Pangolin Safety Lens -d 6

[gandalfthegrey]

Hi All,

From advise given on this forum I have just brought a KVANT Clubmax 3000 and the safety lens –d 6 with bracket. ….. (what an amazing machine)…

The Laser power has been measured (please see PDF):

Red 637 nm: 0,638 w
Green 520 nm: 0,908 w
Blue 445 nm: 1,768 w

We also have Pangolin Quickshow. Assuming Quickshow is on default settings and on 100% power, could anyone please give me a rough estimate (that I won’t hold anyone to) as to the safe distance with the lens attached.

It would also be very helpful if I could also get a rough idea of what this distance would be if the Laser was powered down to 60% via Quickshow.

I’m aware that other factors can come into play so I’m really just looking a very rough idea please.

[gandalfthegrey]

P.S. Sorry, power total 3,289 w

[White-Light]

You need to know the beam diameter and divergence figures for the lasers as well to allow someone to calculate that for you.

If you want to calculate it for yourself / and / or see what figures you need, there's an online utility here:

http://mpe.laserextreme.nl/

Be aware, that even if you get within MPE, there's also scan fail to allow for (unless you have a fast scan fail device fitted).

James Stewart, Norty and several others on here will be able to help you further with that.

BTW Power ideally needs to be measured every time you set up as it can vary according to temperature and other factors. What's in the documentation is no guarantee of the actual power beyond the power measured on that particular day at that particular time.

[gandalfthegrey]

Hi, Thanks for the reply. We do have a good scan fail and shutters as a result of taking advise from this forum and understand we need to do the measurements onsite at the time. I'm just trying to get a rough idea of what to expect with the Pangolin safety Lens -d 6 that we have just got attached.

Beam diameter: 3.5mm
Beam divergence (full angle): <1mrad

[Bradfo69]

Just an observation. There is "safe" and there is "watchable". I don't recall exactly the calculations to go through with that lens in place to give you distance but, you may want to give some consideration to getting some other lenses. I stated off with a -6 - with the theory being that the most divergent lens they make must be the safest... right? Well, the problem was at a distance of only 40 feet (and beyond) it diverged the beam SO much that when a scan went across your face, the brightness lingering that long as it crossed your eyes made you flinch and turn away and really made the show unwatchable. It was sort of like trying to watch a laser show in the dark and having a policeman shine his flashlight into your car window at you. (Not that I would know anything about that ) The beam at that point was about 6"-8" wide.

I've since had the opportunity to get some other powers of lenses and found that the -3 at those same distances was much more comfortable to watch. I don't have the devices necessary to make accurate calculations and this is all really just experimental for me since I couldn't audience scan anyway. My projector with the lens is similar to yours.

There is really quite a bit to this and I'm trying to work towards figuring it out since I'd like to be able to be proficient with the effect (and legal in my country) some day.

[gandalfthegrey]

@Bradfo69, I was thinking along the same lines as you so it's good to see your points and feedback. The beams with this lens are very fat... I can do audience scanning here in Ireland and it's legal once I know how to make the measurements. I plan to go on a safety course once funds permit, but have emptied the bank getting this Laser... I just wish I have a rough idea. I heard on this forum a KVANT 1.7 w was tamed to be safe at 5 meters and still looked good.

[White-Light]

Norty uses the safety lenses so I'm sure he can point you in the right direction, but off the top, you're going to need to know the divergence and beam diameter AFTER the lens, so you're going to need to make your own measurements rather than use manufacturer figures. The MPE calculator I linked you to also has a divergence calculator. I wouldn't imagine the divergence would actually alter but check with someone who uses these lenses.

Personally, I'd contact Norty or J Stewart or someone similar who uses them to confirm you're heading in the right direction with this. J Stewart runs the safety courses in the UK.

With regards to what Brad said, on the watcheable part, I also think it depends to an extent on your audience. My observation is the US guys seem to be less tolerant of audience scanned laser than Europeans, possibly because they aren't accustomed to being scanned. I do agree though, comfort as well as legal should be the aim.

[Bradfo69]

With regards to what Brad said, on the watcheable part, I also think it depends to an extent on your audience. My observation is the US guys seem to be less tolerant of audience scanned laser than Europeans, possibly because they aren't accustomed to being scanned. I do agree though, comfort as well as legal should be the aim.

Yes, there is certainly some truth to that. Legal limits in the US are such that when you do see a professionally done, legal audience scanning show, it's a bit underwhelming. Recently I went to see Justin Timberlake in concert mainly for the lasers since it was highly advertised that it incorporated audience scanning and it was not all that impressive. Unique to see yes, but, very dim. Now... keep in mind that's coming from someone in the hobby who has been scanned regularly at LEM's at full powers and is fully aware of the dangers and can take precautions with knowing when to look away, or hold a hand up to block the aperture and watch with one eye and.. is sober. The balcony in the auditorium at SELEM has always been a "at your own risk" endeavour but is a great place to watch and video from. Over the past 5 years though, the powers of the projectors people bring have increased dramatically and it's become a less popular place for obvious reasons. Back in the day... 700mW to a watt was a big projector.

[gandalfthegrey]

Here's what we have for Ireland, I think it's based on UK laws:

http://www.hsa.ie/eng/Topics/Physica...cal_Radiation/

So if anyone has an idea of safe distance with the lens on in the UK, I think that should be good here too.

[norty303]

The right direction is to get the lens, measure the output, and ensure the static beam is within the appropriate MPE for the response time of your particular scanfail device.
Given the complexities of the different beam characteristics in a multi colour, and sometimes multi technology (DPSS, pure diode) projector, predictions are going to be hit or miss.
We've already had a long dicussion on another thread as i recall, and James has already advised Gandalf about the correct course of action so not too much more to be said on the matter really.

Ultimately, if you can't afford to do crowd scanning right, don't crowd scan. It's not as if power meters are that expensive these days, I think someone was selling a lasercheck recently for not much dough.