Category: Lenses

• Some specimens had the W↑D symbol—meaning they belonged to the War Department.
• And during the war, Dallmeyer got fancy and cooked up their own anti-reflective coating. They called it Dallcoat, which was magnesium fluoride (MgF₂) applied on glass. Near the end of the war you'd sometimes spot lenses with a "DC" engraved on them—that was your cue.
• Oh, and serial numbers? They started with two letters, often your only hope of figuring out who the hell made that. "UU" was Dallmeyer, "TT" Taylor, Taylor & Hobson, "VV" Ross, "No." or "EE" was Aldis and "NOC" = National Optical Company—a TTH offspring churning out war glass.

None of this followed the usual peacetime rows and logic. Markings commonly shifted without warning, records were lost, skipped, or never written at all, and the whole affair unfolded in a cloud of urgency, shortcuts and indifference. What we ended up with was a glorious pile of inconsistent engravings, serials with trust issues and styles that resemble something like typographic roulette. You could spend your long, lonely winter evenings trying to make sense of it. So, what do we know about the Serrac above? That it was made between 1939 and 1945. That's it.

Like I said earlier—there were a LOT of types - Pentac, Serrac, Rareac, Dalrac, Dallac, Dalmac, Perfac… Someone in the naming department clearly had a thing for symmetry or a stroke. The one that shows up the most? Probably Dallmeyer Pentac 200mm (8") f/2.9. A sort-of knockoff of the famous American Kodak Aero Ektar 178mm f/2.5. According to legend, every Spitfire had two of them - one on each wing (see diagrams below).

The 360mm (14") range was mostly covered by Dallmeyer, 500mm (20") belonged to Aldis and the Big Bertha - 900mm (36")—was carried by Wray. Not that it really matters—everyone built everything, lenses got swapped like socks and wartime production wasn't exactly a fan of order.

In the darkest days of Britain and Europe, Dallmeyer did something that, seen through today's market logic, feels almost unthinkably chivalrous. Rather than splinter its production capacity in the endless chase for profit (not that they were running a charity though), the company focused fully on supplying the military effort. No double-dipping, no hedging bets between the front line and the commercial high street. They tightened operations, prioritized the war machine and even took time to boost national morale. Below are excerpts from wartime press materials (mostly sourced from an excellent reference linked here) and even a catchy acrostic:

During the pre-Christmas seasons of 1939 to 1944, the factory regularly released upbeat little notes into the advertising ether, confidently predicting the war would soon be over—until eventually, they were right. In the September 1945 issue of Trade Bulletin magazine, they finally nailed it: a half-page ad appeared with a headline that said it all, with all the relief of a deep exhale:

PEACE

"The door is now unlocked, and Dallmeyer lenses will soon be once more available for distribution by the photographic and cinematographic dealer."

Alright, enough history lessons—let's get back to the actual shooting. For aerial reconnaissance, they used super-fast optics with the widest possible coverage, so you could snap as much ground as possible even when the light sucked and weather was British. These lenses were mounted under the plane (where else, seriously?), and the combo of speed, focal length, and coverage meant one thing: these were massive, heavy beasts. They often paired with giant shutters and automatic film feeders that churned out film by the kilometers. Fucks given about size or weight: 0.

• Films came in all sorts of formats—single sheets or rolls—and were closer to technical films used for copying or scientific purposes than your average everyday film. The main priorities were high resolution (lines per millimeter—lpm), sharpness and boosted contrast. They even sometimes used special developers—forget your normal photo lab chemistry.
• LPM (lines per millimeter) measures how fine the detail your lens and film can resolve. The higher the better. If your winter evenings are still too long and boring, feel free to dive into these links here or here. GL & HF.

• Canada balsam (marginally also Canadian turpentine) is a mixture of oil and resin obtained from the Balsam Fir (Abies balsamea). It is traditionally used, for example, as a medium for fixing laboratory specimens, as it is invisible when dry. When it is mixed in a 1:1 ratio with xylene, it produces a mixture with almost identical refractive index (which is very similar even without xylene) as a crown glass (n = 1.55). This is why it has found applications in the binding of lenses and optical systems. When you don't have anything to do during the long winter evenings and you feel like burning the mucous membranes or teasing the nervous system is the thing, I recommend opening a bottle of xylene.
• Today's lenses and optics are no longer cemented this way—UV fixation is used. It's an irreversible method (which can be a disadvantage, older lenses could be re-cemented by heat) and does not change over time, so you no longer encounter element separation caused by balm degradation.

• Let's talk about the image circle. If it's too small, you'll end up with vignetting: dark corners, shadowy sides, or in the worst case scenario a sad little circular image floating in black like you used a bad lenshood. But if the coverage is generous enough (like here), the frame stays well-lit, sharp across the board and gives you plenty of wiggle room for all those glorious camera movements—tilts, shifts, swings and whatever will row your boat.

Give the Claron a proper stopping-down, yank that bellows out and boom—at 1:1 magnification, the image circle balloons to 1036 mm. That's over a goddamn meter. One meter by one meter. What can you shoot with that? Anything. Whatever the hell you want. With this lens, you answer to no one. This chunk of glass will fulfill your most unhinged large format fantasies and still leave a few millimeters of coverage as a dessert. Just be careful at airport security—they might not share your enthusiasm. Try walking through a radiation detector with a thorium-packed artillery shell like this in your carry-on, and chances are you'll be the one fulfilling someone else's wildest fantasies. Someone with a gloved hand and a flashlight.

Now, let's finally take a look at the lovely bunch that had the decency to show up! There were a wide range of focal lenghts varying from those made for 35mm toys all the way up to proper ULF monsters (ultra large format). Personally, I'm into the bigger ones—can't afford a Hummer, so I make up for my tiny weenie with large lenses. And obviously the bigger the lens and the camera, the better the photographer. That's just science. 

• 480mm f4.5—well, there I was on a weekend, minding my own business like a proper café-dwelling layabout, skipping the real work in favor of a decaf soy pumpkin spice venti latte - when BAM! Out of nowhere, an absolute coconut of a lens smacks me in the face. One of the rarest pieces of glass ever to roll across this planet. Just another Sunday. Where am I even supposed to put another one? Sigh. Anyway, my current 480mm version is nothing less than a 3.6kg behemoth of glass and blackened aluminum, which, over its long existence must have annihilated entire goddamn battalion of the big toes. Very few were ever made, and even fewer have survived. The price tag back in the day must have been eye-wateringly high, whether you were a commoner or a noble. Unfortunately, the signature hasn't survived, as it was sometimes engraved on the lens hood—which, in this case, is missing (other versions had the engraving on the barrel and a permanently attached hood, so at least you couldn't lose it). The image circle is absolutely monstrous—it swallows a 40x50cm frame like it's nothing. Yes, that's half a meter of photographic overcompensation.