Hello Mr. Chamberlain, You have two conflicting requirements for your project's instrument ; an instrument that measures color temperature (CCT) and CRI, yet is low in cost. Low-cost instruments almost exclusively measure light only then ship the data to a host computer for the computations. One indicator for this class of instruments is that they do not have their own information display. Examples include the i1Pro, Lighting Passport, fiber optic instruments, etc.. When an instrument has an information display it has its own internal computation engine and the cost for the instrument is much higher. Examples include the Konica-Minolta FD-7, Photo Research PR-655, and so on. For the lowest cost solution I recommend the X-Rite i1Basic Pro 2 (SRP $1199) combined with SpectraShop ($95). This solution will measure light sources (including flash) at 10 nm intervals and can calculate CRI, CQS, duv, CCT, power, and more. See http://www.xrite.com/i1pro-2-color-calibration-profiling-solutions for i1Pro 2 information and http://rmimaging.com/spectrashop.html for SpectraShop information. This combination will also measure reflective and transmissive objects, so it can adapt to any additional needs. This combination will work with both Mac and PC. The next lowest solution would be the Asense Lighting Passport (SRP $1775) and works with iOS devices such as iPhone, iPod and iPad. It measures light sources only (no mention is made of flash). More info can be found at http://lightingpassport.com/index.html. This instrument measures at <8 nm resolution. The software for this is PC only at the moment. Another solution would be the Moreland Lighting MK350 ($2195), which measures lighting only but it does have its own display. Here is a link to its information page http://morelandlighting.com. It measures at 1 nm intervals (a good feature for spiky light sources) and can save data onto SD cards. The main software is PC only, but exporting the data in Excel format to an SD card will allow Macs to get to the data too. Other solutions using fiber optic spectroradiometers will cost considerably more. Examples here are Ocean Optics, StellarNet, Edmund Scientific units, and others. These solutions definitely require a host computer to do the computations. Most of these offer PC only software. The next step up would be instruments such as the Konica-Minolta FD-7 ($6000+). This is a standalone instrument with an information display on the instrument. Instruments such as the ones from Photo Research are very expensive ($12000+), are standalone and are very adaptable. But they are probably a bit outside your budget. These are only a few choices, more can be found with a bit of searching. Robin Myers On Mar 10, 2014, at 4:05 AM, Joseph Chamberlain <drjchamberlain@gmail.com> wrote:
Roger, Jan-Peter, Danny, Steve, Matthew, Jose, Fons and Graeme,
I can't thank you enough for all your answers and help with this question. Your answers have helped me and given me the information I needed to find.
Are any of you aware of an inexpensive spectrophotometer capable of measuring the spectral power distribution of light sources in similar increments (5 or 10 nm intervals or segments) ? I have contacted Minolta and they do have some interesting measuring instruments but the cost is a bit prohibitive for my project. In addition it would be nice if the instrument could also measure color temperature and CRI.
I do have another question but will initiate another thread with a different subject line so that it becomes easier to follow.
Thank you very much again for your answers and all your help.
Joseph.