Re: Question regarding an homebuilt focusing schlieren system

[EErnest Hoeldtke <fred@xxxxxxx>]



I have added your name to my address book.   Will postpone for now, but lens engineering was more on an art than engineering

and after a thousand definitions you could end up  starting to understand   "THE CIRCLE  of  CONFUSION"  what a load of .. and remember that overexpose_underdevelop leads to blank and underexpose_overdevelop leads to blank and the circle of

confusions leads to blank blank blank it e blank.  not my ideas fred@xxxxxxx

 

----- Original Message -----

From: Frímann Kjerúlf

To: List for Photo/Imaging Educators - Professionals - Students

Sent: Wednesday, February 22, 2006 7:24 PM

Subject: Re: Question regarding an homebuilt focusing schlieren system

Bill, Andy

 

When you talk about surplus copy lenses, are you talking about lenses from photocopy machines?  I've just opened up an old photocopier machine I had in my garage, and there is no usable lens in there.

 

Surplusshed.com looks like a good source, but now it comes down to my lack of knowledge in lens engineering.  From the little I know then my guess is that two lenses like the L4146

from the surplusshed website, stacked together, might do the trick. That lens is:

 

TYPE: Double Convex

DIAMETER: 35.5 mm

FOCAL LENGHT: 444 mm

COATED: no

 

Also, I'm getting pretty curious on lens science.  Any good hints on website or books that might be helpful?

 

 

regards

Frímann

 

 

 

On 2/20/06, wpettit@xxxxxxxxxxxxx <wpettit@xxxxxxxxxxxxx> wrote:

Frimann,

If you can't obtain surplus copy lenses at your location, check out http://www.surplusshed.com  I've bought a lot of surplus optics from them and they are a relible supplier.  I'm sure they can ship internationally.

Bill

-----Original Message-----
>From: Fr�mann Kjer�lf < kjerulf@xxxxxxxxx>
>Sent: Feb 20, 2006 4:24 PM
>To: List for Photo/Imaging Educators - Professionals - Students < photoforum@xxxxxxxxxxxxxxxxxxxxxx>
>Subject: Question regarding an homebuilt focusing schlieren system
>
>Hi there
>
>
>I'm currently planning to set up a focusing schlieren system as a
>project at my school.
>
>I'm using the technique andrew davidhazy describes on his website:
>
>http://www.rit.edu/~andpph/text-schlieren-focus.html
>
>My question is: Will this setup work with my Canon EOS / FD lenses ?
>
>What I have is :
>50mm f/1.4 FD by Canon
>50mm f/1.8 EOS by Canon
>100mm f/3.5 by Vivitar
>100-300mm f/4.5- 5.6 by Canon
>
>Andrew says on his site: "It is desirable to use a large aperture,
>relatively long focal length lens for the imaging lens. Some surplus
>copier lenses can be applied for this purpose. "
>
>So I guess my 50mm lenses will not do the trick?
>
>
>Thanks in advance for any answers
>Fr�mann Kjer�lf
>

--

Best Regards
Frímann Kjerúlf