5mW, adjustable focus useful or not?

[deank]

I'm trying to decide between several 5mW green lasers, and i was wondering if there's any use for adjustable focus on a laser of this power?

Cheers

 

[qumefox]

More features usually aren't bad. But it really depends on what your intended use of the laser is. If it's just to point, the focus probably won't be of very much use. For experimentation use, being able to vary the beam size can come in handy.

 

[anselm]

Yeah, but at this power level? You won't see much light if you spread it out/defocus it.
Besides, it'd be kinda hard even finding a 5mw focusable in the 1st place.

 

[deank]

More features usually aren't bad. But it really depends on what your intended use of the laser is. If it's just to point, the focus probably won't be of very much use. For experimentation use, being able to vary the beam size can come in handy.

I am buying it for fun and experimentation. Can you please list some use cases where having the ability to control focus would be useful ?

 

[deank]

Yeah, but at this power level? You won't see much light if you spread it out/defocus it.
Besides, it'd be kinda hard even finding a 5mw focusable in the 1st place.

Laser Glow Altair has manual focus. It is $79 compared to Lyra that seems to be identical pointer without the focus control which sells for $49.

Laserglow Technologies - Handheld Lasers, Alignment Lasers and Lab / OEM Lasers
Laserglow Technologies - Handheld Lasers, Alignment Lasers and Lab / OEM Lasers

 

[deank]

Sorry my mistake, 5mW Laser Glow Lyra is $59, or $20 less than Altair.

 

[Leodahsan]

If you do not really want the focus feature (eg don't need it) you can get a new wish laser.. the cheapies. Commonly they are ~15mW and are interesting to play with..
if you share with us what type of experiments you are gonna do with 532nm lasers.. maybe you can get further help

 

[deank]

If you do not really want the focus feature (eg don't need it) you can get a new wish laser.. the cheapies. Commonly they are ~15mW and are interesting to play with..
if you share with us what type of experiments you are gonna do with 532nm lasers.. maybe you can get further help

This will be my first laser, I expect to be using it for usual things, playing with my dog, pointing things out, occasional astronomy use, turning off street lights . Anything else I can think of, as I said I never had a laser before.

And it's not that I don't want a focus feature, it's just that I want to know what it would be useful for in a 5mW green laser? I did my homework on google and one use for adjustable focus is that it can be used for burning things more efficiently, but you can't do that with 5mW anyway. So again, would appreciate if someone can tell me for what kind of use would focus control be desirable on a laser of this class.

 

[Leodahsan]

for your purposes, no.
focus control isn't really needed in such occasions.

 

[deank]

for your purposes, no.
focus control isn't really needed in such occasions.

When is it needed?

 

[Leodahsan]

A focusable 5mW is needed when you have some kind of laboratorial experiment that explicitely needs lasers involved.. in a lower density.
Can't see another necessity, tho.

(unless the laser is around 50mW, where focused it can burn easier)

 

[mod101]

Focus is usually for higher powered lasers so you can either focus the laser to a point (and lack a beam) or you can focus to infinity for a beam (and lack a focal point). With a 5mw there is no reason to focus to a point because you cant burn, so you pretty much only want it focused to inifinit constantly. If you get a focusable one you'll constantly be fiddling with the focus instead of just enjoying your laser.

 

[deank]

Focus is usually for higher powered lasers so you can either focus the laser to a point (and lack a beam) or you can focus to infinity for a beam (and lack a focal point). With a 5mw there is no reason to focus to a point because you cant burn, so you pretty much only want it focused to inifinit constantly. If you get a focusable one you'll constantly be fiddling with the focus instead of just enjoying your laser.

Thanks that makes sense. I've given up for the manual focus control for this class of laser.