Which scanners

[colouredmirrorball]

kHz or pps ?!

That should be the same, correct me if I am wrong

[buffo]

Which ones are the best: 20 kHz scanners at 20° scanangle or 30 kHz at 8°?

That should be the same, correct me if I am wrong

No, not quite. 20Khz implies that the scanners can move from one limit to the other 20,000 times per second. This is absolutely not the case.

The *small step* maximum bandwidth for a set of 30Kpps scanners is 2500 Hz. And that's for a small step. (Not max travel) And even then, you'll have significant distortion.

Consider your ILDA test pattern. At 30Kpps the center circle is ROUND and INSIDE the square despite the fact that the actual pattern is made up of 12 points in a polygon that lies OUTSIDE the square. So that shows you how much distortion you've got even with a 2.5Khz signal.

Bottom line: A set of scanners that could perform at a true 30Khz would have a speed rating of 360,000 points per second.

Adam

[colouredmirrorball]

OK, I think I got the point. Thanks for correcting me, but still I don't have an answer to my question: 20 or 30K?

[andyf97]

No, not quite. 20Khz implies that the scanners can move from one limit to the other 20,000 times per second.

If I am not mistaken this is called the Resonant frequency.
Step Responce time I think is more related to pps but i am far from an expert. Maybe Laserworld can shed some light on this.

This is absolutely not the case.

The *small step* maximum bandwidth for a set of 30Kpps scanners is 2500 Hz. And that's for a small step. (Not max travel) And even then, you'll have significant distortion.

Consider your ILDA test pattern. At 30Kpps the center circle is ROUND and INSIDE the square despite the fact that the actual pattern is made up of 12 points in a polygon that lies OUTSIDE the square. So that shows you how much distortion you've got even with a 2.5Khz signal.

Bottom line: A set of scanners that could perform at a true 30Khz would have a speed rating of 360,000 points per second.

Adam

[zerowaitstate]

Usually you sacrifice one for the other IE

wider scan angle slower rate - bigger image in shorter distance but less detailed.

narrow scan angle faster rate - smaller image at same distance but more detailed or crisper image.

more expense = Higher scan angle and higher speed.

Narrower scan angle obviously means that you need a longer distance to to get a bigger graphic etc

Pick what is important to you and purchase accordingly ... Again i reccomend spending more up front for Cambridge Technology Scanners More money up front, but a superior product.

[Zoof]

I have Raytrack 35 plus from JM lasers and I've great results with them.

[allthatwhichis]

OK, I think I got the point. Thanks for correcting me, but still I don't have an answer to my question: 20 or 30K?

If your scanners can do 20 at 20, then they will probably be able to do 30 at 10. Your 30 at 8 will probably only be able to do 20 at 15. I am speculating of cource.

I personally would not worry about completing a list; I would look at your budget and that will determine a short list for you to choose from. Less than $1000, DT40s; more than $1000, CTs...

[Frixxion]

Wow you guys are fast posters :P. I have read that those CT scanners are extremely good, but I'm afraid I don't have 1400 dollars lying around . I want to do beams and some animations, but mainly beams. Do you think the scanpro30 will be OK for me?

[andyf97]

FRixxion,

I have some complete used sets of ct6800 with amps, cables power supply etc.., make me an offer in euro by PM.

[heroic]

None of these have anything to do with speed:

- DT40s are both more stable and have better mirrors than ScanPro30s.

- ScanPro30s are fast but tend to drift a lot.

- CT6800s scan fast and wide, and can accurately target beams- this is important if you want to use bounce mirrors or optical effects in the room (think: mounting lumia wheels in the ceiling space )

- Cheap scanners tend to drift a lot and their tuning seems to need adjustment more often

- The self-protective properties of cheap scanner/amp combos may not be as good as those of more expensive ones.