Thanks to everyone for the suggestions and explanations. It sounds like the Coolpix 4500 is still a good camera for hemispherical photography for a number of reasons: the camera body is hinged to point up at the canopy, the 180° fisheye lens does not cut off the edges of the image, and although the pixels may be low compared to newer cameras, it is more than sufficient for the image analysis software. The Coolpix is also inexpensive. While there are combinations of newer cameras and lenses that could be used, the advantage (more pixels) does not seem to be worth the increase in cost (over 10x more expensive). This is exactly what we needed to knowthanks!
For those of you that asked, the details of the project we are working on can be found here: www.ecologyofbirdloss.org Below are the responses we receieved: *the Coolpix 4500 is frequently used because both it and the 180° fisheye lens that fits it are cheap and easily replaced. higher-quality DSLR cameras will take larger images, but a circular 180° lens is often tremendously expensive. (most fisheyes are only 180° diagonal-to-diagonal, meaning they produce a cropped rectangular image, not a complete circular hemisphere) THAT SAID: the majority of image analysis software doesn't particularly care about image size or resolution, and the Coolpix 4500 is more than sufficient. if you want to get "Fancy", it would make more sense to go for a dedicated light metering system such as the Li-Cor, rather than spend money on an overly-elaborate DSLR. *I recently bought an Olympus Stylus Tough 2 which is water proof to 45 and has a f2 lens. It accepts accessory lenses with its adapter including a fisheye lens that is waterproof to 45 feet. GPS is also built in. I love the camera and fisheye lens combination. Seems like you could make it work. *The lens you choose is more important than the camera. However, you should consider how the aspect ratio of the sensor (e.g., cameras capture less of the image viewed by the lens) will impact the resulting image. Camera brand is a personal preference. Camera equipment is expensive to purchase upfront; buy what you can afford. Another possibility worth looking into would be a light meter. *Couple of years ago, I we took more than 1000 canopy photographs using the same camera that you mentioned and the photographs came out really well. I don't think camera is important, but try to use good fisheye lens. *Many of the newer cameras, although marketed as hemispherical lens, fail to capture the full 360 degrees needed for analysis of these photos. Although dated, the Coolpix does a good job with this. If you go with a newer model, be sure to verify you are getting the image you need before you invest in the camera system. I have a 'new' fisheye lens for our 'newer' SLR digital camera that is just collecting dust - as it cuts the top and bottom sections of the image off. I have used HOBO loggers to collect light intensity data within forest gaps. A few years back, I programmed the loggers to record at specified time intervals left them in place for circa a week. I did not have enough to cover all my gap locations, so I never actually ended up using the data for analysis - but I'm confident that I could have and that these data would be highly correlated with the results of hemispherical photos.
