Author Archives: Steven Christenson

Not Eclipsed!

The total Lunar Eclipse of February, 2018 reminded me of my travails from my first effort to shoot an eclipse in 2010.

My First Eclipse Attempt: 2010

In December 2010, I was crestfallen to see the weather reports. The last total eclipse of the moon visible from North America until 2014… and the weather everywhere within a reasonable 3-4 hour drive was predicted to be 90% clouds and worse. It seemed my eclipse was going to be eclipsed by cloud cover.

At about 9:15 PM, PST on December 20th, however, I looked up and saw… THE MOON!  Sure, it was scintillating in a little sucker hole playing with me. But I decided to play along. I hastily hauled out the Canon 5D Mark II, the 70-200mm f/4 IS L lens, the 1.4x Telextender, and the Gitzo carbon fiber tripod. Why those? Because that’s what I found first.

My equipment was scattered about in my office still recovering from the wet weather from earlier in San Jose. Indeed, I did not find the batteries for my Canon 50D camera.

By the time I got set up, I realized that the moon would very soon be contacting the earth’s umbra (darkest part of the shadow). So I quickly got to shooting what I could. Never mind that it was cold and I was not dressed properly.  Soon enough the clouds would come and I could dart into the house to hurriedly collect what I was missing.  The first shot I got was with the moon in the earth’s penumbra. Not particularly remarkable, unfortunately.

Through various breaks in the clouds I was able to get photos from first umbra contact all the way up to totality. Including a serendipitous shot of an airplane headed, probably, to the San Francisco airport or some other place to the north west.

Airplane Transits the Partially Eclipsed Moon
Airplane Transits the Partially Eclipsed Moon

What settings did I use for these shots? f/7.1, ISO 200, and 1/400 of a second exposures. Why so fast? Because, my friends, the moon is BRIGHT. Even partially eclipsed, even already in earths penumbra it is a big bright object. Shooting the moon is a definitive case where your camera absolutely cannot get the right exposure if left to itself. A good exposure must be manually set. I arrived at my settings by a few quick trials. I started at about 1/200th at f/5.6 and noticed that I was getting some over exposed areas (on my LCD screen the overexposed pixels blink white). I then decreased the aperture and continued to tweak the focus.

I wanted the moon images to be as well exposed as possible – especially knowing that the thin clouds were going to dim the image. My goal was to get detail in the moon, I did not care about the clouds or stars. In fact it is impossible – except at a very slender crescent or during a total eclipse to get detail in the moon AND also show stars in the sky. Why? Because the moon is so, SO bright.

I definitely made a slew of mistakes. The most significant one is that I should have put the telephoto lens on my 50D body which is a 1.6 crop camera. Had I done that all my moon images would have been about twice the size of what I actually got. Not having my camera all packed away in my bag meant some lost opportunities here.

I also thought  that perhaps the 5D would have been a good choice to get a sequence of shots showing the progression of the eclipse. The idea was to get the moon in the bottom corner of the frame and take a series of shots as it moved to the upper left of the frame. This also did not work for several reasons. The first problem was that the cloud “holes” came at irregular intervals – so spreading them across the frame evenly was not going to happen. The second problem was purely my failure to correctly guess the path the moon would follow in the sky.  Had I been a little smarter I’d have switched lenses when I realized the timelapse path was not going to work. But instead I tried again a few times.

I also realized that when the eclipse was total, the moon was going to be quite dim and the superior high ISO performance of the 5D II was needed. For the totally eclipsed shot, the ISO was ramped all the way up to 1600 and the exposure dropped from 1/400 to 1/6 of a second. That is a HUGE difference. The slower exposure meant that details in the moon would be blurred and the stars at this telephoto range would become dashes rather than dots.

Jewel [C_029690]
Nearly Total – With enough bright area left to form a halo in the clouds

Epilogue:  February, 2018

Sadly I was NOT much better prepared. After studying the weather forecasts, I headed to the coast where it is often really yucky with fog, low clouds, and on-shore winds that bring dampness and salt spray. It was surprisingly clear. My goal was to take a series of shots showing the progression of the eclipse ending at sunrise with the moon hovering over the Pigeon Point Lighthouse. I had done all the calculations as we cover in our Catching the Moon Webinar. (And also somewhat described here)

I imagined something like this effort, but better done.
Plan C: San Jose City Hall Eclipse Sequence

As it came about in 2014, we had to go with plan C due to weather. So I was excited that the weather forecast for the coast was much better in February, 2018. Some oversights on preparation conspired against me. I had not jotted down the proper GPS location and on site I had no cell signal, so couldn’t (re)calculate the spot. That left me wandering about trying to find the little tree and path that was featured on the satellite view… and NOT finding it.

Instead I ended up wandering into a thicket of brush that had an abrupt downward slope. That was fall number 1. Several efforts (and falls) later I tried setting my tripod down THROUGH the gorse all around… only to snap the leg off of my tripod. Now I needed to take  trek back to the car for my backup tripod. (Fortunately I had one!).

Since I got a late start, I scrambled to try to get a couple of series of panoramas on which to overlay the moon trajectory. However the moon was already in complete eclipse by the time I had everything set up. It was only then that I realized I was not getting the details I wanted out of the moon. I was using a 70mm f/4 lens, and the long exposures were streaking the stars and blurring the moon. So while I did get a FEW shots, they weren’t the ones I had imagined. My problem, in a nutshell, was that I was trying to get the moon AND the stars … which I did, but at the cost of streaking and blurring.

Orb to Rule the Night

By the time twilight started to appear, it was obvious that my location was about 1/4 mile distant from where I wanted to be… the little tree that I thought might form the right edge of my panorama was far off. The moon was NOT going to land anywhere near the Pigeon Point Lighthouse, so I packed up and ran up Highway 1 closer to the calculated location. I had to abandon the sequence plans, throw on the big tele-extender and HOPE the moon would survive visibility through the now obvious off-shore fog bank. Of course it didn’t. It fizzled as it got near the target.  I did get a consolation prize of sorts, though. This image hit 80 THOUSAND views in a few days – becoming my most popular photo on Flickr EVER. Sadly it’s not the image I imagined.

It's A Little Bit Broken
Photo from the end of the total eclipse of February, 2018

What Did I Learn?

To get a decent eclipsed moon shot with details, either you need a very fast telephoto lens, or to use a mount to track the moon. I also need to be willing to lose more sleep. I woke up at 3:00 AM, but the 90 minute drive meant that the umbral (dark part) of the eclipse would be starting as I arrived.

I also realized that if I’m going to spend the better part of a day mapping out the moon trajectory toward a landmark like the Pigeon Point Lighthouse, I’d do well to record some GPS locations (where to park, where to stand), and even get a Google map pre-downloaded.

Hopefully you, dear reader, will learn from my mistakes because you won’t have enough time to make them all yourself!

Top Ten Destinations in the West

Well, What Sea?

Well After Sunset Along the Pacific Coast


I know my top ten may not be the same as your top ten. After all what interests me may NOT interest you (though for the life of me I can’t think why not!)  As a Landscape Astrophotographer I tend to gravitate to interesting views, unusual geology, natural landscapes and places where the sky is dark and clear at night.  I’m not a city guy. The chance that you’ll find me in a tavern or night club is extremely slim.  And while I do appreciate great architecture, and (ancient) history you’re much more likely to find me on a mountain top or along the shoreline or in the desert. Forests feel crowded to me unless they are surrounded by granite, basalt, sand dunes or lava.  Flat is usually boring.

I also want to be frank that this list is based on the places *I* have been. There is an equally long list of places I have NOT been but where I wish to go.  I’ve also narrowed this list to Nevada, California, Western Utah and Arizona. I am listing my destinations in order of the eye appeal and “spiritual oneness” I get from visiting them.  I’ve also provided some hints what seasons are best, and the amount of effort it takes to reach these places.

 

    1. Nightfall at Cathedral PeakYosemite National Park.  There is a really good reason Yosemite is so heavily visited. The first time I drove into the valley with the family I went slack-jawed. It is hard to imagine how beautiful Yosemite is. And the first time I stood on Half Dome – long before permits are required to make that hike – I literally wept – and not just because the hike was arduous, but because the view makes the heart flutter.  You feel tiny and the granite feels big and solid.  Yosemite is a very large park and there are four primary areas to visit.
      A> The valley which in the summer is overrun with tourists, and noise and distractions but quiet and beautiful when snow laden in the winter.  The summer is also when the mighty Yosemite Fall becomes a whimper. To really be astounded the best time to visit Yosemite Valley is in the early spring.  Late April to Early May.
      B> Another area of Yosemite worth visiting is the entire Tioga Pass road: especially Tuolumne Meadows area. There is awesomeness nearly everywhere along the 54 miles of road and it is always less busy than the valley. Warning: Tioga Road (Hwy 120) closes November through May.
      C> A third place that is justly popular for its scenic splendor is Glacier Point. The road to this amazing overlook is also closed in winter.
      D> And finally there is Wawona and the Mariposa Grove of Big Trees. Impressive, but not as impressive as the huge trees elsewhere in California e.g. in Big Basin State Park.
      There are also many, many spectacular landscapes to be seen far from anywhere a car can go. Some of the most rewarding views of Yosemite require backpacking into the High Country, like the photo above which is Cathedral Lake – a trail from Tioga Road.


    2. Reaching for the Sky Alabama Hills near Lone Pine, California. Lone Pine is a small town with plenty of restaurants. But at the doorstep of Lone Pine are the Alabama Hills – bizarre rounded rock formations many of which you have probably seen before in movies like Planet of the Apes and car commercials and westerns.  It’s a gorgeous landscape with so, so many places to explore. There is plenty of quiet in Alabama Hills and there are many places to roll up and enjoy the dark skies and the fantastic rock formations. Rising out of Alabama Hills is mount Whitney – the tallest mountain in the United States – the lower 48, that is.  Alabama Hills is lovely in any season – prefer late fall – but beware the summers can get hot. 100 degrees Farenheit is not unusual.  A high clearance vehicle is definitely a plus if you want to go on some of the dicier roads, but not needed for the main roads.  There is a good reason we offer workshops here. It’s awesome.

    3. Mono Lake South Tufas before Dawn [4776] *Explored*Mono Lake near Lee Vinning, California.  Mono lake has a very alien vibe due to the tufa formations that have been revealed because of Los Angeles’ thirst for water.  Mono Lake has grown touristy – it’s not unusual to see a busload of photographers disembark and jostle for the best spots to set up a tripod. Despite that, Mono Lake is well worth a look. Not far from Mono Lake are other interesting attractions like Bodie – a ghost town, June Lake and the June Lake Loop, and the entire stretch of the Eastern Sierras all the way down to Alabama Hills. Any season is good to visit Mono Lake, but winters are harsh and cold.

    4. Dream Highway [C_071601]Big Sur. Big Sur is the name of a town in about the middle of a region loosely defined by a long stretch of winding Pacific Coast road (Highway 1) that runs from Carmel, California all the way down to Cambria. The Hearst Castle which is an interesting historical, artistic, and cultural anomaly can be found in San Simeon. The road hugs tall mountain cliffs with sheer drop offs into the often churning Pacific Ocean below. If I have to pick a favorite spot in Big Sur that’s easy. Pfeiffer Beach.  Often in the summer in particular Big Sur can be cold, foggy and windy, but really any time is good to go. If you’ve never dipped a toe in the Northern California Pacific Ocean, don’t expect it to be warm EVER.  Big surf comes in the winter – from November to February. Accommodations along Big Sur are scarce, expensive and heavily booked especially when school is out. And there are LOTS of destinations worth visiting: Point Lobos, Pfeiffer Beach, McWay Falls in Julia Pfeiffer Burns State Park.

    5. Famous III [C_035478]
      White Mountain, near Bishop, California. If you want to see the most amazing and oldest living things on the planet you will need to drive up White Mountain to the Patriarch Grove or at least to the Schulman Grove.  And while Bishop to the West and Nevada cities to the east are doing their best to light pollute the skies, it is still well dark there and you will see the Milky Way if you look.  Like many other places, the road is often closed in the winter, but it usually closes later than the Sierra roads and opens sooner.


    6. The Overlook at Zabriskie Point 7118Death Valley National Park.  First you need to know that Death Valley is HUGE. And yes, it is extremely hot from late spring to mid fall. But the spring flowers can be amazing and the scale of the place is hard to fathom.  And while it is a desert, you may be shocked at how colorful it is. As with many places in the west, the most desolate and difficult to reach areas of Death Valley are the most interesting: the Racetrack Playa, the peculiar Darwin Falls, Eureka Dunes and Dante’s View.  Expect to travel hundreds of miles to see all these things and to pay a princely sum on gasoline.  If you go, you had better visit Zabriskie Point – sunrise is better than sunset at the point. Accommodations are hard to find.  If forced to choose between Death Valley and the Grand Canyon, Death Valley wins easily.

    7. Watching the Watchman [42-011228]Zion National Park, Hurricane, Utah. I’ve visited Zion in the winter when snow and Navajo Sandstone conspire to make a beautiful landscape, and in the summer. I preferred the winter. My wife took this photo.

    8. Snow Flocked Bryce Canyon [IMG_151594]Bryce Canyon. Unfortunately I have only visited in the winter. It was drop dead gorgeous with the snow and the hoodoos.

    9. The Colorado River Makes A Grand ArcHorsehoe Bend. The scale and grandeur of this magnificent bend in the Colorado river is every bit – and more – breathtaking than any vista I’ve ever seen in the Grand Canyon. And Horsehoe Bend has the great advantage of being very close to the Antelope Slot Canyons and Page, Arizona. Page is a large enough city to rest and resupply in. Lake Powell is nearby, too. Horsehoe Bend is “just one place” and is easily accessible with about a 1/2 mile walk from the road.

    10. The Goodbye Look [5-001753]
      Antelope Valley Slot Canyons. On Navajo tribal lands it’s worth every penny you might be charged for a tour.  When you stroll through this majestic place – even if you do so amidst throngs of tourists you’ll find it hard to not feel a oneness with the beautiful and intimate windswept colors and curves.


    11. Black Rock Desert, Gerlach, Nevada. If you look up the definition of desolate, this place might well be mentioned in a footnote.  Unless you make the mistake of going during the Burning Man festival in which case this empty flat dry lakebed ringed with modestly sized mountains becomes a sprawling metropolis of what seems like a zillion people. Or so I’ve been told. The good news is it is still very dark here.  It did not make my top ten, but it did beat out the rest of our list.

    12. Lake Tahoe – Many places around this picturesque lake to drink in photos and views.
    13. Mount Shasta – Right off highway 5 going north/south you’ll find vistas, waterfalls, and some remarkable history and views.
    14. Lassen National Park
    15. Sedona, Arizona – Hard to argue with the wind sculpted Navajo Sandstone all around.
    16. Tucson, Arizona – Not only are there desert stretches, the Saguaro National Forest, Mount Lemmon, and the Santa Catalina Mountains, but also Kitt Peak Observatory and many dark areas around. Unlike, e.g. Phoenix which is Las Vegas – like in its light pollution intensity.
    17. San Francisco – As cities go, San Francisco has many lovely vistas and landmarks. Especially from, e.g. the Marin Headlands.
    18. Seattle – like San Francisco, Seattle has some great views, landmarks and vistas. They are a little harder to find because of the heavy forests all around. But when it is clear enough to see the Space Needle, Mount Ranier, or the snow covered Olympic Mountains, it is awesome.

    How Do These Rank Against my Top 7 Most Beautiful Places in the World?

    I’m not as well-traveled as some, but I’ve been quite a few places. Here are my top 7 most gorgeous places to be – ranked from 7th to 1st.

    • Horsehoe Bend, Page, Arizona. Described above.
    • Antelope Slot Canyon, Navajo Lands near Page, Arizona. Described above.
    • Petra, Jordan.  The ancient, expansive and elaborate hand carved tombs of this ancient Nabatean city are winsome. And to make the stay even more pleasant the many Bedouin people I met while there made me feel very welcome.
    • Yosemite Valley, Yosemite National Park, California.  Described above.
    • Patriarch Grove, White Mountain, California. Described above.
    • Thira/Oia/Firostefani, Santorini, Greece
    • Granite Park, Inyo National Forest, California. On my GPS I put “Saw God here” – it was THAT awesome. Granite Park is well above the tree line at about 11,000 feet and it will take a serious back-packing effort to reach it.

Got a top 5 super favorite place in the west we did not list? Please comment (and include a photograph).

You Need a Good Head and Great Legs

Me (to wife): “My head is unstable and I have ordered a new, $300 one.”
(wife): “I knew about the instability, but I didn’t realize you could buy a new one.”

Tripod and Panoramic Head in action

If you search around the internet you will find plenty of product reviews. One of the best reviews I ever read said something like this: “Save one thousand dollars by buying the right gear now instead of later”. He proceeded to describe how cheap tripod legs and cheap heads ended up costing more than had he bought the good gear from the beginning.

Wait, “heads?”, “legs?”

There are four parts to a tripod that are important to get right: legs, head, release, mounting plate.

 

But First… A Short Commercial

Merry Christmas and Happy Holidays! Harold Davis and I will be conducting a workshop that you may want to attend. Registration is through Harold’s web site.

Tripod Anatomy

  1. Legs – The part that touches the ground, and yes the bottom of the legs is called the feet.
  2. Head – The part that is attached to the top of the legs and provides the ability to rotate and tilt the camera at various angles.
  3. (Quick) Release system – The method by which the Head can attach to the camera via…
  4. Quick Release plate – the part that you attach to the camera and mate to the release system. You can directly screw your camera on to many different heads, but you do not want to do that because it is really, really inconvenient.

If any bit of those is wrong, you have an unstable or even equipment-hazardous situation. Trust me, I started with “K-Mart” tripods (had 3 – each of which didn’t last long), 2 Manfrotto aluminum tripods (one is broken), and ONE Gitzo carbon fiber tripod. I have also owned at least 9 different heads including a pan-tilt head, SunFoto, Manfroto, Acratech, and a gaggle of off brands. The ball heads were bought for various purposes. I have also dealt with 3 different kinds of attachment systems: direct screw-in to the camera (really inconvenient), Manfroto style plate clamp (better), and Arca Swiss clamp (best of the bunch). I have also used a gaggle of different “quick release” plates from cheap off-the shelf, to custom made for my camera(s), including L-Brackets.

Trial By Fire

Trust me when I tell you I have discovered a lot of what not to buy, and can say confidently that if you want a stable, good quality camera support system you need to get all four components right. And doubly so for night photography where long exposures REQUIRE a tripod or other solid support system. My tripods have been to the top of Half Dome, Mount Whitney and Clouds Rest. I have used the “legs” as a walking stick to keep me from falling into rivers and ravines, to test stability of the ground before taking a step.

Many Paths to Failure – Plate and Clamps

Let me provide some examples of the myriad of ways things can go wrong: all of them have happened to me, by the way.

If the quick release plate is attached with a low quality screw or bolt… the bolt could snap and your camera and lens will tumble to the ground.

If the quick release plate is difficult to get a snug fit (or requires a special tool that you do not have with you), your camera will wobble or twist in the breeze no matter how stable everything else is.

If the plate is difficult to get into the latch (release clamp), you may think you have it ready to go, only to see your camera fall off the tripod onto the ground or down a granite staircase.

If the plate you have on the camera does not mate with the clamp on your tripod… oops. You’ve lugged your equipment for nothing.

If everything is solid except the clamp does not snug down well, you have wobble and ruined photos.

… and we have not even gotten to the head or the legs yet!

More Failure: Head and Legs

If your head requires superhuman strength to keep it from creeping under the weight of your camera and lens (or super human strength to undo it)… you get either painful fingers or a “sinking” camera angle.

If the tensioning on the head is either locked-like-super-glue or floppy-as-a-wet-rag, you may either have to give up aiming the shot as you want, miss the shot, or have the rig flop over when the camera does. And the flopping camera may pinch your hand, or mash your fingers or smack you in the face (Reminder: All these have happened to me!)

Even if the leg locks seem to be working well, unusually cold (or hot) weather may render the locks ineffective and your tripod may slowly – or suddenly – fall over.

If the legs cannot be adjusted wide-enough or accurately-enough or low-enough, a breeze or strong gust of wind may blow your rig over.

If the fully extended legs are so short that you fully extend the center column to keep from hunching over and hurting your back – you have turned your tripod into a wide-stance monopod that may not be able to bear the load.

If your center column has a tightening collar or wing nut directly below the weight of your camera, you may accidentally over loosen the column causing the camera to slide down and pinch the living daylights out of your hand.

If your legs are spindly, they may induce vibration, or just snap when you accidentally bump them.

… I could go on … but I am hoping you understand how hard knocks, broken lenses, and broken tripod components all add up to a severe lack of enthusiasm for all but the best built of components.

Recommendations?

So here is where you might expect me to make recommendations, right? I usually avoid making recommendations because gear changes, and people have different reasons for choosing what they do. My criteria are pretty simple: I want stability, versatility, durability, and light-weight – in about that order.  While the first three seem to be pretty obvious criteria, the light-weight aspect was something I learned over time, too. It was a chore to lug my > 8 pound aluminum leg Manfrotto with a Manfrotto head to the top of Half Dome. By comparison my < 4.5 pound Gitzo plus Acratech head seemed like a feather. Manfrotto made a smart move when they bought Gitzo.

You might have noticed that I did not list price as important. It used to be, but too many failed choices made me realize that choices that are less than great become costlier in the long run.  In a similar vein I bought half a dozen sleeping bags hoping to get something lightweight and WARM until I finally spent almost $300 on a bag (Big Agnes Lost Ranger) and pad that provided the most comfortable, warm sleep – and was also lightweight. I’ve spent more for a single night in a hotel than for the sleeping bag, but that bag has kept me snoozing on many chilly nights in the wilderness. Indeed one night I had TWO cheap sleeping bags nested inside one another while in a tent in Grandview Campground at 8,600 feet on White Mountain and I was still shivering. The next time I went with my Big Agnes. The night was even colder, but I was snug as a bug in a rug.

I had similar experiences with camera backpacks. I liked the design of a Tamron bag. It lasted about a year until the zipper broke. The second bag lasted less than a year. By contrast, my F-stop Tilopa bag has been all over the world over 4 years now – sometimes as my primary and only luggage. To say I’m happy with its durability would be an understatement – and that it cost me 4 times as much as one Tamron bag ($320 vs $95), means I’ve broken even so far – without the inconvenience of dealing with broken gear.

What About A Ball Head And Tripod Legs?

Acratech GPS-s

  • Acratech Head (pretty much any one), but the GP-s is a nicely designed lightweight capable head unless you have a huge camera.
  • Gitzo carbon fiber legs, but NOT the Traveler series which is too flimsy and too short.
    I specifically recommend the Mountaineer Series 2. It is the best trade-off between weight, stability and usable height.  If you’re willing to pay a penalty in extra pounds, the Systematic series (3, 4, or 5) are good except for two things: The Systematic doesn’t have a center column and sometimes that column is useful – like when trying to shoot straight up since the camera may end up hanging partially below the level of the head. The other thing about a series 5 Systemic that bothered me was that I was shocked to discover that the leg locks must be untightened in a specific order to fold it all up because if an upper leg is not tight, the lock on the lower leg will just spin. The mountaineer doesn’t require that silliness.
  • Really Right Stuff with carbon fiber legs. Pretty much all of them are well done, light and sturdy.  The RRS ball heads are good too, it’s just that they are all heavy, heavy, heavy.

But, but those are expensive choices! Yes. I suppose paying $430 USD for a good head and $950 USD for good legs sounds like an excessive amount of money. But: how much did your camera and lens cost? How much will your back thank you for carrying a smaller load?  And finally, how much are you willing to risk watching your camera and lens flop over in a gust of wind?

Disclaimer

I write what I know – not what people or manufacturers or merchants ASK me to write. I paid retail price to purchase all the gear I’ve discussed. In other words, these are honest, unbiased, hard won evaluations of various gear. If you can purchase this gear at a local store, I recommend that you do so. You may spend a little more, but there is serious value to talking to real people, testing out gear in person, and in keeping a local business viable.

One Reason To Consider the Alabama Hills Workshop... The awesome landscapes

Down with the Noise!

Clouds, Coast and Milky Way (vertorama)

We need to start with a definition.  What is noise?  A reasonable, widely excepted definition is that noise is any artifact or defect that reduces the overall fidelity of an image. But this definition is too broad because defects like glare and chromatic aberration would be included. Glare and chromatic aberration are caused by the optical system, not by the sensor. So a better definition is needed.

Noise Means: Variations in luminance (brightness) and chrominance (color) in an image that are not in the object being imaged and not caused by the optical system. These variations generally are perceived as colored speckles and resemble grain in film photography.

There are, however, many types of noise – each having different causes and thus different solutions.

Astonishing Fact Number 1

Every image has noise!  Indeed, noise often aids in creating sharpness.

Astonishing Fact Number 2

Usually the problem is not noise but with noise that overwhelms the “signal”.

The Five Kinds of Noise

There is not just one kind of noise. There are five. Ok, there are actually MORE than five kinds of noise, but here are the most significant ordered from most to least likely to overwhelm a night image.

  • Random (quantum effect) noise.
  • Fixed pattern noise (banding)
  • Stuck (Hot Pixel) Noise
  • Offset noise
  • Shot Noise – applies to very dim subjects and shadows

You may see different terminology in other articles. For example “Fixed Pattern Noise” is often used to describe stuck/hot pixels.  For me “stuck pixels” while often annoying are one of the easiest to control using “dark frames” – or with newer cameras, require NO work. More on that in a moment.  Let’s briefly address each kind of noise, what causes it, and how to best prevent it.

Random Noise

Despite what you may have been lead to believe, random noise IS random. Speckles can appear anywhere on your image in light or dark areas. These speckles are caused by *random* quantum effects.  Electromagnetic induction, electro magnetic fields, gamma rays, sunspots, static charges, impurities in the electronic substrate, and blind bad luck. ALL of these effects are magnified by heat which is the single nastiest mafioso of noise. Longer exposures produce more noise. And “Dark Frame Subtraction” (an element of Long Exposure Noise Reduction aka LENR) can do *nothing* to alleviate random noise. Soon however we will tell you how to reduce noise the way an astrophotographer does.

Fixed Pattern Noise (e.g. Banding)

The more you push an image, the more likely you are to see vertical or horizontal banding – or both.  Pushing refers to high ISO sensitivity or large increases in exposure in post processing. Pushing also refers to using lower quality sensors at well above their quantum efficiency – which we will explain in a moment.  As with random noise higher ambient temperatures can intensify this type of noise.  Another example of fixed pattern noise refers to pink, purple or overly bright areas in an image. Early cameras were particularly prone to this form of noise because the electronics of the camera were unevenly heating the sensor – and as has been pointed out above, temperature is the enemy of a clean image.

Stuck / Hot Pixels

To be precise, it’s usually not “pixels” that are stuck or hot – it’s sensels. Because each pixel is comprised of two green, one blue and one red sensel it’s often easy to tell which of the sensels is defective by observing the color of the pixel. If red – the red sensel is registering a value higher than it should. “Stuck” sensels usually result from one of the following causes:

  1. Measurement errors in the electronics (e.g. photon collector doesn’t empty properly, current leakage), or an unusually high offset bias.
  2. Physical damage to the filter (lens) over the sensel – usually at manufacturing time.

Often the higher the ISO, the more offensive a stuck pixel appears – however stuck pixels which are present in every frame can be removed using dark frame subtraction, and indeed modern cameras can remove these automatically. Dark frame reduction is something the camera does when it does “Long Exposure Noise Reduction”.  Sometimes resetting the camera can dramatically reduce the hot pixels. The method for resetting a camera varies, but on many Canon cameras, the prescribed method is to use the manual “sensor clean mode” -> Now and leave it in that mode (with no lens attached) for at least a minute before turning off the power.  Also note that heat often exacerbates the stuck pixel problem, too.

Tip 1: “Reset your camera after it has temperature stabilized and before shooting. Usually this is a simple as “Clean Sensor -> Now” Many modern cameras make note of the stuck pixels and will automatically remove them for you!

Offset Noise

The process of measuring each sensel involves an imprecise analog to digital conversion. The measurement phase can introduce its own error called bias. Rather than reading an unexposed (black) sensel as a zero, some sensels may read 2, some 4 and others 7.  This offset noise is also managed pretty well by LENR and except when it is really bad, is not significant.  Merely darkening the darkest pixels may be sufficient to hide offset noise.

Shot Noise

This is a curious name but it refers to the fact that photons (light) do not arrive at a regular rate – especially for dark subjects like dim stars or the darkest of shadows. Since the camera collects and counts photons, variations in the rate of arrival of photons results in speckling. However normally shot noise is minimal and not noticeable. Shot noise is usually noticed only when severely underexposing or by aggressively brightening underexposed areas.

 

Noise Reduction Methods (Pre and Post Shot)
Type of Noise Pre-Shot  Post Processing
Stuck Pixel(s) Cooler, Camera Reset, LENR Dark Frame Subtraction
Random Cooler, Shorter Averaging, DeNoise, ACR
Banding Cooler DeNoise, ACR
Shot Longer Exposure
Offset LENR Dark Frame Subtraction

 

Looking Noise in the Face

Zooming in on a dark frame – one taken with the lens cap on shows the nature of noise. First is a dark frame without any adjustments.  Some red and green noise is barely discernible.

Dark Frame 1 - Linear Mode, Unmodified

Dark Frame 1 – Linear Mode, Unmodified

Looking at the same frame with an adjustment to boost the saturation and brightness, the nature of random noise is more obvious.

Same Single Dark Frame Boosted with curve to show content.

Same Single Dark Frame Boosted with curve to show content.

Notice how the noise is different in the same area of another frame.

DarkFrame2Boosted

For more examples of noise in dark frames, see this article.

Noise Reduction – The Environment

Sadly, one of the most significant sources of noise is heat – the heat in the air.  Shooting in the desert at 100 degrees Farenheit will always create far more noise than shooting at 30 degrees F below zero.  Can you help the problem by cooling the camera? Yes you can!  Gary Honis built a cooler for his camera (used for astrophotography) and got quite impressively better results. His chart of noise pixels is no longer on the site, but it dropped from thousands of bits of noise to to tens by cooling his camera 40 degrees Farenheit. However beware that if you also cool the lens you’re likely to get dew.  And if you have an open system like in Gary’s Telescope scenario, you may get dew on your sensor, too.  Not surprisingly ALL high-end cameras for astrophotography are cooled. The most extreme are cooled with liquid nitrogen!

The second take-away is this:

Tip 2: If possible, opt for shooting in cooler climes.  If you’re shooting the Milky Way, for example, you can check a Planisphere and you’ll find that you can get the same star configuration at different times of the night in different parts of the year.

 

Noise Reduction – A Better Sensor

You may have seen some velvety smooth night images produced by top of the line cameras and may be wondering if you can achieve such results with your middle of the line equipment. Unfortunately the answer is mostly no.  Generally speaking two things dramatically affect the amount of noise produced in a camera’s sensor with regard to night and low-light images and those are:

  • Sensor density: the more sensels you pack into a given amount of space the less light they receive. Set out a thimble and a bathtub in a rainstorm and it will be no surprise to find far less water accumulates in the thimble than the bathtub. The smaller, closely packed sensels in high megapixel crop-factor cameras have a distinct disadvantage over the relatively lower density, larger real-estate full frame cameras.
  • Sensor design: Modern camera sensels are spaced more closely together so they waste less light. They are also more efficient.  Better sensors also have higher “full well” capacities – that is they can count more photons more accurately before filling up or spilling over. Because of better sensor design it is possible for a higher megapixel sensor to outperform a lower megapixel sensor of the same size.

There is one other measure of a sensor that keeps getting better: it’s quantum efficiency.  In an ideal sensor each photon will increase the count of the sensel it strikes by exactly one.  The efficiency of a sensor can be determined by calculating its “ISO at Unity Gain”.  The higher the number, the better the sensor performance.  DxO Mark calculates approximately this value and represents it as the ISO value in its “Sport/Low Light” rating.  For daylight subjects with gadzillions of photons flying a great picture doesn’t require a high efficiency sensor. But in low light every photon should be counted!

Here are the top 3 Full Frame or crop cameras (plus #4, the one I chose) ranked by ISO of the “Sports Score” (a good approximation of the quantum efficiency) and initial price as of November 16, 2017. Click the image to see the latest chart and to find your own camera.

DxO Mark “Sports” Score by Cost

Tip 3: Learn what your camera quantum efficiency is and shoot near or below that ISO level. Selecting a higher ISO than the quantum efficiency magnifies the noise, while a lower ISO tosses out good data.

Noise Reduction – Software

There are many ways to use software to reduce noise in an image. Tools like Canon’s Digital Photo Professional (DPP), Adobe’s Camera Raw (ACR), Lightroom – which uses the ACR component, and many plugins and filters within Photoshop.  Keep in mind that no noise reduction technique will result in keeping a perfectly sharp image – all methods blur the result.  TopazLabs DeNoise (and inFocus) product claim to have deconvolution techniques to keep edges sharp. The good news is that a slightly blurred sky – like clouds, looks quite natural. What is my preferred method?

  1. Ignore it!  That’s right. Many images that appear noisy when pixel peeped are really quite fine for reproduction at reasonable sizes and viewing distances – especially if no overly aggressive brightening or contrast enhancements are done.
  2. Adobe Camera Raw: I use ACR when the noise is fairly low.  ACR does a suprisingly good job of removing noise if you bump the “Luminance” and “Color” Noise reduction sliders to the right and turn down the Luminance Detail and Color Detail sliders. How much depends on the image and how desperate you are to save it.  NOTE: Lightroom’s controls are the same as those in ACR except that you can selectively apply noise reduction which is preferable. Being too aggressive with the Color noise may eliminate your star colors, so beware!
  3. Use a Photoshop Plugin.  There are a kajillion ways to reduce noise within Photoshop – after ACR – including the “Despeckle”, “Dust and Scratches” and “Reduce Noise” filters (and more). But we find that in Photoshop all the built in ways are underwhelming.  I have tried several plugins including DFine (Nik Software), DeNoise (Topaz), and a few others.  The one that wins for me is TopazLabs DeNoise.  Below are samples of the original, and the DeNoised versions.  I think the result speaks for itself.  But note that I *intentionally* used an artificially high ISO to increase the noise.  A better ISO for the Canon 5D II would be about 1600 ISO – a little less than its 1815 rating by DxO Mark Sports score.

C_061861b_orig C_061861b_deband

Here is a closer crop of the areas most changed by the noise reduction:

The original image and two attempts at noise reduction. Notice that some areas (X) remain problematic

A good noise reduction strategy is to NOT denoise everything.  Duplicate the image to another layer in Photoshop. Apply noise reduction to that layer and then use a layer mask to reveal the noise reduction selectively. In the example above, masking off the Topaz Denoise on the tree would have left a sharper tree.

 

Median / Averaging To Reduce Noise

Yet another noise reduction method – useful for random noise is to do median (using Statistics in CS Advanced or Photoshop CC) or averaging of shots.

On the left is a single 25,600 ISO exposure. On the right, 15 shots averaged but with no other noise reduction attempted.

Hopefully you remember that there are many different kinds of noise. The techniques described above are used for controlling both random noise and stuck pixel noise. But stuck pixels can be managed by doing your own “dark frame subtraction“.

 

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