Infrared Archives - Infrared Conversions, IR Modifications & Photography Tutorials

IR Fireworks

What to do on the 4^th of July… Humm… Grill? Done. Catch up with family? Done. Relax? Done. Watch fireworks? Wait a second… How many of you have photographed fireworks? I’m guilty. But who’s photographed fireworks in IR? I’ve never done that, and probably few have. Let’s give it a try.

I climbed on the roof of my house to get a better vantage point and set-up my full spectrum 5D Mk II with a 720nm filter.

I use a Hoodman Loupe for focusing my 5D, since the filter blocks the visible light and makes the viewfinder useless. This technique works quite well for me and is what I’ve been using for more than 5 years. I wrote a blog on the topic.

I knew about where to look for the fireworks. So I installed my Pentax 67 55mm medium format lens and prefocused before it turned dark. It’s more difficult to focus once it is dark. I connected my shutter release and then waited…

At 9 o’clock on the dot, the fireworks began. I was shooting exposures from about 3-10 seconds at ISO 400 and f/5.6. This seemed to work well. Adjustments in framing, focusing and exposure need to be done quickly, as the fireworks continue. I continued to shoot until my memory card was full. It was close to 9:30, which is when the firework show typically ceases. A quick back of the camera indicated that I had captured some interesting shots.

So where were the trouble spots? First, I noticed that the 55mm lens had some significant internal reflections. I’m not sure if this was caused by the filter, or the basic lens design itself. My EF24-70mm f/2.8 has a similar issue with super-contrasting scenes. I’ll have to set-up an experiment to test my lenses under these conditions. I’ll share the results here. The three photos below, though still interesting show the effect of the internal reflection.

Releasing the shutter release mid explosion halts the motion of the firework and provides a truncated look. Note also a second shell climbing to altitude.

The other problem I encountered was the wind. I was standing on my roof and at times needed to grip the tripod to insure that it didn’t take a tumble. Interestingly, the wind also had an effect of blowing the fireworks. Many didn’t have the traditional firework shape, but rather a skewed , wind-swept look. This was also interesting.

Finally, as with any long exposures on digital cameras, there are some required management of hot pixels. Most modern DSLR’s have internal noise processing, But this requires an equal-length dark exposure for each light exposure. So I prefer to do this off-line using the technique outlined here . Since the exposures were fairly short, the hot pixels are manageable, even by manual removal methods.

I did very little post processing of these images. I set the camera with a custom white balance on a green subject. Most images were posted after a little cropping and re-sizing for the blog format, but not much more than that. I did process several in B&W, since that’s my favorite IR medium. Some photos have a bit of an abstract look to them.

By the time the fireworks show was over, the mosquitoes had found me. So I gathered up my tripod, camera bag, loupe and flashlight and headed off the roof. It all ended well and I enjoyed the experience. I hope you’ll give it a try next year.

Happy 4^th of July…

The Great Minor White and Infrared Photography

Born in 1908, Minor White was something different in terms of how and why he photographed. He incorporated as much of his own beliefs and philosophies into his work as he did photographic technique. His work is a mix of his mentality and the emotion he felt towards a scene or subject. He injected a part of himself into all the photographs he made. Bestowed by him are such words as “The photographer projects himself into everything he sees, identifying himself with everything in order to know it and to feel it better.” and one of my personal favorite quotes about us photographer’s mentality “…all photographs are self-portraits”.

Minor White-By Imogene Cunningham

It was with the existential mindset that White approached his photographs and perhaps there was none of his work as idealistically surreal as his adventures into the world of infrared. Not only was he a prolific photographer in the artistic and technical sense but he was one of the early practitioners of infrared photography who brought it’s incredible appeal to the masses. The IR images he made, just like his other works, projected a world blended with both the physical landscape and his own personal creativity.

By Minor White, 1958

By Minor White, 1955

By Minor White, 1955

Minor White and Infrared

How did Minor White make his IR photographs? With magic…. Well no, not exactly magic, but it certainly looked that way. Minor White used black and white infrared film, usually large format 4×5, to capture his dreamlike scenes. The infrared or more accurately “near-infrared” light spectrum falls around the 700-1200nm range and infrared film is manufactured to be sensitive to these wavelengths. However, seeing as IR film is also still sensitive to other wavelengths of light, IR filters must also be attached to the camera lens in order to filter out other types of unwanted light that falls in the more visible spectral range. It’s this filtration of the normally visible light and the inclusion of the near IR spectrum which we generally don’t see which gives IR photography their ghost-like quality. Development of the IR is surprising the same as many other conventional black and white films and requires basic darkroom techniques and chemicals.

IR Lens Filters

IR 35mm film

You may be wondering, “So why can’t I just use an IR filter on my digital camera to make IR photos?” And that’s good question. The answer lies in the very construction of most modern digital cameras themselves. IR wavelengths are generally unwanted and in conventional photography and therefore modern digital cameras have a built in IR filter that is placed in front of the image sensor to block out IR light. Even if an IR filter was placed on the lens the resulting transmitted IR light would in turn be filtered out by the camera’s own internal filter. So, how can you enable your digital camera to make IR photographs? Read on….

IR Photography in the Digital Age

As I mentioned earlier, the largest obstacle that stands in the way of making IR images with your currently digital camera is the built in IR sensor filter inside your camera. So if you want to venture into the world of IR photography this filter must be modified through an infrared camera conversion process.

New IR translucent filter being installed

This means that your camera’s sensor is now sensitive to incoming IR light. There are also many other possibilities to expand your infrared horizons with today’s digital camera bodies. Full spectrum, color IR, and a host of other tailored IR imaging effects can be produced depending on the type of conversion and IR lens filter combinations you happen to choose. The benefits to Find out more about infrared conversion possibilities here.

A Final Word About Minor White and Infrared Photography

The work of Minor White was profound, beautiful, innovative, provocative, and at times quite sad. His ventures into the world of IR photography showed us a the wonderment that is all around us, yet invisible all the same. His images speak volumes to the life he lived and to the way he approached the art of photography.

Today, we have so many ways to practice IR photowork whether it is with film and filters or with our digital cameras through a dedicated IR conversion. If you are considering the latter route, be sure to learn as much as possible about the possibilities and limits of digital IR conversions. Make sure whoever you trust your beloved camera to has the reputation for quality that you and your gear deserve. Read more about IR digital camera conversion here at LifePixel and be sure to check out what people just like you have to say about the level of service offered by the LifePixel team!

Bracketed Exposures for IR photography

What are bracketed exposures? If you’re familiar with this term, you know how useful they can be. There are multiple uses for bracketed exposures, but they are especially helpful in IR photography. Shooting bracketed exposures is where the camera is set-up to shoot the same scene, but at different exposures.

Nearly all stock cameras are meant to shoot in color. So when we get into the optics and start removing filters or adding other filters, the camera doesn’t work the same. The one area that really takes a beating is the metering. After a modification, the metering will still be fairly close. But shooting in IR or full spectrum will definitely change the way the camera’s metering system sees the world. I find that my full spectrum modified Canon 5D Mk II with a 740nm filter will usually meter a ½ to 1 stop (usually denoted by EV) brighter than a normal scene. Most of my other modified cameras were the same.

The shows a series of 3 bracketed exposures at -1, 0 +1 EV

When I shoot IR photos, I shoot bracketed exposures as a rule. I’ve had too many IR photos where I thought the metering was accurate only to find that there are highlights in the scene that are blown out (camera’s histogram is clipped on the RHS). Shooting bracketed exposures nearly always helps me recover these highlights or even allows me to process a different shot that is at the + or – end of the bracket.

How do you begin doing this? Well, most cameras these days will allow the use of bracketed exposures. This is where the camera will shoot 3 or more exposures for each image. Depending on how you set it up, the camera will typically shoot a normal exposure and one under exposed and another that is over exposed. Some cameras will shoot additional over/under frames and also allow you to skew how these different exposures are framed in the overall bracket. I like to set my camera to shoot the bracketed exposures in high speed mode, so I can get the 3 images in rapid succession with a single shutter button press.

This is the menu option for setting bracketed exposures on a Canon 7D. This one is set for -1, 0 +1 EV

My cameras (as to many) have several programmable settings where I can set f/stop, ISO, exposure mode, bracketed exposures, etc. So I have 2 custom settings that shoot only bracketed. On my camera, C1 is set up for 1 stop over and under. The camera will record 1 normally metered frame, one frame that is one stop under and one frame that is one stop over. C2 is the same operation except for 2 stops over/under. This makes it quick and easy for me to change the camera to different situations where 1 or 2 stops might be needed.

Many DSLR’s have the ability to set custom settings. This one is a Canon 5D MkII

So why else would I shoot bracketed exposures? One great feature is HDR. If you’re shooting a scene that has both bright and dark elements or the scene spans more dynamic range than a single shot can record, HDR or some other technique of exposure masking or blending is the way to do this. It’s also very helpful to have multiple exposures when shooting on the shadow side of the Sun, or toward the Sun. Many times you won’t see the need for HDR until after you return and are processing your images. It’s too late to do an HDR at that point. So by shooting bracketed exposures, you have the ability to do HDR or exposure blending on shots, after the fact.

This is an HDR of the 3 images shown above.

Isn’t shooting bracketed exposures going to wear out my camera? Won’t it take more memory? Yep, for both. Your shutter is now clicking 3 or more times for each scene. All of these shots have to be recorded on the memory card. Of the 7 modern DSLR’s I’ve owned, I’ve only replaced the shutter on one camera (my 30D), and that was at about 3700 clicks, for sure an anomaly. Most prosumer DSLR’s are good for 100k -150k shutter clicks. I’ve never shot 100k shots on any of my cameras. But I’m not a professional photographer. I venture to guess that most other casual shooters are the same. As for the memory consumption, memory cards are cheap.

Another example of scene that benefited from having more than a single exposure

There is a little good news. If you focus and shoot your IR like I described in my last blog, focusing through live-view, the mirror will stay locked up. So the wear associated with the mirror flipping up and down is removed from this operation. It also helps to use a tripod when shooting bracketed exposures, especially if you’re going to be using them for HDR. You can still align the images in post-processing. But it’s easier if the images begin with good alignment. I prefer to shoot all my IR with a tripod.

Scenes that are shot toward the Sun typically have a high dynamic range that benefit from having bracketed exposures

If you’re comfortable with shooting regular exposures with your IR photography, by all means proceed. I find that shooting bracketed exposures helps save many images that might have otherwise been unusable. Happy shooting.

Focusing a Full Spectrum Camera

If you’ve read any of my other blogs, you might know that I started IR photography as a spinoff of my astrophotography. Both of these types of photography have some similarities. First, most cameras need to be modified to shoot IR photos. For the exact same reason, you’ll need to modify your camera to shoot nebula-type astrophotography. This is needed because the internal UV/IR cut filter blocks the both the IR light for IR photography and the H-alpha light for shooting nebula (See my astrophotography series for more details).

When I first got started with astrophotography, I modified a canon 300D (Digital Rebel) with a full spectrum modification. I figured it would be the most flexible. Six years later, I still feel that way. I like the full spectrum modification as I can shoot astro, or any flavor of IR. by adding an original white balance filter allows me to use the camera for regular color photography.

The biggest drawback of a full spectrum modified camera is the need for external filters. These block the light that would normally pass through the viewfinder. Lifepixel calibrates their IR modified cameras for autofocus. But when shooting IR with a full spectrum mod, you loose the use of the viewfinder.

When shooting the 300D, I would compose, focus and prepare the shot with the filter removed. I’d then screw on the filter and set the lens to the higher f/numbers and shoot. It was sort a crap shoot whether or not I’d get what I wanted. It did work and I shot many photos like this. One of my all-time favorites was shot with the 300D, using this technique.

I was enjoying shooting IR and wanted a better way to compose and focus my images. So my second modified camera was a Canon 40D, also modified for full spectrum. It was one of the first DSLR’s that had a live-view option. I found that this was the key to effectively using a full spectrum camera. Since the camera is modified, it sees right through the externally mounted IR filter. So live-view works quite normally. I used this camera for several years before upgrading to a slightly higher resolution Canon 50D. This camera also had a better live-view LCD, which made focusing much easier. Then I finally bought and modified a full frame Canon 5D Mk II. All my cameras were modified with a full spectrum modification.

When you shoot IR with live-view, you can see the scene just as the camera sees it. After all, it’s the main sensor shooting this live-view image. I found that shooting with a green white balance gives the images in the live-view window a more appealing color. It is much easier to compose and focus. Having a custom white balance also makes the post-processing easier.

This is typical of what you’ll see on the camera’s LCD if you shoot without a CWB.

This is the same shot with a Green CWB frame and the camera set to use this frame for CWB.

The biggest problem for me was being able to see the LCD screen, while shooting in the bright daylight hours. I tried shading the camera with a black cloth draped over the camera. But this was pretty tedious and uncomfortable. So I bought a Hoodman loupe and never looked back. This allows you to see the LCD very clearly. On many cameras you can also zoom live view, which will further improve your focusing with the loupe.

Keep in mind that using the LCD for composing and focusing will consume more power than viewfinder methods. So be sure to carry an extra battery or two. Alternatively, if you use a battery grip you’ll have longer sessions before a battery change is needed. This comes at the expense of portability.

The camera & loupe can be a handful to manage if you’re doing hand-held shots. So I resolved myself long ago to shooting with a tripod. I made a custom tripod which is a little more compact and works perfectly for my IR set-up. But nearly any tripod will work, as long as it is stable.

Focusing an IR modified camera can be a challenge. So I thought it might be worth reviewing this topic again. With a little kit and a little practice, focusing becomes an after thought allowing you to concentrate on the other aspects of getting a great image. You don’t have to have a full spectrum modified camera to use this technique. But you should use this technique if you have a full spectrum modified camera. Practice, have fun and happy shooting.

Diffraction and IR Photography

A few years after I began my photography adventure I took a photography class that came free with my first SLR camera. I thought I knew a lot about photography. After taking the class I thought I knew all there was to know about photography. Funny thing is that all these years later I’m still learning, almost on a daily basis. One photography class take away for me were all the details about depth of field and aperture. When I went to any action event, I’d shoot at high f/numbers so everything was in focus (before the days of auto focus). Some years later while working on my undergraduate degree, I became interested in optics. I was hired to work in an optics research lab (see my holography post). It was then I started learning about the wave nature of light and how diffraction occurs. I mostly worked with lasers. So most of my diffraction experience was with monochromatic light (one color). Below is a shot of textbook linear laser diffraction through a small opening. This is the effect on light as it passes through small openings. This also occurs in photography with all the colors diffracting different amounts, but occurring simultaneously.

My interest in photography began to mesh with what I had learned about optics. I had always wondered about white light diffraction, especially in camera optics. It turns out that diffraction can be a fairly significant issue with camera lenses. You can shoot everything at f/22 and have great depth of field and focus. But there’s a trade-off. As the aperture size decreases, diffraction increases and becomes more visible. There is diffraction at all f/numbers though its more pronounced at smaller apertures.

I like to understand where all my lenses are sharpest and where they are soft. So when I added another medium format lens to my fleet, I decided to do a little more testing. Interestingly, my 165mm f/4 LS medium format lens has a minimum aperture of f/32. At this aperture diffraction makes the image quite soft. It is so evident that it’s even evident in the live-view display.

I shoot IR almost exclusively with medium format lenses. Check out my blog topic on medium format lenses. They are huge, but I really like using them. Here’s a comparison to a 50mm f/1.4 Minolta manual focus lens that I bought with my 35mm SLR. These are the lenses I included in my testing for this blog (except for the Minolta lens).

Left to right in the rear: Pentax 67 55mm f/4, Pentax 67 75mm f/4.5, Pentax 67 165mm f/4. Front row: Minolta MD 50mm f/1.4

I found some level of diffraction in all three of the lenses I tested. On this particular test subject (my neighbor’s palm tree), diffraction is much less evident in the 55mm and 75mm lens, but very clear in the 165mm lens. This is partially due to the minimum aperture size of f/32. The animations below are all 740nm IR photos, shot with a custom white balance. No other processing was done.

Pentax 67 55mm at f/4, f/11 and f/22

Pentax 67 75mm at f/4.5, f/11 and f/22

Pentax 67 165mm at f/4, f/11 and f/32

Diffraction is inversely proportional to aperture diameter. So diffraction is less visible as the aperture diameter increases. Unfortunately, diffraction is proportional to the wavelength of the light being shot. This means more diffraction at longer IR wavelengths. For those of us shooting IR, we will likely have to use a slightly larger aperture vs. when shooting the same equipment in color. If you shoot IR around 740nm, diffraction will be about 30% worse than at the center of the visible spectrum (about 550nm). That seems significant but doesn’t seem to affect my images much. However, you should keep this in mind if you’re planning to shoot IR at small aperture diameters (large f/numbers).

You may have noticed something else that is evident when shooting at small apertures. Any dust or streaks that happen to be on the lens, filter or sensor become much more evident at smaller apertures. Take a look at the speck to the upper right of the bird in the 165mm image above. The dust spec is invisible in the f/4 image, but very clear in the f/32 shot. Yet another reason to open up those apertures.

First test shot from my new 75mm Pentax 67 medium format lens (shot at f/11)

I find that most of my lenses are sharp around f/11 when shooting at 740nm. So that’s where I mostly shoot. It matters little to me if the exposures are longer. I always shoot IR with a tripod so I can take full advantage of the lens sharpness. If you’re interested in some light diffraction theory, there’s an interesting article I found discussing diffraction and photography. One last detail to consider. The onset of diffraction occurs earlier in crop sensor cameras vs. full size sensors. So if you’re shooting with a smaller sensor, you may need to open your aperture more than would be necessary on a larger sensor. Lots to keep in mind.

So what does this all mean? Well, if you typically shoot at large f/numbers, with a crop sensor camera and/or shoot IR photos, you can probably increase your image sharpness by opening the aperture slightly. Do your own tests on the lenses that you use most frequently. It’s important to know where your lenses perform best whether you shoot color or IR. Most importantly get out and shoot. It’s the only way to learn.

Manual Panorama Assembly

The weather is perfect, the lighting is just right and you’ve just finished shooting a 3 frame panorama of an interesting scene. You’re anxious to get home and assemble the images. So you grab a cup of coffee, load up your images and proceed with the panorama assembly. Then the reality hits you that you didn’t shoot the panorama in manual and the auto-assembled image looks unusable. What can be done to save this panorama? There are probably many programs out there that do a better job with assembling panoramas than Photoshop. But I use Photoshop and have saved many panoramas in the way I’m about to describe.

I made a similar mistake on a panorama of an interesting shot while in Norway. Could I re-shoot it? Maybe. But many compositions are once in a lifetime shots that can never be duplicated. I processed my images and was disappointed with the result. Below is the result of how Photoshop’s auto panorama routine handled my files of unequal exposure. I’ll show how to get a better result than this using a manual technique. Stemming from my astrophotography, I learned how to do manual panorama assemblies which can sometimes salvage shots that can’t be assembled properly by Photoshop.

Let’s get started. Fire up Photoshop and load up your pano images in separate layers. You can do this manually by opening up each image and doing a Select All and the Copy/Paste. But I like to use the script Load Files Into Stack.

When you’re done you should end up with something looking like this, with your pano images in separate layers (lower RHS).

The images then need to be aligned for the panorama. This too can be done manually but using the Auto-Align Layers is generally the easiest and fastest option. It generally does a very good job. Highlight all the layers in the Pano and click Edit then Auto-Align Layers. I usually just choose the Auto option and let the computer do its work. On my antique mobile workstation and with my 5DII images and Photoshop CS5, this takes a while. When it’s done, you’ll probably end up with something that looks worse than what Photoshop assembled. But be patient.

Having the image in layers like this gives us considerable flexibility to manually blend the layers to produce a usable image. You first might make some curves or levels adjustments, to try to match the brightness of the various layers. It won’t be perfect, but the closer the better. You can also arrange the layers changing which layer is on top. This helps to find the best overlap to aid in the manual blending process.

The magic occurs when the various layers are masked to manually blend the image. The secret here is to use the image that is covering the majority of the scene and manipulate the masks so that it blends the various elements of the image, letting through the images below. Add a layer mask to this layer and then invert the mask (so it’s black). Choose a medium sized paint brush and paint the mask in white to reveal the areas of the image below that you want to see. I start with masking the layer that has the most features that most need hiding or blending. It takes a little practice to see what needs to be hidden and what needs to be revealed and which layer is best on top. But try several arrangements and choose the best result. Below is the result of my layer swap.

Here’s the same image that’s partially masked using a small paint brush with soft edges.

Continue to paint the various features to hide and reveal the areas of the image that provides the best blending. I use a smaller brush with soft edges in a jagged path in areas of finer features. I also like to paint little features so that they lie entirely in one or the other frame. On this image, the crane hook is a perfect example. It split the frame. But whenever possible these important features should lie on one frame. So try to blend the image accordingly. After a little work and experimentation, the image should begin to come together. Here’s what part of my mask looks like.

Depending on your image, you’ll need to duplicate this process on several layers to encompass the entire scene. Sometimes I’ll also do a little blurring of the mask, to help blend the masking even more. It’s not always needed but can sometimes be helpful. If you mask too far and hit the edge of the image below you can step backwards or paint it over again with a black mask color to hide it again. If you’re not familiar with Masking in Photoshop, I’d encourage you to do a little research. There are many masking techniques that can be used and help with manually blending the panorama.

When you’re happy with the image, you can flatten the layers and proceed with the rest of your processing needs. The image I used in this tutorial is a custom white balanced IR image. I generally convert these to B&W, add a little contrast, touch-up and complete the image. Here’s the final result of this panorama.

If your panoramas have a larger exposure difference between frames, you’ll need to do more work on the front of the process. When I forget to shoot my pano’s in manual mode, the resulting exposure difference is usually pretty small and this process works well. This is certainly not a catch-all process. But I can typically generate better results with my manual method vs. what Photoshop does with the automated assembly.

I’ve also use this manual blending technique on a very large 8 frame panorama of the Orion Nebula (over 63MP). The automated results were nowhere close to what I wanted. So I had to manually assemble and blend this image. So the next time you have some panorama images that you thought might not be usable, try a manual panorama assembly and see if you can recover the image into something usable. Happy shooting (and processing).

Short Sticks

Do you use a tripod? I do for almost every shot. The way I shoot IR necessitates the use of a tripod. Could I hand-hold my IR shots? Probably. But I love to shoot panoramas and in poor weather. I’m also a sort of a purist when it comes to getting the most out of the camera and lens. So I always use a tripod. This isn’t just another tripod tutorial. You can find enough of those on the web already. What I wanted to do here is share my struggles with finding the right tripod and how I solved the problem.

For those of you that follow my blog posts, you’re probably aware that I started my IR venture as a spin off of my astrophotography. The stability requirements for long exposure astro photos are much higher than that for photography. I realize that it’s not an apples-to-apples comparison as equipment for astrophotograpy is typically much heavier. But I guess my need for absolute stability rubbed off. When I started looking for a tripod for my IR photography, it should go without saying that my first requirement was a high degree of stability.

I shoot IR with a full frame DSLR and heavy lenses . I love the medium format lenses. Did I mention that they are heavy? Add any filters, lens converters, a battery grip and L-bracket and you’re into a fairly robust system. Even so, many of the lightest tripods will hold the weight of a camera and a lens in ideal conditions. I find however, that the load ratings of some units are a little misleading. Sure these ultralight sticks may hold the load. But I hate having to fiddle with the tripod and wait for everything to flex back to a stable position after making a ball head adjustment. So I knew I wanted a tripod that could also carry a decent load without flexing.

I also like to shoot down low. The desert has some interesting foreground elements. So I also wanted my tripod to be able to work well at low levels. Almost any tripod these days can splay the legs and get low. But this is where the strength of lighter tripods can be compromised. Splaying the legs can reduce the load capability and place additional demands on the materials. Adding to the list, I also wanted something that was fairly compact, for traveling. So with my laundry list in hand, I set off looking for the tripod that would fit my requirements. I never did find exactly what I wanted.

So after some thought, I decided I’d experiment by adapting a stock tripod to fit my needs. I’m fairly handy when it comes to machining, metalworking and the like. I felt confident that I’d be able to make the necessary modifications. I dug around the web until I found a possible candidate, an aluminum leg Benro A3580F. It met a couple of the initial requirements. It is stable and has a good load rating (about 6x my camera load) and was also fairly inexpensive.

I did a little reconnaissance to see if I was going to be able to work some magic on this tripod. It turned out to be a fairly simple design and I decided to proceed. I began by removing and disassembling the legs.

Once I had the legs completely apart, I proceeded by cutting off 5 inches off each segment of each leg. Cutting each leg segment the same amount kept the symmetry of the design. I then cleaned up the cuts and reassembled. Voila, a shortened tripod. There were some other details not mentioned. But in general, it was a fairly simple modification.

Here’s the finished product. It’s substantially shorter than stock. But it still maintains the same (or probably higher) load rating, especially when the legs are splayed.

Here’s a comparison with with one of my larger tripods. I still use the larger tripod for portraits and when I need additional reach. But for nearly all my IR photography, I take the little custom Benro.

Here’s an action shot with the shortie and my 5DII with a Pentax medium format 55mm lens. The set-up is really rigid and required a lot less fiddling when trying to set up a shot. There is almost none of the flex that appears with lighter tripods. It’s hard to describe the satisfaction, unless you’ve experienced such rigidity.

This thing is like a little tank. I call it my “tankpod”. It’s short, really stout and can travel almost everywhere. When I need more height, I can extend the leg segments and get up to about 45 inches (to the base where the ball head mounts). I usually use it with the segments retracted or only the first segment extended. When folded up, It travels well and fits in a carry-on bag. It’s not a Gitzo or RRS, so the build quality is not the same, but is still quite adequate for me.

The last time I presented my shortened tripod to a group of photographers I got a lot of eyebrow raises and eye rolls. It might not be the thing for you. But this modification turned out a tripod that suits my needs perfectly. It now goes with me everywhere I shoot. So if you’re handy and need something specific in a tripod, think about out what modifications might make it what you need. Happy shooting.

Infrared Haze Reduction

Did you ever wonder why IR landscape photos look so crispy sharp? It may not be obvious. But photographing in the near-infrared part of the spectrum has some definite benefits over photographing visible light, especially for landscape photography.

Before we get into the photography portion, let’s take a look at some of the science involved. You might have noticed that infrared light has some ability to penetrate the haze in the air. Why is that? Haze is caused by light scattering off particles in the air. By shooting our photos in IR (longer wavelengths) we can take advantage of some science to reduce the haze that is apparent in our photos.

To help understand the scattering mechanisms, it’s important to understand what I mean by wavelength. Sure it’s related to the color. But why? Light is an electromagnetic wave. All waves can be measured by frequency (like broadcast radio waves) or by wavelength (like light). Frequency in inversely related to wavelength. The color of light depends on the wavelength – the length of the light wave (see the graphic below). If you could see the waves you could measure the distance in order to obtain the wavelength. But the wavelength of visible light is very small. It’s measured in nanometers (billionth’s of a meter). So you’ll need a pretty small ruler. Around the visible light spectrum, the longer wavelengths are associated with orange, red and infrared and shorter wavelengths with blue, purple and ultraviolet light.

Visible light is only a small part of the entire electromagnetic spectrum (EM). You can see where X-rays and gamma rays or microwaves and radio waves lie in the EM spectrum.

Now that the science is out of the way, let’s dive into the photography. What is it that makes the haze apparent in photographs? It’s scattering. But what’s causing the scattering and why? When light hits objects it’s scattered. Blow a little smoke in the air and shine a flashlight on it. What you’re seeing is light being scattered by the smoke particles in the air. But how light is scattered depends highly on the size of the media doing the scattering.

Non-selective scattering is a mechanism that occurs with larger particles (much larger than the wavelength of the light being scattered). This occurs mainly with larger water droplets, ice crystals and similarly sized atmospheric particles. This scattering occurs equally for all wavelengths. So shooting in IR doesn’t provide any benefit over traditional color photography.
Mie scattering is a scattering occurs with atmospheric particles that are approximately the same size as the wavelength being scattered. These particles are typically spherical in nature and are characterized by dust, pollen and water vapor (droplets). Although there is some wavelength dependence, typically all colors are scattered equally. As an example, clouds appear white since the water vapor is being scattered equally across all colors.
Rayleigh scattering is where the magic happens for IR photographers. This scattering occurs mainly on the molecular level, when the particles are much smaller than the wavelength of light being scattered. In the atmosphere this is primarily caused by oxygen and nitrogen molecules. These molecules absorb the light and re-emit it in a random direction, thus scattering the light. However, the amount of Rayleigh scattering that occurs is inversely proportional to the 4^th-power of the wavelength. Knowing this, it is easy to see that infrared light (~800nm) is scattered 1/16 as much as blue light (~400nm).

At ground level, all 3 scattering mechanism can influence the production and of haze. As a result, the haze-penetrating benefits if IR photography are not as strong. Even so, the effects are still quite evident. Take a look at the photo below. The top photo was shot with my cell phone and the bottom with full spectrum camera and IR filter.

A scene photographed with a color camera showcasing the haze on the distant mountains.

The same scene photographed at 740nm. Notice the reduction in haze and improved detail.

I’ve seen the benefit of shooting IR landscapes for many years. However, it is quite shocking to see the difference when shooting from an airplane. There is less dust at higher altitudes. This means that the majority of the scattering is done by Rayleigh scattering. As we already learned, this scattering is highly wavelength dependent. So the difference between visible and IR photos is much more dramatic.

The photograph above is one I shot while flying over central Hungary. It was the first time I’d shot any IR from an airplane. The ground was heavily obscured by haze. After I processed the IR image, I was surprised by the clarity and the appearance of the mountains on the horizon. It’s a perfect example of the powerful haze reduction power of IR photography. This effect is what makes infrared aerial photography such a powerful tool for scientists and those requiring clear images of the ground. Here are a couple of my color vs. IR comparison photos.

Visible Light photo West of Austin Texas

Same photo in 740nm IR

Visible light photo of West Texas, including Guadalupe peak (upper RH side) and Salt Flats.

Same photo in 740nm IR. White Sands National Monument is visible in the upper LH portion of the image, more than 100 miles away.

Hopefully, you pulled something useful out of this blog. But at the very least, I hope you see how IR photography can be used to reduce the haze in photographs. The advantage can be striking and significantly improve the clarity of IR images. I’ve done landscape photography for many years. However, shooting in IR has allowed me to see landscapes in a totally different light (pun intended).

Shooting Infrared Panoramas

Panoramas are the ideal tool for capturing scenes with expansive views or to increase the field of view of a lens. They are also a lot of fun to shoot. However with the excitement of shooting a panorama comes the frustrating reality of assembling the images into to single frame. Without some proper shooting techniques this assembly process can be hit or miss.

Anyone that has tried to assemble panoramas in Photoshop (or a similar image processing program) is aware that some aspects of the individual frames of the panorama don’t always match. This is caused by parallax errors of near and distant objects. With these images there is usually some compromise to the assembly. So some of the image parts will match and other parts may not. These parallax errors are most problematic where the scene has close foreground objects as well as distant objects in the background. So what can be done about this?

Well, lets first look at the problem, parallax. You can easily see the effects of parallax by setting up a couple objects on a counter top, in line with the camera. Place one object closer than the other and aligned so that the object closest to the camera hides the object further from the lens. Now pan the camera and notice the effect. This effect is seen because the camera is not being rotated around the optical node of the lens.

So how do we fix this problem? The use of a nodal slide will allow you to rotate the camera around a predetermined nodal point. The nodal slide allows you to offset the camera so that the axis of rotation is around the optical node (also known as the no-parallax-point or entrance pupil) of the camera lens. Not too many manufacturers publish this information, but it can be determined experimentally. The nodal point will differ from lens to lens and also at different zoom settings on the same lens. To properly use a nodal slide you’ll need a tripod and a head with a panning base (or separate pan head). Below is an example of a nodal slide set up with my 5DII. Although I machined this one, they are available many places at very reasonable prices. Note the blue tape that has information on the location of the nodal point for various lenses. My preference is to use a set-up with an L-bracket attached to my camera. However nodal slide set-ups can be done in many different ways, even on both axes (pan and tilt) for monster panoramas.

Another superb option for panoramas is to use the shift feature of a tilt-shift lens. In my opinion, this produces the best panoramas with the least trouble with assembly in Photoshop. The shift feature of the lens is used to shift the image across the film plane, without movement of the camera itself. Using this technique there are imperceptible levels of parallax. I usually start by composing the scene keeping track of how far the shift feature will frame the field of view. I then shift the lens to one side and begin shooting and shifting. Use care to not move the camera or tripod. One major downside is that a tilt-shift lens can be a pricey solution for panoramas. Another drawback is that it’s typically only possible to shoot up to 3 frames on a full frame camera and maybe 4 frames on an APS-C camera. The use of a nodal slide offers the potential for full 360 degree panoramas, if you ever have that need.

The shot below is a 3 frame panorama shot on a full spectrum modified 50D with a 740nm filter and my 24mm TS-E lens. Without the use of a nodal slide, the parallax errors in this scene would have made assembling this image nearly impossible. The front of the truck is close the camera and the buildings in the background being much further. This would have created large parallax errors and made final image assembly very difficult. But using the shift feature of the lens, the images stitched together without any trouble or compromises.

Now all this being said, there are some situations where panorama shots can be done without any equipment and can even be hand held. But these are mainly done for distant scenic shots where there would be very few problems with parallax. Regardless of what method you use to shoot panoramas, it’s best to overlap the images. I usually shoot with at least 1/4 overlap. It’s also generally best to have the camera in portrait orientation. This will provide the best set of images for final processing.

A tilted horizon can be fairly distracting on a large landscape panorama. So for these I always try to insure that the nodal slide and panning or tripod head are level. Most tripods & nodal slides have a bubble level. But for times where I don’t have a level and can’t see the horizon, I use a $5 hot shoe cube level on the camera. This helps make sure that the horizon is not tilted in the final assembled panorama. Correcting a tilted horizon on a large panorama requires cropping a large portion of the panorama.

Probably the most important point when shooting panoramas is to shoot in manual mode. With the camera in an auto-mode, the camera will typically detect a difference in exposure from shot to shot and adjust the camera accordingly. But having it in manual mode will insure the same exposure for all the shots. The final images will need considerably less work to assemble if there are no exposure variations.

I hope this brief overview has removed some of the mystery and has inspired you to get out and shoot panorama images. I really enjoy shooting panoramas and hope you’ll give it a try. Practice makes perfect. So get out and shoot!