ExpoDisc White Balance Filter Review
The purpose of White Balancing is to find the most accurate color rendition in your photos. Digital sensors are especially sensitive to the different types of light sources that you may be shooting under (sunlight, fluorescent, incandescent and so on). A good photographer should not only be aware of color rendering issues related to white balance, but they should have a plan or a process in place to correct the problem. Cameras will have an auto-white balancing mode which are, for the most part, pretty good. But they are far from perfect, especially under unnatural light sources. For the purpose of metering, your camera sees in shades of gray, and sometimes the cast of a light source can throw off such balancing.
The ExpoDisc is one of the many tools designed to help correct the problem in the camera. The people at ExpoImaging, Inc. were kind enough to loan me an ExpoDisc Neutral to evaluate and review for Shutter Photo. A Portrait version is also available which adds a bit more warmth to your photos. The package I received is exactly like the retail package and includes everything you see in the photo above. Contents included the ExpoDisc, a carrying pouch, a lanyard (with quick-release), a quick-start guide, an instructional CD and an evaluation/inspection card (verification that the ExpoDisc was tested and meets their strict guidelines). Though I'm sure you will want to read everything I have to say, let me cut to the chase and start off by saying that I am sorry to have to send it back. It has already been added to my wish list. But it is not perfect and it is not a device for every application.
The Importance of Getting it Right In-Camera
Before I launch into the review of the product, I want to start off by briefly discussing why getting the White Balance correct in the camera is so important. I have been witness to many a conversation about whether such a tool is necessary if you're shooing in RAW – the opposition arguing that you can balance as part of your workflow. While this may indeed be the case, it's time and effort wasted when a tool, such as the ExpoDisc, would save you a great deal of time on large sets. Those of you who shoot in JPEG would have the most interest in White Balancing, because a compressed JPEG may not contain enough information to get back to an accurate white balance. And even if you want warmer or cooler photos, you need to start somewhere, and starting with an accurate white balance is ideal. Whether you make money from your photos or not, there are certainly better uses for your time.
Using the ExpoDisc
The ExpoDisc works like a lens filter in the way that it fits on the end of your lens (or your filter stack). Unlike a typical filter, it does not screw onto the lens. It has three spring-loaded ball bearings around the lip so that it can easily snap onto and hold firmly on the lens while you take your measurement. When I requested the ExpoDisc for review, I was informed that the size should correspond to the filter size of your lens for best results. I requested one to fit my largest lens. Ignorantly, I assumed that it would be fine to just just hold the larger ExpoDisc in place while taking readings with my smaller lenses. But this turned out to be a lot more cumbersome than I expected. Not because of the ExpoDisc's design, mind you. Rather my camera requires me to hold a button with my left hand to put it in metering mode, then I need to take the reading with the shutter button (right hand). In theory, I could set it in mode before holding the disc in place, but it is still a bit more juggling than would be necessary. Though the lanyard certainly helped, this was not easy to do while holding it with my smaller lenses. With my larger lens – the one the ExpoDisc was fitted for – this was not a concern at all because it just snaps into place and stays there until you're done metering. So I certainly appreciate that bit of advice, and I would offer the same: If you choose to use an ExpoDisc, get one that fits your lens.
Taking a reading with the ExpoDisc was quite easy. Though the process may vary between camera manufacturers, I essentially snapped the ExpoDisc onto the end of my lens, switched to “Pre-set” white balance, pressed and held the white balance button indicating that I was going to take a reading, and took the reading. About 90% of the time, the reading was accurate, and my test photo yielded results I was happy with. For the other 10% of the time, I had to take a new reading while aiming the camera differently. For example, when I was taking a reading outside with snow, I found it more effective to meter from the sky.
In my experience, the ExpoDisc worked best under natural light. To be fair, my camera's auto white balancing also works best under natural light. I experimented with the ExpoDisc for street photography, and I experimented with it in rural, urban and suburban environments. I tried it on sunny days, on cloudy days – I even tried it once in the rain. In all cases, the results were predictable: The ExpoDisc performed well – but only slightly better than the auto white balancing. But my eyes were opened after a snow storm that piled close to 30″ on our front yard. Under cloudy skies with white lawns and salty pavements, I took this set of photos of my front walk. Please note that I did not make any adjustments to either image. The auto white balancing was clearly thrown – everything yielded a bluish cast. The brick of my house appeared purple with drab grout. The pavement was unnatural and the snow – well, you can tell it's snow, but frosty would look sickly. So I snapped on the ExpoDisc and pre-set my white balance. The results of my photos from that point on were mind blowing. As you can see, the pavement looks like concrete, the brick is brick colored, and the snow looks white. Snow is incredibly difficult for the mechanical eye to to get right. Your camera wants to believe that snow is gray, so the built-in meter almost always gets it wrong. Experienced photographers now how to expose and meter for snow. But without some white balancing solution, your camera is not going to get it right. Gray cards are one thing, it's an object in a scene that you meter from. But where I was skeptical of the ExpoDisc was in a situation just like this – I was not expecting a snap on filter to be able to accurately meter a snowy scene. But it worked well, and the snow storm – if nothing else – would have sold me on the ExpoDisc.
Artificial lighting is always tricky. Fluorescent and Compact Fluorescent lighting is cool and causes a bluish cast in your photos. Incandescent lights – especially soft lights and warm lights – will cause a yellow or even orange color cast. The other problem with artificial light is that it dissipates very quickly – its influence on a scene can change within a couple of feet. It's very difficult to balance under artificial lighting, which is why studio lighting is such an important (and expensive) aspect of a portrait photographer's trade. Hobbyists rarely have such luxuries, however. Rarely have I seen a white balancing solution that works perfectly. I'm sorry to say that the ExpoDisc is not an exception. Like many other solutions before it, the ExpoDisc was inconsistent under incandescent lighting. Most of the time it worked, but sometimes, it did not. One lamp in particular was cause for some problems – a 150 Watt 3-way incandescent bulb. In the illustration at right, I have provided three photos. The top was taken with the camera's automatic white balance, the bottom with the preset form the ExpoDisc. The center shot was manually adjusted to more closely match the actual color profile. As you can see, the camera's automatic sensor overcompensated and made the shot too warm. The use of the ExpoDisc resulted in a bluer cast, which is odd considering the source casts a very warm. In this case, I would say that the ExpoDisc yields no clear advantage. No matter how you spin it, the majority of photos with incandescent lighting will need to be verified in post-processing. The only possible advantage is that the ExpoDisc provides is to get you closer to the actual white point as a starting point for your corrective measures. It is, in my opinion, much easier to warm up a photo than to make it cooler without loseing fidelity. The ExpoDisc got me to a manageable white balance. But it is certainly not the perfect solution for such conditions.
Update (Feb 22, 2010): After conducting a series of additional tests, we discovered that if we removed the lamp shade, the resulting image while using the ExpoDisc for balance was not nearly as blue. There was still a slight bluish cast, but the resulting image was fairly close to actual colors – much closer than the example above. We would still consider incandescent light a difficulty of the ExpoDisc system, however, as there would not be an easy way to check – for certain – the accuracy of the color profile before continued shooting. On the other hand, a good photographer already knows not to trust shots under incandescent light, and likely has a back-up plan in place for such photos.
Update (April 21, 2010): Further lab testing debunked our findings. For the full story, read our follow-up post.
To be completely fair, the ExpoDisc performed incredibly well under fluorescent and mixed (fluorescent and incandescent) light. The photo at the top of the page showing off the contents of the package was taken under mixed lighting: Compact Fluorescent, standard fluorescent tubes and an incandescent lamp. The ExpoDisc worked perfectly in this case.
I was skeptical at first, but a few weeks spent with the ExpoDisc quickly changed my mind. I'm a believer now. I had expected the color correction to be inaccurate much more often. In fact, the only time I experienced any sort of incorrect white balancing was under a 150 Watt warm incandescent light bulb – but it was still fairly close, significantly closer than the automatic white balancing, and still much closer than the incandescent setting on my camera. The snap-on feature is a nice touch. When I was advised to select a filter that would fit my lens, my first misconception was that I would have to screw it onto my lens to take a reading – an annoyance I did not want several time throughout a photo walk. I was happily surprised with the ExpoDisc arrived and I did not have to worry about that. The pouch and lanyard were also nice touches. I fastened the lanyard to my camera bag so that it was in easy access, and it was protected from clumsy fingers dropping it to the ground. It's also a good length to hang around your neck.
For those of you shooting under the controlled environment of a studio – this may be easier, but it may not be ideal for your fine-tuning minds. Studio photographers may still favor the over-sized (not as easy to carry) gray cards for their white balancing needs. But for the rest of you, the ExpoDisc is a fine tool to carry with you. It's small, it's accurate and convenient. It will also save you time in post processing – and who wouldn't want that. I find the ExpoDisc to be more accurate and certainly more easy to use than pocket-sized gray cards in the field. Anyone who's tried to shoot in the city will certainly appreciate not having to place a card just right in order to meter for white balance.
As I mentioned earlier, the ExpoDisc comes in two varieties: ExpoDisc Neutral, which I tried, and the ExpoDisc Portrait, which yields a warmer cast. Though I did not test the Portrait, it is my opinion that the Portrait iteration is a bit too specialized. As combined with a preset in your favorite photo editing software, your photos could easily be warmed up routinely since the starting image is corrected. So I'm not so sure the Portrait version is worthwhile.
To be blunt – I will be purchasing one of my own as soon as my budget allows. The cost is about $70-$105 (USD) depending on the size of the filter you need. Without trying one out for myself, I would have said that was too expensive. But after using one, I'd say it's a fair cost. It certainly saves a ton of time and frustration. So yes, this is on my wish list, and I expect to have one of my own before too long.
This is a Shutter Photo Recommended Product
Things We Liked
- Accurate under most lighting applications.
- Easy to use with your camera
- Small – fits in your pocket easily.
- Snaps onto the lens easily without the need to screw it into place.
- Easy carrying options – lanyard and carrying pouch, quick access while in the field.
Things We Didn't Like
- Not perfect under all light sources, such as some incandescent light Update (April 21, 2010): Further lab testing debunked our findings. For the full story, read our follow-up post.