plant-health
plant-health


Author Comment Last activity Moderation
cfastie "I hadn't considered aperture as a reason for the vignetting. I assume it is related to the angle at which the light enters the filter. Dichroic fil..." | Read more » about 8 years ago
Claytonb "@cfastie -Hi Chris, Is it possible that the vignetting your seeing is related to wavelength interference due to aperture size? Have you tried a lar..." | Read more » about 8 years ago
cfastie "I think the Public Lab Store will ship filters to Europe: https://store.publiclab.org/collections/diy-infrared-photography/products/infragram-diy-f..." | Read more » about 8 years ago
GFFchris "Hello, I wanted to ask if anyone has an idea on how to order the Rosco filter to Europe / Germany? Many Thanks! " | Read more » about 8 years ago
cfastie "I took another batch of photos (research note soon) with ISO 200 and the shutter speed at 1/30 second. The f-stop varied between f/2 and f/5.6. It ..." | Read more » about 8 years ago
Claytonb "@cfastie -Great work Chris. Have you tested to see what your max shutter speed is with the DB filter on a normal sunny day with same ISO or slightl..." | Read more » about 8 years ago
cfastie "The angle from which the photo is taken and the angle of the sun do influence the NDVI result. NDVI values are a function of how much red and NIR l..." | Read more » almost 9 years ago
kykytos "Is it important the station in which the photo is taken? I mean, how do you differ infrared reflected radiation from infrared emitted radiation (th..." | Read more » almost 9 years ago
jtraub "Ah, my apologies for getting to this conversation late. I should qualify what I'm about to say by stating that I'm no expert in chlorophyll fluores..." | Read more » almost 9 years ago
gbathree "No worries - this is an important discussion and you're right, it's not at all easy to measure. We've spent a lot of time helping people (mostly b..." | Read more » almost 9 years ago
khufkens "@gbathree, this wasn't as much a critique on the technique, but personal experience has taught me that you have to be really picky on how you alloc..." | Read more » almost 9 years ago
khufkens "As far as I understood is the value light use efficiency value (LUE / phi2) you measure by using PAM fluorescence (LUEpam) conceptually the same as..." | Read more » almost 9 years ago
gbathree "Well... if you're working on maximum photosynthetic capacity. But that's not necessarily the same thing as actual capacity during the day (phi2). ..." | Read more » almost 9 years ago
khufkens "I'm confused by the goal of the experiment. Would just measuring Fv/Fm / or related values on a dark adapted leave not be quicker and more accurate..." | Read more » almost 9 years ago
gbathree "Nice! Yes, light intensity and phi2 are linked at the hip, and changes in light intensity will produced changes in phi2 on the millisecond timesca..." | Read more » almost 9 years ago
cfastie "Hi Giovanni, I posted a response at the plots-infrared Google group: https://groups.google.com/forum/#!topic/plots-infrared/l_dZKqFLGRE Chris " | Read more » about 9 years ago
Giovanni1983 "Hi cfastie, I'm newbie here so I hope my comment will be soon read, even if posted on an old discussion. I also apologize in advance for all the la..." | Read more » about 9 years ago
cfastie "Bob, this is a great idea. A secret admirer sent me one of these and I was very excited. I didn't know that any mortal could order them for only $3..." | Read more » about 9 years ago
bobmathieson "anyone tried the Rosco sample book... only $3.95 from adorama. The swatches will not be big enough for front lens filters on SLRs but easily big en..." | Read more » about 9 years ago
btbonval "If PhotosynQ people want to make their own wiki, they're free to grab the content from your note here or the wiki page I made from your note. Every..." | Read more » over 9 years ago
btbonval "Stripped out all the juicy plant bits and spectral mumbo jumbo. added it here: http://publiclab.org/wiki/multispectral-analysis-for-determining-pla..." | Read more » over 9 years ago
cfastie "I agree that this material is more appropriate for a wiki than a note, but I wanted people to see it. Such a wiki should be built by somebody at P..." | Read more » over 9 years ago
btbonval "Apologies if I was being pedantic. Now that I think about it, cleaning up the note isn't a great solution. Instead of changing this note, the perti..." | Read more » over 9 years ago
nedhorning "Good stuff. From my perspective NDVI is good for mapping vegetation and can provide some indication of overall health and is good at differentiatin..." | Read more » over 9 years ago