Category Archives: Stacking

Why Aim North?

Reaching for the Sky

Reaching for the Sky: 112 images, each f/4, ISO 800 for 60 seconds including a shot from twilight hour for the foreground Alabama Hills, Lone Pine, California

Want to capture Perseid meteors, the Milky Way, and star trails in an awesome location?

Join us for our>>> Field Event: Meteors, Milk Way in Alabama Hills <<<

Sunday, August 12, 2018 (with an optional second night).

 

I live and travel in the Northern Hemisphere. In fact I have yet to travel south of the equator, so my apologies to those of you from the southern half of the planet for my obvious northern bias.  I believe those of you in the bottom half of the planet can just substitute the word South for North everywhere and everything should be correct.  I have added [parenthetical content for those who are in the southern hemisphere where that north/south swap doesn’t work]

The results obtained by shooting a long exposure at night depend quite a lot on which direction the camera is pointed. I favor long star exposures with a northern view for many reasons.

The Advantages of Shooting To the North

  1. Curvature of the star trails is strongest around the north star. Exposures of about 6 hours will appear to be full circles (24 hours of exposures are actually needed to make complete circles and that is not possible in one night except near the North Pole!).
  2. The moon will never intervene into the shot because the moon never passes through the northern sky.  [NOTE: those in the southern hemisphere still have to worry about a moon in their Southern shots]
  3. Cassiopeia and Ursa Major (the Big Dipper) are bright constellations that can always be found in the Northern Sky – so there is always some interesting sweep of stars possible. The region immediately around the North Star, however has dimmer stars which may only be captured through long exposures. [The southern hemisphere suffers for lack of many bright constellations near the southern celestial equator]
  4. With just a smidgen of star hopping skill it is easy to find the north star which, weather permitting, is always visible in the night sky.
  5. The moon sweeps east to west giving long shadows from the right or left of the subject. And when the moon is highest in the sky it can cast strong face light.
  6. The sun also never appears in the northern sky so it is safe to leave a camera running from before sundown to after sun up. Camera damage can result from a long exposure pointed at the sun.  [NOTE: those in the southern hemisphere still have to worry about a sun in their Southern shots]
  7. Since the moon cannot enter into a northern shot a photo can be made regardless of the moon’s phase and for as long as I choose. For shots toward the East, South or West it is important to know the moon phase and location during the hours of shooting to prevent problems from flare or washout. [NOTE: those in the southern hemisphere still have to worry about a moon in their Southern shots].
  8. The stars in the north move the slowest through the field of view which allows them to be brighter and reduces inter-exposure gaps in the trails.
  9. If I know my latitude I know how high to point the camera and be guaranteed to get a circle in the view.
  10. I do not need to know what constellations will be visible in the direction I will shoot.
  11. Two major meteor showers (the Perseids and Quadrantids) and 3 periodic meteor showers (the Giacobinids or Draconids, the Ursids and the Andromedids) are well placed in the northern sky.

The Disadvantages

There are a few detriments to pointing north, however:

  • Not every situation lends itself to a view from the south.
  • It takes a longer exposure to form a pleasing arc.
  • To get a circular arc, I must include at least 10 degrees or so above and below the North Star. The farther north you are, the higher in the sky the center of rotation. Those at more northerly latitudes will be more constrained in their choices.
  • The altitude (degrees above the horizon) of the north celestial pole may constrain the choice of lenses to very wide-angle – and may force you to use portrait mode. Or you can create your exposure by stitching together foreground and sky shots.

Another Northern View

Grand View [C_009613-686br]

Looking North from Grandview Campground, White Mountains, Bishop, California.  Shot at ISO 800, f/3.2 for 6 minutes each. Began at 10:11 PM and ended at 5:35 AM. That is 75 shots x 6 minutes = seven and a half hours. Grandview is at latitude 37 degrees North, so the center of the circular pattern is 37 degrees above the horizon.

What About OTHER Directions?

Southern View

Woosh

Woosh: 19 images. Each image: 6 minutes, ISO 800, f/3.2, Canon 5D Mark II, 16mm; Patriarch Grove, White Mountain, California

Eastern View

Valley of Stars (Remix) *Explored*

Western View

Stars and Stripes [5_065561-626li]
Granite Park - 53 Minutes (edited)

Notes

Contrary to popular belief, Polaris, the North Star, is not the brightest star in the sky. Sirius is the brightest star. The brightest objects in the night sky are the moon, and the planets Venus, Mars, Jupiter and Saturn. Also while Polaris is quite NEAR to the North Celestial Pole, it’s not exactly there so even Polaris will make a trail.

This is a reissue of an article originally written in October 11, 2010; Thoroughly revised and updated.

Darken Mode Stack Tip Using AdvancedStacker PLUS 18

Published: March 15, 2018

The new Advanced Stacker PLUS 18 is our attempt to make processing simpler. One of the things we find we often do is run multiple stacks (Lighten, Darken, Streaks, etc) to determine which effect(s) work the best. Well, we did something for the first time that worked REALLY well, so we will start by sharing that, even though Advanced Stacker PLUS 18 is not yet ready for publication.

In a nutshell, we created this:

Orion, Falling

From this:

Long Streaks Stack Result – no modifications  f/4, ISO 1600, 15 Seconds. Nikon D600, 24mm x 250

There are several obvious differences between these images.

  1. Because there was strong moonlight (and other light), the sky is over-bright and lacks contrast.
  2. The wind together with surrounding lighting (including flashing red lights from a passing fire truck) caused strange artifacts in the palm trees.
  3. Different colored light sources lit the palm trees differently (notice the really cyan colored palm fronds in the second tree from the left).
  4. There was utility wiring intruding into the image.

The Processing

Stacker 18 allows you to simultaneously stack in multiple modes. For example, to create this effort I used Lighten, Long Streaks, Darkest, and Average modes. I ended up NOT using Lighten or Average modes in this case. Is there extra overhead keeping more stacks? Yes, there is. However we’ve paired down the stacks to as few frames as possible to keep the overall footprint low.

Once the stacking had finished, the result of the Long Streaks was a bit unappetizing due to the red and other artifacts in the trees (see second image). However the Darkest mode stack effectively removes all of the stars – and as it happens, all of the strange highlights in the trees.  First we applied a Curves adjustment layer to the Long Streaks and darkened it.

Blending a Clean Foreground with the Star Trails

Darkest Stack results

The next operation was to find a way to blend the darkest mode stack (right) with the Long Streaks stack while preserving the star trails  and getting the cleaner looking foreground.

 

Duplicate the Darkest mode result (it’s a single layer) on to the Long Streaks stack. Then drag the darkest mode stack to the top layer. Set the new layer blend mode to normal, 100%.

Next we need to mask out the sky of the Darkest stack so that the long streaks will show through. The tool for that is to use Select -> Color Range. Holding down the shift key allows you to click multiple areas of the sky to add to the selection. You can vary the fuzziness of the selection to determine how closely the color has to match the sample. The mask will probably need some manual cleanup afterward, but as you can tell from the selection in the image below, just clicking different areas in the sky produced almost exactly what is desired.

Photoshop Color Range Selection

After pressing OK you get a selection. The next step is Layer -> Create Layer Mask from Selection -> Hide Selection Once you have a mask, you can paint on it to clean up any artifacts. Adjust the opacity of the darkest layer to make it “look right”. In this example, the combined image looked best at about 93% opacity.

Correcting “Off” Colors Due to Light Source Issues

The penultimate step was to create a Hue and Saturation adjustment layer. Lock the adjustment to the Darkest layer (hold the Alt/Option key and click on the boundary between the adjustment and the darkest layer). Then click the “Finger selection”  (just below the word Presets). Now there is an eye-dropper which you use to select the color that needs correction. In this case, clicking the dropper on the cyan colored palm frond is the right move. Adjust the saturation slider way down, lightness down, and fiddle with the hue to make the bizarre color more natural.

Aggressively toning down the cyan colored palm fronds

Removing Wires (and other distractions)

Finally we also used the Spot Healing Brush tool to “heal out” the utility wires. Here is a short-cut for healing out a straight line. Click the beginning of the area with the spot healing brush, then hold shift and click the end of the line. Shift causes the brush to be applied in a straight line between the first and second clicked points. The shift-trick works with almost all brushes. Two other tricks with the spot healing brush tool are to:

  • Start where the surrounding area has a predictable substitution (not a busy area) and work outward from there
  • Use as small a brush as you reasonably can

For example you can adjust the spot healing tool brush size to about double the width of the utility line, then click the healing brush tool where the arrows point below. Next work your way outward toward the tree on one side, then the other.

Summary

Here is a summary of the steps taken – not including the palm frond “naturalization” or spot healing described above.One more trick worth noting… the histogram shown on the Curves adjustment will give you a clue what may need adjustment.

Want to know what we consider the top 5 most used photo editing skills? Read here (and part 2 and part 3).

Time Stacks

Published: March 6, 2018

One of the great things about developing a repertoire of tools  and tricks for processing photos is applying those tools in creative ways. While we were furiously working on Advanced Stacker PLUS for creating star trails and processing night sky images, one clever fellow: Matt Molloy gained great acclaim by stacking sunset and sunrise shots of clouds skittering across the sky. Matt Molloy coined the phrase Time Stacks for that type of image.

Phoenix Leaping

Phoenix Leaping – 20 separate frames combined in Lighten Mode plus an extra foreground frame.

Where Steven lives in the Silicon Valley, it is difficult to get good conditions for clouds. Indeed, the San Francisco Bay Area has so many blue sky days that having clouds is a stretch – in the Bay Area the options are either low thick clouds (fog), or zero clouds. However occasionally conditions are right – or Steven travels where conditions are right – for creating these shots. Of note are dry climates with mountains and high winds during seasons with moderate moisture in the air. In March in Palm Springs, California, for example Steven watched as clouds formed due to the uplift of the Mt. San Jacinto mountain range and dissipated quickly as the young cloud wandered eastward away from the peak. Literally you could watch clouds form and dissolve in a matter of minutes. In the image above, you’ll notice that some low clouds moved slowly and didn’t dissipate. Because the denser low clouds were in the shadow of the mountain they grew dark and ominous.  You can see more variations on the same theme by checking out this set of images.

Exit Criteria

Exit Criteria – Alviso, California on one of the few days when clouds were present

What Conditions and Equipment Do I Need?

  1. You need partially cloudy skies and the clouds can not be slow creepers. The clouds should be vigorous sailors. How fast? Fast enough to cross a significant field of view in about 20 to 30 minutes. They need to move into an open area of the sky – clouds moving over other clouds won’t be as interesting.
  2. Like any compelling shot, the frame should include a worthwhile foreground.
  3. And finally, it helps if these conditions all occur near sunset or sunrise so you can get extra color in the shot.

Equipment

  • You will definitely want to use an Intervalometer (or an on-board Intervalometer if your camera has one). Shooting at regular intervals results in a more pleasing outcome.
  • A sturdy tripod is also a must.

What Settings Should I Use?

  1. Select a moderate aperture (f/8, for example), and a low ISO (200). The goal is to get a shot that is relatively long to get a little cloud blur from the cloud motion.
  2. Since most interesting results occur right at or after sunset, start the exposures at 1 to 2 stops over exposed. Subsequent shots will get darker and finally dark to a point where the images will be too dark  to use (e.g. 2 stops under exposed).
  3. While it may be tempting to adjust the exposure during shooting, we have found that strategy does not work well.  You never really know which shots you will want to combine. Therefore it is best to do large sets (40-50 exposures) all using the same settings.
  4. Change settings (and optionally re-orient your camera), then get another substantial sequence.
  5. Be sure to include an exposure optimized for the foreground in the beginning and/or at the end of each sequence.

The trickiest part is selecting the interval between shots. The speed of the clouds across the frame is the key here – and that can vary dramatically depending on your conditions. One possible method is to shoot once every other second, then cull out the interval that works best (which could be 10 or 20 second intervals), but a less memory and processing intensive approach may be to use 5 or 10 second intervals between shots (or longer if your clouds are sluggish).

Also keep in mind that not all clouds will move at the same speed (or in the same direction!), nor will they be illuminated alike.

How Do I Process the Shots?

This is actually the easy part: use the same tools you would use to create star trails. That is, stack the images in Lighten mode. Understand that if clouds move over clouds the net result is sometimes quite unexpected – the brighter clouds (regardless of color) win.

How Processing Was Completed (Click for larger image)

Above is a snapshot illustrating how this shot (62 frames in the life of clouds) was finished in Photoshop. Two image contrast enhancements were added. The bottom layer is the stacked (lighten mode) image, the next image up is the intentionally over-exposed foreground. Notice that the “Darken bright foreground” is linked to effect ONLY the foreground image. Also note that darkening, and in many cases increasing contrast has the affect of increasing color saturation. No saturation or vibrance enhancements were done here. As with Star Trails, we also recommend that you do not alter any of your shots before you stack them – stack them in their raw form with NO adjustments. The result will look flat until you apply manual corrections and curves, but by not altering your shots before hand, the stack will work better and you are far less likely to introduce strange artifacts.

Variations on Time Stacks

Of course your Time Stacks do not have to be daylight subjects like this solar eclipse which was shot with a solar filter for all the shots except the last which was taken at sunset.

Annular Eclipse Sequence [C_040079+5s]

Time stacks can also include night events like a lunar eclipse

Plan C: San Jose City Hall Eclipse Sequence

Get creative and try other Time Stacks and share with us what you get as a result via comments!

Want to see the technique preferred by Matt Molloy, master time stacker? See his tutorial here.

Bad Bridge Behavior (2014)

This discussion applies to Windows machines in particular. We welcome your comments on whether the same problem occurs on Macs.

In Summary

Installing Photoshop CC 2014 on a Windows machine may have unpleasant side effects and one of those side effects is being forced to use ONLY Photoshop CC 2014 from Adobe Bridge.

The Details

Adobe Bridge is a rather powerful tool. In fact, we recommend it when using the Advanced Stacker PLUS. However during a live webinar recently Bridge stymied us.

Despite the release of many CC 2014 versions, there is currently no Adobe Bridge CC 2014 – the latest available is CC. Within Adobe Bridge CC a double click of a JPG or RAW file opens the file clicked in the most recently installed version of Photoshop EXCEPT if there is already a version of Photoshop running. If, for example you have Photoshop CS5 running and the most recent install is CC, then a double click would open the file in CS5 rather than CC. Adobe Bridge default file open still behaves the same way even after upgrading to Photoshop CC 2014. However other parts of Adobe Bridge do not behave the same.

The Tools -> Photoshop -> Batch operation previously worked just as described. No matter what the default version of Photoshop, using the Tools -> option would kick the currently running Photoshop and elicit Photoshop’s Batch menu. UNFORTUNATELY, The “Tools -> Photoshop -> Batch” operation does NOT work the same way once you install Photoshop 2014 CC.  With Photoshop CC 2014 installed, Tools -> Photoshop -> Batch will ONLY open Photoshop CC 2014. If you have another version of Photoshop already running, the Tools operation effort silently fails.

You can determine what version of Photoshop will be invoked by the Bridge -> Tools menu by selecting a file and doing  a “right click” and inspecting what is listed in the Open With list.

Default association

Default association

 

Also particularly unpleasant is the fact that only ONE of the Photoshop CS versions is listed as a choice in the Open With dialog even though on our windows machine we have 4 versions of Photoshop installed (CS5, CS6, CC and CC 2014). We’d love it if we could choose which Photoshop to open, but Photoshop CC 2014 confuses Windows into thinking that ALL versions of Photoshop are CS 2014. Normally in the the windows file browser you can right-click a file and “choose a default” program to open it.

Windows_ChooseDefaultPgm

Here we’ve chosen to associate a default to a PNG file.

Window_FileAssociation_Step1 The next step is to navigate to the program we want to open with by default… Here we will select the Photoshop CS5 folder, and next the photoshop.exe
Windows_SelectAssociation

After selecting photoshop.exe in the CS5 directory, we are disappointed to see the result look like this:WindowsPSCC2014_Confused

To Change Associations For Different File Types

While Photoshop does continue to make useful improvements, not all of those improvements are as easy to navigate. If you would prefer that Adobe Bridge open a different default version of Photoshop you can change the file associations within Adobe Bridge as shown. (Select Edit -> Preferences or Ctl-K).

Changing File Association

Changing File Association – click for a larger view