Photone - Grow Light Meter 4+

Best app on the AppStore to estimate PPFD for growing plants. I’m a botanist, and so I know this app won’t replace a $400 par meter, but for quick estimations with your phone? This app is more than worth it. The hold feature is super useful. The background shows a grainy picture that gives you instant feedback that you are aiming your phone correctly, which is a unique feature that even the expensive PAR meters do not have. A suggestion to the developer for a future update would be for the background preview picture to freeze when the hold option is used. The hold option right now freezes the reading which is useful for measuring at actual leaf locations and orientations, but the background picture does not freeze with the reading. It would be amazing for the background image to freeze with the hold measurement, so when you pull your phone back you could see that you were aiming the phone correctly and you could see what you were aiming at when the hold measurement was taken.

Thank you very much for your kind and useful review! We will definitely consider the background image hold for a future release!

Originally, I had written a review stating how displeased I was for paying $5 for the Full-Spec LED addon. Then, I decided to see what others had said in their reviews of the app, and found an interesting bit of information that really helped me. I was getting inaccurate PPFD reading (300 directly next to a light source for plant cultivation), and was absolutely baffled by the number I got. However, I noticed multiple people, as well as the developer state that the use of a diffuser (like a tissue) is important in some instances. I just tried this and feel the PAR reading is incredibly more accurate than what I originally thought it to be. My apologies to the developer, and thank you to everyone for bringing useful information to the reviews. I would certainly now recommend this app knowing what I do.

Hi Funmcfunster,

Thank you very much for your review! We greatly appreciate your insight and are happy that you get good use of our app!

Best regards,
Dominik

Only reason I gave 4 stars is due to the fact that this is the only device I have used to measure light output of my full spectrum LED’s. So I’m not entirely sure how accurate its measurements are, or what the standard deviation of the measurements would be. One thing that could be added is a standardized diffuser that would be consistent, it worries me that if I don’t use the exact same thickness and type of paper every-time I may get inaccurate readings. However from the experience I have with the app it works amazingly and seems to give me relatively accurate readouts within a few 1000 Lux or a dozen or so par from what is advertised by the manufacturer of my current light and from what I’ve seen online people using high end spectrometers and other devices get similar data readouts… if your new to growing or just want a general idea… this app is the way to go 1,000%. Will not let you down just take your readings with a grain of salt.

Hi Blackout9642,
Thank you for your detailed review and your input! Happy to hear that our app is helpful to you. The deviation between devices is low as we've tested ALL supported iOS devices in our light lab and created specific factory calibrations for them. So as long as you're using the same diffuser, the absolute measurement is comparable between devices. What is introducing a bit of variation (~6% standard deviation in our tests) is the paper diffuser itself due to placement and paper structure. Your input on this is very valuable. You can also reach out to our support if anything else / related comes up.
An update would be greatly appreciated when you've had the chance to test multiple devices :)
Best regards,
Dominik and the Photone Team