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Posts Tagged ‘Time Lapse’

The Lunar Eclipse that Wasn’t

Posted by Tom Benedict on 23/12/2010

I had plans to photograph the lunar eclipse.  Ooooh, did I ever have plans!

This all started when a friend of mine mentioned that he needed a single image that said: “Time Lapse”.  This is no small feat since most time lapse work results in a video, not a still image.  Once he explained the use he had in mind, though, the video idea went out the window.  It really did need to be a still.  We tossed some ideas around, and finally I remembered a project I worked long and hard on, but never really made headway with.

Back when I was doing a lot more 4×5 photography than I am now, I was given a box of things that came from various sources inside the family.  One was a camera of my great grandfather’s, a “pocket” Kodak camera that pre-dated the Great Depression.  It took a roll film I couldn’t find any more, and it had what looked like a lens built along the tessar design (symmetric doublets on either side of an aperture stop) set in a wonderful old shutter.  It was dirty, gunky, and not looking so great, but I knew it was a diamond in the rough.  I couldn’t wait to remove it from the original camera and mount it in a 4×5 lens board.

At the time I worked in a chemistry lab that was making optics.  I was also learning machining at the time, so I was up to my elbows in tools and optical cleaning equipment.  I disassembled the lens (not a huge trick with a large format lens) and disassembled and cleaned the shutter.  Keep in mind this shutter dated from the 191x era.  I wouldn’t do this with a modern shutter, which looks a lot like a Swiss watch once you get the cover off.  This shutter had “Big Parts”, a term coined by a friend of mine the first time he popped the hood on a 1960’s era Mustang and compared it to his 2000’s era Mustang.  Yep, dem be bigparts!

Cleaning took almost no time, and once everything was back together I discovered the real joy with this lens and shutter: the cable release also cocked the shutter.  So once it was installed on the camera, you could make exposure after exposure on a single sheet of film without touching the camera.  This means diddly squat if you’re doing straight photography, but it’s seriously cool if you’re doing multiple exposures.

I mentioned I was working in a chemistry lab making optics.  We were making diffraction gratings, and part of my job was to document our work to the best of my ability.  Imagine you’re seeing me making wikkid sounding snickering noises and rubbing my hands together, because that’s exactly what I did when I learned this was a job function.  “To the best of my ability” meant, to me, “You get to have a truckload of fun photographing what you do, and get paid for it.”  Oh yeah!

One question we were trying to answer was how much light was diffracted into each order of the grating.  We came up with a pretty good setup for measuring this, though the setup built by the guy they hired after I left was far better.  But for fun, I aimed a HeNe laser at one of our gratings and photographed the light diffracting off of it using multiple exposures.  Here’s the sequence:

  1. Do a normal “lights on” exposure of the setup.
  2. Turn off the lights, open the shutter.
  3. “Paint” the incoming beam with an index card, your finger, a piece of paper, whatever.  Keep a consistent pace as you do this.
  4. Then “Paint” the outgoing beams coming off the grating with that same index card, finger, etc.  Again, keep a consistent pace as you do this.
  5. Close the shutter, and turn on the lights.

What you get are these beautiful light beams floating in space, casting all the right reflections, and looking entirely like a movie special effect.  It also did a great job of showing that we got most of our light in one order (we had the grating arranged in littrow for all tests) and that the other orders had very little light in them.

The lens and shutter worked like a champ!

That’s when I got the idea of photographing a sunrise.

My idea was to do something similar to the laser beam trick, but use the shutter to capture the sun at various times during the sunrise.  I figured five minute intervals would be about right.  The only difference from the camera’s perspective is that the sun is a lot brighter than our laser beam, so I had to dump a lot of light.  I couldn’t afford the neutral density filter I needed, so I used two sheets of Kodak TMX film, overexposed and developed, placed in front of the lens.  If I remember right, this dumped the sunlight down enough that I could use something approaching a normal exposure without burning a hole in my film.

Unfortunately it never happened.  I tried diligently for several months, but every sunrise session ended in disaster.  I even drove out into the country, but things still seemed to go wrong.  The idea works.  I’ve seen other people do it.  But I never managed it.

Still, nothing says time lapse like a dozen suns rising from the horizon in a single frame.  And doing this with a digital camera and Photoshop would be even easier than doing it with a single sheet of film.  I tested the idea out at the beach, and even though my focus was off and the images were fuzzy, I processed them anyway and proved to myself it would work.  I got ready for the eclipse.

The morning of the eclipse I pulled up the GOES10 satellite feed to see what the weather in the Pacific was like.  Lo and behold, there was this continent-sized tropical storm bearing down on us like a freight train.  I felt like one of the agonized character drawings from Hyperbole and a Half!  I could feel my hair poking up and my eyes bugging out.  GAAAH!  “I could drive somewhere!” I thought.  So I started checking web cams all over the island, including those at the summit of Mauna Kea.  Hey, how cool would that be!  Photographing a lunar eclipse from the summit!  Nope, they were opaque, too, and the summit had snow warnings.  As the clock rolled forward, despair began to set in.

After dinner, we took the kids out to the driveway to look at the completely overcast sky.  We were all wailing to some degree at this point since the kids had been looking forward to it as much as I had, albeit for different reasons.  Sadly, my wife and I put the kids to bed and moped a little.  Eventually she went out to look, just in case.  I stumbled out after her.

Sometimes life has a way of slamming the door in your face, locking it, throwing the deadbolt, and sucker-punching you through the mail slot.  Earlier in the week I’d bruised my ankle putting my son’s bicycle away.  As I stepped out of the house this searing pain shot up my leg as I rammed my bruised ankle into the scooter he’d parked in front of the door.  I stumbled past that and stepped on the pile of… of… THINGS! the kids had left on the porch.  I careened away from the pile and whacked into a board they’d been using as a bike ramp.  I reached down with a trembling hand, trying to decide whether to put the board off to the side or just throw it in a fit of rage.  That’s when my glasses fell off.  In the dark.  At that point I knew if I moved I’d squish them.

I finally shuffled over to the house, found a book light, and used it to find my glasses.  Somehow they’d folded themselves neatly and were sitting on the ground lenses up.  Go figure.  I used the light to clear off the porch enough to navigate, and walked over to join my wife.

The only ray of light at the end of this story is that she didn’t turn to me and say, “The most wonderful hole opened up in the clouds, and ohMIGOD you should’ve SEEN it!”  That would’ve sent me over the edge.  Nope, she just shook her head and sighed.

We watched the dim light of the moon slowly fade behind the clouds as it went into eclipse, then walked back into the house to read a little before going to bed.

Ah well…  There’s always sunrise.

– Tom

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Video for a Still Photographer

Posted by Tom Benedict on 26/11/2010

 

I’m a still photographer.  I’ve known this myself for years, but I’ve also had this pointed out to me by others.  The first time someone made a point of mentioning it to me was right after I’d finished a short course on broadcast video production. I think their exact words were, “You’re terrible at video.”  Yeah.  Thanks.

My class partner and I actually did make a video that year, and oddly enough it was shown on TV far too many times.  It’s not because of its stellar production or camera work.  I’m certain it’s because they were short on material and this one took up a full thirty minute slot.  We’d shot video of a Physics Circus, an extravaganza of physics lecture demos all jammed together into one extremely entertaining event.  Anyone who thinks physics is boring has never seen a pencil blown through a sheet of 3/4″ plywood by a fire extinguisher, or seen the kind of damage you can do with a giant Tesla coil.  Physics is FUN!  It’s also highly photogenic.

It could have been a lot more photogenic.  Unfortunately one of the two people throwing the show was an uptight dweeb who didn’t want cameras in his face.  So we were forced to keep our cameras firmly attached to tripods at the back of the room.  Of course this didn’t stop someone else from using their camcorder handheld at the front, and getting all kinds of good footage of the event.  When they reviewed it, their comment was, “There’s no motion to the cameras.  You’re terrible at this.”  Yeah.  Thanks.  That’s because you made us not move.  The irony was lost on them.  And as awkward as our video was, it still got more screen time than anyone else’s.  Go figure.  I honestly think it’s because ours was edited to length.

I’ve made some videos since then, but comparing those to my still photography, it’s still achingly apparent that I’m not good at video.  I look at a really well produced sequence and see they have these sweeping crane shots or these dramatic focus pulls, so I try the same effects and it’s invariably bad.  Comically bad.  But that’s ok.  Everyone who cares knows I’m a still photographer.  When I make a video, it’s ok for the audience to laugh or groan at inappropriate moments.  It’s all good.

Until now, that is.  The final product of the PUSH N8 project is a video.  A video.  In the infamous words of Charlie Brown, “AAAAAAAAUGH!”

So I’ve been doing some homework.  I went on a bunch of review sites to find out what the favorite, least expensive video production software was for Windows.  Turns out I already had it installed as part of the software package that came on my computer.  Score! Now all I have to do is learn it.  No small thing, but at least I have a plan:  In addition to being a still photographer, I’m also a masochist.  And for a masochist, the best way to learn a thing is to do it badly, realize I’ve done it badly, reflect on that, and do it again less badly.  Wash, rinse, repeat.  So instead of doing one video, I’m planning on doing one video per week for the duration.  The hope is that by the time I get to the final video product, I’ll at least be familiar with the software.  Ideally I’ll also be a little better at video production, but I’m not holding my breath.  At least by then I’ll be more intimately aware of my shortcomings, so I’ll be more practiced at feeling bad about them.  But I hope I get more out of it than that.

To pull off the first video I want to do, I need to make a time lapse sequence.  60 seconds of screen time is 900 frames at 15fps, or 1800 frames at 30fps.  Just about perfect for what I have in mind.  I’ve done time lapse sequences in the past, typically at 60-120x speedup, and have bracketed them with a title card and credits and tossed them up online as being only slightly more interesting than watching paint dry.  (Hey!  Now there’s a time lapse idea!) So I know I can do time lapse videos.  But a couple of things make this one different:  First, it’s faster.  The thing I want to video will be moving at human-perceptible speeds already.  Past about 15x speedup, it would be just nonsense images crammed together.  Second, I finally have video editing software that will do full 1920×1080 HD video!  So instead of editing my frames down to 640×480 or even smaller for NTSC, I get to edit them to 1920×1080 pixels.

Obviously this presents several opportunities to screw things up.  And since the action I want to make the video of is more or less a one-off (think: dropping a glass and watching it shatter, whoops no more glass!) I can’t afford to screw up.  So I’m making a test video first: a glass of ice water melting.  Ok, fine, so I’m back in the category of watching paint dry.  But at 30x normal speed, that might actually be interesting!  And even if this is boring as sin, it’ll at least let me prove all the steps necessary to get from point A (no video, no technique, no nothing) to point B (a working video and the knowledge that I can make this work).  You get the idea.

I started by writing a CHDK script for my Canon A650IS that simulates holding down the shutter button.  This generates a stream of 4000×3000 JPG files taken at a rate of about one per second.  Next, I got a glass, filled it with ice and water, and got busy.  No sweat!

As it turns out it wasn’t that simple.  It took me four sets of images before I got one that didn’t have insurmountable technical issues, and even the fourth had bad white balance.  See why I try to test these ideas offline before I try them on the real deal?  R&D is great and all, but I like to use tried and true techniques when my ass is on the line.  (Note to self:  Camera loses some settings when power-cycled.)  But I persevered and came up with a good set of images to work from.

Next I used Imagemagick to re-size them to 1920×1080 using the following command:

for i in *.JPG; do echo $i; convert $i -resize 1920×1440 -gravity Center -crop 1920×1080 HD/$i; done

These were then run through Adobe Photoshop 7 in batch mode to correct for the bad white balance.  The bad white balance was due to operator error, and now the operator has learned better.  Since I don’t plan to do this in the future,  no documentation for this step.  Besides, this was just plain embarassing.

Next I ran them through VirtualDub, which I’ve used in the past to do video de-shaking.  Turns out VirtualDub will also do time lapse:  Using VirtualDub for Time Lapse The codecs I have in VirtualDub don’t support compressed 1920×1080 video, but since these sequences are short there’s no real penalty.  I saved it as uncompressed video and ate up several gigs of disk space in the process.

Title cards were added to the first and last images in the sequence and saved as 1920×1080 JPG images using Photoshop 7.  In this case I used the Batik font, but I’m not sure what my plans will be for future videos.  This part, at least, is old hat since I did something similar for my SPIE 2010 poster.

Finally, I ran all this through CyberLink Power Director to make the final film, which I then posted to Vimeo.  Watch it if you dare.  Dare to be bored, that is.

– Tom

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