State your opinion… Wait…
There's a difference between discussion and disagreement. None of use know the difference, LOL. Here we go again!
EDIT: It's all a mute point really. The difference is in us and what we want, nothing more. Some people want a Vette, some want a Toyota. Some don't care. Some are color blind and think the red car is pink. Doesn't matter. Why do we want the brightest light, who cares, it doesn't matter, we want it, that's all... and we will argue about it till we die and it doesn't matter.
Just sayin
Yeah, the inverse square law related to luminance at different ranges, not to do with the logarithmic nature of brightness (defined as subjective perception of luminance) perception.
This is a good and relatively simple academic introduction to the area: http://www.google.com/url?sa=t&rct=j&q=jnd%20psychophysical%20threshold%20for%20luminance&source=web&cd=1&ved=0CDMQFjAA&url=http%3A%2F%2Fwww.ict.griffith.edu.au%2Fteaching%2F1008ICT%2Fdocs%2Fhumanvision.doc&ei=8-P7UJudEe2z0QXmzoHQDA&usg=AFQjCNFnXSwgQ72GBAunho2LrZERX6je3A&cad=rja
’Physical differences in stimulus can be measured directly using physical devices such as light meters, scales and other devices. It is not possible to measure subjective impressions of stimulus directly (Fechner 1861) but we can measure Just Noticeable Differences (JND) for incremental changes in stimulus level. Weber’s Law (1834) of Just Noticeable Differences provides a very rough gauge of JND to stimuli within their normal ranges of intensity.
Weber expressed his law as: C = ∆I/I, where C = 0.08 for light intensity, C = 0.05 for sound intensity and C = 0.02 for kinaesthetic intensity.’
What this means is that accoording to Psychophysical detection thresholds a Just Noticeable Difference for luminance will be at around 8% increase in intensity. This may vary according to a number of factors and to a certain extent between individuals however.
For a less academic introduction, this BBC programme ‘Do you see what I see?’ is a really good watch: http://www.dailymotion.com/video/xl7cgh_horizon-do-you-see-what-i-see-part-1-4_shortfilms#.UPvlKfIZl7Q
That is a link to Part 1, 2,3 and 4 should be accessible in the bar of options to the right.
Is 800 lumens a lot better than 600 lumens? Does it matter?
That’s very interesting stuff RedForest.
And Old-Lumens – I’d say “you’re right on the money” as regards personal taste, personal opinion and preferences. This is a hobby and everyone has a right to value a Gold flashlight more than a Black one – or vice versa.
Boaz is a seasoned, experienced and knowledgeable veteran here on the BLF and he was the one that said that there is little or no difference between 800 and 600 lumens “in the real world” (to paraphrase) and as the eye perceives the level of lighting. That’s not to say he wasn’t taking a little “poetic license” in making his comment.
There is also a very big difference between a comparison of lights when side-by-side and when used at different times for the same function. That said, I myself feel that I can probably see a little bit more with an 800 lumen light than with a 600 lumen light – but 100 lumens may be too small a difference to “remember” from one outing to another.
This is a very controversial subject, particularly since people on the BLF are so conditioned to paying attention to the numbers – and often invest their hard-earned money based on those comparisons.
Certainly it’s true that the eye is a logarithmically calibrated device. Otherwise you wouldn’t be able to get around in a dimly lit environment and still be able to see on a bright summer day at noon. As a result, anyone that claims that a relatively small percentage difference in output (as measured in lumens) is very significant for most purposes is probably trying to justify their purchase more than facing reality.
Please remember that I am among those who like to show my friends just how far a certain light is able to throw and just how bright another may make a room. I’m also influenced by the relative attractiveness of the industrial design employed in one flashlight vs. another.
Nevertheless, I started this thread with the intention of stimulating debate and possibly bringing certain truths to the surface - truths that may otherwise remain unspoken or unrealized. Please don’t take any of this too personally. We’re just having a discussion about our hobby here.
Thanks for listening.
Bob
Yes, it’s a valid point. 200 lumens added to a 600 lumen light will look no-where near as bright as 200 lumens added to a 50 lumen light.
The early Psychophysics referenced here often made use of a 50% accuracy value when determing detection thresholds (contemporary methods make use of a 75 or 82% threshold), so it would mean that an 8% increase in stimulus intensity was noticed 50% of the time by trained observers. It doesn’t mean that an 8% difference is a large one. For a perceived doubling of light intensity I believe the objective luminance must be increased by a factor of between 3 and 4, with significant individual variation.
One other thing to bear in mind is that CCT does also have an effect on perceived brightness. -So while a 600 lumen light may be indistinguishable from an 645 lumen light of the same spectral characteristics if you introduce the other factor of varying CCT (so one is warm while the other is cool) then you must take that into account.
Higher CCT light sources generally appear brighter than lower CCT ones, so that means that even with a cool and warm white option both at 600 lumens the cool white will probably appear brighter anyway. This effect is then slightly increased by the small increase in efficiency of a cool white LED over an equivalent neutral or cool white.-
Actually, this effect of CCT on perceived brightness is already taken into account in lumen ratings, which are already weighted according to the peak sensitivity wavelengths of the human eye. So please disregard the bit above this (I’ve tried to cross it out but it never seems to work on my account).
With regards to Edwin Land, a good demonstration of this is shown here: http://www.youtube.com/watch?v=3DiCvHiDWiY
It’s all to do with ‘colour constancy’, which is maintained by higher cortical processing rather than anything in the retina.
Just to throw a spanner in the works 
what you see reflected back when you shine a light is not even the same light that left your flashlight 
Kuma Bear, thanks for an interesting topic of discussion.
What seems to get lost in all these tint and CRI threads is that we are all different. A big thanks to Old Lumens who always seems to point this out in these types of discussions. Do people with brown eyes see color differently than those with blue eyes? Do women see color differently than men? (I already know the answer to that from shopping trips for paint with the wife). Does everyone have the same depth perception, night vision, acuity? Are we all using these lights under the same ambient conditions or for the same intended uses? Taking away all the lux meters, integrating spheres and other tools we use to measure light, what happens when said light hits the rods and cones in our eyes and how does our brain process that information?
For anyone to say that one tint is better than another is just expressing an opinion of what they perceive to be better. Any discussion on tint should start with "what's your favorite color?"
Boaz, I love you man, but as an ex-landscape designer of perennial gardens, I would suggest that if you really want to get slawjacked about color rendition in a garden, don't do it at 2AM with any flashlight, instead start by studying Claude Monet. 
Sorry, couldn't resist. I am not an expert on color. But I remember many discussions on the subject in drawing & painting classes in college. All of the above are paintings done at different times of the day/different times of the year. All can be called "Natural Light". Don't you all think it's a bit silly to expect that one emitter does a better job of capturing "natural" when natural varies so much? Food for thought in an interesting discussion.
For the Curious: More on “The Land Effect” or “Retinex Theory”
Follow-Up to this thread’s OP
The links below bring the reader to more fascinating information
related to the discussion about
Edwin Land’s experiments with, and theories about,
color perception.
RedForest was kind enough to find this YouTube Video of Land demonstrating part of his theory on the BBC in 1985. His demonstration only scratches the surface of the subject but I find it totally mesmerizing. I list it first because it is the easiest way to understand and visualize what I was trying to describe earlier in the OP. I hope you enjoy it:
http://www.youtube.com/watch?v=3DiCvHiDWiY
The following link takes you to a discussion of Land’s discovery, the serendipity involved and the utter fascination and incredulity that led me to try to duplicate it while in Junior High School (with partial success):
http://www.wendycarlos.com/colorvis/color.html#discovery
The next link takes you to Wikipedia’s listing of related articles and information:
More specific information from Wikipedia on the subject:
http://en.wikipedia.org/wiki/Retinex_theory#Retinex_theory
An illusion that takes a “babystep” toward demonstrating the phenomenon:
http://en.wikipedia.org/wiki/Same_color_illusion
A discussion explaining a Theory of Color developed by a German many decades before Land’s experiments but having a surprising amount in common with Land’s theories:
http://en.wikipedia.org/wiki/Theory_of_Colours
I hope that some of you enjoyed reading through this material. I’d be happy to explain how my son and I took the theory in a somewhat different direction to produce a working example of part of the Land Effect in 1993. The results were quite startling.
Regards,
Bob
Thanks for that link, RF UK. That was a fascinating program, enjoyed it a lot!
That is, if one wanted NW even with a CW led would using a colorized filter replacing a clear lens give basically the same effect as if the led to begin with was NW? It seems to me that if camera type filters were applied on flashlights that one could have the best of all flexible worlds regarding tint.
But you lose a lot of lm
I’ve come to realise, as I hand out a few lights, I grossly underestimate things. Key point:-
I built an m10 with the now famous intloutdoor 4a driver and a u3 1c emitter. I liked it, but mainly for the host and the UI, I saw the output as “acceptable”. I then wanted to do a give away, I like to give away things I like, so, I ordered another m10, already had another driver, the m10 came with a u2 marked star, so I passed on an emitter swap. Dale won the give away, recieved the light and is I feel its fair to say blown away by it.
In comparison, I built a trustfire t2 with an xp-g 4c driven at 1.7a….
Now, we all know that a u3 at near four amps is considerably “brighter” than an xp-g at less than 2 amp……
Two things blow me away about that t2, first and foremost how “nice” both the colour of the light and its colour rendition is, second, its throw, (slightly off topic here I guess) the dimmer on two counts, light, impresses me far more than what was a “hotrod” of a light. Give that same hotrod to someone else, someone with, it has to be said an impressive collection of lights, their blown away with it!
I give up on lumen figures, I’ll build what I find I like (after much experimentation in both tint and output) for me. If others get to experience this and are more amazed, well that’s just ace, but I won’t worry if their less happy, unless they paid me to build it….
I think it is pretty save to say that it is impossible to see the the difference in 2 neighboring bins R4/R5 or T4/T5 with the naked eye and without special equipment and if you have a "high" R4 and a "low" R5 the difference can be only 1 Lumen in theory. I said it many times before that I have the feeling that people tend to concentrate the discussions on the wrong topics, eg. one should worry about driver efficiency multiple times more than about binning levels. (goes especially for battery/driving voltages far away from the forward voltage of the emitter)
I still remember the discussion where people had the impression that their XM-L T6 (318-341 L @ 700 mA) seemed "darker" than the XP-G R5 (260-277 L @ 700 mA) in their Xeno E03 lights... so difference in beam profile (throwy/floody) tricked peoples eyes to a considerable degree... way more than one bin step ever could.
I think we may be double dipping on the effect of eyes perceiving different wavelengths differently. The definition of lumen already includes the effect. A 600 lumen 2700 CCT light is putting out more energy as light than a 600 lumen 6500 CCT light.
True, that’s a good point. Not sure how I missed that the first time 
Actually in theory the higher bin can be dimmer. Cree claims a +–7% error in their flux binning. That’s about a bin worth of difference in the error margin. The higher bin is more likely to be a little brighter but it’s not certain that it is. That adds even more weight to your argument.
In a best/worst case scenario the XM-L T6 is at least as bright (318*0.93=296L) as the XP-G R5 (277*1.07=296 L)...and some people still had the impression the the XP-G was "brighter". This is why I think concentrating on bin alone is nothing more than a specification "trap"... especially newbies have to be warned, that they probably won't even see a difference on a T6 vs U2 XM-L in a normal every day usage. If I can get the U2 for the same price than the T6..... OK... I take it, but I would think twice about spending $5-10 more on a light just to have the latest and greatest on paper... as some premium brands charge for having the better bin. A driver can make a difference of more than 100% in efficiency and that's where you should look for efficiency in the first place. (see the link that I posted above)
You can argue all day how much horse power a car engine has to have..... 10 HP more or less, if the car is missing two wheels... the discussion is kind of pointless.
There’s so many issues involved and so many that want to quote classical mathematical calculations and yadda yadda yadda. I can’t remember all that stuff and find that in the end it’s all kind of mute anyway. I’m a photographer. Try to get a flash to put photo quality light on a spinning moving football 85 yds away. Is it going to be the same light you could put on it at 10’? Nope, not even close. Playing with our flashlights it’s a very similar deal. Distance eats light. Especially when you’ve got a high percentage of your light output being produced in a “cone” of light, in other words…spill. Shine the light into the night sky, how much does the beam spread? That’s why it doesn’t get a mile downrange. Now create a pencil beam thrower, what can you see when using it at 200 yds? 1 window of a house, with nothing peripheral? Depending on what/why you’re looking that’s everything or nothing at all. I find that most of the time I want to see it all, a broader spectrum of what’s to the sides as well as what’s downrange.
Just took a photography related test on color perception. Very interesting test. The experts claim that 1 in 12 men have some degree of colorblindness. As compared to 1 in 220 women. Interesting. What’s your favorite beam tint again? Everyone is raving about the “pure white light” of the Nichia 219. I don’t find that to be true at all. It’s a light brown or dirty color to me. All 6 that I have are similar, but not white. Granted, colors do look more vivid under the 219 than any of my Crees. To me.
So what it all boils down to is like Justin said, you go with what works for you. If that means learning where your own strengths and weaknesses are then finding the tools that fit your needs, then do the research or have fun experimenting til you find the magic. Then try to find the reflector that lets all your precious light go just where you want it without losing 30% of those hard earned lumens. Don’t forget the driver, the cells, the heatsink…that’s what’s so fun about this obsession, finding all the components that…when assembled…give the ultimate satisfaction!
The single word that applies best for me is one I see in Photography all the time…Compromise.
Seems to me that many of us have different preferences when it comes to the combination of flood and throw. My son - like many - enjoys a lot of flood with his throw. However the other night I was able to show him that excess flood can make it much more difficult to see a target in the distant throw zone.
My personal preference is generally for a small spill with throw (like the DST has). If I want flood, then I’m almost always working at much shorter ranges than where I am looking for throw.
Preferences can vary with the surrounding terrain and working distances, but I’ve noticed here on BLF that sometimes people are wowed by a more floody thrower than by brute throw - even to the extent that the terms are sometimes confused. The way different people react to aspherics is probably a good example.
As we gain experience, we tend to seed the differences - and hopefully learn to apply the differences to be the most useful for whatever or location, circumstance, and need. As we gain that experience, it is what helps us to know more about what we like and why - and also to know what to ask to help others.