IKEA sell a Tradfri bulb (304.413.80 in Europe) which has a 2200K colour temperature and 250 lumens output, which I've been using as a bedside lamp for the past year. At the brightest setting it is more than enough to read a book (usually we use it at around 50%), and it dims enough that we use it as a night light for kids.
The new EU light labelling requires a spectrum to be posted online. This bulb still has a blue peak, but it is mainly red:
The bulb dims well without flickering, but my only complaint is it doesn't dim that much. This seems to be the case with all ZigBee bulbs I've tried. A Philips Warmglow with a separate dimmer can be dimmer smoothly from off. Does anyone know why ZigBee bulbs don't do the same?
There are a number of factors involved in LED lighting quality, and annoyingly not all are tested for in reviews or shown on specs.
Think of an LED as a capacitor designed to leak electricity that emits light whenever it leaks in one particular direction. It's a bit handwavy but it works here. Depending on the design it might require more or less charge or voltage before the electrons jump over the diode (the light-emitting leaking step), and those characteristics affect how it behaves under different inputs.
One really common thing that affects the quality is the AC/DC conversion is handled. LEDs are DC. A common cheap solution is to use a half-wave rectifier, meaning half of the time the LED is "off". Technically it's more like "half of the time there is no charge build-up so the electrons won't always jump over the LED and the amount of on/off time varies based on specifics" (again, being a bit hand-wavy).
The result is mostly the same: with a HWR the LED isn't always emitting light. Normally these flicker too fast to directly see the flickering itself when looking at the lamp, due to afterimages (the frequency depends on the frequency of the AC input, so typically 50-60 Hz). But you can see it when looking at anything illuminated by the lighting and it drives me absolutely bonkers because it increases my eye-strain.
Example: with solutions that don't throw away half of the AC input waving your hands will result in smooth "motion blur", and with a HWR you'll see a stroboscopic effect. Another common example is cheap Christmas lights: if you move your eyes quickly they'll look like dashed lines, not smooth ones.
Now I hope that no dimmable LEDs use HWRs, because dimming will amplify the relative time the light is off. That will make the flickering worse. But we can't tell ahead of time because reviewers don't test for it! In fact, since there are no specs we can't even tell if any brand changes things between production batches. So I honestly can't say if this applies to Philips or Zigbee.
The new EU light labelling requires a spectrum to be posted online. This bulb still has a blue peak, but it is mainly red:
https://eprel.ec.europa.eu/screen/product/lightsources/84738...
The bulb dims well without flickering, but my only complaint is it doesn't dim that much. This seems to be the case with all ZigBee bulbs I've tried. A Philips Warmglow with a separate dimmer can be dimmer smoothly from off. Does anyone know why ZigBee bulbs don't do the same?