Posts Tagged ‘focus stacking’

More focus stacking with CamRanger

April 10, 2017

When I started experimenting with completely automated focus stacking using CamRanger, I couldn’t tell what, if anything, was happening. In fact, I wasn’t sure the process was working as advertised. So I devised a plan to photograph a simple subject (a six-inch ruler in this case) and use “focus peaking” to track what happened. By the way, it’s worth noting that my Canon EOS 5D Mark II DSLR camera doesn’t feature focus peaking, but the CamRanger app does!

During initial testing, I shot several small focus stacks. The following screen capture shows the display on my iPad mini (with retina display) running the CamRanger app; the focal plane of the lens is highlighted by red focus peaking.

Here’s a screen capture from another test, showing the final location of the focal plane (highlighted in red).

I made a movie that demonstrates what happens when CamRanger creates a focus stack. It was fun to watch the focal plane advance along the ruler as CamRanger captured the shots automatically!

The movie begins with a small focus stack using a “Large” step size (the largest increment of three options). When focus stacking is active, notice that most of the screen is covered by a translucent gray layer that prevents the user from changing settings accidentally. I cancelled the focus stack after two shots. Next I changed the step size to “Medium” and started a new stack. Notice that the focal plane of the lens begins where the last focus stack ended. The new step size is noticeably smaller.

Automated focus stacking using CamRanger (2:12)

As shown in the right side bar of the CamRanger app, I set the camera to shoot RAW plus small JPG. Both file types are recorded on the memory card in the camera; thumbnail versions of the JPG files are displayed at the top of the iPad screen. Although I usually shoot RAW only, JPG files can be transferred via WiFi faster than RAW files!

I set the CamRanger app to wait 10 seconds between shots, in order to allow adequate time for the camera to write the image files to the memory card, transfer the JPG thumbnail from the camera to the app, rack the lens to the next focal plane, and for the external flash units to power cycle.

My first finished automated focus stacks

I created a 30-layer focus stack using a medium increment. The following photo shows the JPG version of the first layer.

I used Adobe Photoshop CC 2017 to create a medium-increment focus stack using the small JPGs because they can be processed faster than RAW. The resulting composite image is shown below.

Finally, here’s the resulting composite image of a five-layer focus stack created from large increment/medium JPG photos. In my opinion, the output looks almost as good as the composite image created from five times as many layers.

Lessons Learned

  • Given a choice, run the CamRanger app on the most powerful tablet you own. I use my iPad mini rather than iPad 3 (with retina display). Although the iPad 3 screen is larger than the iPad mini, it features a slower processor. That being said, the iPad 3 is perfectly suitable for using the CamRanger app for other less processor-intensive tasks.
  • Some lenses, such as my Canon EF100mm macro lens, can be set for manual focus and the CamRanger app can still rack focus automatically. It may be necessary to set other lenses for automatic focus in order to work with focus stacking in CamRanger.
  • If possible, use continuous light sources rather than external flash units. I love me some flash triggers, but they’re not 100% reliable. If you’re shooting stills and the flash fails to fire, it’s no big deal — just shoot another shot. Not so when you miss a critical focus layer. I use a combination of two small LED light sources and a Canon Speedlite tethered to the camera by a Vello flash cable; the Canon flash optically triggers a small Nissin i40 external flash (in SD mode) used for backlight.
  • Turn off “sleep mode’ for my Canon 580EX II Speedlite. (C.Fn-01 set for Disabled.)
  • It’s challenging to determine how many layers to shoot for a given focus stack, especially when using smaller step sizes. Don’t sweat it! Simply shoot more layers by starting where the focal plane is at the end of the last focus stack. Repeat as necessary until you capture as many layers as needed.

What’s next?

Going forward, my plan is to experiment with automated focus stacking using subjects that are more complex than the ruler featured in this post. Preliminary testing suggests it could be challenging to create perfect composite images of objects that are more three-dimensional than the ruler.

Sidebar

I used QuickTime to create the embedded movie (shown above) by tethering my iPad mini to a MacBook Air laptop computer and following the excellent directions provided in How To Display your iPad or iPhone on your Mac (9:44), a tutorial video by Terry White, Adobe Evangelist.

Related Resources

Full disclosure: There are hardware/software solutions for wireless tethering and automated focus stacking that are less expensive than CamRanger. Remember, you get what you pay for!

Copyright © 2017 Walter Sanford. All rights reserved.

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Another foray into focus stacking

April 2, 2017

I used CamRanger to remotely control my Canon 5D Mark II DSLR camera with an Apple iPad 3 (with retina display). The camera was set for manual exposure and One-Shot AF. I used an aperture of f/5.6 with my Canon 100mm macro lens; I think I’ll use f/8 next time.

Apple iPad 3 (with retina display) | screenshot of CamRanger app

The CamRanger app for Apple iOS can be used to set the focus point by tapping on the iPad screen. I focused on the toy dragonfly in approximately 10 places and tapped the “Capture” button to take a photo. The following photo shows one of the resulting images, focused on the head of the dragonfly.

ISO 100 | f/5.6 | 1/200s | Manual White Balance (Flash use)

Adobe Photoshop CC 2017 was used to create a “focus stack” composite image. As you can see, most of the toy dragonfly is in focus but there are some places that are slightly blurry/ghostly. The obvious solution: Focus on more places (that is, take more pictures), although that might be unnecessary using an aperture of f/8 or smaller.

Composite image created using Adobe Photoshop CC 2017.

Going forward, my plan is to progress from manually setting the focus point by tapping on the iPad screen to using the automated focus stacking feature in the CamRanger app. Baby steps, Bob!

Tech Tips:

The following equipment was used to shoot all of the photographs in the focus stack: Canon EOS 5D Mark II digital camera, in manual mode; Canon EF100mm f/2.8L Macro lens (set for automatic focus); Canon 580EX II external flash, off-camera, in manual mode; Canon 580EX external flash, off-camera, in manual mode; and a Yongnuo YN-622C-TX E-TTL II Wireless Flash Controller for Canon plus a two-pack of Yongnuo YN-622C II E-TTL Wireless Flash Transceivers for Canon. Additional backlight was added to the scene using a Nissin i40 external flash unit (off-camera, in SF mode).

Adobe Photoshop CC 2017 was used to create the focus stack and post-process the composite image.

Copyright © 2017 Walter Sanford. All rights reserved.

Gomphidae exuvia

May 3, 2016

A dragonfly exuvia was spotted by a friend at an unknown location in Northern Virginia. This specimen is a member of the Family Gomphidae (Clubtails). Here’s the decision tree I used to tentatively identify the exuvia as a member of the Clubtail Family.

  • The specimen has a flat labium (not mask-like).
  • Antennae are club-like (not thin and thread-like, as in Aeshnidae).
  • Eyes not exceptionally large compared to the size of the head (not large, as in Aeshnidae).

Gomphidae is the second largest family of dragonflies, so it could be challenging to identify this specimen to the genus and species level.

Photo Set 1

A dragonfly exuvia spotted at an unknown location in Northern Virginia. This specimen may be a member of the Family Gomphidae (Clubtails).

Head-on view, ventral side up.

Notice the labium isn’t mask-like, that is, doesn’t cover the face of the larva/exuvia.

A dragonfly exuvia spotted at an unknown location in Northern Virginia. This specimen may be a member of the Family Gomphidae (Clubtails).

Head-on view, rotated 180°.

A dragonfly exuvia spotted at an unknown location in Northern Virginia. This specimen may be a member of the Family Gomphidae (Clubtails).

Anal pyramid view, ventral side up.

A dragonfly exuvia spotted at an unknown location in Northern Virginia. This specimen may be a member of the Family Gomphidae (Clubtails).

Head-on view, dorsal side up.

A dragonfly exuvia spotted at an unknown location in Northern Virginia. This specimen may be a member of the Family Gomphidae (Clubtails).

Lateral view, right side (facing forward).

A dragonfly exuvia spotted at an unknown location in Northern Virginia. This specimen may be a member of the Family Gomphidae (Clubtails).

Lateral view, left side (facing forward).

Photo Set 2

A dragonfly exuvia spotted at an unknown location in Northern Virginia. This specimen may be a member of the Family Gomphidae (Clubtails).

Dorsal view.

A dragonfly exuvia spotted at an unknown location in Northern Virginia. This specimen may be a member of the Family Gomphidae (Clubtails).

Ventral view.

Photo Set 3

Gomphidae-exuvia_focus-stack_Ver3

Composite image.

The preceding composite image is a stack of 11 focus layers, moving from front-to-back across the face and head of the exuvia. Notice the labium isn’t mask-like, that is, doesn’t cover the face of the larva/exuvia. Also notice both antennae are club-like and most of the right antenna (facing forward) is missing.

Photo Set 4

The following macro photo shows a close-up of the face and head of the exuvia. The photo clearly shows the flat labium doesn’t cover any part of the face. Look closely at the full-size version of this image and you will notice two movable hooks at the front of the labium (see annotated illustration); they are reddish in color and the one on the left (relative to the photo) is more clearly in focus than the one on the right.

A dragonfly exuvia spotted at an unknown location in Northern Virginia. This specimen may be a member of the Family Gomphidae (Clubtails).

24x magnification.

Most, but not all, species of Gomphidae larvae are burrowers. The specimen is noticeably dirty — perhaps that indicates this individual is a burrowing species of clubtail dragonfly.

Tech Tips:

The following equipment was used to shoot the preceding photographs:

Adobe Photoshop CC 2015 was used for minor touch-up work on the background of all photos.

Related Resources:

Copyright © 2016 Walter Sanford. All rights reserved.

In-home photography “studio” set-up

September 2, 2015

Mike Powell, a good friend and photowalking buddy, left the following comment on my last post (First foray into focus stacking macro photographs):

You might consider including a shot of your setup (maybe with your phone), to help us visualize a little better your setup. Source Credit: Mike Powell.

In response to Mike’s good suggestion, I decided to write a follow-up post featuring photos of the gear used to take the 13 macro photographs that were focus stacked to create a composite image of a toy damselfly finger puppet.

The previous post was, by design, rich with technical detail. My goal was to answer the overarching question, “How did you do that?” I chose to feature some of the macro photographs, rather than the gear I used to shoot the photos. By reminding me of the old cliche, “one picture is worth a thousand words,” Mike’s comment tells me I didn’t achieve my goal.

In-home "studio" set-up used to shoot macro photographs of a toy damselfly finger puppet, purchased from the Visitor Center gift shop, Huntley Meadows Park.

Table top used for staging photographs.

The following items are shown on the left half of the black table top, listed clockwise from the upper-left corner of the table:

In-home "studio" set-up used to shoot macro photographs of a toy damselfly finger puppet, purchased from the Visitor Center gift shop, Huntley Meadows Park.

The view from behind the tripod-mounted camera.

Yep, that’s what you think it is — a repurposed 1/2 gallon plastic ice cream container used to elevate the subject from the staging table. I placed the Qudos Video Light underneath the upside-down plastic container. An inexpensive intervalometer is shown hanging from the camera tripod.

In-home "studio" set-up used to shoot macro photographs of a toy damselfly finger puppet, purchased from the Visitor Center gift shop, Huntley Meadows Park.

Sunpak LED-160 Video Light turned on low power.

Look closely at the full-size version of the preceding photo. Notice the purple fringing that appears around the front panel of the Sunpak Video Light. The optical phenomenon is called chromatic aberration, color fringing that occurs sometimes in photographs of high contrast subjects such as the video light.

In-home "studio" set-up used to shoot macro photographs of a toy damselfly finger puppet, purchased from the Visitor Center gift shop, Huntley Meadows Park.

Close-up of several smaller items.

The following items are shown from left-to-right across the horizontal center of the preceding photo:

In-home "studio" set-up used to shoot macro photographs of a toy damselfly finger puppet, purchased from the Visitor Center gift shop, Huntley Meadows Park.

Side view showing camera mounted on focus rails.

The preceding photograph shows my Panasonic Lumix DMC-FZ150 superzoom digital camera mounted on a Neewer Pro 4-Way Macro Focusing Rail Slider using a couple of Manfrotto quick-release plates. Although the quick-release plates aren’t essential gear, they make set-up and tear-down easy and fast.

The camera was set for manual focus: For the first photo, coarse focus was achieved by physically moving the tripod into position; fine focus was achieved by racking the focus rail back-and-forth until the subject appeared to be in focus in a magnified view shown on the camera LCD. Next the focus rail was locked down. An inexpensive intervalometer was used to press the camera shutter button without causing camera shake. Manual focus method No. 2 was used for all remaining focus layers (see “Related Resource,” below).

In-home "studio" set-up used to shoot macro photographs of a toy damselfly finger puppet, purchased from the Visitor Center gift shop, Huntley Meadows Park.

A small toy damselfly “perching” on translucent plastic.

The toy damselfly was placed on an 8″ square sheet of white 1/8″ thick 40% translucent acrylic plastic and lighted from below using a Qudos Video Light (not shown). I didn’t realize how far the toy damselfly’s nose sticks out ’til I looked at the preceding photo — no wonder its nose is slightly out of focus in my composite image!

A small plastic ruler is shown for scale. Anyone care to guess why the ruler from the Calvert Marine Museum is seven inches (7″) long rather than six inches?

Bottom line: The set-up looks and sounds more complex than it is in reality. Don’t let this deter you from experimenting with focus stacking macro photographs — it’s fun and the results can be rewarding!

Related Resource: Focus Stacking Tutorial for the Panasonic FZ200 and Raynox Close Up Lenses, a YouTube video by Graham Houghton. Two techniques for using manual focus are described in the video. I used the second manual focus method in order to fix the camera angle/position (15:52/25:58).

Copyright © 2015 Walter Sanford. All rights reserved.

First foray into focus stacking macro photographs

August 31, 2015

On 30 August 2015, I spotted a large, mutant damselfly at Huntley Meadows Park. Kidding! It’s actually a small toy damselfly finger puppet that I bought at the HMP Visitor Center gift shop last year.

I used a Raynox DCR-250 close-up filter with my tripod-mounted Panasonic Lumix DMC-FZ150 superzoom digital camera to shoot 13 focus layers, moving from front-to-back across the head and thorax of the toy damselfly. The toy was placed on an 8″ square sheet of white 1/8″ thick 40% translucent acrylic plastic. The subject was lighted from the side using a Sunpak LED-160 Video Light, and from below using a Qudos Action Waterproof Video Light for GoPro HERO by Knog. In retrospect, I should have used a third light source to illuminate the subject from the front, such as an off-camera external flash unit.

The Raynox DCR-250 close-up filter is a relatively inexpensive solution that enables my Panasonic superzoom digital camera to be used for macro photography. Set-up is quick and easy — the filter simply clips on the front of the camera lens using a universal adapter, just like a lens cap. I use a 52mm-to-43mm step-down ring to mount the Raynox close-up filter more securely. (See “Editor’s Note” at the end of this post.)

Since depth-of-field is very shallow with a close-up filter, I used Adobe Photoshop CC 2015 to create the following composite image in which the entire subject appears in focus.

Mutant-Damselfly_focus-stack_Ver2

Composite image (13 focus layers)

Look closely at the full-size version of the preceding composite image and you can see the toy is a little dusty — I should have used my Giottos Rocket Blaster Dust-Removal Tool before I started shooting photos!

The Raynox DCR-250, like other close-up filters and extension tubes, reduces the minimum focusing distance between the lens and subject. Each focus layer was taken using 6/24x zoom telephoto at an estimated working distance of six-to-10 inches (~6-10″) from the subject. It’s worth noting the in-camera manual focus digital distance scale incorrectly showed the working distance was between three and six feet!

A toy damselfly finger puppet, purchased from the Visitor Center gift shop, Huntley Meadows Park.

Focus Layer 1 (of 13) | ISO 100 | 29mm | f/6.3 | 1/8s | -0.33ev

The composite image isn’t perfect. For example, the nose seems to be slightly out-of-focus in Focus Layer 1. Also notice there is some “flaring” (for lack of a better term) on the sides of the thorax shown in both Focus Layer 1 and 13 that was retained in the final version. Overall, not bad for a first effort.

A toy damselfly finger puppet, purchased from the Visitor Center gift shop, Huntley Meadows Park.

Focus Layer 13 (of 13) | ISO 100 | 29mm | f/6.3 | 1/5s | -0.33ev

Imagine how cool it would be to create a focus stacked image of a real odonate! Easier said than done. I’m exploring several solutions, one of which seems do-able in the field. In the meantime, experience gained from my “studio” experimentation should help when it’s time to photograph several odonate evuviae I have collected.

Related Resources:

Editor’s Note: The generic step-down ring I use is currently unavailable from Amazon. A more expensive version of the step-down ring is available from B&H Photo.

Copyright © 2015 Walter Sanford. All rights reserved.


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