Question for all you Candela / Lumen Experts

Using these two flashlights as an example. .

Fenix E25
- 187 lumens
- 156 meter throw
- 6,112 intensity (cd)

Fenix PD32 Ultimate
- 760 lumens
- 155 meter throw
- 6,000 intensity (cd)

Question:

If you were to shine these two lights at a surface (let's say a white barn 200 feet away)

Would you expect the hot spot portion of the beam to look mostly identical (barring any artifacts)

I realize the spill might be very different on the two lights, but would the hot spots be very similar in their perceived brightness and illumination capability?

Thanks!

No, not at all. The E25 has a XP-E that will give a small and tight hotspot. The PD32 Ultimate is equipped with an XM-L which produce a very wide hotspot. Since the two reflectors are about the same size, you can than conclude that the PD32 will be more floody and will illuminate a much wider space than the E25.

In abstract space far from all objects, a correctly-determined lux reading will tell you how intense the spot is. These two lights will light up the side of that barn with about the same intensity, but the PD32 will create a larger bright spot than the E25. There are other considerations, though. The PD32 will light up the near area with more light. In most circumstances, that makes distant illumination look dimmer. In heavy fog, I find that trying to see very far with ANY light in my hand is nearly futile, but lights with larger output patterns make this even harder.

Thanks for the info!

wjv said:

Using these two flashlights as an example. .

Fenix E25
- 187 lumens
- 156 meter throw
- 6,112 intensity (cd)

Fenix PD32 Ultimate
- 760 lumens
- 155 meter throw
- 6,000 intensity (cd)

Question:

If you were to shine these two lights at a surface (let's say a white barn 200 feet away)

Would you expect the hot spot portion of the beam to look mostly identical (barring any artifacts)

I realize the spill might be very different on the two lights, but would the hot spots be very similar in their perceived brightness and illumination capability?

Thanks!

Click to expand...

The hotspot portion will be a similar brightness level
however the PD32 will likely have a much larger hotspot

We would need Lux/CP readings for the spill to determine what the spill is like

As a rule of thumb...the cd or lux at 1 meter is telling you how far the beam can reach...but only the hot spot's range to drop down to 0.25 lux on target.

(How far can the beam reach before its at 0.25 lux on target)

The lumens is how much light is being sent out.

If two lights have the same RANGE, the one with more lumens will be putting more light on the target, but, it will still be SPREAD OUT so that the brightness of the target will still be 0.25 lux...but you simply see more of the target/a larger area lit up.