Fazal Majid's low-intensity blog

Harking back to Kodachrome

My father took most of my childhood photos (like these) on Kodachrome slide film. Kodachrome was the only color game in town for a long time, but was eventually superseded in the marketplace by C41 color print films and finer grained E6 slide film.

Kodachrome has a distinctive sharpness (acutance, not resolution), and excellent durability when stored in the dark. Many photographers still shoot Kodachrome for its special “look”, even though processing options are diminishing and Kodak jacked up the price. Kodak recently announced it is closing its Fair Lawn, NJ processing lab, the last Kodak-owned plant in the US for Kodachrome, and there are now only three labs left worldwide that can run the complicated process (Dwayne’s in Kansas, Kodak in Lausanne, Switzerland, and a lab in Japan). Kodachrome was actually discontinued for a while, and brought back after strident protests, but the writing is on the wall.

Projectors and light tables

Every now and then, we would dust off the slide projector and have a slide show. I even remember building a surprisingly effective slide projector when I was 9 using Legos, a flashlight and a jar of peanut butter filled with water as the lens. Slide projectors are hard to find, a pain to setup and most people groan instinctively when one comes up, associated as they are with dreary slide show of other people’s vacation pictures. The LCD computer monitor is the successor to the projector, and many people no longer have prints made at all, perhaps because they subconsciously realize that the 500:1 contrast ratio of a LCD monitor yields significantly livelier images than prints can achieve.

A light table is just what the name implies – a piece of frosted plastic illuminated by daylight-balanced fluorescent tubes. Basic models like my Porta-trace shown above are inexpensive. Loupes, on the other hand, are a different story.

Loupe basics

Loupes (French for “magnifying glass”) are high-quality magnifiers, originally used to help focus images on a ground glass, and later to view slides or negatives on a light table. You can find them in all shapes and sizes, at prices from $15 for a cheap plastic model, all the way to over $300 for a Zeiss loupe for viewing 6×6 medium format slides. Slides viewed on a light table with a high-quality loupe are a treat for the eyes, because of the high contrast (1000:1) that you cannot get with prints (more like 100:1).

There are two ways you can use a loupe: use a high-power (10x or higher) to check slides or negatives for critical focus), or a medium-power loupe to evaluate an entire frame (usually 5x-6x for 35mm, 3x-3.5x for medium format). Viewing an entire frame is more challenging than just checking for focus in the center, because the loupe must provide excellent optical quality across the entire field of view. There are variable magnification (zoom) loupes available, but their optical quality is far below that of fixed magnification loupes, and they should be avoided for critical examination of slides or negatives.

I have accumulated quite a few loupes over time. The most famous brand in loupes is Schneider-Kreuznach, a German company noted for its enlarger, medium format and large format lenses. Many other brands make high-quality loupes, including Rodenstock, Pentax, Nikon, Canon, NPC, Leica and Zeiss. I do not live in New York, and have thus not had the opportunity to compare them side by side at a place like B&H Photo, so I pretty much had to take a leap of faith based on recommendations on the Internet at sites like Photo.net.

• Peak 10x Plalupe
• Contax Carl Zeiss Triotar T* 5x (larger photo)
• Edmund Optics 50x direct view measuring microscope
• Calumet-branded Rodenstock 3x Aspherical loupe for 6×6
• Calumet-branded Rodenstock 4x Aspherical loupe for 35mm
• Edmund Optics 10x Hastings Triplet
• Schneider 10x magnifier

Peak

The Peak was my first loupe. Dirt cheap, and reasonably good for the price, but that’s pretty much all it has going for it (more on that below).

Zeiss

I was put off by reports on the plastic construction of the new line of Schneider loupes, and opted for a Zeiss loupe instead, based on the reputation of Zeiss lenses (my first camera was a Zeiss, and I also have a Zeiss lens on my Hasselblad).

The Zeiss Triotar 5x loupe (the box does not mention Contax, but as it is made in Japan, it is presumably made in the same factory) comes in a cardboard box that can be turned into a protective case by cutting off the tabs on both ends. It does not include a carrying pouch or protective box, which is regrettable, specially for a product as expensive ($160), but apparently most high-end loupe manufacturers do not bother to include one. It does not include a neck strap either, which could be more of an issue for some. How can you look like a glamorous New York art director without a loupe around your neck? More seriously, the strap is particularly useful if you are going to use the loupe for focusing medium or large format cameras against a ground screen.

The loupe is shipped with two acrylic bases that screw into the loupe’s base. One is frosted, and is used as a magnifier to view prints or other objects, with ambient light filtering through the base to illuminate the object. The black base is used to shield out extraneous light when concentrating on a slide or negative on a light table or a ground glass. Some loupes have a design with a clear base and a removable metal light shield. Which design you prefer is mostly a matter of personal taste. The loupe has a pleasant heft to it, and impeccable build quality. The main body of the loupe itself is solidly built of black anodized metal, with a knurled rubber focusing ring.

The optical quality is what you would expect form Zeiss. Crystal clear, sharp across the field of view, and no trace of chromatic aberration in the corners. You can easily view an entire 35mm frame and then some, although I suspect eyeglass wearers might find the eye relief a little bit short.

Edmunds pocket microscope

The Edmunds direct view microscope is a versatile instrument, available in many magnifications, with or without an acrylic base (highly recommended) and with or without a measurement reticle (metric or imperial). Due to the high magnification, the image has a very narrow field of view (only 3mm), and is quite dim. Unlike the others, the image is reversed, which requires some adaptation time. The level of detail you can observe on slides taken with a good film like Fuji Provia 100F, using a good lens and a tripod, is absolutely stunning. This is a rather specialized instrument, but well worth having in your toolkit.

Rodenstock

The Rodenstock 3x 6×6 aspheric loupe has a list price of $350 and usually retails for $250. Calumet Photo sells the exact same loupe under their own brand for a mere $149 (I actually got mine for $109 during a promotion), which is not that much more than a cheap (in more ways than price) Russian-made Horizon.

There are naturally fewer loupes available to view medium format slides or negatives than for 35mm. Schneider, Mamiya/Cabin, Contax/Zeiss and Rodenstock make high-grade loupes for this demanding market. If you have a “chimney” viewfinder on your MF camera, you can actually use that as a loupe.

Rodenstock is famous for its large-format and enlarging lenses, and this loupe is very highly rated. The construction is plastic, but still well-balanced and not too top-heavy. It does not carry the feel of opulence that the Zeiss has, or even the very nicely designed Mamiya/Cabin loupes (more on that below), but is still clearly a professional instrument. It has a two-element aspherical design for sharpness across the entire field of view, and coated optics. It comes with a red neck cord, and the base has a removable plastic skirt that slides in place and can be reversed between its clear and dark positions. The eyepiece has a rubber eyecup and a knurled rubber grip for the focusing ring.

I compared it side by side at Calumet San Francisco with the Cabin 3.5x loupe for 6×4.5 or 6×6. The Cabin had a solid metal constuction (somewhat top-heavy), but its screw-in skirts are less convenient than the slide-in one used in the Rodenstock, and the image circle is too tight for my Hasselblad 6×6 slides. I think that loupe was really designed for 645 format and opportunistically marketed for 6×6, when the 6×7 loupe would actually be more appropriate for that usage. The optical quality is very similar and both are excellent loupes. I did not try the Mamiya/Cabin 6×7, unfortunately, as it was not available in the store, but in any case the Rodenstock was a steal.

The optics are excellent, as could be expected, with crisp resolution all the way into the corners and no trace of chromatic aberrations. There is a smidgen of pincushion distortion, however, but not enough to be objectionable (I took the slightly convex curved square skirt out to make sure this was not just an optical illusion).

One thing to watch out for: even though the optics are coated, they are very wide and you have to be careful to keep your eye flush with the eyecup to obscure any overhead light sources like lightbulbs or fluorescent panels and avoid seeing their reflections in the loupe’s glass.

The most comprehensive resource for medium format loupes on the Web is Robert Monaghan’s page on the subject.

Edmunds Hastings triplet

This isn’t really a competitor to the other loupes, as it has a very narrow field of view of only 10mm in diameter. It is also tiny, and I carry mine in my gadget bag. It has a folding jeweler’s loupe design with a folding metallic shield to protect it. Optical quality is of the highest order.

Schneider 10x

Despite its plastic construction, this loupe exudes quality. Unfortunately, the strap is really flimsy – the rubber cord is merely glued into the metal clip, and will easily pull out. I glued mine back, and crimped it with needle-nose pliers for good measure, but I don’t know how robust this arrangement will be.

The optics are excellent, without any trace of chromatic aberration. The usable field of view is surprisingly wide for a loupe with this magnifying power, although your eye has to be perfectly positioned to see it. I estimate the FOV diameter at 20mm, as you can almost see the full height of a 35mm mounted slide. I have an Edmund Optics magnifier resolution chart (it came with the Hastings triplet), and the Schneider outresolves it across the field of view . This means the Schneider exceeds 114 line pairs per millimeter across the frame, quite remarkable performance.

The importance of a good loupe

For a real-world test, I took my 6×17 format Velvia 100F slides of the Golden Gate Bridge, and looked at the suspension cables. The picture to the left shows the details I was looking at (but the fuzzy 1200dpi scan on an Epson 3170 does not remotely do justice to the original). Each bundle of 4 cables (4 line pairs) takes 0.04mm on the slide (I used the 50x Edmunds inspection microscope to measure this), hence you need 100lp/mm to resolve it. The Schneider 10x, Edmunds 10x and Zeiss 5x loupes all resolve the four cables clearly. My old el cheapo Peak 10x loupe did not, nor the Epson scanner, which led me until recently to believe my slides were slightly blurry because I had forgotten my cable release that day. So much for the theory you do not need an expensive 10x loupe to assess critical focus because only the center counts…

Update (2012-02-10):

In 2007 I added a Calumet-branded 4x Rodenstock aspheric loupe to my collection. Unfortunately, it is now only available under the original brand, for 2.5x the price I paid for the rebranded one, but you may luck out and find old-new stock at you local Calumet Photo store. The market for loupes has mostly evaporated, along with the popularity of film, and choices today are pretty much limited to Schneider and Rodenstock.

The Rodenstock 4x loupe has one great ergonomic feature: instead of interchangeable clear and dark screw-in skirts, it has a clear skirt and a sliding dark outer skirt. This allows you to switch very quickly from inspecting prints to slides, without the laborious swap the Schneider or Zeiss force you into. Optically it is excellent, sharp across the field and with only a smidgen of pincushion distortion. I have not tried the 4x Schneider loupe, which gets rave reviews, and cannot comment on whether the ergonomic improvement in the Rodenstock warrants a 50% premium in street price over the Schneider.

One loupe I cannot recommend, on the other hand, is the Leica 4x magnifier. It has severe distortion across the field, which is ridiculously limited at 3 or 4mm, and optical quality is worse than a cheapo plastic loupe from Peak.

Update (2012-02-25):

I added a Schneider 4x loupe to my collection. Build quality and strap is similar to their 10x loupe. It is sharp across the entire frame, with only a smidgen of pincushion distortion. It is also noticeably brighter than the Zeiss Triotar or the Rodenstock 4x, and has more contrast as well. The contrast makes it seem superficially sharper than the Zeiss or Rodenstock, but examination of the Edmunds test chart shows all three loupes outresolve the chart.

I think this will be my new favorite loupe for 35mm use.

Telcos look at instant messaging providers with deep suspicion. Transporting voice is just a special case of transporting bits, and even the global Internet is now good enough for telephony (indeed, many telcos are already using IP to transport voice for their phone networks, albeit on private IP backbones). The main remaining barriers to VoIP adoption are interoperability with the legacy network during the transition, and signaling (i.e. finding the destination’s IP address). IM providers offer a solution for the latter, and could thus become VoIP providers. AOL actually is, indirectly, through Apple’s iChat AV. This competitive threat explains why, for instance, France Télécom made a defensive investment in open-source IM provider Jabber.

Two recent developments promise to change dramatically the economic underpinnings of the IM industry:

1. Yahoo announced a few weeks ago it would drop its enterprise IM product. Within a week, AOL followed suit.
2. AOL and Yahoo agreed to interoperate with LCS, Microsoft’s forthcoming Enterprise IM server. Microsoft will pay AOL and Yahoo a royalty for access to their respective IM networks.

These announcement make it clear neither Yahoo nor AOL feel they can sell successfully into enterprise accounts, and certainly not match Microsoft’s marketing muscle in that segment.

The second part, in effect Microsoft agreeing to pay termination fees to AOL and Yahoo, means that Microsoft’s business IM users will subsidize consumers. This is very similar to the situation in telephony, where businesses cross-subsidize local telephony for residential customers by paying higher fees. For most telcos, interconnect billing is either the first or second largest source of revenue, and this development may finally make IM profitable for Yahoo and AOL, rather than the loss-leader it is today.

Apparently Microsoft has concluded it cannot bury its IM competitors, and would rather make money now serving its business customers’ demand for an interoperable IM solution than wait to have the entire market to itself using its familiar Windows bundling tactics. Left out in the cold is IBM’s Lotus Sametime IM software.

Businesses will now be able to reach customers on all three major networks, but this does not change the situation for consumers. The big three IM providers have long played cat-and-mouse games with companies like Trillian that tried to provide reverse-engineered clients that work with all three networks. Ostensibly, this is for security reasons, but obviously the real explanation is to protect their respective walled gardens, just as in the early days the Bell Telephone company would refuse to interconnect with its competitors, and many businesses had to have maintain multiple telephones, one for each network. It is not impossible, however, that interoperability will be offered to consumers as a paid, value-added option. Whether consumers are ready to pay is an entirely different question.

The European Union E-Privacy directive of 2002, the US CAN-SPAM act of 2003 and other anti-spam laws allow legal action against spammers. Only official authorities can initiate action (although there are proposals to set up a bounty system in the US), but enforceability of these statutes is a problem, as investigations and prosecutions are prohibitively expensive, and both law enforcement and prosecutors have other pressing priorities contending for finite resources. Financial investigative techniques (following the money trail) that can be deployed against terrorists, drug dealers and money launderers are overkill for spammers, and would probably raise civil liberties issues.

There is an option that could dramatically streamline anti-spam enforcement, however. Spammers have to find a way to get paid, and payment is usually tendered using a credit card. Visa and Mastercard both have systems by which a temporary, one-time use credit card number can be generated. This service is used mostly to assuage the fears of online shoppers, but also provides a solution.

Visa and Mastercard could offer an interface that would allow FTC investigators and their European counterparts to generate “poisoned” credit card numbers. Any merchant account that attempts a transaction using such a number would be immediately frozen and its balance forfeited. Visa and Mastercard’s costs could be defrayed by giving them a portion of the confiscated proceeds.

Of course, proper judicial oversight would have to be provided, but this is a relatively simple way to nip the spam problem in the bud, by hitting spammers where it hurts most – in the pocketbook.

Deborah Copaken Kogan

Random House, ISBN: 0375758682  Publisher, Buy online

I picked up the hardcover edition of this book from the sale bin at Stacey’s Booksellers, as the Leica on the cover just beckoned to me.

This is an autobiography by an American woman, almost a girl, who moved to Paris, fresh out of college, to break into the tightly-knit (and not a little macho) community of photojournalists. Who knows, I might even have crossed paths with her when I studied in Paris. She was certainly not the first female war correspondent, Margaret Bourke-White springs to mind (even though she is not referred to anywhere in the book), but women were still a rarity, specially one as young and inexperienced. She started as a freelancer and eventually ended up working for the Gamma agency, one of the few independent photo agencies left.

For some unknown reason, many of the prestigious photo press agencies are based in Paris, starting with Magnum, founded simultaneously in Paris and New York by Robert Capa (the man who took the only photographs of D-Day), Henri Cartier-Bresson, George Rodger and Chim Seymour. Others like Gamma, Sygma and Sipa followed, but most have been acquired since by large media conglomerates like Bill Gates’ Corbis. The move to digital, with the corresponding explosion in equipment costs is one reason – the independent agencies simply couldn’t compete with wire services like Reuters or Agence France Presse (AFP), the latter being government-subsidized. Saturation is probably another, and press photographers struggle to make a living in a world with no shortage of wannabes. Just read the Digital Journalist if you are not convinced.

Shutterbabe is not a mere feminist screed, however. Engagingly written, with very candid (sometimes too candid) descriptions of the sexual hijinks and penurious squalor behind her trade, this book is a pleasurable read and features a varied rogues’ gallery ranging from the cad (her first partner) to the tragically earnest (her classmate who is executed by Iraqi soldiers while covering Kurdish refugees). It only touches in passing on photographic technique, as the general public was clearly the intended audience, but more surprisingly, does not include that many of her photos either. The main thread reads like a coming of age story, with the young (25 year old at the time) woman moving on from her thrill-seeking ways and discovering true love and marriage in a life marked by death: deaths of friends and colleagues, victims of strife and war in Afghanistan or Russia, but also orphans dying of neglect in Romania.

A photojournalist is always in a rush to get to the next assignments, and she recognizes her involvement with her subjects’ culture as superficial, unlike that of her locally based correspondent colleagues or those who would nowadays be called photoethnographers. There is more humanity in a single frame by Karen Nakamura or Dorothea Lange than in all of Deborah Copaken’s work. Much like her idol Cartier-Bresson’s work, there is a certain glib coldness, perhaps even callousness to her attitude. On her first war coverage, an Afghan who is escorting her (so she can make her ablutions in privacy) has his leg blown off by a landmine, and she hardly elicits any concern for the poor soul. Granted, this is the “Shutterbabe”, not the reborn Mom. but it is hard to imagine one’s fundamental personality changing that much.

The author is not uncontroversial. She featured in a nasty spat with Jim Nachtwey, one of the most famous photographers alive, and who is obliquely referred to in Shutterbabe‘s Romanian chapter (where she implies she found out first about the terrible situation in the orphanages, and nobly tipped him so the story could come out). The follow-ups are here and here.

Her observations of the one culture she is immersed in, the French one, seldom go beyond the realm of cliché. Glamorous but feckless and chauvinistic Frenchmen! Sexpot Frenchwomen! Narcissistic French intellectuals!

In the end, she returns to the United States with her husband, and moves into an equally short-lived career in TV production to support her family. A happy ending? One hopes. I for one am curious about how her children will react to the book when they are old enough to read it.

The current version of Internet Protocol (IP), the communications protocol underlying the Internet, is version 4. In IPv4, the address of any machine on the Internet, whether a client or a server, is encoded in 4 bytes. Due to various overheads, the total number of addresses available for use is much less than the theoretical 4 billion possible. This is leading to a worldwide crunch in the availability of addresses, and rationing is in effect, specially in Asia, which came late to the Internet party and has a short allocation (Stanford University has more IPv4 addresses allocated to it than the whole of China).

Internet Protocol version 6, IPv6, quadrupled the size of the address field to 16 bytes, i.e. unlimited for all practical purposes, and made various other improvements. Unfortunately, its authors severely underestimated the complexity of migrating from IPv4 to IPv6, which is why it hasn’t caught on as quickly as it should have, even though the new protocol is almost a decade old now. Asian countries are leading in IPv6 adoption, simply because they don’t have the choice. Many people make do today with Network Address Translation (NAT), where a box (like a DSL router) allows several machines to share a single global IP address, but this is not an ideal solution, and one that only postpones the inevitable (but not imminent) reckoning.

One misconception, however, is that that the slow pace of the migration is somehow related to the fact you get your IP addresses from your ISP, and don’t “own” them or have the option to port them the way you now can with your fixed or mobile phone numbers. While IPv6 greatly increases the number of addresses available for assignment, this will not change the way addresses are allocated, for reasons unrelated to the address space crunch.

First of all, nothing precludes anyone from requesting an IPv4 address directly from the registry in charge of their continent:

• ARIN in North America and Africa south of the Equator
• LACNIC for Latin America and the Caribbean
• RIPE (my former neighbors in Amsterdam) for Europe, Africa north of the Equator, and Central Asia
• APNIC for the rest of Asia and the Pacific.

That said, these registries take the IP address shortage seriously and will require justification to grant the request. Apart from ISPs, the other main kind of allocation recipients are large organizations that require significant numbers of IP addresses (e.g. for a corporate Intranet) and that will use multiple ISPs for their Internet connectivity.

The reason why IP addresses are allocated mostly through ISPs is the stability of the routing protocols used by ISPs to provide global IP connectivity. The Internet is a federation of independent networks that agree to exchange traffic, sometimes for free (peering) or for a fee (transit). Each of these networks is called an “Autonomous System” (AS) and has an AS number (ASN) assigned to it. ASNs are coded in 16 bits, so there are only 65536 available to begin with.

When your IP packets go from your machine to their destination, they will first go through your ISP’s routers to your ISP’s border gateway that connects to other transit or final destination ISPs leading to your destination. There usually are an order of magnitude or two fewer border routers than interior routers. The interior routers do not need much intelligence, all they need to know is how to get their packets to the border. The border routers, on the other hand, need to have a map of the entire Internet. For each block of possible destination IP addresses, they need to know which next-hop ISP to forward the packet on to. Border routers exchange routing information using the Border Gateway Protocol, version 4 (BGP4).

BGP4 is in many ways black magic. Any mistake in BGP configuration can break connectivity or otherwise impair the stability of vast swathes of the Internet. Very few vendors know how to make reliable and stable implementations of BGP4 (Cisco and Juniper are the only two really trusted to get it right), and very few network engineers have real-world experience with BGP4, learned mostly through apprenticeship. BGP4 in the real scary world of the Internet is very different from the safe and stable confines of a Cisco certification lab. The BGP administrators worldwide are a very tightly knit cadre of professionals, who gather in organizations like NANOG and shepherd the Net.

The state of the art in exterior routing protocols like BGP4 has not markedly improved in recent years, and the current state of the art in core router technology just barely keeps up with the fluctuations in BGP. One of the control factors is the total size of BGP routing tables, which has been steadily increasing as the Internet expands (but no longer exponentially, as was the case in the early days). The bigger the routing tables, the more memory has to be added to each and every border router in the planet, and the slower route lookups will be. For this reason, network engineers are rightly paranoid about keeping routing tables small. Their main weapon consists of aggregating blocks of IP addresses that should be forwarded the same way, so they take up only one slot.

Now assume every Internet user on the planet has his own IP address that is completely portable. The size of the routing tables would explode from 200,000 or so today to hundreds of millions. Every time someone logged on to a dialup connection, every core router on the planet would have to be informed, and they would simply collapse under the sheer volume of routing information overhead, and not have the time to forward actual data packets.

This is the reason why IP addresses will continue to be assigned by your ISP: doing it this way allows your ISP to aggregate all its IP addresses in a single block, and send a single route to all its partners. Upstream transit ISPs do even more aggregation, and keep the routing tables to a manageable size. The discipline introduced by the regional registries and ISPs is precisely what changed the exponential trend in routing table growth (one which even Moore’s law would not be able to keep up with) to a linear one.

It’s not as if this requirement is anti-competitive, unlike telcos dragging their feet on number portability – the DNS was precisely created so users would not have to deal with IP addresses, and can easily be changed to point to new addresses in the event of a change of IP addresses.