Tag Archives: intervalometer

Struck by Lightning – an Interview with Phil McGrew

My friend, and fellow moonatic*, Phil McGrew found himself instantly thrust into the international spotlight for an image he captured from his office window. The occasion was a rare display of violent weather in the San Francisco Bay Area.

The photo has gone viral with over a 200,000 views on Flickr (1,474″favorites”) as well as international appearances.  For mysterious and unfathomable reasons, Phil’s photo didn’t make it to the famed “Flickr Explore” which clearly is not measuring how phenomenally great a photo is!

Bay Bridge Lightning Strike!

Photo by Phil McGrew - The Sizzle Heard Around the World. Used with permission.

More than just a few people have “honored” Phil by copying his photo and posting it among their own work. I understand the temptation. But that’s just plain wrong (not to mention a violation of copyright law).  Phil has given me permission to show his photo and tell his story.

You may be here because you’re looking for some specific information.  If so, here is the cheat sheet – or just read on for more interesting data.

Is this Photoshopped? Is it Real?

First let’s get a few things right – lots of speculation and conjecture about the photo has swirled on various social networking sites. None of that related to anything Phil ever said or wrote. All of it due to misquotations and assumptions.

Phil took the photo from his office window. Those “dots” are rain on the window because Phil wasn’t too eager to put his brand new Canon 5D Mark III out in the elements. The ISO was set to 100, and f/10 was the f-stop.  The photo was captured using an intervalometer that continuously snapped 20 second photos. He didn’t try to “time it”.

Here is how Phil describes it:

The photograph is a single, 20-second exposure. The Daily Mail interview implied that all 8 strikes hit at the same time. There are actually 9 strikes, and some people argued that the lightning didn’t all hit at once. All I can say with certainty is that there are no strikes on the photo before or after this one, so all the strikes had to have occurred within the 20 seconds. Some people commented that the photo must have been compiled in Photoshop because it didn’t look like there were any cars on the bridge. However, in a 20 second exposure, car headlights and taillights appear as a streak. Because our vantage point is higher than the traffic deck that streak of car lights also seems to blends in more so it looks like part of the bridge.

What Was the Most Difficult Part of Getting this Image?

The most difficult thing was getting my office completely dark so I could eliminate reflections on the window. I have five computers, six monitors, a mini cell tower, and a router. Like a lot of home offices, it’s full of lots of electronic things with blinking lights. 

Can I Buy This Image?

Phil is overwhelmed with requests at the moment but he is feverishly trying to set up to sell and license the image.  Check Phil’s website:


He hopes to have an order page set up soon.

Can I Use this Photo on My Desktop?

Not legally, no. Making a personal copy is a violation of copyright law. However the Google Photos Screen Saver is able to pull and display photos from Flickr and other sources.  For example if you add this to the “Google Screen saver” it will pull in the latest of Phil’s shots.


How Did You End up on the News?

You may have seen Phil’s shot. It was featured on the NBC Nightly News with Brian Williams, and his shot has been widely shown on local, national and international news stations.  Here is how that came about.

My girlfriend Sherry urged me to contact the NBC Bay Area news the first night because we knew they’d be featuring the storm, and by the time I realized I had lightning and that it was in focus and not overexposed, there was still time to make the 11:00pm broadcast. I had a contact number for the assignments desk because I had contacted them previously to let them know about a great story featuring Eric Harness.  (NOTE: That is Eric Harness of StarCircleAcademy!) He’d found a camera in a creek bed while hiking in Yosemite and used social media to post a few of the photos in an attempt to locate the camera’s owner.  I called the assignments desk again to tell them about the photo, and posted it to my Flickr account so they could see it. They decided they’d like to use it during the broadcast. We thought it’d probably just appear once at the beginning of the weather segment, and we were shocked that they actually showed it four times during the broadcast, mostly as an interstitial, but still, it was fun to see.

Are You Really 49 Years Old, You Seem Much Younger?

I think one thing Phil definitely regrets is being made several years older needlessly.  When I asked him whether he was indeed 49 his answer was:

No, but I hope to be someday so I wasn’t too upset when the Daily Mail listed me as 49. I thought it made me sound more experienced.

It’s also a good case of “don’t believe everything you read.”

Is This Lightning Strike Your Favorite Shot?

Definitely not. My favorite shots are the ones I’ve had to work for. Lunar and solar alignments require some effort to plan. As a former nuclear engineer, I love the challenge of doing calculations to figure out where the moon or other planets are going to be and when, then scouting out the best location and angle to get an interesting shot. Then, of course, you have to hope for clear skies, which is never a given here in the Bay Area. The lightning show was more of a “I’m going to set up the camera and see what happens, maybe I’ll get lucky” event. In fact, once I set it up, I went into the other room and watched TV for a few hours. Don’t get me wrong, the attention that it’s gotten has been an amazingly fun and overwhelming experience, and I’m really grateful for all the kind words and interest people have shown in it. I never thought I’d be on local or national news, or appear in back-to-back issues of San Francisco Magazine, without having committed a serious crime. However, I’d have to say that one of my favorite photos is the full moon over the Transamerica building in San Francisco with the Golden Gate Bridge in the foreground. It took quite a bit of planning and the sky ended up with some really amazing colors. It was kind of a “magical” moment where everything just went right.

Moonrise Over San Francisco

Photo by Phil McGrew. Used with Permission

What Subjects Most Interest You?

I gravitate towards night photography. But I’m still trying to figure out what kind of photographer I am so I always try to shoot a variety of subjects. My Flickr account is a little all over the place because just about everything interests me. Night scenes, animals, landscapes. The only thing I don’t really shoot much is people. I think that’s because I’m actually pretty shy and I’m never really sure how to approach them.

Are You Surprised About Your Instant Fame?

I can’t think of anything that hasn’t surprised me. The first night I thought it was great that the local NBC late news showed it four times during the broadcast. I still have no idea how an image clearing house in the UK found it on Flickr, but I was surprised when they called me later that evening to ask if they could distribute it. The next morning, it appeared in the Daily Mail and people started forwarding it to me, and obviously, their other friends. It just sort of took off from there. Before the Daily Mail article, my main goal for that day had been to try to catch the jet fly over for the Giants home opener. I certainly wasn’t expecting to get hundreds of emails and Twitter posts, much less do interviews with local news stations. The whole thing has been one surprise after another. 

What Photographs and Photographers Most Inspire You?

I didn’t study photography formally so I’m probably not as familiar with the “greats” as other people are. However, I’m always inspired when I surf Flickr and see the amazing night photography featured.  I get assistance and inspiration from a variety of photographers I interact with whether they know it or not.  The greatest influences thus far are people I’ve personally shot with and they include Steven Christenson, Harold Davis, and Fred Larson.  There are so many people out there with interesting views and great composition that it doesn’t seem fair to only name a few but that’s the top three.

NOTE: Steven and Harold are also founders of StarCircleAcademy – thanks for the plug, Phil!

More Exposure for Phil

Phil Appears on CBS News, San Francisco

Astro101: Checklist

From the simple to the extraordinarly complex here is a list of things to take when you venture out to do astrophotography:

Starter Kit – Camera & Tripod

  • Camera
  • Wide field, fast lens (40 degrees or more, f/1.8)
  • Sturdy Tripod
  • Intervalometer – though a simple remote push button will work, too.
  • Memory cards
  • Batteries (plenty)
  • Binoculars
  • Green Laser (optional), see Target that Fuzzy
  • Planisphere / star chart / smart app like Star Walk.
  • Red head lamp / flashlight with red cellophane over them.

That’s about it.  This approach allow visual observation, and photographs of large areas of e.g. the Milky Way.

Intermediate Kit

Starter kit plus:

  • Intervalometer
  • Equatorial Drive + Polar scope + batteries  (Polarie for example)
  • Head/mount to put the camera on the Equatorial drive.
  • Stadium cushion or garden kneeler
  • Telephoto lens (zoom or prime)
  • Bahtinov Mask (focus aid)

Serious Intermediate Kit

All of the above plus:

  • Deep cycle marine battery (or astro power kit)
  • Laptop with imaging aid program (e.g. BackyardEOS, MaximDL, …)
  • BIG battery for your camera (or converter to use astro power kit)
  • Voltage inverter to power the laptop
  • Red cellophane to cover the laptop screen
  • Small folding table
  • Folding chair
  • Power strip, extension cords
  • Power inverter (convert 12 VDC to AC)
  • Modest sized apochromatic refactor, mounting rings, extensions, eyepieces, star diagonal, dual speed focuser, dovetail plate, heads up finder.
  • Optional: GoTo solution for the mount

Sold Out Astroimager

  • Large APOchromatic refractor or Reflector
  • Massive mount with GoTo control
  • Astro CCD image camera with thermo electric cooling
  • Filters for Hydrogen Alpha, Oxygen, etc.
  • Finder scope
  • Guide scope and autoguider
  • Lots of $$$$.
  • Large car to drive it around.
  • (optional) Sherpa to lift it all.

For more information, please attend a Webinar!  See the training list here, or see all events here.

Collecting and Processing Images

I have a Canon, and an windows machine. These two things together mean that I can use BackyardEOS ($25) to aid in the focusing and capture of night sky images; and I can use Deep Sky Stacker (Free!) to process my images.  Deep Sky Stacker takes some patience to learn, but it is mostly automated.

I understand “Keith’s Image Stacker” ($15) is available for Mac people – though apparently it’s not quite as powerful or as widely used as DeepSkyStacker.

Pricier and more complete options include ImagePlus, MaximDL, and much more. For a full list of options, prices and features, please see Jerry Lodriguss’s site.


Trouble with Long Exposures – Part 2 of 2

In the previous article I discussed 4 of the 6 most common problems that occur with long exposures.  Those problems are:

  1. Poor Focus
  2. Dim Stars (low contrast)
  3. Strange Colors
  4. Purple or Pink Glow

In this installment we tackle these two issues

  1. Gaps in Star Trails
  2. Lots of Noise (Colored Speckles)

Gaps in Star Trails

To oversimplify a bit there are four causes for gaps in star trails created from successive exposures:

  1. Camera limitations
  2. Camera or intervalometer misconfiguration
  3. Processing choices
  4. Weather conditions

Camera limitations: I described this issue in my article “How long does a 30 second exposure take?”  All the Canon cameras I own – including the top of the line 5D Mark II require 32.8 seconds to complete a single 30 second exposure. Well there you go: almost 3 seconds of time where there is no exposure. This problem can be compounded by two common misconfiguration blunders:

  • Failing to allow enough time between exposures when using an intervalometer. Or using the wrong drive mode on the camera.
  • Failing to turn off long exposure noise reduction.

To avoid intervalometer misconfiguration I operate in either continuous exposure mode or bulb mode. I use continuous exposure mode when my exposures will be many and a maximum of 30 seconds – e.g. when trying to capture meteors or planning for a time-lapse animation. In continuous exposure mode I set my intervalometer with a start delay and then program an exposure time of several hours… AND I put my camera in Manual, high-speed continuous exposure mode with a typical exposure of 30 seconds. You do not really need an intervalometer for this – a locking cable release is sufficient.

When I operate in bulb mode, I try to get a moderately long exposure. Usually in the 4 to 10 minute range depending on the sky conditions. In this setup it is very important to put the camera in Bulb exposure and program the intervalometer to leave a 3 second gap between one exposure and the next. I have recently discovered, however that the Canon 5D Mark II will work with my intervalometer set to 1 second intervals. That’s goodness. I am still trying to work out whether the problem is due more to the timer or the camera. I do know that in continuous exposure mode all my cameras require 32.8 seconds per each 30 second exposure. Failure to allow a long enough pause between exposures can cause unexpected results.

Photo 1: For the first half of the evening I mistakenly left long exposure noise reduction on. The result was that half of my shots occured at every-other eight minute intervals.

The “dotted lines” in the circle above were caused by leaving on long exposure noise reduction. The result was that the intervalometer timed an 8 minute exposure, waited three seconds and then pressed the shutter for the next 8 minute exposure. However 3 seconds after the exposure completed it was still doing long exposure noise reduction so that cycle was skipped until the intervalometer released the shutter for the next 3 second “off” interval.

I have gotten into the habit of setting my exposure length to 3 seconds less than what I want… e.g. 9:57 for a 10 minute exposure. I then set a 3 second inter-shot interval. I used to set a 10 minute exposure plus a 3 second gap – but the predictability of starting a new exposure every 10 minutes makes it easier to monitor what is going on.

Another cause for gaps: changing the battery. I can offer the following important tidbits when you need to change the battery.

  • Do not wait for your battery to be exhausted. A partial exposure may not stack well or be completely written to your card. Battery exhaustion will likely occur at an inopportune time.
  • Have everything at hand in advance of the change. For example, keep the battery in your front pocket where your body heat will keep it warm.
  • Practice a battery change BEFORE you start your exposures. Only by practice beforehand will you be able to discover that the battery compartment is blocked by your tripod, or impossible to reach, etc.
  • When you DO change batteries beware! Your camera settings may change dramatically!

Processing choices you make when stacking the star trails also affect whether your gaps will be inconspicuous. Do not do any sharpening until you complete your stacking – and even then avoid sharpening the star trails themselves. The method used to stack trails is significant. However, I have observed that people do not notice gaps even in this image of 19 8-minute exposures printed out at 20×30 inches.

Photo 2: Even though it is composed of 19 eight minute exposures the gaps are never noticed even when printed at 20x30.

Weather conditions can also introduce gaps. In a truly dark sky where clouds are not lit by city glow, moonlight or twilight, clouds become “black holes” and block starlight. Low or fast moving clouds can obscure some, most or all of one or more images in the set. This can be perplexing if you happen to be sleeping during exposures which started and ended with clear skies.  Another problem is dew which may form a fog that diminishes or eliminates some or all of the exposures. Vigilance with a rag, the use of a hood or a dew heater are your only weapons against dew.

Lots of Noise (Speckled Colors)

I purposefully left the noise in Photo 1. It’s quite noticeable in the rock silhouette at the lower right and appears mostly as red specs. Annoying? Well, yes, but it is not the end of the world.  In order of effectiveness here are your best approaches to keep the noise manageable:

  1. Shoot at a lower ISO (100 or 200)
  2. Shoot and stack shorter exposures – longer exposures generate more noise.
  3. Capture the foreground and the star trails separately. A better lit foreground will exhibit less noise.
  4. Shoot during colder seasons – lower temperatures result in lower noise.
  5. Control stray light with a lens hood – and close or cover your viewfinder while exposing.
  6. Use high ISO noise reduction
  7. Use noise reduction post processing tools. Chrominance noise is usually most in need of correction.
  8. Use long exposure noise reduction.

Hopefully you noticed that long exposure noise reduction (LENR) is last on the list. If you are trying to stack star trails it is impossible to get continuous trails with LENR on. It is also the least effective unless you are only going to shoot one shot.

Before we go much further, it is worthwhile to note that there are 4 causes of “noise” and each has a different source. The random speckles are usually what is meant by noise. Those random speckles are created by heat, limitations in the electronics, and things as bizarre as electromagnetic phenomenon like sunspots. No kidding. True noise is by nature random and LENR can not do a thing to combat random noise except to diminish it by reducing the luminance of the offending pixels – which also reduces the sharpness of your image. But there are 3 other kinds of noise that are not random though often lumped into the same general category: hot/stuck or degraded pixels, local heat noise (sometimes called amp glow), and high ISO noise. LENR is effective for these because they are not random.

Hot or stuck pixels usually appear as bright pink, red, blue, green, white or purple spots. They are caused by either electronic problems on the sensor chip or by the dyes used to detect the color.  A pixel detects the intensity of the color red by use of a red dye (inkjet droplet) over a sensor site. If that red dye is insufficiently thick, or missing altogether then that pixel location will always read hot if there is any light falling on it – and if the problem is electronic it may read hot even if no light is striking it. Dead or degraded pixels are just the opposite. Too much dye or dead electronics at a pixel site. Degraded pixels are stuck black or darker than the surrounding pixels and are seldom if ever noticed in night photography.

Locally caused heat noise is noticeable in some cameras and is due to the heat of electronics in proximity to the sensor. In my opinion this problem is a design flaw in the camera. However this kind of noise is repeatable so LENR can help correct it. The “Pink or Purple Glow” that results from this flaw was discussed in Part 1.

High ISO noise has an understandable parallel in the world of audio. Take nearly any cheap radio. Turn it up. At some point the sound will become distorted and harsh. This harshness is because there are limitations in the signal, the amplifier circuitry and the speaker used to produce the sound.  Increasing the ISO in your camera is the photographic equivalent of the audio scenario.  At some point amplifying the light measurements made at each pixel makes the noise more obvious.



A wireless intervalometer the unit at the left can also be wired to the camera directly.

You may have noticed that I mention an intervalometer in many of my images. It is an essential tool for making unattended shooting much easier.  Let me take a few paragraphs to explain what an intervalometer is, how it works, and provide some examples – and reviews – of different options.

An intervalometer is an unnecessarily long word for a timer. A sesquipedalian, if you will. Using a timer is a step up from a remote release cord also sometimes called a cable release. A remote release is a device for activating the shutter without having to touch the camera. Any touch while exposing can cause unwanted movement and motion blur. The phrase cable release comes from the old days when pressing the shutter button was a mechanical process and literally required a button and cable system similar to the accelerator in your car.  Nowadays mechanical systems are rare.

The cable release is often called different things just to confuse people.  It may be called a Remote Release a Remote Cord a Shutter Release Cord a Remote Shutter Release Cord and more. Despite the presence of the word remote very few units are actually wireless.

A remote release cord is very handy for preventing camera shake. Nearly every model I have seen has a nice little feature where the shutter button can be locked down for a long exposure.  You DEFINITELY do not want to be holding the shutter button down for a 10 minute exposure. You will get the shakes, your arm and finger will grow numb and your image will suffer. The very act of pressing the shutter button is enough to start the camera moving and thus blurring your image.  If you are going to take star trail images you need AT LEAST a remote release.  Which one? Unfortunately I can not answer that question since every manufacturer has different connections for their cameras. Canon has two different connectors for its DSLR  cameras, Nikon has 3! A release for a Canon Ti Rebel will not fit a Canon 50D. Sadly some Nikon cameras do not even have a remote release connector.

Ok, but what is an “Interval… whatever thing?”

An intervalometer is really just a remote cable with a built in, programmable timer.  Unfortunately every timer is set up a little differently from every other one – though they all do the same thing: press and hold the shutter button for you.  Intervalometers are very handy for taking repeated exposures of a fixed length for a long period of time. Many intervalometers allow you to set

  • A delay before shooting starts
  • The length of each exposure
  • The interval between exposures
  • The number of exposures to take (up to 99, 399 or unlimited)

Some intervalometers also have indicator lights, display lights and beepers to help you keep up with what they are doing.  How you actually configure any given timer differs from brand to brand and style of remote.  For star trail work, you want an intervalometer that fits your camera model and has all of the features above.

Canon Possibilities

As the owner of 5 Canon bodies: the 40D, 50D and 5DMkII, and two point and shoots. I have bought, used, and discarded a variety of remotes and intervalometers. The one I have owned and used the longest is a knock-off of the much more expensive Canon TC-80N3 model, i.e. the Opteka:

Opteka Timer Remote Control with N3 connector for Canon EOS 1D, 7D, 5D, 20D, 30D, 40D, 50D. Might be out of stock or discontinued.

This particular remote – was out of stock at Amazon when I checked. The remote- has been my workhorse for almost three years. You can read my review of it on Amazon or Epinions. A similar (and slightly cheaper model) is the “Shoot” brand.

You can also compare with reviews of three other models: the Satechi TR-A, the Jenis Wireless, and the Canon TC-80n3 all of which I have used.  The TR-A uses a CR2032 coin battery which gave out on the first attempt to use it. The Jenis wireless remote – which seemed like a great idea just doesn’t work. Though there is a Satechi wireless model that is brilliant at about $60 USD.

If you do not want to plunk down money for a cheap intervalometer, there is a more expensive solution  – at least for Canon. You can use the “EOS Utility” with a laptop connected via a USB cable to control the camera. Of course with that method you now also need to carry an additional cable, laptop and source of power.  And if you’re ultra cheap, you can use a rubber band over the shutter button and set your camera in continuous exposure mode.

To use an intervalometer with a camera you must set your camera as follows:

  1. Turn off high speed or continuous exposure.
  2. Turn off any delay timer.
  3. Set the camera to Manual
  4. Turn off auto bracketing
  5. Turn off auto focus
  6. Set the exposure to “Bulb”

If you are using a delay before the exposures begin, you may need to use a “Custom” (C1, C2) setting. When the camera wakes from automatically powering down it may return to the default settings rather than the most recent settings. Using “C1” on Canons allows you to set all the exposure options so that the camera will return to the settings you want even if the camera remains powered off for hours before exposures start.

One more important point: when you set your intervalometer you will have to leave at least a one second gap between exposures. For Canon, you may need to have a 3 second gap between exposures. Why?  See “How Long is a 30 Second Exposure“.