to this explanation. As I understand it, the error says that Google looked at the URL listed in my WordPress-generated site map and decided a different URL was better. I thought that was odd, but whatever. I went looking for a way to inform Google their decision was wrong, and I can’t. Google has decided they know my site better than I do and the “fix” is to change my site to use their chosen URL. Conform to Google. There is no alternative.

In this specific case, the URL was to one of my posts and Google’s chosen URL was to the comments section on that same page. Google is wrong, their link is not the superior link, but they will not hear arguments on their decision. Stalemate. I guess Google will keep using their wrong URL. Looking on the bright side, at least that URL actually points to my content, unlike some other search engines.

Roger Cheng

First Few Weeks With Dell Latitude 9410

Shortly after I bought an off-lease Dell Latitude 9410, I opened it up to verify everything met expectations. After finding no deal-breakers, I buttoned it back up and I’ve been using it for a few weeks. I’m happy with my purchase, here are some notes:

Intel Core i7

The Core i7 processor in my 9410 gives me snappy and responsive performance when I want it, then throttle itself down for low power consumption when I don’t. This means I get useful battery life on par with power-frugal Intel Atom machines, yet never feel sluggish during demanding times like I would with an Atom-based machine. My typical usage pattern results in 4-6 hours of runtime even with just 80% charge (more on that below) which ranks favorably among my past Intel-powered laptops. However, it falls short of my Apple MacBook Air with M1 Apple silicon. Both machines deliver snappy performance, but the M1 never gets as hot and runs far longer on battery.

The power and heat situation is a tradeoff against benefits of having an Intel CPU. All my developer tools are available here. I can run Docker containers without worrying about whether I need to find an ARM64 build. And pretty much every random USB peripheral will have Windows drivers. The biggest stumble so far is dual-booting Windows/Ubuntu: Dell configured this machine with Intel RST, and Ubuntu chose not to play well with RST. There are several possible solutions to this problem. I just haven’t been motivated enough to implement any of them yet.

Tablet/Laptop Convertible

Another thing my MacBook Air can’t do is fold its screen around and turn into a tablet. This was a deliberate design decision by Apple, who chose to keep MacBooks differentiated from iPads. After living with a Windows convertible for a few weeks I’ve decided I’m a fan. I’ve used Windows convertibles before but they’ve all been budget machines with limited hardware that hampered my user experience. This was my first full-power convertible and it means I can finally enjoy the benefits of a transformer and not trip over tradeoffs at every turn.

It’s nice to be able to switch back and forth. This is most useful when I’m reading documentation for software tools. I can switch to laptop mode to type a few commands for a quick hands-on exercise, then return to tablet mode and continue reading. With this positive experience I am much more receptive to such machines in the future, but I’m still not willing to pay the large price premium usually associated with such capability. Buying off-lease secondhand machines is likely to remain my pattern.

Power And Charging

Like my M1 MacBook Air, the 9410 charges via a USB Type-C connector instead of a proprietary power plug. However, this doesn’t necessarily mean I can use any USB-C power source. When up and running it demands 60 Watts. (USB power meter says 20V @ 3A.) This is even more demanding than the M1 MacBook Air, which is happy with 45W. If I plug in a less powerful USB-C supply, the MacBook will alert me that battery is still draining though at a slower rate. In contrast, this Dell would refuse to accept any power at all.

Fortunately, there are two charging systems on every laptop: there’s an operating system driver when the laptop is on, either running or in low-power sleep mode. Then there’s a completely separate firmware-based mechanism when the laptop is off, either in hibernation or completely shut down. Dell’s firmware-based charging system is willing to accepting power from sources that can’t deliver 60W. So if the bundled 60W power adapter fails or if I lose it, I still have alternatives.

And finally: like my Dell Inspiron 7577, there is a BIOS setting for me to restrict battery charging percentage. I set mine to stop charging at 80%. That still deliver enough battery runtime for most of my usage sessions, and avoiding charging to 100% should improve battery longevity. I can always change that setting back to 100% if I ever need extra runtime.

Whether iPad?

I justified this purchase as an alternative to upgrading my soon-to-be-obsolete 6th gen iPad and for my usage it was a success. At the moment I can imagine only two reasons why I might still want an iPad. The first is weight. Three pounds is light for a laptop but that’s triple the weight of an iPad. In practice, this hasn’t been a huge problem as I don’t like holding things up by hand for long periods of time, whether one pound or three. The second differentiator is the Apple app store, but at the moment I don’t need any iPad app exclusives. Maybe something else would arise as motivation for spending several hundred dollars? Until I encounter such motivation, I expect to be well-served by this Dell Latitude 9410.

Roger Cheng

Dell Latitude 9410 Internals: M.2 2280 Confirmed

Buying an used off-lease computer means giving up shiny-new cosmetic perfection in exchange for a hefty discount, a tradeoff I was willing to make. I don’t think I’ll be bothered by the “Grade B” blemishes on my unit and besides, it’s what’s inside that really counts. Purchasing from Dell Financial Services via their retail site https://dellrefurbished.com includes a 100-day warranty to back up their claim that all machines are fully functional regardless of cosmetic state.

My order confirmation email had a pleasant unexpected bonus: it included the Dell service tag for the specific machine I had just bought. I could then put that service tag into Dell’s support site to learn information about that specific unit before it had even arrived. There were still a few weeks left on its original 3 year warranty, though it would expire before the 100 day refurbished warranty would. Another positive attribute was the fact my unit was not equipped with a cellular data (WWAN) module. I don’t expect to use WWAN, and without the module, the machine should have room for a M.2 SSD in the more common, longer, and cheaper 2280 form factor. The factory configuration list included a model number for the factory SSD, which is associated with a M.2 2280 drive.

The machine arrived a few days later and, once I confirmed the machine functioned as expected, I brought up Dell’s service manual and opened up my unit to familiarize myself with its internals and to confirm information listed on Dell support. Compared with my previous Dell laptops, there was much more extensive use of thin adhesive-backed sheets of various materials. Are they for RF shielding? For airflow management? Other purposes? It’s hard for me to tell but their presence is not surprising in a device designed to be thin and light. I just have to keep in mind I can only remove them a few times before their adhesive gives out.

Modern component miniaturization allowed smaller circuit boards, freeing up more internal volume for the battery. Which needs to be disconnected and the system depowered before I disconnect anything else. This battery plug was very securely fastened and difficult to remove. Far more difficult than any previous Dell laptop battery connectors I’ve encountered. Hard enough that I triple checked I didn’t overlook some other mechanism I was supposed to release before unplugging the connector. But there were no other mechanisms, it was just a really tight fit.

After the system was depowered, I quickly made my way to the SSD to confirm it was indeed a M.2 2280 unit. This will make future upgrades easier and cheaper than the less common M.2 2230 type used in WWAN-equipped units. Speaking of which, I don’t think I can (easily) retrofit mine with one. The module connector is there on the logic board, but I don’t see any loose wires that would be appropriate for plugging into a cellular modem. So my machine probably lack cellular antennae as well. Though if I ever come into possession of a M.2 2230 SSD in the future, I might be tempted to give it a shot anyway for curiosity’s sake. Compatible WWAN modules seem to cost about $30-$50 from various Amazon vendors and maybe I can rig up a less elegant antenna. As long as I keep my expectations modest for such a project, it might still be an interesting data point. In the meantime I’m content to use the machine as-is.

Roger Cheng

Dell Latitude 9410 Cosmetic Grade B

I’ve decided to buy an off-lease Dell Latitude 9410 from Dell Financial Services, via their retail web site https://dellrefurbished.com. All of the machines have been evaluated to be in good functional order, but some of them have cosmetic blemishes separated into cosmetic grades. Cosmetic grade A are for machines in good shape, and grade B indicate machines that are in… less good shape at a lower price. Since I’m a cheapskate, I ordered a grade B unit and in my specific case, it wasn’t bad at all!

When the machine arrived, my first surprise was the label at the bottom: “Refurbished to Dell specifications by FedEx Supply Chain” I expected the evaluation and refurbishment process to be done by a Dell subcontractor, I just didn’t expect to see the FedEx name. Prompted by this surprise, I did a bit of research to find FedEx TechConnect, with uncertain relationship to “FedEx Supply Chain” formerly GENCO. To me it seems like an odd side gig for FedEx to take on, but I’m not a MBA at FedEx business development.

I found some damage on the keyboard. It means the backlight would shine through these damaged corners, not something I’d notice while I’m typing and looking at the screen. This damage is not a surprise in hindsight: when the screen is flipped around to turn this into a tablet, its keyboard becomes the exposed bottom of the device. The previous user of this laptop must have set the tablet down on something that caused this key cap damage.

Another problem with this device was the rubber strip at the bottom: it’s gone. There’s supposed to be a layer of light gray soft material overmolded onto this hard black plastic core strip. With the soft layer gone, all I have is this ugly looking strip. Fortunately I don’t have to look at it when I’m using the laptop. As a substitute, the refurbish process added cheap square stick-on rubber feet.

The stick-on squares are much thicker than the missing rubber strips. In laptop mode, this meant a larger gap at the bottom for better air cooling. But the thickness gets in the way when I fold the screen around for tablet mode: I couldn’t fold the screen completely flat when these thick rubber pads are in place. I will look for slightly thinner stick-on rubber feet to replace these thick squares, with the goal of restoring full tablet mode form factor while preserving laptop mode air cooling. I consider this a minor detail that is within my ability to fix, and not a big deal.

I found no noticeable damage on the screen, the metal body, or lid. Those were bigger concerns buying “Grade B” and my unit is practically pristine on those fronts. I don’t think the slightly scratched keyboard would bother me very much, and I can replace the stick-on rubber feet. I’m perfectly happy accepting those blemishes in exchange for >80% discount off original MSRP, especially when its internals look perfectly fine.

Roger Cheng

Dell Latitude 9410 2-in-1 Laptop/Tablet Convertible

When I learned I will need to replace my iPad in the near future, I saw an opportunity to give the Windows laptop/tablet convertible concept another try. My earlier encounters were marred by bloatware, or weighed too much for a practical tablet. A secondhand Acer Aspire Switch 10 worked admirably well but it was still heavily constrained by its modest hardware. I had been curious to see what the form factor is capable of in a modern sleek lightweight powerhouse. Getting one means paying a lot of money to buy new, which I was unwilling to do. But now that I can buy a heavily discounted off-lease unit from https://dellrefurbished.com, I’m going to give that a try.

I started keeping an eye on the “Tablets and 2-in-1 Laptops” section of the site. Batches of various machines came and went. Low end offerings are built around humble Intel Atom processors. They go up through high end machines with Intel Core i7 CPUs. I would pull up Dell’s specifications for various model numbers and eventually started focusing on a high-end model that came through with some regularity: Dell Latitude 9410. When new, these cost in the ballpark of two thousand dollars, and frequently end up in the hands of senior corporate executives as much a status symbol as productivity tool. Now they are listed for around $700, which is a decent price for its capabilities. But if I can get one with a 50% discount code, that would bring it down to $350. Over 80% discount from original MSRP and exactly the cost of a new 10th generation Apple iPad.

Latitude 9410s that come through dellrefurbished are pretty well equipped. Usually a CPU from Intel’s Core i7 line, and usually with 16GB of memory and 256GB or 512GB SSDs for storage. The touchscreen has 1920×1080 Full HD resolution, mounted on a double-jointed hinge that allow the user to fold the screen all the way around for a tablet-like form factor. All this in a package that weighs in the ballpark of 3 pounds. As is typical of Dell machines, there is a service manual available showing its internals. I was mildly disappointed to see its memory chips are soldered to the board and could not be upgraded, but at least SSD storage uses standard M.2 NVMe form factors. Units with cellular data (WWAN) modems are constrained to short M.2 2230 SSD. Units without WWAN have room to use M.2 2280 SSD which are more common.

Contemporary reviews say the Latitude 9410 is a very capable machine in a great form factor but came at a very high price. Well, dellrefurbished discount code can solve that last part, but why would they need to discount so heavily to move inventory? My conjecture is that, while this is a great Windows laptop/tablet, it doesn’t exist in a vacuum. The Latitude 9410 was launched in 2020, and what else launched around the same time? Apple’s M1 that caught Intel flat-footed. Apple Silicon launch had all the buzz in tech press, soundly beating equivalent Intel chips in power efficiency. Either more processing power at the same level of electrical power consumption, or far lower electrical power consumption at the same level of computation power. Apple laptops with the M1 chip have battery life that puts Intel-based machines to shame. Four to six hours of battery runtime isn’t bad for an Intel CPU laptop, comparing well to those that came before. But they look pretty sad next to all-day (or even multi-day) use people get out of Apple Silicon laptop battery. This and many other advantages of Apple’s 2020 laptops meant the Latitude 9410 had stiff competition both as useful tool and as status symbol.

Now in 2024, people who want to spend a few hundred dollars on a few-years-old used laptop might be more inclined to look at old Apple Silicon machines instead of an Intel-based Latitude 9410. If so, that would explain why Dell Financial Services has to discount them heavily to find buyers. Whether my conjecture is correct or not, the fact is I can now get a great deal on what used to be Dell’s top-of-the-line Windows laptop/tablet convertible. Especially if I’m willing to accept some cosmetic flaws.

Roger Cheng

Windows Convertible As iPad Replacement

I recently learned that Dell Financial Services operates a site to sell their off-lease computers. And even better, they’re willing to crank up discounts to move inventory. I spent a few fun weeks window-shopping their machines for sale, ranging from super tiny thin clients that bolt to the back of a monitor up to beefy servers designed for a data center equipment rack. But I have no real need to buy a computer. I’ve got my XPS 8950 desktop for gaming and VR. I’ve got my laptop for portable computing. I’ve got an old machine running TrueNAS, another running Proxmox, and several more old computers standing by waiting for a purpose. After a while I realized I was thinking too conventionally.

During this time, Apple released iPadOS 18 preview and a list of hardware they intend to support. Absent from that list is my 6th generation iPad. I bought it after disappointing experiences with a Windows 8 tablet and an Amazon Fire tablet. The tablet ecosystem is built around Apple’s iPad, and I’ve found products that undercut an iPad on price lack the hardware for smooth user experiences. For tablet centric usage scenarios, it was much more pleasant to use an iPad over the Samsung or Amazon Fire. On the flip side, I frequently felt limited by a tablet’s intentionally restricted capabilities. One example: I enjoy reading digital documents on an iPad, including documentation for software development tools. But when I get to a hands-on section, I have to switch hardware because an iPad is very deliberately not a general purpose computer and I can’t develop software on it.

With the knowledge that the clock is ticking on my 6th generation iPad, I started browsing for a replacement. My key priority is a USB type-C connector because I don’t want to deal with Apple Lightning cables anymore. Which meant the 10th generation iPad available for around $350. As I shopped around to see if I can get one for less than $350, it occurred to me that I should consider a Windows tablet/laptop convertible device. I had dismissed them for a long time because of first-hand experience with underpowered hardware and I wasn’t willing to pay the premium for high-end convertibles. But now I have a resource for heavily-discounted Dells business machines! I am willing to give Windows tablets another try when I can buy a powerful off-lease tablet/laptop convertible for new iPad money.

Roger Cheng

Refurbished Dell Computers from Dell Financial Services

My experience with my broken Dell XPS 8950 didn’t turn me off of Dell computers. Despite the large time sink, it was eventually fixed under warranty with no financial cost to me. So I was intrigued when I learned about dellrefurbished.com, operated by Dell Financial Services. (DFS)

I bought my XPS 8950 as a refurbished item from the “Deals” section of dell.com. That section listed nearly-new machines that were returned to Dell for whatever reason (buyer’s remorse, etc.) and resold with full warranty. This is different. Just as many automakers have a financing arm to lease cars, this is Dell’s financing arm to lease computers to businesses. This way Dell gets to move inventory, and corporations get the tax advantages of leasing. At the end of the lease, those computer are returned to DFS. Because DFS is not in the business of sitting on equipment, they then need to sell those lease-returned computers.

I had vaguely known such operations existed, but I didn’t expect a retail web site. I had assumed entities like DFS would make wholesale transfers to dedicated retailers of secondhand machines like PC Liquidations or the many vendors operating under Amazon Renewed, the Amazon umbrella for refurbished goods. But I was wrong and here is a retail site. I guess DFS decided there’s enough money on the table to be worth the effort of running a retail site? Whatever the reason, once I learned of the site I kept an eye on it over several weeks. To get a feel of how it operated and the kind of inventory that shows up, then sold off.

Machines for sale are limited to the business-focused subset of Dell’s product line. Meaning OptiPlex desktops and Latitude laptops instead of the consumer-focused Inspiron lines, and no gaming PCs with high-power GPUs like my XPS 8950. Some of the engineering-focused Precision machines have CAD-centric Quadro GPUs, which are a step behind gaming GPU power but far better than nothing. And more importantly, Quadro equipped Precision desktops frequently have power supplies sufficient to feed a mid range gaming GPU if I wanted to retrofit one. These all look like fairly capable machines. DFS is not competing at the bottom end of the market: even the most heavily discounted machines will cost more than lowest bidders on Amazon.

Oh yeah, about those discounts. From what I can tell, DFS initially list machines at a premium over market price, looking for people willing to pay more to buy “directly” from Dell. Instead of, say, a no-name Amazon vendor. But as previously mentioned: DFS is not in the business of sitting on equipment. As inventory ages, discounts pile up to move them out. Usually 10%-20% will bring DFS prices in line with market price, but then the discounts keep going. 30%, 40%, even to 50%. (Observing over several weeks, I never saw discount beyond 50%.) The discounts make some machines mighty tempting! Now all I need is an excuse… um… justifiable reason to try one.

Roger Cheng

Camera Update: Resin Printing, Lens Repair, and JIS

My Canon PowerShot SD1100 IS digital point-and-shoot camera is currently broken. I found a broken gear that I feel I should be able to fix, but have not yet been able to. The fact it feels just out of reach made me reluctant to tear it completely apart for curiosity’s sake, so I reassembled it to the best of my ability hoping to return to the topic in the near future. In the meantime, some updates on the topic:

SLA Printed Replacement Gear

I posted my broken gear on Mastodon, and among the responses are two opinions that it should be within my reach to 3D print a replacement gear. Not with the FDM printers I have, though. Printing at this scale requires SLA resin printers. Sample pictures of a figurine printed on a modern SLA printer shows amazing details, which is a promising start, but there’s more to printing a functional gear than resolution. I’m concerned about dimensional accuracy because resin shrinks as it cures. Something not too critical in a decorative figurine, but very important for a gear. I have a SLA resin printer that’s several generations behind the state of the art, and it has yet to print anything. This gear may be my motivation to finally set up a resin printing area to properly control all the nasty chemicals involved in SLA printing.

Sigma Lens Repair

With my introduction to photography equipment disassembly, I now have more interest in reading more about the topic. Hackaday article Broken Lens Provides Deep Dive Into Camera Repair pointed me to the write-up Sigma 45mm f/2.8 Lens Repair & Analysis. Even though I haven’t used Sigma cameras or taken any of them apart, it looks like they share many fundamental similarities. Which included the incredibly intricate internals. Photography repair is not for the faint of heart… my eyes are too old to work at such scales unassisted. My budget digital microscope is a start, but I will need better gear if I want to get serious about camera repair.

JIS (Japanese Industrial Standard) Screw

A valuable lesson from the Sigma teardown document is my first introduction to screws of the Japanese Industrial Standard, which are common in photography equipment consistent with the fact a large fraction of the industry are Japanese brands. Officially designated JIS B 1012, they are superficially very similar to Philips fasteners but not exactly the same. Using a Philips driver in a JIS screw will usually work but risks damaging the screw when the going gets tough.

Odds are good that fasteners inside my Canon point-and-shoot camera are actually JIS screws, and I might have damaged a few of them during my teardown. Or have I? I took a closer look at my iFixit Mako driver kit. I remember thinking it was odd that there were two separate sets of Philips driver bits in there, it never occurred to me that one of them are actually JIS drivers until I checked them carefully and saw “J1” marked instead of “PH1” on a very similar driver. If it weren’t for that marking, I would not have been able to tell them apart. The fact both types were in my driver kit, and that I didn’t know they were different, meant there was a chance I accidentally used the correct JIS drivers for my camera teardown. If so, that would have been out of pure luck.