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Blending exposures for greater depth of field

Wednesday, April 7th, 2010

I recently blogged about my winter project of shooting agaves locally.  In prepping for this shoot, I wanted to make sure the entire plant was in focus, and I knew using my depth of field table, that it was essentially impossible using my 24-105/4 lens:

  • The example I’ll use in this post was shot from a distance of ~2 feet at a focal length of 47mm and aperture of f/10; using my Canon 30D, my total depth of field is 0.2 feet.  That isn’t nearly enough to get the entire agave in focus.

To circumvent this problem, I wanted to take multiple exposures at different planes of focus then blend them in Photoshop to produce an image that is entirely in focus.  The problem I was having is that by doing it manually, I couldn’t find a self-feathering method to make the blend look “clean”.  Fortunately Photoshop CS4 has an image blending feature that mostly automates the process for you.  I’ll describe my experience using one of my agaves as an example.

The first step was to take the shots.  I composed the shot like I normally would, and took one or two tests to make sure the amount of fill flash looked about right.  To get the proper diffusion, I taped a piece of white printer paper to my 430EX and underexposed by ~ -1.5 stops EV.  After the shot looked “right”, I took three exposures, each one at a different plane of focus:

While these three images do not look much different, you can see subtle differences; by looking at the main floret protuding from the plant, you can see that it is increasingly out of focus as you scroll through the images.

Once I got home, I converted the RAW files in a way that looked good to my eye; when you are working with multiple exposures, make sure to ‘synchronize’ all of your adjustments so all your shots look the same!  This is easy to do in ACR.  Then, I opened the files in Photoshop CS4.  The first step is to load the files into a stack and align them.  You can do this by going to File–>Scripts–>Load Files into Stack

Select the option “Add Open Files”, and check the box that says, “Attempt to Automatically Align Source Images”.  This will load your base images into the script, and will align the images, because even if you shot from a tripod (using mirror lock-up) there will be some slight differences between the images.

Once the script runs, you will want to select all three layers on the layers palette and go to Edit–>Auto-Blend Layers…

Select the option to stack the images and make sure the “Seamless Tones and Colors” box is checked.  This will produce a perfectly feathered and mostly blended image using your base images.  At this point, I suggest you inspect the image at 100% to make sure it is indeed perfectly blended.  On some images, the script has done a great job, and on others I’ve had to reload some images as separate layers and mask off the “in focus” part.

Even if it doesn’t work perfectly, this method will get you most of the way there.  If you like the result, you can flatten the image and edit as you normally would.

Agave attenuata, blended and converted to black and white

Agave attenuata, blended and converted to black and white

There are times you may not necessarily need to use this method; for instance, sometimes simply stopping down to f/16 or f/22 may get you the depth of field you need, but remember, as you stop down, you are losing resolution.  Thus, shooting at a wider aperture and blending exposures can be beneficial if you plan on printing the image.

Posted in Photoshop, technical, technique | 1 Response »
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Abstract Wild Animal Park photos

Monday, April 5th, 2010

A few posts ago, I talked about a great day at the San Diego Zoo’s Wild Animal Park.  Its a fantastic place to visit, but with large crowds and harsh midday light, photographing animals can be difficult.  Maybe I’m just in an abstract mood lately, but I found a lot of interesting patterns in bird feathers, etc.  One particular shot I liked was of a Chilean Flamingo (Phoenicopterus chilensis), which I’ve honestly never found to be a photogenic bird (at least not in captivity).

By underexposing the image by 1 2/3 stops, I was able to largely blacken the background, and introduce some contrast to the contours of the feathers.  That allowed me to boost the vibrance and saturation a bit, giving an eye-popping splash of color to the Flamingo I’ve always struggled with.

Flamingo feathers, detail

Chilean Flamingo, detail

Not only have I been in an abstract mood lately, I’ve also been in a black and white mood.  Thus, I converted this to black and white as well, really cranking the red channel up to make it contrasty.

Flamingo feathers, detail black and white

Black and White

I like both of these a lot, for different reasons?  Do you have a favorite?  I’d love to hear about it in the comments!

Posted in General, Photoshop, technique | 2 Responses »
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House on Fire ruin–a vertical panorama

Monday, February 8th, 2010

In my last post, I discussed a few techniques that can be used to effectively shoot panoramas.  All of my examples were of grand landscapes, and they were all landscape-oriented panoramas.  I want to use this post to point out another time you can shoot panos to yield great results.

Last November, we visited the Cedar Mesa area near Blanding, Utah.  Since we were limited on time, we chose to visit a familiar and often photographed Ancestral Puebloan ruin that’s been nicknamed the “House on Fire” (also called the Flaming Roof ruin).  I blogged about that visit here, in November.  While at the ruin, I envisioned someday wanting to print it very large, and wished I had a medium format camera with me.  Additionally, I really wanted to emphasize the “flames” exiting the roof of the ruin.

So, I took 3 landscape-oriented images, but rather than putting them next to each other, I stacked them on top of one another,  thus producing a larger image.  If you click on the image, you’ll see a larger version–the detail is amazing!  That said, it would look even better printed on canvas over your couch :)

A view of an Ancestral Puebloan ruin near Cedar Mesa, Utah

"House on Fire" vertical panorama, Utah, November 2009

Posted in General, locations, technical, technique, utah | 2 Responses »
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Shooting panoramas with minimal equipment

Saturday, February 6th, 2010

As a photographer, or even a nature lover, you’ve probably stood staring at a wide vista wondering how you can possibly do that view justice in your photographs.  Maybe you’ve even wanted to be able to print that picture large to give a room in your home the same feel as actually standing there.  Have you ever thought about taking multiple images of a scene and stitching them together into a panorama?

Shooting “panos” has become more popular in the last few years with the advent of point-and-shoot digital cameras that stitch the image in-camera for you, but if you want to shoot a panorama with your SLR, there are some things to consider.  First, and this should be a no-brainer, pick something interesting to shoot.  It may look impressive as is, but if you pick out something with substance, it will look even better!

So you’ve got your vista picked out.  Now what?  In my experience, the key to producing quality panoramas is making sure your tripod is level.  If this is the case, you will have much better luck at the stitching process.  I have used two different methods to level my gear; the first is via a 2-stop process that’s super cheap.

My tripod does not have a built-in bubble level, so I start by removing the head, and placing a bubble level (~$3 at Ace Hardware) on the tripod.  Tinker with the lengths of your tripod legs until you level the tripod.  Now, put your head back on, and you’ll see that it can rotate on a level base.

using a bubble level to level my tripod

By removing the head and using a spirit bubble level, I can make sure my tripod head is rotating on a level base.

The second, and more recent, method I’ve used is by putting a leveling base on my tripod.  I use the Manfrotto 438 leveling base, but other companies like Acratech also make them.  They’re more expensive than my first method, but they’re way faster and you don’t have to fiddle with your tripod legs.  To level your camera on your tripod use a hot shoe level like the Jobu Designs Dubble Bubble level.

tripod head with manfrotto 438 leveling head

My tripod head can be leveled easily and quickly using the Manfrotto 438 leveling base.

level and set up for shooting panoramas

After leveling my tripod head, I level my camera on the tripod using a hotshoe level.

OK, now you’re level.  The rest of the pano practically shoots itself.  I usually work from left to right, making sure to overlap my images by anywhere from ~1/3-1/2.  This makes for a lot of images (many of mine are 12-15 images) but you’re almost sure to get a better stitch at the computer.

A couple of other things to consider before we discuss stitching:

  • To shoot vertical or horizontal…that is the question.  In stitching, you’re almost guaranteed to lose a little of the top and bottom of your images because the software will correct for barrel distortion.  Because of this, I almost always shoot my panos in a vertical orientation.  That way I’m left with an image that is a little more proportional, instead of something VERY long and skinny!
  • Just like with any shot, sharpness matters.  When I shoot panoramas, I almost always use a cable release and set my camera to shoot in mirror lock-up mode.  This reduces any possible vibration, hopefully ensuring a better stitch.
  • Do not change your focus or any camera settings while shooting your panorama.  However, consider bracketing your shots.  That way you have more to work with at the computer, and you can even consider making an HDR panorama (let’s save that for another blog post, please).
  • I haven’t addressed the problem of parallax yet.  Unless you are rotating on the nodal point of your lens (or using a pano slider), you will have parallax issues if anything in your pano is closer than ~10-15 feet.  The cheap solution is to make sure trees, rocks, etc are further than ~10-15 feet from my camera, and that seems to work to subdue parallax.  The obvious downside to my method is that you’re constrained as to your compositional choices.

So, now you’ve got your image files, and you’re back at the computer.  Can you simply align them in Photoshop manually, then crop the canvas down to its final size?  I think this works for most people ~1% of the time (I’ve managed to do it once, and I’m 99% sure it was dumb luck).  Every other time, the barrel distortion, as well as other factors, will necessitate the use of software to help you stitch your images together.

Panoramic photograph of Zabriskie Point at sunset, Death Valley National Park, California

Dumb luck. I stitched this 4-image pano together manually--I've never gotten it to work since.

For stitching panoramas, I use the software package Panorama Factory.  I like it because it has a fully automatic mode, which should work really well if you leveled your rig properly and provided enough overlap between images.  Alternatively, Panorama Factory allows for various levels of manual stitching, letting you define stitching points, and for the occasional difficult to stitch image, I like that mode a lot as well.  If you are interested in shooing HDR panoramas, Panorama Factory will stitch different sets of exposure identically so they overlay perfectly.  I have to admit that I’ve tried this once, and it didn’t work quite as smoothly as I’d like.  I’ve found that using the auto-align feature in Photoshop CS4 works well before blending images.

So, that’s basically it.  This tutorial was meant to get you taking beautiful panoramas using a minimal amount of equipment.  I hope you enjoyed it.  Feel free to add to the comment section if there’s anything I missed, or needs corrected.  Hope you can find this useful!

A panoramic photo of the Ritter Range, Sierra Nevada, California

An 11-image panorama of the Ritter Range, Sierra Nevada, California

    Posted in General, Photoshop, california, hdr, technical, technique | 8 Responses »
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    The evolution of an image, and the value of critique forums

    Saturday, January 30th, 2010

    Like any artist or hobbyist, photographers spend a lot of time learning skills to make themselves better–they want to make their images better, they want to better define their vision, and, alas, they try to make their websites better too.  In the midst of all the things out there to help you improve your photography, a very simple move you can make is to start participating in an online community that includes image critique forums.  Both Bret Edge and Justin Reznick have recently blogged on this topic, but I wanted to throw my $0.02 in, with a slightly different twist.

    I began participating in photo critique forums over at Photo.net in 2005, not long after I started shooting.  At the time my images were pretty bad–by all measures, they simply weren’t that good.  While I did receive some constructive feedback, I mostly got images bashed by non-nature photographers.  They weren’t trying to be mean, but as I said, the images were pretty bad.  However, in 2006, I discovered Naturescapes.net and began participating in earnest.  My photographs, well, they still weren’t good, but I quickly became part of a community that helped me learn to improve not only my technique behind the camera, but also my post processing skills as well.

    There are many important steps you can take to help improve your photography, and I believe that participating in a forum is one of them.  If you decide to participate, you SHOULD expect to put in just as much as you get out of it.  In other words, you need to participate, not just post a photo now and then, expecting everyone to fix your problems for you.  Also, you SHOULD feel free to ask questions.  In my personal experience, the forums I participate in are filled with people way more knowledgeable than I am, and I know I’ve looked like a doofus more than once with my questions.  While they may be snickering, people are always very nice in answering questions.  You also SHOULD have fun with it.  Although we are critiquing others’ photographs, forums are really a celebration of what we love doing: photography. Embrace that.

    That said, if you decide to participate in a forum, you SHOULD NOT take it personally if someone says they don’t like one of your photos.  Ideally, that person would give you some reason as to why they don’t like it, but if they don’t it shouldn’t matter.  Photography–like any art form–is highly subjective, and if someone says s/he doesn’t like it, it shouldn’t stop you from liking your photo.  Beauty in photographs goes way beyond the surface, and viewers cannot always detect the special meaning behind a photograph. With that in mind, you SHOULD give critiques as you would want to receive them.  Not only will receiving critiques make you a better photographer, critiquing others’ photos will help that as well.  In that sense, participating in a forum will help crystallize your own photographic vision.  Finally, you SHOULD NOT be intimidated or threatened by other peoples’ outstanding images (yes, I know of people who feel very threatened…that for every good image someone else makes, they lose business….hogwash).  I feel honored to be able to share my work with these fantastic photographers; their work continues to inspire, motivate and humble me.  That’s the way it should be: photographers should encourage and inspire one another…not compete.

    So what does the title of this post have to do with all this?  I write the above because I know what a valuable resource photography forums are, and I’ve just had (yet another) experience that proves it to me.  Last November, I made a quick run out to Joshua Tree National Park, with the intention of photographing Arch Rock.  That night, I took a star trail image, with the arch as the main subject, but I could never get it to work for me…something about the processing just looked “off”.  Last weekend, I saw a similar image of another arch, and thought, “Hey, I’ve got a shot very similar to that…maybe I can get it to work for me!”

    When I got home, I pulled up the RAW file and processed it.  I wanted the arch to have a very warm feel, as I’d painted it with my headlamp, and I wanted it to stand out against the sky.  What I ended up with was a cool effect, but not what I remember seeing.  I posted it to Naturescapes.net and, while everyone agreed it looks cool, it just seemed a little too bizarre.

    Arch Rock at night, Joshua Tree National Park, Californi

    Attempt 1, Joshua Tree National Park, California, November 2009

    Even with city lights nearby, I do not remember the sky looking that golden…er…pumpkin…that night.  While it occurred to me to use some layer masking, Alister Benn made some invaluable comments in guiding me on re-editing this image.  Alister is a master of night photography, and with his comments in hand, I re-edited the image, really making it pop.

    Star trails over Arch Rock, Joshua Tree National Park, California

    Star trails over Arch Rock, Joshua Tree National Park, California, November 2009

    What I didn’t do is make a bombastic, unrealistic image from a RAW file.  I used valuable comments from a critique and discussion forum to process an image so that I had a realistic representation of the scene.  Many thanks to Alister, and to all my online friends for making for making this a great community of photographers!

    Posted in General, Personal, national park, technique | 6 Responses »
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    Cross bedding abstract, Zion National Park

    Thursday, January 14th, 2010

    Sedimentary rocks are normally deposited as horizonal layers. Even when folded or tilted by faulting the originally horizontal layering is obvious. Upon closer examination, however, you may see very fine layers (usually 1 to several mm thick) that are at an angle to the main bedding. These tilted layers contained within larger layers are termed cross bedding.

    What a mouthful right?  As sandstone is formed, sand is laid down, either by prevailing wind current, or water current.  However, over geologic time, those currents shift, causing sand to be laid down in a different direction.  What you get is cross bedding.  I love all the cross bedding in Zion National Park and thought it would make for a good abstract photo.  To make this, I intentionally underexposed the photo by ~1 stop, to emphasize the shadows, then I converted to black and white in Photoshop and applied a very light tint to the image.

    Cross bedding abstract photo, Zion National Park, Utah

    Cross bedding abstract, Zion National Park, January 2010

    You can see all of my Zion National Park images here.

    Posted in national park, technique, utah | 1 Response »
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    The beauty of star trails

    Thursday, November 5th, 2009

    I’m hoping sometime soon to write a blog post about star trails, but until then, I’d like to share an image from my recent Sierra Nevada trip.  This is similar to one that I posted earlier, but instead of showing static stars in the night sky, it shows star trails, over the course of about 25 minutes.

    Mobius Arch startrails, Alabama Hills, CA, October 2009


    Posted in california, sierra nevada, technique | 2 Responses »
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    A visit to the aquarium

    Saturday, October 17th, 2009

    Yesterday my office mate and I visited the Aquarium of the Pacific in Long Beach to scope out potential field trip activities for our Zoology students.  I was able to take along my camera and photograph some of the unique life they have there.  This type of shooting carries with it several difficulties, including low light (I shot at ISO 1000 or great the entire time) and curved glass on displays (autofocus has a hard time with this, I found out).  However, its also really fun to shoot here because of the huge diversity you get to photograph in a very short time.

    Angel FishCopperband Butterflyfish, Aquarium of the Pacific, Long Beach, CA, October 2009

    Sea JellySea Jelly, Aquarium of the Pacific, Long Beach, CA, October 2009

    I also had the opportunity to play with some really fun abstract images at the aquarium as well; something I don’t get a chance to do very often.  This image is an intimate shot of a sea anenome:

    Sea Anenome AbstractSea anenome abstract, Aquarium of the Pacific, Long Beach, CA, October 2009

    Over the next few days, I’ll share some more images from this really unique and fun location.  We’ll be visiting again next month, so the lessons about shooting under these conditions can be applied again as well.

    Posted in california, locations, technique | 1 Response »
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    Pines & Grass

    Thursday, October 8th, 2009

    We happened to plan our family camping trip to the Tioga Pass area on the same late August weekend that a front was passing through, so all of my sunrises (and sunsets) were horrendously windy.  Rather than curse the lack of calm water (which I admittedly did a little of), I was struck by the way the pines tended to stand tough against the wind, while the grass was swept about.  I tried to capture that contrast with this image:

    Pines & Grass, Tioga Pass, CA, August 2009


    Posted in california, locations, technique | No Responses »
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    Sphinx moths

    Tuesday, September 22nd, 2009

    A friend of mine in Laramie Wyoming reported snow yesterday; here in southern California we’re baking in nearly 100 degree temperatures, but that means that insects are still out, and I can still photograph them!  One of my favorite insects is the sphinx moth.  Sphinx moths are a family of moths (Sphingidae) comprising about 1,200 species; the white-lined sphinx moth (Hyles lineata) is very common here in southern California.

    White-lined sphinx moth, 2009

    I caught this individual flying around in my garage one evening (they’re nocturnal).  After catching it, I did what any good biologist would do: I put it in the fridge.  Why?  Because I wanted to do what any good photographer would do: take pictures of it.

    After letting it cool down, I placed the moth on some vegetation in my front yard.  Using my 300/4 lens with a 1.4x teleconverter, I was able to fill most of the frame with the moth at the minimum focusing distance.  I used a flash with -1 2/3 stops compensation to act as a fill flash.

    Moths–like all insects–are ectotherms, meaning they are “cold-blooded”.  In other words, they have to derive their body heat from somewhere other than metabolic sources.  You and I are endotherms–we produce our own body heat via our metabolism.  So, as this guy warmed up from being in the fridge it started to move around more and more.  But, it still needed more heat to be able to fly.  That’s when things got interesting.

    Ectotherms have to derive their body heat from external sources (usually the environment–this is why you see lizards and snakes sunbathing), but sphinx moths display something called ‘periodic endothermy’–they flap their wings at a very rapid pace to build enough body heat to be able to fly:

    White-lined sphinx moth beating wings in a display of ‘periodic endothermy’, 2009

    Beating the wings in this manner generates a large amount of heat, which can then be used for flight.  This moth displayed this behavior for about 3 minutes, then took off.  It was a great interaction, a good physiology lesson, and I got some great pictures out of it!

    Posted in General, technical, technique | 1 Response »
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