HB,
Indeed! I do understand how springs work, and what the k value is. I was thinking, after looking at the picture of the LS20 spring (stock one), that the very top coil, or about 180 degrees of it, is indeed a "dead" coil, not involved in the compressive force. But, perhaps I am wrong? No way to tell, I guess. Which is why I will not be modding my spring until I have an exact replacement in hand.
I went back to the L1 today, specifically with an eye towards activation force, and I've got to say that I find my LS20 and PD-S easier to activate and to hold on high despite the greater force requried. I think this is because I find the grip involved to give me a lot more leverage over the grip involved in the L1 and A2. Once those muscles come up to speed, they just love to do their job--or that's been my experience.
Anyway, thanks for letting me use the pic, guys! It's a neat picture and an unusual one. Very cool.
As for my review, believe you me, I am looking forward to being able to post the finished product. It's been an ongoing project for months now. I finished with the beamshots, finally. I wanted to do something different than the usual to try to show what the eye really sees. For the low modes, this wasn't a problem, but for the high modes, this is a problem. Conventional wisdom is to lock the f-stop and shutter speed and ISO at the best compromise, and let the camera just "tell the truth". The brighter lights will be overexposed to some degree, and dimmer lights underexposed, but this is an actual reporting of the real differences in brightness of the lights. Or so the reasoning goes. But, it's never seemed faithful to me. It's not what I see when I'm out using the lights. It's not the truth, although it is certainly objective and outside of any sort of personal bias that might infect a review.
But, to my thinking, if you don't trust a reviewer to be objective and to tell the truth to the best of his or her ability, then why bother reading one of his or her reviews? :shrug: So, I took a different approach for my main set of comparison beamshots (or at least the highs). Well, backing up, I should say that I didn't use a white wall. I used a set of shelves against the wall at the top of our stairway landing, which is just chock full of my wife's craft supplies and craft products--stuff she's made and/or embellished with chiogami paper. It's very colorful and vibrant and busy. And right smack in the middle of that is the ColorChecker color chart (the mini version). Anway, where was I . . . ah yes, so even for the low beams, it's not a conventional sort of beamshot. It's not about the light itself but more about what you can see in the light and how well you can see it. It's pretty interesting to see, really. The low beam from the LS20 is so much more faithful than the A2, really, and it shows. Also, you can clearly see how the low beam from the LS20 just illuminates the entire wall, showing almost every detail--great information for the eye--whereas the lows from the PD-S and L1 are more just a spot of light, with a lot more darkness surrounding it.
So, but, yeah, the high beams. So the thing is that if you set the exposure for the hotspot, then the outer areas are so underexposed that you actually lose information there--they get dimmed out. And if you set the exposure for the outer areas, then the center of the hotspot gets washed out, and you lose information there. So I took two shots of the PD-S and L1 and A2 high beams. One with the hotspot properly exposed, and one with the outer areas properly exposed. I then opened the more exposed ones (with the outer areas properly exposed) in Photoshop, and then opened the shot with the hotspot properly exposed, and added it as a layer on top of the first shot, and then set the opacity of the top layer to 50 percent. Thus the hotspot beneath shines through, increasing its brightness, but there is the extra information there due to the properly exposed top layer, and the otuter areas which were too dark benefit from the background layer shining through with some information there. This is a way to increase the dynamic range of photos--or so I have read--and it worked great to create a beamshot that actually was close to what my eyes saw. It's not perfect, of course, but it's closer.
I also had the lights suspended behind and above the camera, shining straight on to the ColorChecker, while the camera was below and in front of the light, looking at a shallow angle upwards at the colorchecker chart. This is another trick I use to get a more even light to fall across the cameras field of view, and also helped to create a set of beamshots that (to my perception) more faithfully protrays my own experience of the lights I am trying to compare against each other.
I also took some more traditional longer-throw shots from my second story window down onto the grass, to emphasize the greater throwing ability of the PD-S and L1, vs. the LS20 and A2. And I will be doing a set of closeup shots of the ColorChecker chart for CRI comparison purposes.
Plus, I took a bunch of shots of my hand holding the LS20 to show just how freaking amazing that light is, ergonomically. How three fingers fit just so on the clip. How no matter where the clip ends up in any of the grips, it doesn't interfere and almost always improves the grip, how the light can be handled in any of five grips, and so on. And how this is in sharp contrast to the clips on the L1 and A2. How there is really only one grip on those lights.
I'm trying to really do justice to the LS20--how amazing it is--and honestly, I don't think I will be able to really convey it, show it, but I'm giving it my best shot.
The graveyard shifts haven't been kind to my verbal functioning, so the writing of the review is going a lot slower than I had hoped. But it's coming along. It's getting there.
But, don't expect too much! It's sure to disappoint under the weight of too much expectation, I would guess! I'll do my best, but that may not be good enough, I fear. LOL!
:twothumbs 
