Pangolin Safety Scan lenses - looking for "rough" experience-based advice

[White-Light]

You're right, non-audience scanning shows done well are often better.

Well it's a matter of opinion and we'll have to agree to disagree there.

I've seen a lot of overhead shows both on video and a few live, and I've yet to ever see a single overhead show or effect that has impressed me. By contrast, even a simple interaction with the beams from the simplest of audience scanned effects impresses and provides a feeling of interaction that you just can't get elsewhere.

This isn't some tug-of-war battle you play with the parties involved; you won't get very far if that is your attitude.
You have also forgotten another important party, the venue. Any "proper" venue has a clearly defined policy of what it will and will not permit.

Well I guess thats the difference between being hired laserist and a promoter. A good hard dance promoter wouldn't use a venue that refused to allow audience scanned effects in my opinion. I agree Dan, that as a hired laserist, you're probably not going to turn away work if the venue says you can't audience scan, although, personally, I would take the opportunity to perhaps show the venue operators how it can be done safely before a show and give them that experience, and perhaps change attitudes for the future, as a result.

That was the opening gambit of the EU's laser safety directive when it was last open for revision.

I wouldn't know so I can't comment beyond saying that it wouldn't surprise me.

But as I said earlier, it won't stop it, just drive it underground and once that happens, all safety goes out of the window because at the end of the day, if you're using laserists who are breaking the law anyway, they're very unlikely to get certified, take measurements with expensive equipment or frankly give a toss beyond providing a visually impressive show.

We've seen that in the US and I know of examples in the UK which I've refrained from posting on here so as to avoid giving the impression of promoting illegal scanning. eg. I know one night that used to scan the closest point of the audience at (according to rough figures put through Maurice's online calulator) at an estimated 3,900 mw/cm2 or 390x MPE if you prefer (I knew a little about that particular laser - approaching 1.5W 532nm, 2 mrad, 3mm beam, approx 2 metres to audience).

I'm not going to comment further on that as I don't want to promote illegal scanning...

I fail to see how this would get you anywhere... if you can provide a decent case for it, I would offer the use of mine.

I think the point behind it was Pangolin produce a guidance table of spot size for lens power vs distance for lasers where the M2 is known.

(Just pointing out to the casual observer that these are rough guidelines and don't alleviate the need to take measurements).

http://www.pangolin.com/_Files/SafetyScanManual.pdf

[danielbriggs]

Ah... M^2. That isn't directly related to beam profile. M^2 is a metric of the quality of the beam, and how it propagates; which is something I can also measure.

[drm916]

I attended a conference where Bill was present. He said if anyone has any questions about the lens to just contact pangolin directly. They have the best information available to help you pick a lens.

[norty303]

John, buy the -6 lenses.
I've found I basically don't use any of my others because it's still possible to go way over MPE even with a 2W projector at 20m
I just do a static beam measurement based on the max irradiance for the relevant exposure time frame.

[White-Light]

Sounds like you need some fast scan fails (or for someone to give the H&S brigade / law makers a kick up the backside over the dangers of momentary 4xMPE exposure in the very rare occasion that a scanner fails during a show whilst into the audience).

H&S really has gone crazy when we're worrying about the mere possibility of a very very rarely occurring equipment failure leading to a momentary 1/4 second 4 MPE exposure. Fair enough if MPE was an absolute line, but it isn't. 20 years of data from Europe on prolonged exposure saying otherwise and we're worrying about a 1/4 second 4MPE exposure that has no evidence of causing damage in living humans and probably will never happen in most audience members lifetime. We've gone absolute safety crazy. I'm just surprised we're allowed out without helmets and knee pads.

The again when you have people in positions of influence within the industry reportedly promoting restrictions based on the dangers of possible flash blindness from nightclub lights, what do you expect. I have to wonder just how many people have staggered to their deaths thrashing around blindly off the dance floor before staggering their way down the corridors to the nearest stairs and then swan diving their way to the bottom, all due to disco lighting / lasers in the last 50+ years. The figures must be horrendous!

Anyway, I know the reason why Bill made lenses of differing powers was to avoid the fuzziness you get from having too powerful a lens at too great a distance.

That said, I'm not saying John shouldn't take your advice about lens selection, you're in a better place to select than me. Just that in general you should avoid using large powers at long distances if you want to keep the beams looking tidy.

I'm pretty sure Bill has said to me in the past that he wouldn't allow exposure to any beam of less than (I think from memory) 1 inch diameter.

[norty303]

Yes Al. But John doesn't own the kit to do large gigs over long distances (afaik, since we discussed it on another forum) so I'm advising him based on the likely jobs he's going to do with his kit.

[jbinks]

John, buy the -6 lenses.
I've found I basically don't use any of my others because it's still possible to go way over MPE even with a 2W projector at 20m
I just do a static beam measurement based on the max irradiance for the relevant exposure time frame.

Perfect. This is exactly what I wanted to hear!

I was originally thinking of getting the full set, but based on what you've said I'll just get the -6's and go from there.

Thanks!
John

[norty303]

I bought a set plus a few extras but I got them to make up the set of 2 each of -4,-5 and -6
They will do you a set of all -6 if you want it! Just ask

[jbinks]

So would you say it's worth getting the -4, -5 and -6 set then?

I appreciate that the -6 is probably going to get the most use, but there would be a few events where I would be able to locate the projectors far enough back on the stage to perhaps need the weaker lenses. Just trying to determine if the (relatively minor) additional expense is worth it.

Cheers,
John

[norty303]

I originally got 8 lenses, the 6 set plus a pair of -3
I've since returned the 2x -3 lenses for another pair of -6 and I can't recall ever using the -4 lenses.
For me, even on the bigger jobs, you want to 'hit' the crowd quite soon anyway, so you need a strong lens for the front people.

I prefer to use the lens to control exposure rather than a combination of BAM and lens, but you could always use a less strong lens and BAM combo if you wanted to.

There is no right or wrong way of doing it really, so long as you control the hazard.