Time Lapse Under the Train

Well now all I can think about is what a time lapse shot from under a train would look like. Nice. In any case, I wanted to share a new time lapse I shot last night in Harlem. It's a spot I'd visited before during the day but when I was wandering last night looking for a good spot to set up, it struck me that I never thought to capture the scene by night, which is obviously way cooler.

The basic set up is a Canon 70D, 50mm lens at f/10, ISO 100 and a 5 second exposure time. I also used a variable ND filter set at about ND4 to draw out the exposure time a little longer.


The Best Description of Aperture and Depth of Field

In the process of scripting a short instructional video about Time-Lapse Photography and dealing with Aperture Flicker, I recently started digging deeper into the physics of lens optics to try and better understand the relationship between Aperture and Depth of Field. I was never very good at physics in high school but in my research I came across this description written by the late Gary W. Sims of the Stonehaven Laboratory. It is by far the best and most accessible description of this relationship I have ever found. It also explains how variable aperture lenses work as well as the price differential between standard zoom lenses and fixed aperture lenses like those in the Canon L Series. It's still complicated and requires a measure of persistence but I wanted to share it here if for no other reason than to make it accessible somewhere beyond the random Photo.net message board where I found it.


As you've probably heard, a very small hole in a surface like a thin wall will display a focused image (of a landscape say) on another flat surface placed behind the wall. No lens is required. That's called a "pinhole camera" in English. Basically, the light from any given part of the scene has only one path to follow through the hole to the image plane behind the "wall."

Actually, many paths exist, but they are so tightly grouped together that they fall within so small an area on the image that it appears to be in complete focus without help from a lens. The smaller the hole, the better this appearance of focus. (Up to a point. Different topic.) But a small hole admits little light. So the scene must be in bright sunlight, and the area behind must be a fairly dark room for our eyes to pick up the faint image projected. Most film is less sensitive than our eyes, so the problem is worse when we want to capture the image for posterity. So we must make the hole bigger to capture enough light.

When we make the hole bigger, light from any given portion of the scene has more paths to follow. The optics of a lens bring each of those paths to the same point on the image plane -- or that's what we try to accomplish. The bigger the hole, the harder the problem of designing a lens that will bring each path to the same point for the three critical frequencies of light. (Light of different frequencies is refracted by a different angle through any given optical material.)

A factor you may not have noticed yet is that lenses with longer focal lengths tend to have smaller maximum aperture numbers. That arises from another effect. A lens of short focal length has a wide angle of acceptance of light. That's roughly a right angle (90 degrees or Pi/2 radians) for a "wide-angle" lens. A "standard" lens takes in a little less than 45 degrees, and a very "long" lens is down around ten degrees acceptance angle. The wide lens is accepting light from most of the scene. The "standard" lens accepts well under half the light that actually reaches the lens, and a long lens accepts almost none of the light.

Of course, that's our intent. We use a lens of longer focal length to restrict our image to a smaller part of the scene. But the effect of accepting light from so little of the scene is that it takes a bigger hole to capture enough light from that part of the scene to expose the film. Picture it this way: The film is the same size, but the part of the scene that must provide light to expose that film area is much smaller when we use a longer lens. That means the hole must be bigger if the focal length is longer if we want to expose the film in the same length of time.

If we measured aperture in millimeters, photographers would go crazy trying to compensate for the focal length of each lens to figure exposures. So we use a ratio. We say that a lens has an aperture of f/4 to mean that the hole is 1/4 the focal length. So a 50mm lens (standard in 35mm format) at f/4 will have a hole 50/4 or 12.5 mm across. At the same aperture number, a 100mm lens will have a hole of 100/4 or 25mm diameter. That gives the longer lens a hole with four times the area, so it can capture the same energy from an area of the scene that is four times as small.

Incidentally, when you price zoom lenses, you will notice that expensive zooms have a single maximum aperture number, like the Canon 28-70mm, f/2.8L that costs about U$1350. (The L stands for lust I understand.) Less expensive zooms, like the Canon 24-85mm (at U$350) have a range of aperture numbers specified. For that example, the range is f/3.5 to f/4.5.

That might give the impression that the less expensive lens closes down its aperture as it zooms, but in fact the opposite is happening. The hole actually expands from about 7 mm at the short focal length to 19 mm at the longest focal length, but the aperture ratio is decreasing because the optics are limited in the size hole they can properly focus. To hold an f/3.5 aperture at the long lens the hole would have to be 30% wider, or 24 mm across. The professional class lens starts at a 10 mm hole -- already half as big as the less expensive lens ever reaches -- and it expands to a 25 mm hole at the long end. Canon breaks off the short zoom at 70 mm, but they have a 70-200 mm that picks the range at the same aperture ratio of f/2.8. When that other lens reaches 85 mm focal length at f/2.8, it's hole is over 30 mm across. This is more than half again as wide as the 19 mm hole that the optical design of the less expensive lens can tolerate. At the long end, a Canon 400mm, f/2.8 lens has a hole that is 143mm across (call it 5.6 inches if you prefer). That's big enough to put your arm through.

Managing the optical paths through such a wide hole is not trivial, but even more important, when a wide hole and a wide angle of acceptance combine, the optical calculations keep supercomputers very busy. Thus the Canon 50mm,f/1.0L is a stunning achievement in "consumer" optics with a 50mm hole and an angle of acceptance of 40 degrees. ("Consumer" is relative. This time, I just mean it doesn't take a government to own one at "only" U$2,500 retail.)

The absolute size of the hole, and the angle of acceptance, are two of the dominant factors in designing a lens, and meeting that challenge requires sophisticated manufacturing after inordinately expensive design processes. That's why you'll find the smallest aperture numbers associated with the most expensive lenses.

On the other end of the scale, the design challenge of a big hole with a narrow angle of acceptance is less for something like a prime lens at say 200mm -- but a big hole means a wide lens. That means each element in the lens is physically larger, requires more high-quality glass (et al), and more surface area to polish, coat, and so forth. You can plot a neat curve that will predict the price of a lens and its weight very nicely from the maximum physical aperture it reaches.

The smallest hole is mechanically easy to achieve since we just swing the diaphragm blades closer together. Over quite a range, this just makes the lens' job easier, since the sheave of paths the light can follow is much narrower. Optical limits do arise at the smallest holes, but an aperture of say f/16 is easy to manage in the design and manufacture of a lens. Canon lenses typically provide f/22, and f/45 is available on the longest lenses (where that is not really a very small hole in absolute dimensions).


Gary W. Sims Stonehaven Laboratory

Shooting GRITTY for TEDxGramercy

GRIT Logo.jpg

One of the steps I took to start building connections when I arrived in big, bad New York this summer was to stalk all the TEDx events this fall in NYC listed on the TED website. I sent messages to each organizer just saying that I was a shooter and if they needed an extra hand with their event or another camera, I was interested in helping out. After a couple months went by and I forgot about it, one of the organizers of TEDxGramercy returned my message and we spoke briefly about their event on September 27th and their need for a promo video.

The team I ended up meeting with in Washington Square Park this week was a ton of fun to work with and we spent Sunday afternoon in the park just hanging out, talking to people passing by about the event and encouraging them to tell us what they thought of the theme of this years event, "GRIT." In a corner of the park's central sidewalk hub we set up red and white wooden letters spelling TEDxGramercy and passersby wrote their thoughts on the idea of GRIT in chalk on the sidewalk.

The event gave me a chance to really put the 70D through it's paces for the first time since I first acquired it back in June. One of my hopes when I bought the camera was that I could use it for jobs where both photos and videos were needed and the ability to switch back and forth between those two modes was critical. I can't express how liberating it was to be able to flip back and forth between video and stills mode knowing that at any time, even if I was in the middle of filming a clip, I could just hit the shutter trigger and the camera would stop what it was doing (even pausing the video recording) to take the photo(s) I wanted (before resuming the same video file I was recording a second earlier).

I chose to stick with my 40mm pancake lens all afternoon, mostly because I needed to record audio with my video and favored the silence of the STM lens on the 40mm to the slightly louder USM focusing motor of the 50mm. I found myself fighting to keep the footage stable without any Image Stabilization but that promo video I pitched to the group was meant to be rough and...well...gritty...so a shaky cam look worked perfectly fine. This was actually the first time I shot a people-oriented video since moving to the US and I have to say that the whole common language thing still feels like a warm fuzzy luxury after three years of working with Hebrew and Arabic speakers.

That being said, here is the promo video. You can find out more about TEDxGramercy at www.tedxgramercy.com as well as links to their Facebook, Twitter and Instagram, where I hope to contribute more content in the next couple weeks.

To Macro Extension Tube or not to Macro Extension Tube...that is the Question.

I have a deep and abiding love for macro photography. On one level, it's a technique that I kind of consider cheating in the back of my mind. It's kind of like black and white in that respect. Take a picture of most things and switch it into high contrast back and white and it makes anything look moody and interesting. Same with macro. Take a picture close enough of anything and you're likely to capture something new and different. Taking my technique to a new level has been an interesting process and my most recent endeavor has involved Extension Tubes. Fun times.

When I started shooting on my 70D, it took me a while before I really got it into my head that getting even a small subject in focus required stopping down to f/8 or smaller. Moving to a 50mm f/1.4 lens from a Tamron 18-200mm f4.5-5.6 was heaven in terms of blowing out the background but I now faced the problem of a prohibitively narrow depth of field.

Stack (Small).jpg

Click to see more detail...

A couple weeks ago I started experimenting with focus stacking in order to solve the problems associated with narrow depths in macro. It basically involves taking a series of images of a subject and adjusting the focus point with each picture you take. Photoshop then aligns the series of photos, even compensating for "breathing" in the lens as you move from one end of the focus range to the other, and compiles the photos into a single composite using the most in-focus parts found in each image. Making tweaks to the final composite isn't particularly easy but the software is generally reliable under reasonable conditions. You can see a few of the early results here.

Once this technique became a viable tool, the challenge became getting close enough to get truly interesting shots. I'm currently operating with three lenses: a 70-300mm with a minimum focus distance of 1.5m, a 50mm with a minimum focus distance of 0.45m and a 40mm pancake with a minimum focus distance of 0.3m. In lieu of buying a dedicated macro lens, macro extension tubes presented themselves as a possibility for expanding the macro capabilities of my current lenses. These tubes connect between the camera body and the lens and allow the lenses to focus significantly closer to the end of the lens. But when I considered getting a set of these, I had a few questions to which I couldn't seem to find answers online.

My first question was the difference between getting a 13mm, 21mm or 31mm extension (or all three). To answer this question, the image to the right is the same 50mm lens with six different extension tube set-ups all shot at f/2.8. As a second point of reference, the image below shows the magnification of a quarter with a bare 50mm on the left and all three tubes stacked to 65mm on the left. You can see in the bottom image (if you click and expand it full-screen) just how narrow the depth of field is at f/2.8. In both cases, the first shot is at 0.45m and the closest focus is about an inch from the end of the lens.

As much as I wished I could pick one ideal size and not purchase all three together, there really is a great deal of flexibility when it comes to the different levels of magnification allowed by combining the three sizes. I also debated between getting the auto-focus version (which allows communication between the camera and the lens or sticking with manual focus for half the price.

I did find two notes online about the limitations of the manual version. One, autofocus doesn't work and two, you cannot control the aperture and are limited to the widest setting of the lens. This is not strictly true. One thing you can do is put the lens directly on the camera, adjust the aperture to the setting you want, press the DOF preview button and while holding it down, disconnect the lens. Then when you put the lens and the manual tubes on, your lens will be locked at that aperture. In reality, after testing with both photo and video mode, the autofocus through the extension tubes is marginally useful. When adding extension tubes, you drastically cut down your focus range so autofocus can't fix that problem. My own take on the situation is that if you're taking stills, there's really no need for autofocus whatsoever. Aperture is the real issue. If you don'tmind changing aperture the way I describe above or if you have a lens with a manual aperture ring, groovy, save the money. But unless you're shooting on a camera that has video autofocus on par with the 70D (none come to mind) the autofocus isn't something you'll need in reality.

One context where it worked well was using the 13mm tube with the 50mm lens at f/8 for video. With that set-up you're limited to focusing between 6 and 10 inches from the end of the lens so it's a good set-up for shooting insects. It's close enough to get good magnification of things like bees pollinating flowers but not so close that your bumping the bugs with your lens or blocking the light. The video autofocus has sufficient latitude to track your subject in the four inches of focus range at f/8 and it performs pretty well. When you're going for maximum magnification using all three tubes stacked together, forget autofocus. Go with manual and shoot either in Live View or through the viewfinder using your DOF preview button to get an accurate view of what will be in focus.

The final takeaway for me was that the extension tubes are incredibly versatile but it's by no means a magic bullet to replace a dedicated macro lens. You're gonna have to spend hours playing around with them and figuring out exactly how they behave in order to find out just what you can do with them but if your anything like me, you'll love every second of it. My hope is that this post was at least helpful in illuminating the subject a little more.

Now I'm going to post this and go decide if it wouldn't have been a better idea to make a video explaining all this than trying to write it down.


One Roll of Film

The process of exploring photography in New York City has taken me to some unexpected places. I've been working on refining specific skill sets and setting different tasks and challenges for myself designed to push me out of my comfort zone. With my recent acquisition of my Canon 70D and small collection of lenses, I've been working hard to put this new gear through its paces and figuring out what role this new kit will play in the future of my creative profession.

Big Ass Lens.jpg

One assignment suggested by Jared Polin (among others) was to cover the back of the camera and limit yourself to a simulated single roll of film. Thirty-six chances to get it right with no chance to see the images until your back home. I tried out the experiment today exploring a four-mile section of Riverside park between 123rd and the George Washington Bridge today and I have to say that I was not prepared for how much I learned in just a single afternoon.

The first and most obvious effect of this self-imposed limit was a drastic reduction in the speed with which I attacked the urban canvas. Expecting that 36 photos would be a frustrating straightjacket, I began the activity without a real sense of what shooting 36 photographs feels like. With a 32BG card, even shooting full RAW means I've got space for over a thousand shots before changing magazines. What I soon found out, though, was that there is a distinct difference between visually scanning for any subject that is remotely interesting and scanning for a subject that is worth being one of those 36. Rather than racing along trying to get as much coverage as possible, my pace slowed and I became much more mindful of the subjects I chose as well as the story I wanted to tell with each frame.

Screen Shot 2014-07-30 at 12.56.52 AM.jpg

My first subject was a street located under cavernous metal trusses holding up the elevated West Side Highway. Normally I would have taken a couple wide shots with the 40mm and a few closer detail shots with the 70-300mm but under this new paradigm, I really wanted to capture the essence of the space. Whatever the fuck that means. I spent a good five minutes trying out different lenses and zoom variations as well as changing my position on the slanted concrete platform leading from the bridge supports down to the street level. I eventually settled on a rule of thirds configuration with the bridge supports taking up a third of the horizontal space on the left and right as well as about a third of the vertical space. Once I had the framing set, I waited another five minutes or so before the alignment of the parked cars, traffic patterns and pedestrians aligned themselves before pressing that fateful shutter button. After that much planning and thought went into the composition, the crisp snapping sound of the mirror rising and falling inside the camera becomes an incredibly sexy sound.

Truth be told, I actually used three of my 36 frames on this section of covered road. The first frame was underexposed (by a lot) and I only realized my mistake when I saw the light meter after firing the shutter. Right as I took the second picture a bus started to enter the frame so I needed a third to be sure I got the shot and the one above is shot number three.

Screen Shot 2014-07-30 at 1.12.05 AM.jpg

About an hour later, I happened upon a beautiful butterfly dancing from flower to flower and I expended four frames on this guy. The image to the right is the first of those four and the challenge I was faced with hear was, “How long can I afford to wait for the perfect shot when my subject might fly off into the woods at any moment?” As I composed, I found myself thinking back on the examples I’d seen of film or even plate photographers economizing their shots. I thought of Ansel Adams hiking for an entire day with one glass plate in his backpack and expressing discomfort with the casual triviality of carrying half a dozen plates at a time. I remembered the scene from The Bang Bang Club when Kevin Carter is explaining to Greg Marinovich how seasoned photographer Ken Oosterbroek works from the outside of a scene in toward the middle and then cups his hand over the lens to shoot a black frame once he’s gotten the shot he was looking for. This tells the darkroom tech which shot is the keeper. Finally I pondered the scene in The Secret Life of Walter Mitty when Walter finally tracks down the elusive photographer Sean O'Connell on a craggy mountain-side in Afghanistan after chasing him down the entire movie. Sean was on an assignment to photograph snow leopards which he tells Walter are called the ghost cat because it never lets itself be seen. As a snow leopard  emerges from a crevice, Walter asks why Sean isn’t taking the picture and Sean says, “Sometimes I don’t. If I like a moment…I mean me personally…I don’t like to have the distraction of the camera. I just want to stay in it.” Whether or not these lofty thoughts were justified as I lay sprawled in the grass, they certainly added a layer of profundity to the experience.

It took about five hours to walk the eight mile round trip to the George Washington bridge and back. What I realized when I got home and loaded the pictures into Lightroom, was that as I looked through those 36 shots, I knew exactly what I was thinking as the shutter fired each time. I know what caught my eye as I walked past. I knew how I mentally composed the shot and which lens I ultimately chose. I remembered the process of framing the shot and deciding how much I needed to compensate for back-lighting when I read the light meter. If I had gone out and taken a hundred or two hundred photos, I wouldn’t have spent nearly as much time choosing, framing and waiting for each shot to be ready and I wouldn’t have remembered the process of calculating all the settings with enough detail to learn from those choices later.

It was a very unique experience and I don’t know how quickly I’ll feel like doing it again but I’d definitely recommend the experiment to anyone looking to step back in time a little and learn something new.  




Central Parking

As of this month, I've made the transition out of Israel and into our year of living on the move. Whilst my wife is doing rotations at different hospitals during her fourth year of medical school, we'll be on the move for much of the coming twelve months. We're currently living in New York City and I'm also taking time to reflect upon my creative work thus far and refocus both my own practice of photography and videography and the web infrastructure that supports it. I will be trying out a handful of new concepts over the next few months and I hope to share a great deal of this process of exploration here. One of the benefits of living on 123rd Street in Harlem is quick access to Central Park. I'm still getting my bearings after moving here a week ago but I've found that doing a lot of walking with my camera helps me to connect with my new temporary home. Having lived in the desert for the last three years, the simple beauty of grass, green leaves and chipmunks still feels exotic.

So from today's forway into the Elm forests of The Park, I give you Sparky. It took me a while before he and his little friends let me get this close, but he's a cute one.



Time Lapse (The Hard Way)

I am, as anyone familiar with my work will know, a huge fan of time lapse photography. I have a particular fascination with sunrises, sunsets, cloud movement and flower blooming. The one thing that ties all of these genres together is that all I really have to do is show up. Yes, it's my job to pre-visualize the scene and decide the proper exposure as the light changes throughout the scene, but once all those calculations have been made, I basically sit on my ass.

Two weeks ago, I did a time lapse that was exactly the opposite.

The Bengis Center for Entrepreneurship and High-Tech Management hired me to do a series of promotional videos for their upcoming Innovation Israel conference in June. One of the ideas I pitched was a time lapse of a mosaic design, using colorful seeds and beans. As I got my equipment together and set up the shot, the ideas occurred to me that the sequence would look cool if I picked up and placed the Screen Shot 2014-05-26 at 12.08.59 PMbeans using chopsticks. I picked out a decorative pair of chopsticks and, knowing that this would be a very long process, settled in for the long haul.

What I didn't anticipate, however, was that about two hours into the process, my shoulder began to ache from the constant, repetitive, precise movements. The logic of this pain made sense but no sooner had I noticed the discomfort that the rate at which the pain increased began to increase seemingly exponentially. Five minute breaks to rest my shoulder turned into ten and twenty minutes breaks until even the portions of the mosaic that required the use of a spoon were hardly bearable. Five hours after picking up the last bean, my shoulder let out a shivering ache of relief as I positioned the last white Lima bean in place.

It took about twenty minutes to pull the footage from my camera, compress it into a ten-second sequence and render it for playback. As satisfying as it was to finally see the fruits of my labor, I could almost hear an audible sigh from my shoulder that seemed to say, "Really? You put me through all those hours of pain for that?" I promptly told my shoulder to stop whining, took an ibuprofen and went to bed.

Maybe next time I'll use bigger beans. Also, the musical credit goes to my friend George Kent from his song "Last Cigarette" that was recorded while we were at the Contemporary Music Center together. I tried to get in touch with him for permission to use the track but I got no response from the email address I have on file for him. If you're out there, George, a university in Israel might owe you some money.

Enjoy the video

[youtube http://www.youtube.com/watch?v=Sk1zwHPAIpk]

Lookback: "Friday Mornings"

Every once in a while, I get an email from ReverbNation letting me know I've achieved a new chart ranking in my local area. Before I got into videography, I was on a course to be a professional singer/songwriter. I still hang loosely to those musical roots and my hometown on ReverbNation and MySpace Music is still listed as Port Townsend, Washington. It's a small hippie community across the Puget Sound from Seattle and I am currently #10 on the local ReverbNation charts.

During college I spent a semester at theScreen Shot 2014-04-28 at 2.25.00 AM Contemporary Music Center on Martha's Vineyard (and I have the ankle tattoo to prove it). During the summer after CMC, I wrote and recorded my fourth full-length album entitled "Back-Seat B-Sides" which included the song Friday Mornings which was a tribute to the shenanigans 25 musicians get up to when they're sequestered on an island for six months. At the end of that summer in 2007, I conscripted a couple friends (Ian Leslie and Chelsea Hampton) to come out with me one afternoon to shoot a music video for Friday Mornings. It remains the featured video on my ReverbNation page so I thought that for this week I would reflect on the memory and the tech.

I don't have access to the original source files but I believe that the camera we used for this project was a Panasonic DMC-FZ7. It recorded video at a whopping 640x480 VGA resolution onto MMC cards (the precursor to the SD card). At the time I didn't even really understand what video resolution was. During high school, I shot little video projects all the time with my friends using our family's DSC04526Panasonic Hi8 tape-based camcorder but there was no editing to speak of. The best we could do was a simple teleport effect which involved stopping the camera and turning it back on once the subject or object had been removed from the scene. But I digress.

This music video was shot over the course of an afternoon and it was the most complicated video I had done to date. This wasn't the first multi-cam style project I had done but it was on this project that I first formulated the source-to-timeline ratio that I still use for most of my projects today. Since everyone involved had time on their hands we decided that since the song was a little over four minutes, we decided we needed to shoot 20 minutes of solid content. To this day, I still usually aim to shoot enough content that I have five times as much final, usable content than I need for a given project. For synchronization with the music, I wore an earphone (which you can see in a few of the shots) plugged into my trusty Toshiba HDD120 mp3 player.

At the time, I was still trying to figure out exactly what my   style or musical genre was going to be. I struggled while at CMC with putting a label of any kind of myself or the music I wrote. I was more or less comfortable with the term "acoustic alternative," probably because the term sounded vague and undefined yet intentional.Screen Shot 2014-04-28 at 2.34.33 AM I wanted the music video to capture a moody, brooding feeling in terms of imagery so a handful of the shots were filmed lying on the train tracks running West past the Messiah College campus towards Shippensburg. At the time, I self-described my style as being "emo-at-heart" and I think a lot of the serious staring into the distance was a fading attempt to still fit into that bizarre niche.

Looking at this video eight years later, though, I have I'm distinctly impressed by the framing and composition. I would have to check but I don't think that either Chelsea or Leslie had much experience shooting video before this but I can honestly say that some of the shots they came up with are damn impressive. I'm not by any means ashamed for this to be one of my early works. The song itself always had a transparent simplicity that I found refreshing and that early combination of sepia and film scratches comes across nicely.

I hope you enjoy it as well.

[youtube http://www.youtube.com/watch?v=6U4cE8N1jAA&w=420&h=315]

TEDxBGU Promos

Screen Shot 2014-04-21 at 2.58.37 PMIn preparation for TEDxBGU this, which is happening on May 11th at Ben-Gurion University, a group of us on the organizing committee got together to shoot a short series of promo videos for the event. I had sketched out some basic jokes beforehand but most of the dialogue was just improvised on the spot. Most of the time we went into the elevator to film a scene while the people outside worked on writing the next sketch. It was basic, fun little series to shoot and edit and I think my favorite part was re-using the outro audio from the Eli Lewis iPad video I shot back in 2012 (available HERE).

We've been releasing them one at a time over the past month and a half and the last one just went up today. I've dropped in the entire playlist below, but you might have to click through to YouTube to navigate through all of them. Enjoy.

[youtube http://www.youtube.com/watch?v=videoseries?list=PLUwJxKldnPHQAvplM-xHbPLO5jgVkTVZb]