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445 versus 473 visual comparison

davidgdg

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I just fired up my 473 labby (65mw) to compare the output with my 445 custom daguin (570mw).

I tried taking some pix, but the colours and brightness are not captured at all. All I get is bright white blobs. So old-fashioned words will have to do.

Three things struck me:

1. The colours are remarkably close. I had expected that the 445 would be more inky-indigo and that the 473 would be more of a sky blue, but honestly it is hard to see much difference. Both are a brilliant medium blue. The main difference is that the 445 induces more fluorescence so that it tends to have a violet haze around the main blue spot. But this depends on the surface and is not always present. Without knowing which was which, it would be hard to tell the difference from the spot colour alone.

Verdict: A draw

2. The difference in brightness was much less than might be expected, given a 10 fold power difference. Some of this is attributable to the increased sensitity of the eye to the longer wavelength (about 3 fold - so that 65mw of 473 would supposedly appear equal in brightness to ~ 200 mw of 445). But I think it also reflects the fact that the eye's perception of brightness is logarithmic. These things are very subjective, but I would say that the 445 appeared perhaps twice as bright as the 473, but no more.

Verdict: 445 wins, but a closer result than you might think from the raw numbers

3. The spot from the 473 is much more of a starry point. This of course is because of the DPSS as opposd to bar diode output. Aesthetically the 473 is much more pleasing to the eye.

Verdict: Easy win for the 473

Conclusion: Get both if you can ;-)

David
 



Traveller

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Hey,

glad to hear you got your 473 back :wave:

Thanks for the comparison! "Apparent" brightness and color is probably more useful than a photo, given how hard it is to photograph "color" accurately. However, I would still appreciate it if you could give it a try? Not the "dots", mind you, just the beam at aperture themselves. As I have no idea what (photo) gear you have or your photographic experience level, might I refer you to my post regarding photographing lasers in general?

I recommend mounting the two lasers in tripods (I'm sure you long since bought a few of those DX cheesy plastic tripod-wannabes like the rest of us ;)) above a dark (preferably black) surface. You don't need to photograph 3 meters-worth of beam, just the first 5~20cm emanating from the aperture. I placed my (real) camera tripod more or less above the lasers, so as to photgraph the beams (almost) at right-angles.
Here are two examples:






Note that my 445nm laser looks purple in one and blue in the other. That's because I was messing with the camera's white balance. The purple version was manually done using a white sheet of paper (... go figure) and the truer, blue version was in auto-mode*. The point being you can take a shot and then if the color is not true to life, adjust your camera's white balance until you are satisfied. The shutter speed, ISO and aperture values are listed in each photo.

*I'm wondering if Chromatic abberation didn't come into play on that shot seeing as the hosts are correct (color-wise)... :undecided:


If you're not up to the task (or don't have the necessary gear), no one will hold it against you of course, but it's actually easier than it sounds, so I took the liberty to make the suggestion...

Cheers :beer:
 

davidgdg

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Thanks Traveller. I'll see what can be done. I don't have an SLR but I have a decent Samsung digital. Just need to find the charger....

The 473 I used for the colour comparison was a labby from O-Like. My CNI 473 arrived back on Friday, still dead, and is going back tonight for the third time ;-(
 

Traveller

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My CNI 473 arrived back on Friday, still dead, and is going back tonight for the third time ;-(
OMG :eek:
I'm sooo sorry... :( what's Glenn's take? Better yet, let me check the CNI GB threads so as not to derail this thread.
 

Elektrotechniker

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One think I've noticed on 445 is that, although the beam appears more BluRay-ish, the dot is pure blue!
 

BShanahan14rulz

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Traveller, is that an ultrafire A10 host? Was there a lot of custom fab to get that to work?

Great beamshots, btw. They look so nice that it almost looks photoshopped.
 

davidgdg

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Ok ninth time lucky.





This is a fairly successful beam shot from the 445 nm daguin custom (570mw).

Exposure was 1/10th of a second. Taken with a 3G iphone (!!).

The picture was taken by looking along the axis of the beam (from the side the camera won't capture anything).

In real life the beam looks less solid and more violet, so this is slightly misleading, but it's a start. I have yet to succeed with the 473 as the beam is not as bright, but I'll keep trying.

David
 

Canuke

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One think I've noticed on 445 is that, although the beam appears more BluRay-ish, the dot is pure blue!
That's because looking at the dot "crushes" your eye's response, and all you see is the blue. To really detect subtle hue differences, you have to look at much more muted versions of the light, in the middle of the eye's response curve.

In my case, I could see the hue differences between the 445nm output, and two LED lights I have, a 455nm royal blue and a 470nm blue, by bouncing them off a white ceiling and looking at the illumination of the room itself. Where the bounced 455nm stayed pure blue all the way into darkness, the 445nm reflected light started to take on a violet-ish hue into the shadows, while the 470nm took on an almost aqua look by comparison. Apparently, for my eyes, 455nm is pure blue, with 470nm nudging the green side and 445nm the violet.
 




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