Is 6200 lumen noticeably brighter than 5000 lumens?

The Q8 can be used with a single cell. It’s a parallel circuit.

Maybe you have a camera with a manual mode? You could keep exposure, ISO, and WB constant and take pictures for both lights. Please show :slight_smile:

Perceived brightness and actual brightness in those output figures is like comparing 1200 degrees to 1800 degrees. Your eyes and skin won’t be able to tell the difference. Also the color temperature of the light makes it complicated since 5700k seems brighter than 4000k even though the actual
lumen #’s aren’t far off.

The test was outside at night. Shining them at faraway buildings and the Q8 show them up better than the K65. It could be because of the color spectrum. The flood parts seems to be the same.

That's $65 Q8 vs the $120 K65 (new was $200) and the $65 Q8 won.

To the naked eye, no.

As a generality, each time lumens are doubled, the human eye perceives about a 20% increase in apparent brightness.

That makes sense. I guess I expected too much out of the K65. Too bad it's bad.

Of course the Q8 won, after all it was BLF project :slight_smile:

Had the same issue with my first Convoy S2, one with 4x7135 and the other with 8x7135. To my eye they were exactly the same on high.

Keep in mind their is a mode group on the Biscotti S2s that sets 50% as the max output setting. Be sure both lights have the same output settings enabled before comparing.

6200 lumens appears to be 11% brighter than 5000 lumens, which is not very noticeable.

The weather outside is really nasty, wet and cold so I did a hallway test instead. Surprised me how they compared. Your responses?

Q8:

<a href='https://postimg.cc/5jGgw9Qt' target='_blank'><img src='https://i.postimg.cc/NfGnv5gR/IMG-20200213-221139.jpg' border='0' alt='IMG-20200213-221139'/></a>

K65:

<a href='https://postimg.cc/vcVzXR5t' target='_blank'><img src='https://i.postimg.cc/8Py0pN59/IMG-20200213-221419.jpg' border='0' alt='IMG-20200213-221419'/></a>

Q8 wins.

The K65 is just a throwier light. The Q8 is lighting more of the stuff to the sides with its brighter spill, but look at from the hotspot of the K65… that’s light being reflected from the hotspot and it’s clearly brighter than the Q8 in that regard.

Really though without putting these in a lumen tube or sphere there’s no way to know for sure. But some things to consider:
1 - The Q8 will gradually dim as the cells have lower voltage. You will only have max output with fully charged cells.
2 - There are many reason other than sheer output to buy an Acebeam. I think they have much better construction and QC than Thorfire/Sofirn (< no that theirs is BAD by any means) and would just generally be more dependable.

The K65 may be using a buck and/or boost circuit in its driver which should give better efficiency or at least even better sustained output over the Q8 as well.

The Acebeam appears to have a much brighter spot. Nice searchlight.

The K65 uses the batteries in series so it's 16+ volts. The Q8 are all parallel so I guess it's amp driven. I see that the K65 is everything it's meant to be but with a faulty switch. Also the head has a burnt smell.

I see better with the Q8 than I do with the K65. I can't see the K65 selling for $200 when I got it for $120. Later I found out it was a used item.

After comparing the Q8 and the K65 the Q8 was a lot better deal at $65.

Judging by the photos you posted above, the Q8 appears more floody.

As I have learned but they seemed to be the same outside.

Even neglecting the fact that two different lights can have total different characteristics (throw, tint and all that) I would argue that there is almost no visible difference between 5000 lumen and 6000 lumen. On that level a difference of 1000 lumen is just not that much.

compare 300 to 1300 lumens and its like day and night - but 5000 vs 6000 is about the same.

Lumen differences don’t scale linearly with your perceived brightness of the light. It will take like 4x the lumens to achieve what looks like 2x the brightness.

What does scale linearly with perceived brightness is lux, or intensity, which is an attempt to measure what your eye sees. If light A has 3x the lux of light B, it will appear 3x brighter in the hotspot, but it won’t throw 3x farther.

Our perception of beam intensity would scale the same as lumen output. Think about turning the brightness up on a light: the lumen output and beam lux go up by the same amount. Lux is just lumen per square meter afterall.

That’s almost a 25% difference so yeah technically you will be able to notice it.
However, differences in deflectors or beam shape also have an effect so you can’t really compare unless it’s two of the exact same light.