Category Archives: Composites

Time Stacks

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.


  • 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.

Back In The Saddle

It is premature to say we are back in the saddle after a long hiatus, but Steven Christenson did recently join forces with his mentor: Harold Davis for another “Dark of the Moon” Shoot in the Eastern Sierras. We have plans in motion to do more workshops like this beginning in 2018 (planning date is early September).

Harold and Steven at Lathe Arch. Photo by Julian Köpke.

As is our custom, we arrive early and re-scout our planned locations during daylight – as well as checking other potential locations. Not every location is suitable for our participants. Some locations are too dangerous, or too difficult to reach due to vehicle clearance or hiking distances or too small to accommodate participants. One pretty place that fails some of those tests is Steven’s favorite spot he calls Pointy Land.

Pointyland Redux

Three shot panorama of “Pointy Land” in Alabama Hills, California

Give Us A Tip, Will You?

On the optional last night we went to a place that while large in area and easily accessible is not able to accommodate many photographers jockeying for the premium views. Such a place is the Lady Boot Arch below.

It seems appropriate to leave you with a processing tip (thanks for asking). The shot below was created from two exposures. The filename we gave it is LaserBoot_C-5550+75.psd The name serves to identity both the photo AND the two images (C-5550 and C-5575) that we used to create it.

Laser Boot

Layers and Adjustments

Here is what the processing looked like from the “Layer Palette” of the image above.

Alignment Headaches

The tricky part in assembling the images was that the ball head had a problem. The head was not stable and it rotated left and right slightly between shots. We had to figure out how to align the images.  Here are some things that DID NOT work:

  • Using Lightroom Photomerge. (“Sorry at least 40% image overlap must be present”)
  • Using Photoshop Merge to HDR Pro. “Composite mode” balked that the photos could not be merged, while the “Automatic mode” produced an image like the one below.
  • Using Photoshop Align Layers – “Not possible”

Photoshop could not figure out how to align the two nearly identical images. The laser and lit foreground confused it.

So how did I get them to align? Selection, slight rotation and “nudging”.  Since there was a lot of green bleed on the laser image (C-5575), I masked off that bleed – look at the layer mask on the bottom image in the “Photoshop Layers” image above.

Merging Images

To make it simple to merge the laser image with the light painted foreground, I:

  1.  Used the “Quick Selection tool” on the sky of the laser image,
  2.  Deleted the sky. Delete? Yeah, just the delete key. That operation makes the selection go bye-bye and become transparent. The same effect can be done using the Eraser tool, but that is just too much work!
    Note: I should have first duplicated the layer in case I needed to do more work on it.
  3. Set the lighted foreground (C-5550) to Lighten mode. Removing a potentially conflicting sky from the image below results in an accurate sky that did not need much cleanup.

We show one of the adjustments (Sky Color Correction). The actual curve(s) to use depend on the sky you start with. A careful observer will notice a lot of Curves Adjustment Layers. Curves can do almost everything all the other adjustments can do (lighten / darken / contrast / white balance and much more) so I recommend learning how to use Curves. Indeed we use curves so much that the Advanced Stacker Plus has a dedicated hot key: F9 to create a custom contrast enhancement adjustment layer.

Once the masking and adjustments were all just as I wanted, the almost last step is to do Ctl-Alt-Shift-E (Cmd+Alt+Shift+E for Mac people). That finger twister is a little noticed but VERY handy shortcut that does the same thing as “Flatten image” – but it does the flatten to a new layer and leaves everything else alone. If for some reason the finger-twister does nothing, be sure to select a visible document layer – not an adjustment layer. After the magic twister sequence, drag the newly created layer to the top.

I name the final layer: combined/heal. On that layer any distractions can be cleaned up using the spot healing brush. In Laser Boot photo there were a few hot pixels and some distracting marks on the rock that needed attention.  If there is some significant noise reduction to do the heal layer can be cloned again and Noise reduction applied.

A Parting Image

We like this image created the second night of the workshop. This is a conventional star trail, but apparently Flickr-ites loved it. It became Steven’s most popular image ever.

Reaching for the Sky

Not surprisingly, the image was created using the same foreground/background blending technique described earlier.  The background was stacked with Advanced Stacker PLUS. But there was not any movement, so it was easy to combine the two shots.  If you’d like to see another gorgeous view of this landscape from a different perspective, check out Harold Davis’ shot: Forgotten Kingdom (and read about it on his blog)

Steven in Galen’s Arch with composite Milky Way background. Foreground by Julian Köpke.

Wait, looks like we have two more images for you. The image above is a complete cheat: a combination of an iPhone daylight shot by Julian Köpke, and one of the pieces of the Milky Way we shot for the image below. We make no guarantee that the sky can be oriented like that in the arch. We included the above shot because it used the same foreground/background blending technique we just discussed – but with a bit more manual mask painting.

The image below is a Milky Way from horizon to horizon. North East is at the top, South West at the bottom.  We included this image here because … we like it.

Overarching Majesty

One of the reasons we like this image is that the Milky Way is natural – not processed to death.  We could have cloned out the camera, but thought it provided a nice context.

We Are Always Tweaking

Original Publish Date: 12-November-2015
Last Revision: 12-November-2015

When we get questions on our older columns, we often answer them directly and update the articles to reflect new information. For example, when we originally published our three part series on Finding and Photographing the Milky Way we had no clue they would be our most read articles. Over time we added more charts, and tables, including a table listing when the best time is to spot the Milky Way – alas, not October through February.

The Milky Way Series

Pointy Land
The articles in the Milky Way series are:

Meteors and Meteor Showers

Celestial Slasher [C_224-9234]

We have also made periodic updates to our articles on photographing meteors and meteor showers.  We point this out because the best shower of the year is the Geminids and that shower occurs December 12-14.  Start planning right now!

To help you out, we have begun adding “Original Publish Dates” and “Last Revised” dates to our articles.  Of course most of the principles we have written about are timeless.

Geometry and The Moon

Please do not run away. We are about to use adult language here. For example we will be using the word trigonometry. Still here? Good.  Here is a very pedestrian looking lunar eclipse photo taken with a 280mm lens*, cropped.

Near and Distant Neighbors

Very Ordinary Photo of the Lunar Eclipse with the planet Uranus in the lower left.

This past lunar eclipse several of us put our heads together to try to come up with a more creative photo than the one above. We had a trigonometry problem, however. On the West Coast the last moment of totality occurred at 4:24 AM PDT. We were brave enough to be out at any time of night – even if it meant extreme sleepiness in our day jobs but our problem was that the lowest the moon would be in the sky at the last bit of totality was 32.6 degrees above the horizon. We determined that angle using Stellarium, by the way. Unfortunately there is pretty much nowhere to go to get a nice large moon near an interesting object when the moon is almost 33 degrees high.

Wait: Why do we want the moon and the object to be similarly sized? Here is why… we want the moon to be noticeable like the Fantasy version below, not merely “present” like the real photo on the right. Even bigger would be better, right!?


Notice above right (Reality) and below how tiny the moon is compared to the building in the foreground?  Indeed, if you see a photo taken from anywhere on the West Coast where the eclipsed moon is significantly lower in the sky or larger than shown against foreground, you know it has been “photoshopped“.

Plan C: San Jose City Hall Eclipse Sequence

In short, it is nigh impossible to get the large moon effect with an altitude (angle) of 32 degrees here is why:

Calculating the Angles

Calculating the Angles

Just how far away do we need to be in order to get the moon the same size as an object of interest:

114.6 x object size

In other words, an object that is one foot tall, requires us to stand 114.6 feet away to make the 1/2 a degree angular size of the moon the same angular size as that 1 foot tall object.  The number “114.6” is from this calculation:

1 / TAN (0.5 degrees)

Yeah, that is trigonometry. Using still more trigonometry it is possible to calculate how high above the horizon a 9 inch tall object has to be so that it is “moon sized”.  We did that for you in the “Calculating the Angles” diagram above. Once you calculate the distance from the camera of 85.9, you can multiply that by the sine of the angle to calculate a height of about 46 feet! Here is the trigonometry:

Height = 85.9′ * SIN (32 deg)

You can go one step farther and calculate the distance from the object with ‘distance = 85.9 * COS(32 deg)’.

Of course after all that calculating you will still need to find a location, have contingency plans for weather and so on. At StarCircleAcademy we have built some tools and put together materials to help in all these endeavors.  We teach these things in our NP111 Catching the Moon Webinar.

The Road To The Temple

Below is where we ended up. This image is from our friend and co-conspirator Andy Morris.

Lunar Eclipse over Temple by Andy Morris of PhotoshopScaresMe

Four of us plotted and schemed to get an interesting shot. Above is Andy Morris’ result.  Click the image and you can read a great article about how he created the shot using Photoshop Skills at his site: In fact, it’s a great article which we strongly encourage you to read. You’ll learn how he composited the images together in Photoshop as layers.

The Long Conversation to Pick a Location

Andy has more details including how alcohol played a part in the process. Mostly I, Steven, was the wet blanket explaining why the geometry was all wrong.

  • The Stanford (Hoover) Tower looks like it is shrouded in trees from the needed angle
  • Bank of Italy (formerly BofA) in SJC doesn’t work
  • The main problem with the wind turbines is that the angle to the top of them is something around 12 degrees above the horizon which is 40 moon diameters below the eclipse.
  • Here is why the GG Bridge doesn’t work…
  • This seems to be the best solution I could find: the Coit Tower…
  • Darn. It would appear the coast is out. Forecast calls for Fog from SF to HMB
  • This might make an interesting foreground (see below)… Somebody want to check if they will mind us being on their property in the wee hours?

*Ok, we lied, it was actually a 70-200mm lens with a 1.4 TC on a full frame camera, but the net is the same: 280 effective mm focal length.

Where did you go and what did you get in your planning efforts?  Post a comment and link below… we’d love to see what you came up with!