Saturday, July 5, 2014

Macro Photography on the Cheap

I’ve never been big on macro photography, but lately I decided to get a bit more serious about it. Since I lack any current macro capability for my Canon 5D MkII, I’ll need to spend anywhere from $750 to $1,800 (and easily more) for a 100mm macro lens and ring flash. But whoa—I didn’t intend to get that serious about it! I needed a more practical approach, but one that would still yield high-quality results.

There are roughly three options to choosing macro equipment: close-up filters, extension tubes, and of course macro lenses. A set of three close-up filters are about $80 (more or less depending on filter size) and about $200 for a set of extension tubes from Kenko. I have used both in the distant past and you can score some surprisingly good results. This time, though, I wanted a true macro lens; but I was leery about the cost and lugging an extra lens around that I'm unlikely to use often.

Go Short
To solve my problem, I decided on a macro lens in the 50mm range rather than in the more preferable 100mm range. The advantages are a substantially lower cost, lower weight and size, and better depth-of-field. The disadvantage is the more restricted working distance and less flexibility in using a flash. I chose the Canon EF f/2.5 Compact Macro lens for $269 (after a mail-in rebate). It weights less than 10-ounces and is so small I can toss it in my bag and hardly notice it's there. But this particular lens comes with a major concession: it’s a 0.5x and not a true 1:1 macro. I reasoned that wasn’t a problem since my macro tastes lean towards backing off the main subject to show more of the surrounding environment. In retrospect, though, a 1:1 would have been nicer; but this lens has so far satisfied most of my needs. For $80 more, you can get a Sigma 50mm macro lens with a true 1:1 ratio.

Choosing a "Lite" Touch 
The next consideration is a flash. I favor a ring light over dual-opposing flash heads, but in either case you’re staring at several hundred dollars. A flash is the best way to freeze a jittery subject and makes handholding the camera possible. On the other hand, the flat lighting it creates may not suit all subjects. Since I was looking for the “el cheapo” approach, I picked using a combination of two devices. To provide fill-light I bought a Sunpak LED ring light for $28, and to tame wind motion, a $43 Wimberley Plamp II. In addition, I bought a $20 Westcott Pocket Pack that includes a reflector and diffuser.

The only other necessity was a $3 step-up ring to fit my existing polarizer to the macro lens. I already had a spare 52mm UV filter for lens protection, but that’s totally optional. The front element is deeply recessed and well protected and, after all, it is a relatively inexpensive lens. So for a total outlay of less than $350, I was prepared to do some serious macro photography. But as always, there are concessions.

The Downside
If you’re itching to capture a busy bee on a rose petal, this setup isn’t conducive to that. The working distance is too close (which may scare off the bug—or get yourself stung!) and no flash to freeze the motion. And in my case, the lack of a 1:1 lens prevents me from turning a bug into horror-movie size. But for the majority of plant and flower close-ups, it’s more than adequate.


Canon EF f/2.5 Compact Macro (full-frame), $269 after mail-in rebate
(Note: Canon always seems to have some sort of rebate program going on). Besides the previously mentioned Sigma, Nikon also has a similarly priced lens with 1:1, but isn't full-frame. The Canon, despite its cost, is well built and a very sharp lens. Its low cost is due in part to its 15-year old design that uses a dated non-USM focus motor; and of course, its lack of 1:1. It is very small and lightweight and unobtrusively occupies a small recess in my camera bag. Canon does offer an extension tube to convert this lens to a true 1:1, but its cost would make the total package a poor value. If you’re hard-over on wanting 1:1, get the Sigma (or the Nikon if you have a DX camera).

Sunpak LED Ring Light ($28)
This isn’t a “flash”, but instead a 12-LED “flashlight”. It does not communicate with your camera and it’s not normally bright enough to be the main light source. But it works well as a fill light, especially when it’s difficult to maneuver a reflector near the subject. It is very lightweight and fits easily into position. It has two light intensity settings, though you’ll likely use the highest setting most often. The only problem I’ve encountered is to remember to shut it off.

Wimberley Plamp II ($48)
This is the only commercially available device I found for the express purpose of holding a flower or leaf steady. It is an articulating arm that clamps to a support (usually your tripod) while the other end clamps to whatever you’re trying to hold still. In addition to holding the subject steady, it can also reposition the subject for a better camera angle. Make sure to buy the Plamp II version with a redesigned clamp that is more versatile and holds flower stems without damaging them. The Plamp can also be used for any other “third hand” need, such as holding a reflector.

Though this device sounds like a great idea, in practice it has limitations. For one, even if the stem is kept still, the flower petals will still move if it’s breezy enough. Even the Plamp’s articulating arm is sensitive to a strong breeze. There is also an important precaution to take when using this device. You need to use either a remote shutter release or your camera’s self-timer. Wimberley warns that even mirror slap can vibrate the articulating arm. I thought that was an exaggeration at first, but for certain the slightest touch to the camera does set off vibrations through the Plamp (unless the Plamp is clamped to something other than your tripod). I have all my camera’s custom functions set to enable mirror lockup and the 2-second self-timer. If I’m extremely careful, I can get by with just that, but using a remote shutter release in addition is the best procedure. Though far from perfect, the Plamp is nonetheless the next best tool to a flash to combat wind motion—and it's a lot cheaper!
The redesigned Wimberley clamp has a screw adjustor, an inside notch to hold a reflector, center
soft-rubber pad to gently hold a stem, and a larger cavity near the outside to hold thicker items.

Westcott Pocket Pack $20
This includes both a 12-inch diffuser and reflector, which is a good deal since you can easily pay $20 each if bought separately. Most important is the diffuser that you’ll need to tame contrast when forced to shoot under sunny conditions. The reflector can be a handy adjunct to the Sunpak, and mandatory if you decide to opt-out on the Sunpak. The Plamp can easily hold either device in any position if the need arises. However, when a reflector exceeds 12-inches in size, the Plamp becomes more limited.

This shows all the items in action: Overhead 12-inch diffuser screen, Plamp II,
Sunpak Ring Light, and the Canon 50mm macro lens fully extended. 

Parting Shots
The following are a few "lessons learned" so far.

Red Herrings
Regardless if you’re shooting only raw, make sure to set your camera’s Picture Style (Canon) or Picture Controls (Nikon)—or whatever your brand camera calls it—to neutral. The reason is to prevent the histogram display from being significantly and erroneously skewed. Macro photography often entails bold colors and the histogram may mislead you by indicating excessive channel clipping (especially the red channel) that doesn’t actually exist in the raw file. Also, never rely on just the luminance histogram since that may hide any clipping in an individual color channel.

Portable Rain
If you want that nice fresh-morning dew look on your flowers, don't forget to pack a small water-spray bottle with you. I use a tiny 1-oz atomizer that goes a long way. However, I suggest you shoot a dry shot first just in case the wet version turns out, well—all wet. Also, avoid spraying your camera like I've almost done a few times.

Holy Macro
Macro photography requires a lot of ground-level work, and that means a lot of kneeling. Kneeling on wet, or worse, rocky ground can range from annoying to downright painful. The cheap solution is to pickup a pair of gardener's knee pads. I found a nice pair at Target for only $13. Admittedly they can look a bit dorky, but hey, we're photographers not fashion models.

Reclining on the Job
If you're starting to get jazzed about macro and also happen to be in the market for a new tripod, I have a suggestion. Look for a tripod that allows the center column to be positioned horizontally (for example, my Manfrotto 055CXPRO3). This allows you to cantilever the camera away from the tripod legs for more flexibility in framing a subject, especially when it's embedded within other foliage. Otherwise, you're apt to damage the surrounding foliage while trying to cram the tripod's legs into position (this will make you very unpopular at arboretums or other public gardens).

Annoying Backgrounds
Background foliage can be a distraction to any main foreground subject. Of course you can shoot wide-open to blur it out, but that doesn't leave you much DOF to work with. Another option is to insert a background. I bought a 9 12 inch piece of stiff black felt (less than $1 at any craft store and other colors are available) that in many cases supports itself by resting on any background branches or leaves. However, if you want to avoid a "studio look", then you can address the problem in Photoshop using either the Blur filter tools or Blur Gallery. In addition, I find heavy vignetting further helps isolate the background. 

Wednesday, June 18, 2014

Exposing to the Right (ETTR)

The Darker Side of Photography
A challenge in digital photography is recording detail in the darker tones. The problem is noise and reduced tonal information. Noise is relatively straightforward, less signal (that is, less light) and the noise becomes more dominant. The other reason, reduced tonal information, may not be so intuitive.

Your digital camera records illumination linearly, which means the output signal increases the same amount for equal increases in illumination. This is how the luminance is recorded in the raw file. But, if you view a pure raw file on a monitor, it would look awful! The image would be very dark with some brighter blotches scattered about. The reason is our eyes perceive tonal variations by large differences (essentially in stops of light) and not incrementally. So the software remaps the tonal values in the raw file to suit the human eye. This is gamma encoding and is essentially allocating the linear values in an exponential fashion to an 8-bit file’s 256 tonal values (or the 65,536 values in a 16-bit file).

Where're the Bits!
Now the problem. A digital camera with a 12-bit output can represents 4096 different tones. The first one-stop difference (that is one-half the light) is one-half of 4096, or 2048 values. The second stop difference is one-fourth of 4096, or 1024 values, and so forth for succeeding stops. Note that the first stop takes up 50% of the camera’s digital values. Add the second stop and collectively they horde 75% of all the tonal values —and there are a lot more stops to go!

These 4096 “linear” values are then gamma encoded to an 8-bit or 16-bit file for both viewing and editing in Photoshop. To illustrate, I’ll use an 8-bit file as an example. To provide a rough idea what is happening (while ignoring profiling and many other factors for the sake of simplicity), the 12-bit values between 2048 to 4096 representing the first stop are mapped to the 8-bit values of 186 to 255. That assigns 70 tone values representing the first stop. The next stop’s 12-bit values between 1024 to 2048 are mapped between 136 to 185, which assigns 50 tone values for the second stop. As this goes on, you can see that succeeding stops are represented by fewer and fewer bits, thus the reason why the darker tones have less digital information. This also illustrates why editing in 16-bits instead of 8-bits is so important.

When trying to lighten dark tones in Photoshop, “stretching” them into a higher luminance region begins to pull apart the minimally defined tones and that creates posterization and exaggerated noise. This is why editing in Camera Raw is better because you’re working with the linear data—not the gamma encoded data—thus gaining more editing latitude. Still, regardless the file type, the best way to improve the dark tones is simply increase the camera’s exposure. That means moving the histogram to the right, and thus the expression ETTR.

Go to the light!
The main idea of ETTR is to keep increasing exposure until you observe clipping of important highlights in the histogram. Then, edit the file in Camera Raw (preferably not Photoshop) to restore the darker tones with presumably better tonality and less noise. Sounds simple, but it has its pitfalls. First, it is sometimes difficult to distinguish in the histogram the “important” highlights from the rest (specular or otherwise) and that may lead to clipping those highlights. You are also more prone to clipping a single color channel without realizing it. Then there’s the hassle of performing repetitive exposures and rechecking the histogram each time. Finally, when restoring the darker tones you may incur a minor color shift.

ETTR has both its advocates and naysayers, however I feel there is merit to this approach as I’ll soon demonstrate. The biggest gain is in the reduction of noise. However, in my case, this is only an occasional benefit. The reason is my heavy use of HDR and that most my other images generally occupy most of the histogram. The benefit will likely be when shooting with a graduated ND filter, especially as a backup to an HDR shot (that I highly recommend). Sometimes when shooting with a grad filter, especially a strong 3-stop filter, the tonal range may become compressed. Other situations are shooting in overcast or any similarly soft-lit and low-contrast condition.

If a scene’s contrast is compressed, remember that the camera exposes toward a midtone, thus in many cases automatically increasing the exposure in the dark tones. If, for whatever reason, the histogram does congregate more to the left side, then increasing exposure towards the midtone is advisable. Situations can vary greatly, but generally I wouldn’t let the bulk of the darker tones go much beyond a third to half-way into the histogram (probably +1 EV should be the most you’ll ever need). More importantl is to allow a conservative guard band to protect the highlights from accidental clipping. In my opinion, unrecoverable clipped highlights do more visual damage to an image than any blocked shadows.

The easiest way to incorporate ETTR into your routine is simply bracket every exposure. Currently, I still find my customery third-stop bracketing sufficient. Nevertheless, I examine the histogram each time and if the highlights have sufficient headroom, I’ll increase the exposure accordingly. If you’re not an HDR shooter or are a heavy grad filter user, then a better option is to create an “ETTR” custom function. Enable auto-bracketing to either a third or half-stop and then set the manual exposure override to over expose by that increment. For example, with one-third stop bracketing, every shot records 0 EV, +1/3 EV and +2/3 EV exposures that you can later decide which one is best in Camera Raw.

ETTR Example
Below I show identical images with mid to dark tones extracted from a larger scene. The exposure was based on the overall scene, not on the extracted image. The image was shot using a Canon 5D Mark II. Fig-1 is a normal exposure and Fig-2 is a 1-stop overexposure. In Camera Raw, I brightened the normal image by roughly one-third stop (Fig-3) while darkening the overexposed image by minus two-thirds stop (Fig-4). In both cases I applied equal amounts of Shadows recovery. Both images are nearly equal in luminance and tonality, and essentially appear identical with no perceivable color shift. Except, under magnified inspection the noise content is noticeably higher in the normally exposed image, as shown by the highly-magnified image in Fig-5 compared to the overexposed image in Fig-6. (Note, I enhanced the enlargements to make the difference noticeable on screen.)

A one-stop increase is definitely an improvement, but does it really make a difference in the practical world? In many cases, probably not. The noise is so minimal anyway that minor noise filtering will take care of it without damaging sharpness. And if left alone, the noise is low enough that it’s unlikely to be noticed.

On the other hand, some may think this is a great idea when you're forced to shoot at a high ISO (for example, to combat wind). Well, "maybe" so. Except, you have to increase the exposure time anyway, so you're probably no better off than shooting at a lower ISO. Unless there's a technical reason to do otherwise, you should always shoot at ISO 100 where this technique makes more sense in extracting that extra bit of noise performance from your camera.

Figure 1
Normal Exposure
Figure 2.
1-stop overexposure
Figure 3.
Normally exposed image brightened in Camera Raw by about one-third stop 
Figure 4.
Overexposed image darken in Camera Raw by about two-thirds stop.
Both the normal and overexposed images now look very similar.
Figure 5.
Some detectable noise in darkest recess
of the normally exposed image in Fig-3
Figure 6.
No detectable noise in one-stop
overexposed image of Fig-4.

Saturday, January 25, 2014

HDRsoft's New Photomatix's Version 5.0.1

Late 2013, HDRsoft released version 5 of their popular Photomatix software. The update is free to current users who purchased Photomatix 4.0 after October 2010; otherwise it’s $29. The most significant new feature relative to landscape photography is a new Tone Mapping method called Contrast Optimizer. It produces realistic looking images while still enhancing shadows and highlights. I found it a better alternative to Exposure Fusion/Natural for natural rendering; however, I didn’t see it challenging HDR Efex Pro as my primary HDR software. Another new feature of note is Fusion/Real-Estate, intended for rendering interior scenes with an outside view through a window.

Contrast Optimizer Example
To test out Contrast Optimizer, I processed an image of Lundy Lake shot at dusk with three frames bracketed at ±2-stops. This was a very high contrast image and was aided with a grad filter. Nevertheless, the frame to capture the shadows was slightly underexposed. That made for a good test case to see how well Exposure Fusion could restore the shadow detail compared to the other processes. Below I show the results with each process: HDR Efex Pro 2, Contrast Optimizer, Exposure Fusion (natural), and Details Enhancer. The horse race was really between HDR Efex Pro and Contrast Optimizer. Exposure Fusion had the most problem with extracting shadow detail and Details Enhancer had the most unnatural look (especially noticeable in the foreground rocks). To be fair, when the frame that captures the shadows is better exposed (i.e., more exposed than in this example), Exposure Fusion can be a more formidable challenger. In the past, it was my most often used method whenever I used Photomatix.

The winner is HDR Efex Pro, due largely to its superior 32-bit editing capability; for example, the curves and graduated filter tools. As you see in the new Contrast Optimizer control panel, it’s relatively light on editing controls. On the other hand, a simpler interface may appeal to many. I could narrow the difference in Photoshop, but I would loose the 32-bit editing advantage. Though you can’t judge HDR performance based on one image, I can definitely say Photomatix has significantly closed the gap in this new version. If you have Photomatix 4.2 (or earlier), I highly recommend you upgrade to version 5.

Contrast Optimizer Control Panel
A simple and easy to use control panel.
However, the spartan panel also means less
editing capability compared to HDR Efex Pro.

HDR Efex Pro
Overall, a better rendering than Contrast Optimizer, but not dramatically. The differences can be evened up a little in Photoshop. Note that though the shadows are a bit darker than Contrast Optimizer, that was intentional when I added a bit more contrast.
Contrast Optimizer
A bit more touchup in Photoshop, and you have a well-rendered image. However, you loose the 32-bit advantage when working in Photoshop.
Exposure Fusion/Natural
Shadows were blocked up, but given more exposure in the shadow frame, the results would have been much better. Previously, when I was primarily using Photomatix, I used Exposure Fusion almost exclusively and was generally happy with the results. That said, Contrast Optimizer is a definite improvement.
Details Enhancer
I could have diddled more to improve this image, but why bother. There were times I had to resort to Details Enhancer over Exposure Fusion, but even then I wasn't getting the most satisfying results. Simply put, when HDR Efex Pro 2 was introduced, it blew away Photomatix's tone mapping for natural landscape rendering. Now with Contrast Optimizer, Photomatix is back in the fight.

Fusion/Real-Estate Example
I tested this new method on an old church mission interior shot and found it did a good job in naturally rendering the bright outdoor detail. On that basis alone, you can argue that Photomatix did a better job than HDR Efex Pro, except it's not that simple. HDR Efex Pro better captures the effect of a brightly window-lit room. In this image, the lighting effect is more important than the uninteresting outside. The real benefit of this new Fusion method is described by its name: Real-Estate. If you are an agent who wants to highlight a living room that has an ocean view, then you want the outside to be well exposed and colorful. This also holds true for certain landscape images; for example, using an old barn's interior window to frame an outside scenic view. Here you are using the window only as a framing element, so you want the outside scene to be properly exposed. You could argue it's better to shoot such a situation with two exposures only: one for the outside and the other for the inside of the barn, and merge them manually in Photoshop. That may well be true, so my advice: shoot it both ways!

HDR Efex Pro
If I want, I could improve the outside detail using Control Points. However, the objective of this image is to capitalize on the window light's interior illumination effect.
Exposure Fusion/Real-Estate
The outside lawn and shrubs have more detail and saturation than the HDR Efex Pro version. Although I prefer the HDR Efex Pro's image better, there are situations I explain in the above text when Exposure Fusion may be the better tool. Even with this example, it's still a well-rendered image and a little more work in Photoshop will easily make this a wall hanger. 

Monday, September 2, 2013

Apps for the Landscape Photographer

I recently acquired some iPhone apps that may prove useful for landscape photography. I have yet to field test them, so the following are only first impressions after some playing around. I’m planning several photo trips starting next month and I’ll update this blog if my opinion changes with actual field use. The apps are: PhotoPills, The Photographer's Ephemeris (TPE), CameraAngle, and Pocket Light Meter. TPE is available for all platforms, including desktop, while the rest are iPhone only.

PhotoPills and The Photographer’s Ephemeris (TPE)

The essence of these two very similar apps is to indicate the sun and moon coordinates during any time of day at any global location. TPE has been around for some time and most photographers are probably already familiar with it. PhotoPills is a new challenger that adds some impressive features. PhotoPills is $10 while TPE is free for desktops, $5 for Android and $9 for iOS. Note that PhotoPills' iPad version is just a ported iPhone version and doesn’t utilize the larger screen.

The screenshot below of TPE (iPad version) shows the purpose of these apps. I placed a red pin on one of my favorite spots to photograph the Court of the Patriarchs in Zion National Park, specifically the Abraham Peak with the Virgin River in the foreground. The direction of the rise and set of the sun and moon are shown by the radiating lines from the red pin for the selected date of 19-Nov-2013. Orange is sunset, yellow is sunrise, dark blue is the moonset, and light blue is the moonrise. Moving the time scale below rotates thin yellow (for the sun) and blue (for the moon) lines to show their position anytime during the day. All the ephemeris data is displayed in the bottom panels. I also placed a grey pin on Abraham Peak to determine its distance and elevation, which is indicated in the lower right panel. The grey pin aids in determining if and when either the sun or moon is at some desired coordinate relative to a landmark.

PhotoPills does essentially the same thing and additionally throws in extra tools relating to depth-of-field, exposure conversion, star trails, and time-lapse photography to name a few. Beside the extra frills, what PhotoPills really brings to the table is its superior search capability for determining when (and if) the sun or moon is in a particular coordinate. If you ever had a favorite site that you always wanted to photograph with a full moon precisely positioned within the scene, then this is the must-have app.

PhotoPills, being a first version, does have some drawbacks. One is its location database and search engine. While most major landmarks can be found, it’s hit-and-miss on lesser ones. For example, TPE had no problem finding two popular state parks along Lake Tahoe (Sugar Pine and Sand Harbor). PhotoPills couldn't find them. This is most frustrating when, say, you’re at a particular location and trying to “pin” a nearby landmark to assess elevation and distance, but PhotoPills can’t find it. Instead, you have to try to pin the landmark using the satellite imagery, which can be difficult (if not impossible). The iPhone-size screen and other interface annoyances only compound the frustration. Presently, I see PhotoPills more a long-range planning tool while TPE is better for everyday field use.

Example using PhotoPills
I live near a 19th century lighthouse that I would someday like to photograph with a long lens capturing the upper portion of the lighthouse with a full moon next to it. (See my blog post, Moonshot, for more info on shooting the moon.) The free TPE desktop version lacks any automatic search for a predetermined sun or moon position. Instead, you have to manually hunt for it. The tablet versions have a search capability, but only in the azimuth direction that doesn’t include elevation. Though finding a predetermined position is easier with the tablet version, you still are left with some manual hunting to find the desired elevation. However, if you can accurately find and “pin” your desired shooting spot as well as whatever landmark you’re aligning to, then PhotoPills is the perfect tool.

In the PhotoPills screenshot below, the red pin shows my intended shooting location. I placed the black pin (equivalent to the grey pin in TPE) to trace the line-of-sight I want the full moon to be, which is slightly to the right of the lighthouse. Also, for the moon to be in proper alignment with the lighthouse, its elevation needs to be about 10-degrees. How did I know that? I’ll explain that when I get to the CameraAngle app. Usually, you can place the black pin on a landmark (a mountain peak for example) and the app indicates the elevation angle and distance (same as TPE’s grey pin). But building heights are not in the database and must be determined separately.

Now, based on the black pin’s position, I have PhotoPills search when the moon will be at that azimuth and elevation. I can control the search window size to as much as ± 5-degrees in either azimuth or elevation. In this example, I set the search field from 9 to 13 degrees elevation and ± 2 degrees in azimuth. PhotoPills then lists all the moon phases for that coordinate. You can sort the listing and show all the full moons first. The listing is color coded to indicate if the moon is at night, during the day, or during the golden hour. I want it during the golden hour since that's the most photogenic time and the contrast issues with the moon are minimal. From the screenshot below, you can see that the next best opportunity isn’t till May 2015. In the above screenshot, notice that the full moon (thin blue line) on 2-May-2015 aligns both in azimuth and elevation with the dotted black-pin line at 7:37pm, which is exactly at sunset–perfect! (To see the black pin's coordinates you  finger-swipe the top banner showing the sun and moon's rise and set times.) If you can tolerate more slop in the moon’s position, then widening the search area will yield more results that may occur sooner.

TPE is the must-have field tool that should satisfy 99% of your needs. I feel that for determining routine sun and moon ephemeris data, TPE is more user-friendly and the larger screen support (for tablets and desktops) is one main reason why. The free desktop version is sufficient by itself, but if you don’t carry a laptop out in the field, then you’ll need the tablet or smartphone app. To be fair, if you are relying only on a smart phone in the field, then PhotoPills may be a better choice (if you have an iPhone). The reason is TPE was also annoying to use on a small-screen phone. And if establishing a precise sun or moon position in your compositions is an important part of your photography, then PhotoPills is the best tool for that job. Also, the extra tools may have some appeal. Just beware that PhotoPills can still be frustrating to use at times.

[Update. I recently tried a new app called LightTrac by Rivolu Pte Ltd. It is available for both iOS and Android for $4.99. My first impressions are it's essentially a lite version of TPE. It is user friendly and a few bucks cheaper. This might appeal to someone wanting something with no frills and is easy to use. Otherwise, I didn't see any reason why it would replace TPE for me, which is more versatile and nearly as easy to use.] 

CameraAngle by Geometry ($0.99, iPhone only)

In the above lighthouse example, I knew in advance that I wanted the moon to be about 10-degrees in elevation. Often, the only way you can precisely position the moon or sun within a composition is to be there. But, you still need a way to measure elevation and so you need an inclinometer. There are many inclinometer apps, but sighting an angle with them is rather cumbersome. CameraAngle solves this by using your phone’s camera. Simply line the crosshairs where you want the moon (or sun) to be and read the angle. In the screen shot below, you see approximately where I wanted the moon to be relative to the lighthouse. (Note that it shows the angle as negative for reasons I can’t explain.)

Pocket Light Meter by Nuwaste Studios (free or $0.99 to remove ads, iPhone only)

I can imagine many DSLR users asking why would I ever need a light meter? Well, generally you don’t, but it can useful in certain situations. In my ebook on HDR, I talk about using a light meter to help determine the dynamic range of a scene so you can set the appropriate bracketing range. I have a spot meter that is the perfect tool for that task, but to be honest most times I determine bracketing based on experience and a little trial-and-error. Still, with a light meter conveniently in your hip pocket (or wherever you keep your phone) you may find it useful to quickly size up a scene’s dynamic range. Though Light Meter is not a spot meter, it’s close enough to be useful.

Now I can imagine another question: why not just use the DSLR’s internal light meter (assuming you have a spot mode). The problem is you want to know the range in stops. Cameras normally indicate exposure by shutter speed and f-stop. Trying to figure the stop difference between two exposures takes a little math. Instead, you want to read exposure in EVs (Exposure Value). That way it’s easy to mentally subtract the two numbers in your head to determine the dynamic range in stops. That’s exactly what Light Meter can do for you.

In the screenshots below, you see two readings of a daylight scene in a local park.  The stop difference between the sunlit and shadow areas is: 14.21 – 10.08 = 4.13 stops. You can tap the red rectangle anywhere within the screen or simply repoint the phone to measure the desired area. But there is a drawback: the dynamic range is actually more than 4 stops and probably closer to 5 stops. The problem is the large measuring area. This makes it difficult (if not impossible) to pinpoint either the highlight or darkest shadow without being thrown off by surrounding light. This is why the 1-degree spot meter is more adept at this job. The silver lining, though, is this drawback may work to your advantage.

The reason is the true dynamic range of a scene isn’t necessarily the bracketing range you need. As I explain in my HDR ebook, you need only pull back the highlights and shadows about one-third from their histogram ends. Any light meter, instead, wants to place them roughly in the middle, which is too far. So for the above example, though 5-stops may be the true dynamic range, a 4-stop bracketing range may be more appropriate (i.e., set your camera’s auto bracketing to ± 2 stops). So it’s possible that most times merely subtracting the two readings is close enough for government work. Still results can vary, so you may need to empirically determine a correction factor that works for you. Remember that precision accuracy isn’t necessary. You just need to get close enough so, at most, you need only tweak the bracketing range a little after previewing the histograms.

As for the general accuracy of Light Meter, first off, displaying EV to two decimal points is totally ludicrous and a complete false sense of accuracy. Nevertheless, I compared Light Meter to my Minolta spot meter and most times the readings correlated reasonably well. Actually in one case, while my spot meter was thrown off by the color of a reflective surface, Light Meter nailed it. I’m guessing Light Meter may use the color information to correct for any non-midtone-like colors. However, Light Meter could get quirky at times. The red rectangle is not a precise metering area and sometimes seemed to exhibit a hysteresis-like variability in its readings relative to its red boarder. But that’s needless quibbling since, as I said before, all you need is a reasonable approximation of the dynamic range. Plus Light Meter costs less than a buck while a good spot meter is over $500!