Gnurple dot Net

I have a habit of making lots of blog posts for awhile and then lulling.

Is lulling a word? Vote now: 1-800-DEV-NULL.

As I was saying, the Gnurple dot Net post frequency is a journey of hills and valleys. Allow me to describe the current valley in a chronologically sorted sort of way (heh):

MEDIA CENTRE

I’ve got a much longer pair of posts in the work on this subject. When this lull ceases and I finish them up, I shall dole them out.

For now, the short story is that I bought a media centre, discovered it was crappy, decided I could build a much better one for about the same cost, returned it and then built a much better one for about the same cost.

It isn’t done yet - is a project like this ever really done? - but it works.

APATHY

A couple of projects are important to me: (1) weekly photo assignments, and (2) daily Every Day Objects photos. They’re important but they take a lot of spare time. I’ve set them aside for an indefinite (but temporary) while so I can use that time for better things.

I set them aside in favour of things that needed doing: (1) building the media box (done); (2) working on wedding stuff (not done); (3) working on summer house projects (half done - A: the shed is moved, B: the pool is up, but C: the fence still needs fixing and D: the new shed needs building).

Unfortunately, building the media box has opened a huge new time sink: (4) wasting time in front of the boob tube.

Flash-back to a handful of years ago (I haven’t got an SFX budget so you’ll have to imagine your screen going all wavey with a sort of echoey theremin sound and blurred haloes of light ’round everything) when I gave up TV for two reasons:

(1) I can’t stand advertisements. Given the choice between watching a show frequently interspersed with long series of adverts and watching nothing, I chose nothing. (or rather, I chose to watch DVD sets rather than broadcast TV)

(2) I felt that watching TV had become a time-wasting bad habit; that there were better and more productive ways for me to spend that time.

With the media centre skipping commercials is trivial, eliminating problem (1). Now I’m faced again with problem (2), and I need once again to generate the willpower it took to break away. Some people have that kind of willpower available all the time. I don’t.

HUNNYBEAR’S B-DAY

Last weekend we celebrated. We *wanted* to have a Saturday pool party / BBQ. The dismal weather forecast convinced us to postpone by a weekend, though it turns out that the weather was OK on Saturday after all, with just five minutes of rain in an otherwise sunny day. I got a sunburn on my shoulders from hanging outside too much. I failed to make a hammock out of a bedsheet.

Instead we invited some friends to sushi dinner and a movie. The one-word review of Don’t Mess With the Zohan: Stupid-funny. (What? A compound word is one word. C’mon, just say it like it’s one four-syllable word. Yucandewit.)

I think my birthday present for Mah Hunnybear didn’t suck because she’s been carrying around and playing with it everywhere since I gave it to her.

KITTY TROUBLES

Today I awoke to a pretty horrible morning. Last night just after I went to bed I heard cat hissing. I got up and found that three cats had a fourth cat cornered behind a chair. I broke that up and brought the fourth cat to sleep on the bed with me.

At 05h00 I heard a loud cat-like noise. We have 5 cats in our house, so this happens sometimes and I really didn’t think much of it and went back to sleep.

When I got up two hours later, I looked around to make sure things were alright.

They weren’t.

I found that same fourth cat I’d brought to bed lying on a chair under the dining room table, a spot she normally takes. However, when I went to pet her I found injuries: she’d been scratched in the eye. There was blood.

One trip to the vet and $320 later, she’s locked by herself in a room with a cone collar on so she can’t rub her eye and receiving external and internal antibiotics. She gets another trip to the vet on Friday.

I really hope her eye (and the rest of her) survives this.

I was just reading David Tejada’s blog. Tejada is a professional photographer. He makes his living making pictures and he does it very well. He earns respect and admiration.

In his blog he describes his images and photo shoots in a way that is not only technically useful to photographers but is also a pleasure to read. This, too, deserves applause.

On the other hand, his technical writing skills could use improvement. For example: “This photo will give you a good idea of the type of fog issues we where dealing with…”(’where’ vs. ‘were’ is not just a typo, the two are consistently confused throughout); “Yesterday it was 80 degrees out, what gives.” (run-on sentence; period vs. question mark)

I don’t want to suggest any disrespect for Tejada, nor to suggest that he should focus on improving his skills. He’s a photographer, not a writer. We’re too busy being blown away by his images to be blown away by his writing.

Despite the technical flaws, his writings are, as I said before, a pleasure to read. I can think of material that is technically better but much less interesting to read. Gnurple dot Net, for example.

THE POINT (at last!)
So where am I going with this? While I read through his latest posts, noticing these little imperfections, I wonder why it matters. After all, despite these mistakes, what he means to say is obvious.

As long as the meaning is clear, it’s not important to write correctly, is it? Visits to LiveJournal and Facebook suggest that a lot of casual writers entertain this theory.

The short answer is that mistakes distract the reader from following along.

A writer’s goal, be they casual or professional, is to share their ideas and experiences. Recall the last book you read that really drew you into its story. For me, that’s Stephen King’s The Dark Tower.

Do you notice that as you get into a story, you don’t realize there’s a real world around you anymore? Your significant other is standing before you, in the nude, offering a glass of your favourite drink, and you don’t even notice?

You lose track of time. The fact that you’re reading words and flipping pages become as unconscious and involuntary as breathing. Your consciousness is deep into following the thoughts and experiences the writer has presented. Your eyes see the words, but your mind is there inside the story.

At some point, you notice that you can’t actually read the words anymore: it’s gotten too dark outside. The real world suddenly snaps back into place. Cats are meowing for food. The ice in your drink has melted. You smell smoke coming from the oven.

Reading across a mistake is one of the things that snaps you out of the story and back into the real world. Reading is like taking a nice, calm drive through the country, and a mistake is a nasty pothole. Or perhaps it’s like watching a breathtaking scene in a movie theatre when suddenly somebody walks past you, muttering “excuse me” as they move down the aisle, their shoes squeaking on the disgusting, sticky floor.

Once you get yoinked out of it and back into the real world, it takes a bit of time and effort to get back in. Where were we? What just happened? Ah, yes, Spidey just beat the bad guys off and disappeared up the wall and hey, did I just miss a scene of M. J. in a soaking wet shirt? Daaamn!

One or two mistakes in an otherwise pleasant journey, as with Tejada’s writing, are fine. Too many, though, and readers get frustrated and give up. It’s a psychological balance. Add one too many weights, and the scale tips over.

It’s like driving down that country road.

One pothole? Fine, that’s OK, the sun is still shining and look at the wind rippling through the grass and BUMP! Another one. Meh. Ah well, the road’s OK now and look at the cows out standing in the field, little puffs of white cloud above them in a dark blue sky and BUMP! OK, that’s it! This road is terrible! How far is the end? Is there another route?

In an earlier post I mentioned participating in the 80k bike tour for charity. I was recruited by a friend to join him and his team. Here is my report on the event.

PRE-TOUR
The plan: wake up at 07h15, leave at 07h30. Arrive on site at 08h00, a half hour before the 80k tour starts.

The reality: I awoke at 06h40 or so, terribly unusual weekend behaviour for me. Partly due to having had a refreshing mid-afternoon nap the day before, I imagine, but mostly I suppose I was anxious about the tour.

I ended up goofing off by reading RSS feeds until after half-past seven, then scrambling to round up my gear, check tire pressure, etc. before leaving. This sort of last-minute rushing about is entirely normal for me, unfortunately.

It was raining lightly, about 10°C outside. If I were biking the half-hour to work I’d be wearing my bike shorts, a shirt and a windbreaker. With the prospect of spending 4 hours in the cold rain, I added ski pants.

About 5 minutes into my trip to the site, my clothes were soaked through to my skin. At this point I realized I’d left my wallet and water bottle at home. How will they identify my unconscious, dehydrated body lying on the roadside?! More importantly, how will I buy post-tour beer? Silly thoughts like this do tend to wander through my head.

ON SITE
I’d made arrangements to meet the teammate who would be participating in the 80k with me. The others were doing the 35k; we two were the crazy ones. I arrive at the start point at 08h15 and begin searching.

08h20: no teammate. I suppose he should have a name other than teammate. Let’s call him Wartbag. That’s probably the name I’d be using for him right about now anyways. He has my bib - with my entrant number printed on it so they can identify my unconscious, dehydrated body - as well as my complimentary “thanks for coming out” tour t-shirt and my $30 gift certificate for raising $440 for the charities.

08h25: no Wartbag. They’ve started announcing stuff on the P.A. now. Stories about some of the children who inspired The Tour, the obligatory sea of Spandex jokes and such. I found a bucket full of bottled water and stuffed one in my bottle holder where it rattled about loosely.

My speedometer started reporting crazy numbers such as 574 km/hr. The rain wreaks havoc with the sensor terminals. I reluctantly stuffed it away. I will miss having some sort of progress meter on this long trip, but if it shorts out and one of its chips releases the magic blue smoke I will miss the speedometer more.

08h30: no Wartbag. The tour has started. At this point I’m feeling a bit down. No teammate to tour with, surrounded by cyclists with their fancy bibs, my back all plain and not in any way marked with a nice official-looking number, rain-soaked clothes clinging to wet skin. Trying to wipe my foggy glasses on my soaked shirt in the vain hope of being able to see, you know, things.

I am seriously contemplating abandonment at this time. Just 11k away there is a warm, dry bed. Nobody will notice I’m not among the cyclists. I don’t even have an ID number. Surely the cops will pick me up for not having a tour ID number?

08h35: no Wartbag. It’s decision time, so I choose to do the tour. All these other fine folks are out here in this crappy weather, smiling and cycling in support of a great cause. The idea of looking myself in the mirror after choosing to turn away from this does not appeal.

THE TOUR
It’s five minutes in, and I’m starting to catch up to other riders. My socks are soaked through. My ski pants are clinging as my legs pump the pedals.

Ten minutes in, I meet a friendly cyclist named Mike. We chat for awhile. It’s his fifth year. Apparently the big tour used to be 50k. Then it got bumped to 60. Now it’s 80k. He surmises that their plan is to keep upping the number until it’s just nine crazy cyclists left and they have to run the route with a semi-trailer to haul the fallen ones away. I suggested it was just inflation.

Mike cycles slightly faster than I do. I start to feel a pain in all the diodes on my left side so I slow it down a bit. I look around and recognize where we are; we just got on Herzberg Rd.

The rain has stopped falling, or perhaps it has simply relocated itself from the atmosphere to the inside of my shoes where it squishes.

The world continues to slowly pass by as I incessantly pedal onward. I see trees of green. In between the vast clouds of white I see skies of blue. I pass by a fellow cyclist and greet them with a how do you do. What a wonderful world it is being out in the open air on this bright blessed day on a bicycle.^[1] I wish I’d brought my music player as other silly thoughts like this spawn throughout my brains.

I’m not sure what time it is. Time is starting to become less important. We arrive at the auto-park near the Corel Centre where there is a rest stop. My water bottle is thus far untouched. I drain it and replenish my supply. I eat a slice of orange. It is tasty. I return to my bike.

More time has passed as I cycle along. The sun is starting to peek out through the clouds. I’m just cruising along now, almost effortlessly. Maybe I’m getting into the groove - or maybe there’s a hefty tailwind giving me a boost. I enjoy it with the wary sense that I shall pay dearly for the pleasure later, on the way back.

I see signs for a rest stop but I continue on. I have no idea where I am now, except to know that we are out on country roads. The area is sparsely populated. There are volunteers at various spots along the route. When we pass by, they bang plastic, air-filled sticks at us, kind of like the fans do at hockey games, and yell encouraging words.

Time has almost no meaning. There is only now, and the next time I get off my bike. I’ve reached another rest stop which is also the turn-around point. I drain another water bottle. I cannot stop walking about. I briefly look for oranges but the crowd is too thick so I move on. My toes are cold and wet and becoming numb.

Time has no meaning, but speed does. Before the turn-around point I had lots. Now whenever I try to speed up a gust of head-wind puts me in my place. I soon figure it out: the atmospheric pressure system is directly linked to my bike’s gears. When I shift up, a gust of headwind blows.

Yes, that’s right, it blows.

I pass by that rest stop I didn’t take earlier. If I had a brush and some paint, there’d now be three little water bottle icons on the side of my bike. I avail myself of the plentiful bounty of oranges. These are the finest, most pleasurable oranges I have ever in my life tasted. The nice girl attending the station gives me one for the road.

I bike on. At some point Mike pulls up from behind. When did I pass him by? I ask him how far we’ve come so far. 60k. We chat a little longer, mostly to bemoan the headwinds, but once again his cadence is slightly faster than mine, and I slowly fall behind.

I cannot feel my toes. My legs are cold. I find myself standing occasionally to relieve my butt, which is more accustomed to comfy office chairs than bicycle seats for hours on end.

Time still has no meaning, but the world has changed. Now the houses are closer together and the road surface is smoother. Civilization! A sense of near-completion urges me forward to greater speeds. Or perhaps it is the improved quality of the road or that the headwinds are broken up by all the buildings.

I stop at one last rest stop. The tastiness of these oranges is incredible, as if the goddess of fruits raised each and every one with tender loving care in her personal garden. I can see the spire of Nortel building 5 in the distance. The end is in sight!

POST-TOUR
Speaking of goddesses, no sooner did I cross the finish line and turn back do I see my fiancee standing before me.

Half an hour into the tour, I’d thought to myself, “This isn’t so bad. Perhaps I’ll bike home after the tour.” At around the 60k mark, fighting headwinds and hills and fatigue, I thought, “I do hope Hunnybear shows up so I don’t have to bike home.”

My only thought after (clumsily) dismounting my bike after crossing the finish line was, “I shall chain this medieval torture device up in the basement and never ride upon it again.”

Fortunately, before thoughts of attacking it with an axe and welding touch could set in too deep, I was distracted by hot dogs.

I was ready for my brain to let go of this whole light comparison thing when suddenly, from behind a bush along the sidewalk, the thought occurred to me: “What about strobe light?”

We know from last time on this subject that incandescents - or the sun or any black-body radiators - are true full-spectrum sources of light, unlike compact fluorescents which throw most of their light at certain peak wavelengths.

As photographers we love us our strobes and consider them ideal, if not necessary^[1]. So what kind of light do those babies put out? They work kind of like fluorescent tubes. The gas inside is Xenon, though, and there are no phosphors coating the tube as the light Xenon emits when excited by electricity is visible.

MORE SPECTROGRAPHIC ANALYSES
I did some more of that *extensive research* and found The Double Amici Prism Hand-Held Spectroscope page wherein Mr. Galidakis shares his spectrographs. He has some for incandescent and CFL bulbs as well as for Xenon, which I’ve included (below) for comparison to those from the previous article.

These analyses are slightly different. Last time we saw data plotted from a spectrometer. In these, a digital image is taken from a spectroscope showing the various light spectra, seen on the left. On the right we see a graph showing the intensity of the pixels representing the wavelengths of light seen in the image.^[2]

Although these are not calibrated to show wavelengths and may not be as accurate as the spectrometer output we saw earlier, they’re more than enough for us:

Incandescent Analysis
© I.N. Galidakis

CFL Analysis
© I.N. Galidakis

Strobe Analysis
© I.N. Galidakis

As we can see, a Xenon strobe such as we have in most of our photographic lighting doesn’t make full-spectrum light either, though it comes a lot closer. We know that strobes make perfectly fine light sources for our photography needs, so if I wasn’t entirely satisfied that CFLs are fine for photography before, I am a lot more open to the idea now.

COLOUR RENDERING INDEX
I would like to draw attention to this Wikipedia article on the Colour Rendering Index. “The Colo[u]r Rendering Index (CRI) … is a quantitative measure of the ability of a light source to reproduce the colors of various objects faithfully in comparison with an ideal or natural light source.” This basically describes what we’ve been looking for all along.

The CRI is a scale from 0 to 100. At the high end of the CRI we have incandescent lights (100) and other black body radiators that make great light. On the low end we have crappy sources of light like high-pressure sodium (24). Imagine trying to look at something colourful like a Gretag Macbeth colour chart under a sodium vapour streetlight. Not exactly what you want to be lighting your subject with, yes?

Typical fluorescent light sources score in the 70’s and 80’s on the CRI, according to the chart of typical values on Wikipedia. Xenon strobes aren’t listed but more *extensive research*^[3] quotes them at or above 95. I also found that, while your typical dollar-store CFL might have a low CRI, there are stores selling CFLs with CRIs in the 90s.

I’ve been taking pictures for the Every Day Objects game - which has evolved into a sort of Project 365^[1] for me (72 so far!).

Using a (near) macro lens means a very shallow DoF, so I end up using a tabletop tripod a lot. Trying to get everything positioned and focused can be tricky^[2] with only two hands so allow me to introduce one of my favourite tools:

Helping Hands

Designed for soldering^[3], this little guy is incredibly handy for macro photographers. It’s great for holding and aiming diffusing panels (a.k.a. letter-sized sheets of paper), reflectors (a.k.a. cardboard covered with paper or aluminium foil) and flags.

Sometimes I use it to hold my subject, allowing me to stick a background (a.k.a. colourful packaging and marketing material) well behind the object - and thus use separated foreground/background lighting.

… and now you see the double meaning behind the post title.

AN IMPROVEMENT
Using this a lot means I notice some of its annoyances and quirks. One of these is that the all-metal construction result in each joint having two modes: tight as hell; and floppin’ loose.

When the joint is tight, trying to wiggle the object in front of the lens into a better position is frustrating. Turn the appropriate nut or screw a half a degree loose-wise, and the whole thing falls to gravity. There is no in-between, no gentle friction grip.

Helping Hands - A Better View

Here you can more easily see what I mean. See those wing nuts? When you loosen one just a fraction, the ball joints suddenly become completely slack and everything falls over.

So I have an idea: there should be a rubber washer between each wing nut and its metal plate, so that the friction force can be reasonably varied. Each will also need a thin metal washer between the rubber and the wing nut to avoid friction when turning. I suppose I can find such washers at the local hardware store, though ones this small might be hard to find.

By the same token, each thumbscrew should be tipped with a bit of soft plastic, as a metal-on-plastic friction hold is gentler than a metal-on-metal one. I suppose one way to do this by melting a blob of plastic on the tip of each screw, small enough that it can be forced through the threaded hole.

BONUS PICTURE
Since you’ve managed your way through my post so far, allow me to present one of my housemates: Paddington.

Paddington Yawns

I took this while playing with the umbrella + stand I recently acquired. I know everybody hates pet picture postings (aside from ICanHasCheezburger.com, of course) but that yawn adds a cuteness and personality factor that’s hard to resist.

Thanks, Paddington!

PROLOGUE

My foray into the off-camera flash world began with a PC sync cable plus a pair of hot shoe adapters for camera and flash.

It works, but having a cable hanging off my camera gets in the way and tangles in the camera strap. The coiled wire is a spring that, like a mischievous cat, knocks over my tripod stand.

I made a deal with the voices inside my head: sanity in exchange for a radio flash trigger. A hobby photographer on a limited budget such as myself can’t afford nice Pocket Wizards, so I ordered some Poverty Wizards instead.

I was hooked at once! I stuffed my PC cord into a camera bag pocket and haven’t looked back.

THE MOD
Since then I’ve come across the infamous Gadget Infinity Cactus Transmitter Antenna Mod (GICTAM), best described here. If you’re like me you can’t say no to an opportunity to play with a soldering iron.

I ordered the appropriate Digikey bits along with some stuff for work (sharing shipping saves cents) which arrived less than 24h later - a shipping miracle!

The Bits and Pieces

Step 0: Disassemble the transmitter and yoink the battery.

Step 1: Locate the appropriate place for the antenna. Too far away from the front and the bottom of the antenna mount will strike the PCB. Too far from the side and the hole butts up against the center screw mount that keeps the whole unit together. Too close to the edge and the case depth is too small, so the bottom of the mount will strike the bottom of the case before it’s fully closed.

Step 2: Drill a pilot hole, and then drill consecutively larger holes until the antenna mount barely doesn’t fit. I did it this way so that the threads on the mount would bite into the case a bit when installed. This is not for weatherproofing - moisture is happy to get in via the LED hole or test button - but so that I can control the angle of the antenna. I wanted it to stand as straight as possible when mounted on the camera. What can I say, I’m a stickler for details.

(It ends up standing straight when viewing the camera from left / right, but at a slight angle when viewing from front / back)

Step 3: Get some wire. I cut a handy piece of telephone wire and, yoinked one of the 4 conductors, cut it to 6.82″, which should be 1/4 wavelength of 433MHz. Then solder one end to the PCB by bending the tip of the wire and feeding it through the hole from under the board.

The Innards

Step 4: I wrapped the wire around a large hex key. I kept tightening it around consecutively smaller hex keys until it was coiled just tight enough to fit in the case.

Step 5: Solder the wire to the mount (already fitted to the case from Step 2). I did this with my trusty “helping hands”, a little stand whose ball-jointed arms end with alligator clips. Great for soldering, but I use it a lot more for photography. Perhaps I shall blog about that later.

(With the loose end of the wire in one alligator clip, I couldn’t find a spot for the other to grip the outer case. I ended up looping a bit of wire through the LED hole and gripping that.)

Finally, reassemble the whole thing. The case did close, but the bottom wire bent where it’s soldered to the mount, so you know it’s quite close to the bottom of the case.

The Result

EPILOGUE
As soon as I had it reassembled, I tested it. Frustration mounted when I clicked the trigger a few times and nothing happened, even with the receiver only a few inches away. Frustration mounted in the same way it does when you just finish cooking burgers on the BBQ with some nice, tasty BBQ sauce… and then you try to carry too much and drop a burger on the ground. The sort of frustration that builds up until a sort of safety valve within you pops and out comes a great “Aaugh!”^[1]

But then, aha, THEN I tried it with the antenna mounted. Success! I mounted a flash (at lowest power) on the trigger and tested it on the ground floor, as far away as I could get. Fired every time. I took it upstairs to mah Hunnybear and asked her to yell “FLASH!”, then triggered it from the ground floor. Worked every time, so I went into the basement and tried again. I could barely hear her yell, but it worked every time.

So, bad news that it doesn’t work in “stealth mode” with the antenna off, but hooray for extended range! Guess I’d better not lose^[2] that antenna….

WHAT’S ALL THIS, THEN?

Jim Talkington is a photographer in Cincinnati, Ohio who makes a living making pictures. In today’s world, that’s worth a few nods of respect. Further, he shares his wisdom at his blog, prophotolife.com.

How awesome that is, or how Jim honed his amazing time management skills, is not what I want to explore today. Jim posted an article comparing the quality of various bulbs as photographic lighting. As one of the bulbs was a compact fluorescent (CF) and as I recalled how CF bulbs emit light differently than natural light, I thought I’d post a comment.

That lead to a follow-up article in which Jim compared light from a CF vs. an incandescent bulb. That (only three paragraphs later) is the topic of my mental meandering today. I’ve taken the bulb-ball and I’ll share where I’ve run with it so far:

SPECTROGRAPHIC ANALYSIS
I thought I’d start at my comment: my recollection that CF bulbs emit light differently than “natural” sources of light - i.e. things that make light by being very hot. Some quick googling*extensive research* led me to a site full of spectrographic analyses of various sources of light:

Analysis of Sunlight
© The LED Museum^[1]

Analysis of Flame
© The LED Museum^[1]

Analysis of a 60W Incandescent
© The LED Museum^[1]

Analysis of a CF Bulb (5000K, 13W)
© The LED Museum^[1]

SOURCES OF LIGHT
Sunlight, flame and incandescent light are all governed by Planck’s Law of black-body radiation. They emit light at all wavelengths, with the peak changing according to temperature. Fluorescent bulbs work differently.

Wikipedia tells us that the gas within a fluorescent bulb is excited by electricity, causing light. Sadly, it’s mostly UV light, so the tube is coated on the inside with phosphors that absorb the UV radiation and emit visible radiation (some is converted to heat, but as we can touch fluorescent bulbs it’s not so bad). The mix of phosphors determines the visible light:

Fluorescent Lighting Spectrum from Wikipedia
Click for Explanation

Our Wikipedia page tells us “A typical “cool white” fluorescent lamp utiliz[es] two rare earth doped phosphors, Tb3+, Ce3+:LaPO4 for green and blue emission and Eu:Y2O3 for red.”

So unlike black-body radiation which throws light at all wavelengths, a fluorescent bulb throws most of its light at specific wavelengths. That’s not so bad, though, as those wavelengths are our favourites: the ones that the cone cells in our eyes enjoy; the ones that our camera’s Bayer filtered photosensors detect. The ones our TVs and monitors fling at us daily, namely: red, green and blue.

A PHOTOGRAPHER’S HOOT
In what way does all this matter to us as photographers, then? I suppose what matters most is how the bulb manufacturer chooses to mix their phosphors to make the light appear natural. It’s important to note that not all fluorescents are alike.

Look back at that Wikipedia page again. Note the spectrograph for the halophosphate bulb. “The color rendering ability of these older style lamps is quite poor” says the article. One of the graphs on the LED Museum page shows a “Dollar Store” CFL of this type, implying that they might be living among us today.

So, as photographers interested in using CF bulbs for lighting, we want to make sure we choose a bulb that uses the right phosphors in a mix that closely matches natural light. Looking at the results Jim posted in his comparison, I’d say that bulb he used does a pretty good job.

MY RESULTS
Jim did an excellent job of doing a well-controlled comparison. However, I can’t very well go writing an article about photography without taking any pictures myself, so I tried to replicate his results, to see what I could learn.

Unfortunately I don’t have a Gretag Macbeth^[2] colour checker chart. I did, however, find a “Stride Rite” shoebox at a friend’s house with a very colourful design (what can I say, this is a budget production). I set my camera on tripod in the basement with the shoebox 3-4 feet away. The lamp, scavenged along with 3 bulbs from around the house, I placed at camera right, about 1 foot away.

I shot RAW to avoid worrying about setting the white balance perfectly in-camera. I set the exposure at 1.3″, f/4.5, ISO 100 and took three frames: Frame 1 uses a Philips Marathon^TM 15W CF bulb whose light has a warm glow (sort of) matching an incandescent’s (3000K-ish); Frame 2 uses a Pur-Lite^[3] 15W CF bulb whose CCT seems to be around 5000K, producing a very white light (perhaps I should say, Pur Wite Lite?); Frame 3 uses a 60W^[4] incandescent.

In processing the results, I set the white balance from the white “S” in the lower right corner using UFRaw. In The Gimp, I used Colour : Auto : Normalize to stretch the brightness of the image to fit the maximum range. (I did this after I noticed from the histograms that the brightness didn’t turn out the same across all bulbs. 15W CF is *supposed* to be 60W equivalent) Finally, I used a “Difference” overlay to make the differences clear. Anyways, here are the results:

Combined Results

Col. 1: CF3k, CF bulb, low temp.
Col. 2: CF5k, CF bulb, “pur wite lite”
Col. 3: INC, Incandescent

Row 1: histograms for the raw pictures (before I normalized)
Row 2: the pictures before normalization
Row 3: the pictures after normalization
Row 4: Differences (CF3k vs. CF5k / CF5k vs. INC / INC vs. CF3k)

ANALYSIS

(*) There is a small but noticeable difference, which the “difference” overlay makes apparent.
(*) The difference between CF3k and CF5k is similar to the difference between INC and CF3k. This suggests to me a couple of possibilities:
(o) The differences between phosphors is just as significant (or insignificant) as between CF emissions and natural light emissions;
(o) My own image processing (either WB adjusts or normalizing) might be confusing matters;

LESSONS LEARNED

Instead of a final result, what I’ve done so far is a learning experience. In doing a better study of this I would change a few things:
(*) Reset the exposure between each type of bulb by using a voice activated grey card^[5]. Take a frame as long as the card’s there anyway, to be used for white balancing.
(*) Include more of each bulb type to act as a control. Perhaps the difference between a 60W and 100W incandescent is just as noticeable as between incandescents and fluorescents.
(*) Get a Gretag Macbeth colour checker chart, or at least have handy greyscales to check exposure and whitebalance against.
(*) Take better care in post-processing to be avoid introducing artifacts.

In the meantime, however, I believe that CF bulbs ought to be fine except for critical colour management scenarios I can’t even imagine. I suppose those involved in such scenarios know more about this than I ever will.

UPDATE #1: If you’re visiting from ProPhotoLife.com I’d just like to point out (before you waste your time) that the vast majority of this blog is not photo-related. Here’s a link to the few posts that are tagged ‘photography’, be ye inclined to explore further.

UPDATE #2: I did a bit more digging and posted another article which includes info on strobe light spectra, in case you’re curious.

So Nortel (Telecom company in Ottawa) has this bike tour they do every year to support children’s cancer charities. That’s right, you can help me give children a free cancer!

I’ve decided to join the 80k tour. For me this is a lot of biking, but based on my 140km trip last year, I believe I can do this - with a fair amount of grumbling and sore buttedness.

If you’re reading this and you don’t make a pledge to help me reach/surpass my goal then I will personally contact Trogdor the Burninator and put you on his burnination list. You do not want to be on that list.

CAPTAIN WE GET SIGNAL!!!
YOU HAVE NO CHANCE TO SURVIVE MAKE YOUR PLEDGE

Please pledge now or else I’ll be forced to make another post with more intarweb memes, like this:

MAH PLEDGE
I SHOWS YOU IT.

Be forewarned, this post has no pictures.

NO PICTURES!

YESTERDAY
So, yesterday evening after taking pictures for the Weekly Assignments, I went around to make sure I had everything I needed to bike to work this morning.

Warm gloves? Check.
Ski pants? Check.
Sweater? Check.
Panniers, loaded^[1]? Check.
Brain bucket? Check.

THIS MORNING

I get up. That was my first mistake. Grab some clothes. Fetch the bike from the shed and bring it ’round to the driveway. Strap the panniers and laptop on the bike. Lock the front door, stow the keys in a pannier pocket. Check front tire pressure. 40psi? Pump it up to 70. Check rear tire; it’s at 40psi, too. Pump it up. Remove pump.

Sssssssssssssss.

*sigh*

Put the pump and gauge away. Curse. Remove laptop; remove panniers; unlock door. Curse. Drag everything inside. Curse twice. Grab shower, start car, go to work. Bleah.

Tonight when I get home, I get to enjoy the fun of changing the rear tire tube. Yay.

Savage Chicken is an interesting cartoon:

© 2008 Doug Savage

I appreciate how simple and easy these *appear* to be even though the ideas, the essence of funny contained within each, take inspiration and talent to conceive and express.