Category Archives: Composites

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!?

N_281-608714+C_281-8150

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: PhotoshopScaresMe.com. 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!

Trimming away the Excess (Photoshop)

I created a problem for myself twice and with the Total Lunar Eclipse coming in April, 2014 I suspect I’ll be creating the same problem again.  I wanted to record a time-lapse of the May 20, 2012 Annular Solar Eclipse as well as the June 5, 2012 Transit of Venus.  I used a solar filter and an Equatorial Mount to help me track the sun. Unfortunately getting a good polar alignment during daylight is beyond my skill set. Without good alignment I had to manually repoint the telescope rather frequently. It is not necessary to understand any of the gobbledygook you just read except to know that the sun was MOVING from frame to frame – see the image below.  With all that movement, a time-lapse looks like a jitterbug dance.  In fact, this artsy composite shows just how much the sun moved around in my frame – that is, all over!

Solar Art

Annular Solar Eclipse with un-centered and trimmed frames. AKA Solar Art the “dots” on the sun are large sunspots.

My friends suffered from similar problems and each of them undertook automated solutions to the problem using Photoshop or something similar.  My goal was to solve the problem in a generic way and along the way I learned some useful additional Photoshop tricks.

The Solution

I used the trim feature of Photoshop.  You can find Trim under Image -> Trim.

Trim makes note of the current value of the upper left (or lower right) pixel. It then creates a selection that includes all of the rows and columns that have the same value and inverts the selection. Finally it crops off all of the selected area into the smallest possible rectangle.

An easy way to think of this is: imagine a dark photo with a white frame around it.  By using “trim” the entire white frame will be cut away.  The same approach works if the frame border is black, blue, transparent, and so on.

But there is a catch!  There is no tolerance setting for the trim value so whatever needs to be trimmed must be an exact color match. Unfortunately this presents a problem because even in a photo of a black sky, the black areas are not uniformly black.  Some values may be 0,0,0 but others 1,2,1.  And then there is noise!  Even though you may not notice a difference between two adjacent pixels trim only operates on those pixels that have EXACTLY the same value as the upper left or lower right.

To get trim to work in a reasonable fashion, therefore, we must turn all of the almost black pixels into black (or some other color).  I feel a Photoshop trick coming on here. Our trick is to use a duplicate layer and adjust it to cause it to trim the way we want. We will discard the duplicated layer when we are done.

Trim-o-Matic

  1. Open the image.
  2. Duplicate the image as a new layer.
  3. If the duplicate layer is a smart object, convert it to a raster layer. (To convert a smart object to a Rasterized Layer, open the layer palette, right-click on the duplicate layer and select “Rasterize Layer”)
  4. On the duplicate layer use
    “Filter -> Noise -> Dust and Scratches” with Radius = 3 and Threshold = 3.
  5. Make sure your foreground color is black (x is the hot key).
  6. Use the “Fill” tool (paint bucket) with tolerance set to 40, Opacity 100%, Mode = Normal and no options checked.  Click the extreme upper left pixel. Fill will replace all of the outer area with black. You may want to click multiple times.
  7. If you have some areas that are brighter than the object, you may also want to apply a brightness and contrast adjustment.
  8. Use the trim function on the current layer with all boxes checked and “Top Left Pixel Color” selected.
  9. Trimming changes both the working layer and the original layer below it.
  10. Discard the working layer.

Here are the steps in illustrations.

Rasterizing a smart object

Rasterizing a smart object

PS_DustAndScratches

Dust and Scratches settings

gs_2014-03-23_084744

Filling with black

Filling with black (might need to repeat this)

Dust and Scratches + Fill may not be enough. Fortunately the duplicate layer can be severely adjusted if needed since it will be discarded.

 

Trimming Tool

Trimming Tool

Select Areas for Trimming

Select Areas for Trimming

 

After Trimming

After Trimming

Delete the Extra Layer

Delete the layer that was created for the sole purpose of trimming

 

What If It Crops Too Tightly or Inconsistently?

This set of steps written as an action can be used to automate the process of trimming. There are still a few remaining problems to work out. Sometimes after trimming the total horizontal or vertical pixels of the object the resulting image size will differ by one or two pixels. To solve the “dimension” problem, the simplest method is to use Image -> Canvas Size. Set the canvas to about 20 pixels larger in each direction. Select “center” (the dot in the middle next to anchor) and set the fill color to match the background.

Expand the canvas and center the image

Expand the canvas and center the trimmed image

After Trim and Canvas Size

After Trim and Canvas Size

The above procedure will work quite well for animating a sequence of sun or moon shots – except for eclipses.  Eclipses don’t work properly because an edge of the sun or moon disappears leaving no edge to properly orient with the others.

What can we do when we no longer have constant edges to align with?  Divide and conquer! Instead of trying to apply the same action to all of the images, we will can change edge we select when enlarging the canvas size. We can orient sets of images based on which part of the image remains constant.   Which edge or corner should you pick? Pick the edge that stays the same (if there is one!)  For an Annular solar eclipse, at least one of the directions will never be darkened – that’s the one to pick!  The annular eclipse sequence shows that the upper left limb and lower right limbs of the sun remain present in all of the shots.

Field Rotation

There may still be another problem: Field Rotation. If you’re thinking that perhaps this has something to do with improving crop yields on a farm, sorry to disappoint you. The Annular Solar Eclipse and the Transit of Venus were events that took place over a period of from 3 to 5 hours.  During that period the earths rotation causes the sun, moon and stars to move. It also causes them to “turn” as viewed from terra firma.  You can see this for yourself if you watch the full moon from moonrise to moonset. At moonrise make note of the orientation of the “man on the moon” and compare it with the orientation at moonset. Go ahead and watch. I’ll wait for you.

So what do you do if you have this field rotation?  Either live with it and accept that the animation won’t be entirely accurate, or you’ll have to do a much more complicated set of operations by progressively rotating the images.  That’s more than we want to tackle, so you’re on your own for that!

The Results

The Annular solar eclipse sequence. The Abstract Solar Art image at the top of this article was created from the un-centered and trimmed frames. Obviously this wasn’t perfect – in part due to clouds and shimmer in the atmosphere.

Not seeing the above video? It requires FLASH, so click here to watch.

Obviously this one had some trimming errors… and nasty dust on the sensor but this is the once in a lifetime Transit of Venus.
Not seeing the above video? It requires FLASH, so click here to watch.