Here's something that came to light over on CN. It is a detailed review of the
new Swaros, plus ratings and some spectral transmissions several of the top 42mm roofs, by Gijs van Ginkel.
http://home.europa.com/~telscope/Gi....binoculars.pdf
And, here is Gijs's description of the transmission measurements:
"That was done with a high sensitivity spectrograph described in a paper by Frederix et al. in Applied Spectroscopy Vol 55, nr 8, pages 1005-1012, (2001). Basically the spectrometer consists of a prism for light dispersion with a state of the art CCD camera. A total number of 400 pixels is available to record a spectrum ranging from 450-680 nm. The acquisition time for a full spectrum was in our case 60 sec. A stabilised source of white light equipped with a diffusor was used as a source of white light. Light transmission was measured by guiding the transmitted light from the exit pupil to the spectrometer taking all necessary precautions for reliable measurements. Absolute transmission values were established with lasers and a calibrated power meter. For calculation of the transmssion spectra the instrument background, the lamp spectrum, the lamp background and the dark current of the detector were all taken into account. Care was taken that the response of the spectrometer detector was in the linear traject of the response curve.
If you want to see the set-up in working condition: it is used on a daily basis at the Biophysics Dept., Debye Research Institute of Utrecht University in The Netherlands."
Ron
PS
Off topic, but here is the accompanying review of current spotting scopes:
http://home.europa.com/~telscope/Gi....telescopes.pdf
Good article, especially graphs of transmission.
Interesting review, this high tech lab should be qualified in its findings.
What I find that stands out, is that Swaro. with the new 8x42 HD, SLC, has equaled
the Zeiss 8x42 FL, in transmission. The Zeiss FL with the Abbe Koenig prisms, has
previously held the title.
I guess that means great glass and coatings can also get to the top.
It is good to see the progress made in the latest Swarovski product.