Velocity Reviews - Computer Hardware Reviews

Velocity Reviews > Newsgroups > Computing > Digital Photography > Re: Macros

Reply
Thread Tools

Re: Macros

 
 
PeterN
Guest
Posts: n/a
 
      04-23-2013
On 4/22/2013 1:46 AM, Trevor wrote:
> "Eric Stevens" <(E-Mail Removed)> wrote in message
> news:(E-Mail Removed)...
>> On Sun, 21 Apr 2013 22:57:07 +0000 (UTC), ruben safir <(E-Mail Removed)>
>>> On Sat, 20 Apr 2013 21:21:31 +1200, Eric Stevens wrote:
>>>>> parrellel rays is not focused on infinity
>>>>
>>>> Correct.
>>>>
>>>> Parallel rays are generated by an object at infinity. When you focus a
>>>> lens at an object at infinity the rays from that object to the lens are
>>>> parallel (until they hit the lens).
>>>
>>> How is that possible? An object 6 feet wide focused at inifinity can not
>>> produce parallel light on the lens, otherwise the light would be too wide
>>> to fit on the lens (and a pinhole camera would never work).

>>
>> It would if the 6 feet wide object was an infinite distance away.

>
> Actually no, the light would be warped by the gravitational field of every
> star system between the object and the lens!
>
> Trevor.
>
>


If you want to get theoretical, the gravitational influence of randomly
distributed objects might very well equalize each other. Therefore the
rays would remain parallel.
But, I think the notion of absolutely parallel lines wound run counter
the the theory of relativity.



--
PeterN
 
Reply With Quote
 
 
 
 
Wolfgang Weisselberg
Guest
Posts: n/a
 
      04-29-2013
ruben safir <(E-Mail Removed)> wrote:
> On Sat, 20 Apr 2013 21:19:10 +1200, Eric Stevens wrote:


>> This is a an invariant characteristic of the lens and does not change
>> (unless its a zoom).


> How does a zoom do this?


By moving the center element of a Cooke triplet.

Of course that's only the first tiny step. You need to
replace the 3 lenses with other lens groups, but the basic
idea remains ...

http://www.lensrentals.com/blog/2011...nealogy-part-2

-Wolfgang
 
Reply With Quote
 
 
 
 
Wolfgang Weisselberg
Guest
Posts: n/a
 
      04-29-2013
PeterN <(E-Mail Removed)> wrote:
> On 4/22/2013 1:46 AM, Trevor wrote:


>> Actually no, the light would be warped by the gravitational field of every
>> star system between the object and the lens!


> If you want to get theoretical, the gravitational influence of randomly
> distributed objects might very well equalize each other. Therefore the
> rays would remain parallel.


Actually, nope. It's the same as adding multiple random noise to
a signal or a random walk from a point.

-Wolfgang
 
Reply With Quote
 
Wolfgang Weisselberg
Guest
Posts: n/a
 
      04-29-2013
ruben safir <(E-Mail Removed)> wrote:
> On Sat, 20 Apr 2013 21:21:31 +1200, Eric Stevens wrote:


>>>parrellel rays is not focused on infinity


>> Correct.


>> Parallel rays are generated by an object at infinity. When you focus a
>> lens at an object at infinity the rays from that object to the lens are
>> parallel (until they hit the lens).


> How is that possible? An object 6 feet wide focused at inifinity can not
> produce parallel light on the lens,


Of course it can. Since the view angle of the lens is greater
than zero, the object will record only at a single location.

Hint: Stars are much, much larger than our planet Earth, yet
they come as single dots. And they're not even infinitely
far away. But their rays are *very* *very* *very* close to
perfectly parallel when recorded by your lens.

> otherwise the light would be too wide
> to fit on the lens (and a pinhole camera would never work).


You only need an object-space telecentric lens. Which camera
lenses aren't.

-Wolfgang
 
Reply With Quote
 
PeterN
Guest
Posts: n/a
 
      04-30-2013
On 4/29/2013 8:57 AM, Wolfgang Weisselberg wrote:
> PeterN <(E-Mail Removed)> wrote:
>> On 4/22/2013 1:46 AM, Trevor wrote:

>
>>> Actually no, the light would be warped by the gravitational field of every
>>> star system between the object and the lens!

>
>> If you want to get theoretical, the gravitational influence of randomly
>> distributed objects might very well equalize each other. Therefore the
>> rays would remain parallel.

>
> Actually, nope. It's the same as adding multiple random noise to
> a signal or a random walk from a point.
>
> -Wolfgang
>


vielleicht etwas zu tun <> etwas tun

--
PeterN
 
Reply With Quote
 
Wolfgang Weisselberg
Guest
Posts: n/a
 
      05-02-2013
PeterN <(E-Mail Removed)> wrote:
> On 4/29/2013 8:57 AM, Wolfgang Weisselberg wrote:
>> PeterN <(E-Mail Removed)> wrote:
>>> On 4/22/2013 1:46 AM, Trevor wrote:


>>>> Actually no, the light would be warped by the gravitational field of every
>>>> star system between the object and the lens!


>>> If you want to get theoretical, the gravitational influence of randomly
>>> distributed objects might very well equalize each other. Therefore the
>>> rays would remain parallel.


>> Actually, nope. It's the same as adding multiple random noise to
>> a signal or a random walk from a point.


> vielleicht etwas zu tun <> etwas tun


True but irrelevant.

Getting theoretical: The theory how random influences add is
well established. That they equalize each other is about as
likely as that they completely add to each other, i.e. both
bowing the light in the identical direction. That's both not
"might very well", unless you "might very well" win a million
dollars in the lottery ten times in a row. So I bow to your
immense luck and admit I was wrong.

-Wolfgang
 
Reply With Quote
 
PeterN
Guest
Posts: n/a
 
      05-03-2013
On 5/2/2013 4:27 PM, Wolfgang Weisselberg wrote:
> PeterN <(E-Mail Removed)> wrote:
>> On 4/29/2013 8:57 AM, Wolfgang Weisselberg wrote:
>>> PeterN <(E-Mail Removed)> wrote:
>>>> On 4/22/2013 1:46 AM, Trevor wrote:

>
>>>>> Actually no, the light would be warped by the gravitational field of every
>>>>> star system between the object and the lens!

>
>>>> If you want to get theoretical, the gravitational influence of randomly
>>>> distributed objects might very well equalize each other. Therefore the
>>>> rays would remain parallel.

>
>>> Actually, nope. It's the same as adding multiple random noise to
>>> a signal or a random walk from a point.

>
>> vielleicht etwas zu tun <> etwas tun

>
> True but irrelevant.
>
> Getting theoretical: The theory how random influences add is
> well established. That they equalize each other is about as
> likely as that they completely add to each other, i.e. both
> bowing the light in the identical direction. That's both not
> "might very well", unless you "might very well" win a million
> dollars in the lottery ten times in a row. So I bow to your
> immense luck and admit I was wrong.
>


Ah! but are the gravitational fields random. According to Einstein, they
are not.


--
PeterN
 
Reply With Quote
 
Whisky-dave
Guest
Posts: n/a
 
      05-03-2013
On Friday, May 3, 2013 1:51:04 PM UTC+1, PeterN wrote:
> On 5/2/2013 4:27 PM, Wolfgang Weisselberg wrote:
>
> > PeterN <(E-Mail Removed)> wrote:

>
> >> On 4/29/2013 8:57 AM, Wolfgang Weisselberg wrote:

>
> >>> PeterN <(E-Mail Removed)> wrote:

>
> >>>> On 4/22/2013 1:46 AM, Trevor wrote:

>
> >

>
> >>>>> Actually no, the light would be warped by the gravitational field of every

>
> >>>>> star system between the object and the lens!

>
> >

>
> >>>> If you want to get theoretical, the gravitational influence of randomly

>
> >>>> distributed objects might very well equalize each other. Therefore the

>
> >>>> rays would remain parallel.

>
> >

>
> >>> Actually, nope. It's the same as adding multiple random noise to

>
> >>> a signal or a random walk from a point.

>
> >

>
> >> vielleicht etwas zu tun <> etwas tun

>
> >

>
> > True but irrelevant.

>
> >

>
> > Getting theoretical: The theory how random influences add is

>
> > well established. That they equalize each other is about as

>
> > likely as that they completely add to each other, i.e. both

>
> > bowing the light in the identical direction. That's both not

>
> > "might very well", unless you "might very well" win a million

>
> > dollars in the lottery ten times in a row. So I bow to your

>
> > immense luck and admit I was wrong.

>
> >

>
>
>
> Ah! but are the gravitational fields random. According to Einstein, they
>
> are not.


And how would one measure the DOF of them

 
Reply With Quote
 
Wolfgang Weisselberg
Guest
Posts: n/a
 
      05-06-2013
PeterN <(E-Mail Removed)> wrote:
> On 5/2/2013 4:27 PM, Wolfgang Weisselberg wrote:
>> PeterN <(E-Mail Removed)> wrote:
>>> On 4/29/2013 8:57 AM, Wolfgang Weisselberg wrote:
>>>> PeterN <(E-Mail Removed)> wrote:
>>>>> On 4/22/2013 1:46 AM, Trevor wrote:


>>>>>> Actually no, the light would be warped by the gravitational field of every
>>>>>> star system between the object and the lens!


>>>>> If you want to get theoretical, the gravitational influence of randomly
>>>>> distributed objects might very well equalize each other. Therefore the
>>>>> rays would remain parallel.


>>>> Actually, nope. It's the same as adding multiple random noise to
>>>> a signal or a random walk from a point.


>>> vielleicht etwas zu tun <> etwas tun


>> True but irrelevant.


>> Getting theoretical: The theory how random influences add is
>> well established. That they equalize each other is about as
>> likely as that they completely add to each other, i.e. both
>> bowing the light in the identical direction. That's both not
>> "might very well", unless you "might very well" win a million
>> dollars in the lottery ten times in a row. So I bow to your
>> immense luck and admit I was wrong.


> Ah! but are the gravitational fields random. According to Einstein, they
> are not.


So you're basically saying that the gravitational fields are
ordered in such a way that photons from any random source stay
parallel, at least in a sizeable number of cases.

I'd like a single geometry designed by you where a bundle
of parallel light rays from a single direction are bend by
gravity sources in such a way that they remain exactly parallel.
You can freely place the gravity sources.

Kindly remember that any single gravity source will affect such
a bundle of exactly parallel rays differently, depending on the
mass of the gravity source and the (different!) distance from
the individual ray to the gravity source. In other words:
a bunch of parallel rays *will* be spread when it passes a
gravity source ...

Too hard?

-Wolfgang
 
Reply With Quote
 
PeterN
Guest
Posts: n/a
 
      05-07-2013
On 5/6/2013 2:40 PM, Wolfgang Weisselberg wrote:
> PeterN <(E-Mail Removed)> wrote:
>> On 5/2/2013 4:27 PM, Wolfgang Weisselberg wrote:
>>> PeterN <(E-Mail Removed)> wrote:
>>>> On 4/29/2013 8:57 AM, Wolfgang Weisselberg wrote:
>>>>> PeterN <(E-Mail Removed)> wrote:
>>>>>> On 4/22/2013 1:46 AM, Trevor wrote:

>
>>>>>>> Actually no, the light would be warped by the gravitational field of every
>>>>>>> star system between the object and the lens!

>
>>>>>> If you want to get theoretical, the gravitational influence of randomly
>>>>>> distributed objects might very well equalize each other. Therefore the
>>>>>> rays would remain parallel.

>
>>>>> Actually, nope. It's the same as adding multiple random noise to
>>>>> a signal or a random walk from a point.

>
>>>> vielleicht etwas zu tun <> etwas tun

>
>>> True but irrelevant.

>
>>> Getting theoretical: The theory how random influences add is
>>> well established. That they equalize each other is about as
>>> likely as that they completely add to each other, i.e. both
>>> bowing the light in the identical direction. That's both not
>>> "might very well", unless you "might very well" win a million
>>> dollars in the lottery ten times in a row. So I bow to your
>>> immense luck and admit I was wrong.

>
>> Ah! but are the gravitational fields random. According to Einstein, they
>> are not.

>
> So you're basically saying that the gravitational fields are
> ordered in such a way that photons from any random source stay
> parallel, at least in a sizeable number of cases.
>
> I'd like a single geometry designed by you where a bundle
> of parallel light rays from a single direction are bend by
> gravity sources in such a way that they remain exactly parallel.
> You can freely place the gravity sources.
>
> Kindly remember that any single gravity source will affect such
> a bundle of exactly parallel rays differently, depending on the
> mass of the gravity source and the (different!) distance from
> the individual ray to the gravity source. In other words:
> a bunch of parallel rays *will* be spread when it passes a
> gravity source ...
>
> Too hard?
>
> -Wolfgang
>


I I precisely understood how gravitational forces interact, I doubt I
would waste time responding to you.

--
PeterN
 
Reply With Quote
 
 
 
Reply

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
macros-loop? calling macros X times? Andrew Arro C Programming 2 07-24-2004 09:52 AM
Explanation of macros; Haskell macros mike420@ziplip.com Python 80 11-07-2003 02:22 AM
Re: Explanation of macros; Haskell macros Michael T. Babcock Python 0 11-03-2003 01:54 PM
Re: Explanation of macros; Haskell macros mike420@ziplip.com Python 5 11-01-2003 01:09 AM
Re: Explanation of macros; Haskell macros mike420@ziplip.com Python 1 10-07-2003 04:07 PM



Advertisments