Choosing an LED Light

all good, am quite stoned and my thoughts are drifting.
also i my brain connected the "panel" wrong.
i also derail this COB led thread with the "sun" thing a lot i fear.
basically the difference between sun and our indoor and what makes the difference is driving my mind.
youre of course right that a 30cm more or less distance to the sun dont matter compared to the overall distance.
i know that the definition of hard and soft light is driven by the angle not directly intensity and or distribution of the rays while i would say there is a clear relation which we can use to understand our indoor lights better

Horselover fat said:

1) light reaching all parts of the plant by coming from many angles

For #1 you need a big light source or multiple sources. For the plant it's all the same as long as photons come from all directions.

Click to expand...

This. This is why multiple sources of weaker lights can have better penetration than single sources of stronger light.

Horselover fat said:

2) uniform lighting from top to bottom of plants

For #2 you need distance between the light source and the plant. For short plants a short distance is sufficent, but tall plants need more distance.

Click to expand...

I know what you are trying to say with this and I will use the photography anology as well.

If you shine a light on a person there is a shadow cast behind them. If the light is close to the person, the shadow behind them will be larger due to the angle of incidence. If you move the light further away, the shadow behind the person gets smaller due to the narrowing of the angle of incidence – that is, the angle between the light source and the edge of the person who is casting the shadow.

This we can agree on.

But the missing piece of the puzzle is that we are not trying to reduce the shadow behind the person – we are trying to light the person themself. That means we are trying to light the front, sides and rear of the person.

If we place a light in front and behind the person, we can light their entire body. But this may not be practical if we are trying to light a plant.

Instead, we continue to light the person from the front, but we place two lights to either side of the person. Now we have lit the front and sides and part of the person's back. We have lit more of the person by splitting the light in two and shining it from different angles than if we used one source of light .

No matter how strong the light is, or how near or close it is, a single point of light cannot light as much of the person as two or more light souces coming from different angles. That is why a single COB will not penetrate further than an array of LED strips or panels placed across the entire canopy (at the correct height to avoid wall losses from excessive reflection – as we know, reflected light is lost light as there is no such thing as a 100% reflective surface. All surfaces absorb some light.)

It is all to do with the angles.

So the P word was mentioned...
I think when most people talk about penetration they talk about good buddage on lowers. When asked to specify they tack towards light intensity and explanations of the inverse square.
We tested it out: took measurements under the cannopy of a few different lights: qbs/fotops at 6" qbs on higher power at 16" and some different hids. All the results where pretty much the same: at 2 leafs into cannopy the amount of light was very low compared to regular flower intensity, like 150ppfd. Not enough to build large bud. Yet up to 18" down in the cannopy we could get primo bud from what looked like sucker branches. So "bud penetration" does not seem to have that much to do with the light source penetrating into cannopy, at least not in a standard top lit grow.

Ok guys looking for advice, I recently ordered a new timber cypress 8 3500k light, but the 3500k diodes are out of stock indefinitely, would you A. Take an even mix of 3000k-4000k B. One of those two color temps or C. Wait, possibly a long time.