The $6,000 Beam Expander Experiment

[Trevor]

I just got a 400 2.8, so I decided to run my HeNe through it to see if it acts like a beam expander.

Result: It doesn't. But it yielded cool photos.

The setup, in all its kludged glory:

Trevor

 

[RA_pierce]

LOL.
Hey, it was worth a shot.

I hope that HeNe is low power. It would suck to get smoke in your new lens!

 

[joeyss]

LOL.
Hey, it was worth a shot.

I hope that HeNe is low power. It would suck to get smoke in your new lens!

Learned that the hard way when I tried with my 500mw blu-ray...my binoculars now have a burnt spot on the lens inside even though it was vacuumed sealed.

 

[AAlasers]

What could possibly be in that lens to make it cost 6000?
Just curious, price seems a little steep. Lenses are fairly inexpensive to make. So is an assembly.

Maybe it is superb chromatic and spherical aberration correction?

Also, that would probably make a decent beam expander with a few modifications or focal adjustments. Try putting your laser through a plano-convex or a concave lens and adjust the position of the lenses. I've had luck doing this in the past.

AAlasers

 

[joeyss]

What could possibly be in that lens to make it cost 6000?
Just curious, price seems a little steep. Lenses are fairly inexpensive to make. So is an assembly.

Coatings on multiple lenses,precise ablatement of the glass,even thickness,certain "Binned" optical transmission qualities, and so on.

 

[AAlasers]

Coatings on multiple lenses,precise ablatement of the glass,even thickness,certain "Binned" optical transmission qualities, and so on.

I see. Although the images produced will be as clear and crisp as possible, it is not the way I would spend 6000 dollars.

 

[Trevor]

I hope that HeNe is low power. It would suck to get smoke in your new lens!

Yeah it's a 5mW HeNe. I'm not going to pump anything more through this guy.

What could possibly be in that lens to make it cost 6000?
Just curious, price seems a little steep. Lenses are fairly inexpensive to make. So is an assembly.

Maybe it is superb chromatic and spherical aberration correction?

It's one of Canon's top-of-the-line professional fast telephotos.

If you shoot sports for a publications, you need one to stay competitive. Autofocus speed is bonkers, it's tack-sharp corner-to-corner, even wide open. It doesn't have any distortion, field curvature, CA, or any other optical issue. Its MTF chart is ridiculous.

Most of Euro 2012 and the Olympics will be shot using these. Not something you buy to photograph your kids playing baseball.

Trevor

 

[lazeristasUVISIR]

I just got a 400 2.8, so I decided to run my HeNe through it to see if it acts like a beam expander.

Result: It doesn't. But it yielded cool photos.

Of course not. It is just a focusing lens. You need one more focusing or divergent to make an expander.

Does a lens look dusty, or there are so many reflections in the lens?

Tell us about your camera This kind of lens can not go on something cheap :can:

 

[Trevor]

Of course not. It is just a focusing lens. You need one more focusing or divergent to make an expander.

Does a lens look dusty, or there are so many reflections in the lens?

Tell us about your camera This kind of lens can not go on something cheap :can:

Yeah, I should have realized this was just a focusing element... oh well.

The dust you see is on the front element of the lens. There might be some inside too; every SLR lens has at least some. Though this one is particularly clean, since it just went to CPS for a cleaning and calibration.

Canon 1DX, once it arrives.

Trevor

 

[Blord]

It is the aperture of the lens that makes it expensive. 400mm at f2.8 is considered a very fast lens hence a high price ticket. These are Canon high-end top-of-the-line lenses.

 

[lazeristasUVISIR]

Yeah, I should have realized this was just a focusing element... oh well.

Probably you have some other expensive lenses like 50 , 85, or 135. That might create a very expansive expander :drool:

 

[Deleted member 16589]

Yeah it's a 5mW HeNe. I'm not going to pump anything more through this guy.



It's one of Canon's top-of-the-line professional fast telephotos.

If you shoot sports for a publications, you need one to stay competitive. Autofocus speed is bonkers, it's tack-sharp corner-to-corner, even wide open. It doesn't have any distortion, field curvature, CA, or any other optical issue. Its MTF chart is ridiculous.

Most of Euro 2012 and the Olympics will be shot using these. Not something you buy to photograph your kids playing baseball.

Trevor

"It doesn't have any distortion"

willing to put that claim to the test.

Give me 3 side buy side images 123 where image 1 and 3 have a 25% overlap and image 2 is smack in the middle.

 

[Trevor]

Probably you have some other expensive lenses like 50 , 85, or 135. That might create a very expansive expander :drool:

I'll have to do that.

"It doesn't have any distortion"

willing to put that claim to the test.

Give me 3 side buy side images 123 where image 1 and 3 have a 25% overlap and image 2 is smack in the middle.

I'll do that once I get in the studio.

To tide you over, here's the distortion profile of the ~$1,100 400 f/5.6... which is basically crap compared to the f/2.8.

Canon EF 400mm f/5.6 USM L - Full Format Review / Test - Analysis

0.4% pincushion.

Trevor

 

[Dam]

You've just wasted 6000$ for it becouse it's not working as beam expander. To make a beam expenader from this lens you should spend 1500$ extra and buy this small lens: Canon Normal EF 50mm f/1.2L USM Autofocus Lens 1257B002 B&H and then it will work as 8x beam expander. This lens I recommened you is much cheaper but I can assume you that it will work good.

Great lens, congratz!

 

[Trevor]

I didn't buy it solely as a beam expander. I bought it to shoot sports this coming fall.

...but it seems like passing a laser through it could be a fun exercise. I'll borrow my friend's 10-22 and we'll see how it goes...

Trevor

 

[ElektroFreak]

Did you by chance try running the beam through it the other way round, with the beam exiting the small end?