Re: OT: Images with great timing and angle of view

[Igor Roshchin]

Those are fun. Thanks, Dan for posting.

This image is a good catch as well.
(The caption is "The second face of Sergio Ramos")

http://euro2012.lenta.ru/photo/2012/06/14/espirl/#pic011

Igor

Wed Jun 13 09:45:17 EDT 2012
Daniel J. Matyola wrote:

> Some of these we have seen before, but they are always interesting.
> 
> http://themetapicture.com/timing-perfection/

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OT: Images with great timing and angle of view

[Daniel J. Matyola]

Some of these we have seen before, but they are always interesting.

http://themetapicture.com/timing-perfection/

Dan Matyola
http://www.pentaxphotogallery.com/danieljmatyola

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Re: Angle of View Calculator

[Mark Roberts]

Cotty wrote:

>On 29/08/07, Cotty, discombobulated, unleashed:
>
>>Was made aware of this nifty page. Anything like it for Sony CCDs or 
Pentax?
>>
>>

I have a spreadsheet that shows angles of view for full-frame, 1.3, 1.5 
and 1.6 crops for a variety of focal lengths. What's more it contains 
the math that calculates the values, so it's pretty simple to expand it 
to cover any other formats you're interested in. Download it at 
http://www.robertstech.com/files/angle_of_view.xls

Someday I'll make a javascript version and put it on my web page with 
my depth of field calculator. But don't hold your breath.


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Re: Angle of View Calculator

[Godfrey DiGiorgi]

I use Rui Salgueiro's field-of-view calculator available at this page:

   http://www.mat.uc.pt/~rps/photos/angles.html

He's got the basic film formats right there, and you can click  
"other" and input whatever sensor dimensions you want. DPReview.com  
usually lists sensor dimensions with camera specs.

Godfrey


On Aug 29, 2007, at 11:11 AM, Cotty wrote:

> Was made aware of this nifty page. Anything like it for Sony CCDs  
> or Pentax?
>
> 


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Re: Angle of View Calculator

[Cotty]

On 29/08/07, Cotty, discombobulated, unleashed:

>Was made aware of this nifty page. Anything like it for Sony CCDs or Pentax?
>
>

Ack, just seen the Nikon calculator - I assume the Sony sensor is the
same in the Pentax?



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Re: Angle of View Calculator

[P. J. Alling]

F calc will let you do this for any lens and format, (well real APS H is 
as close as you'll get to a reduced format digital sensor), which pissed 
me off enough that I wrote one in VB which allowed for custom formats. I 
have no idea where the code got to. Probably lost during a move or upgrade.

Cotty wrote:
> Was made aware of this nifty page. Anything like it for Sony CCDs or Pentax?
>
> 
>
> HTH
>
>   


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Angle of View Calculator

[Cotty]

Was made aware of this nifty page. Anything like it for Sony CCDs or Pentax?



HTH

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Re: Interesting article which discusses focal lengh, angle of view and digital sensors

[Antonio]

Would it be fair to say William that you would object to the "any lens in
effect becomes 1.5X longer" part of the following sentence taken from the
linked article as the magnification stays the same, what is cropped is the
angle of view. Hence any lens only becomes 15x longer in terms of AOV not
subject to lens distance?

Antonio



"For example, a 100mm lens on a Nikon D100 digital SLR will produce the same
field of view as a 150mm lens on a Nikon N100 film SLR. This is great for
telephoto fans‹any lens in effect becomes 1.5X longer."

On 14/8/04 4:08 pm, "Antonio" <[EMAIL PROTECTED]> wrote:

> http://www.photographic.com/lenses/204lenses/index2.html
> 

Interesting article which discusses focal lengh, angle of view and digital sensors

[Antonio]

http://www.photographic.com/lenses/204lenses/index2.html

Re: DOF and angle of view or focal length (long)

[Peter J. Alling]

That's also a part of the problem. 

Dag T wrote:

One problem is that if the CoC is much less than the usual number 
today, 0.035mm, the diffraction limit comes into play.  With a CoC at 
half this value, 0.017mm, you will never achieve a sharp image with 
the aperture set at 22.

DagT

På 22. mar. 2004 kl. 17.18 skrev Peter J. Alling:

The Circle of confusion required for an acceptable depth of field 
changes depending on the format.
The smaller the sensor size, the smaller the cof must be.  Also the 
desired enlargement factor
should also be taken into account, (although that last is 
difficult).  This unfortunately isn't hard science
it's more like cooking.

Re: DOF and angle of view or focal length (long)

[Dag T]

One problem is that if the CoC is much less than the usual number 
today, 0.035mm, the diffraction limit comes into play.  With a CoC at 
half this value, 0.017mm, you will never achieve a sharp image with the 
aperture set at 22.

DagT

På 22. mar. 2004 kl. 17.18 skrev Peter J. Alling:

The Circle of confusion required for an acceptable depth of field 
changes depending on the format.
The smaller the sensor size, the smaller the cof must be.  Also the 
desired enlargement factor
should also be taken into account, (although that last is difficult).  
This unfortunately isn't hard science
it's more like cooking.

Re: DOF and angle of view or focal length (long)

[graywolf]

Here we go again.

Basically DOF depends on COC, magnification, and aperture (not f-stop). If you 
decide to use the same size final image, say an 8x10, then COC and overall 
magnification become constants. So the DOF depends entirely on the apperture. 
D=f/N where f = focal length, N = f-stop, and D = diameter of the aperture. 
Notice that f and N are used only to determine D, they in themselves have 
nothing to do with DOF.

From the above it is obvious that the smaller format will have greater DOF 
simply because the aperture at a given f-stop is smaller.

For what it is worth, subject-distance, focal-length, and enlargement-factor 
determine magnification. These factors are why those numbers are involved in the 
formulas you usually see. COC if you are talking about an 8x10, or 8x12, print 
is a constant. Why someone would want to know the DOF on the negative is beyond 
me unless they are only making contact prints.

--

Jens Bladt wrote:

Some of you people are very knowledgeable when it comes to optical science.
So, I would like to ask you this:
On the internet there is an ongoing discussion about this subeject.
Some say, that smaller formats have greater DOF (Photonet). They say that in
order to get comparable images, I must use shorter focal length to go with
the smaller format, thus achieving greater DOF. They are using circle of
confusion (COF) theories to support their point of view.
I (and Photozone) say, that smaller formats only show a part of the image,
captured by a specific focal lenght. If I shoot the same scene twice with
the same camera, same lens (focal length( and same aperture and focus point,
you will get identical images on let's say APS and 35mm film - that is for
the part, that is covered by the smaller format (e.i. APS). I say that the
DOF of these two identical images - is exactly the same. I say that focal
length, aperure and focal distance determins the DOF.
IMO COF theories are somewhat subjective, because the point to where a point
looks like a disc, depends on the degree of enlargement. I think that the
smaller image, captured by a shorter focal length needs more enlargement,
thus less appearing less sharp.
What is right and wrong here?

Jens Bladt
mailto:[EMAIL PROTECTED]
http://hjem.get2net.dk/bladt






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http://graywolfphoto.com
"You might as well accept people as they are,
you are not going to be able to change them anyway."

Re: DOF and angle of view or focal length (long)

[Peter J. Alling]

The Circle of confusion required for an acceptable depth of field 
changes depending on the format.
The smaller the sensor size, the smaller the cof must be.  Also the 
desired enlargement factor
should also be taken into account, (although that last is difficult).  
This unfortunately isn't hard science
it's more like cooking. 

William Robb wrote:

- Original Message - 
From: "Jens Bladt"
Subject: DOF and angle of view or focal length (long)

 

Some of you people are very knowledgeable when it comes to optical
   

science.
 

So, I would like to ask you this:

On the internet there is an ongoing discussion about this subeject.
Some say, that smaller formats have greater DOF (Photonet). They
   

say that in
 

order to get comparable images, I must use shorter focal length to
   

go with
 

the smaller format, thus achieving greater DOF. They are using
   

circle of
 

confusion (COF) theories to support their point of view.

I (and Photozone) say, that smaller formats only show a part of the
   

image,
 

captured by a specific focal lenght. If I shoot the same scene
   

twice with
 

the same camera, same lens (focal length( and same aperture and
   

focus point,
 

you will get identical images on let's say APS and 35mm film - that
   

is for
 

the part, that is covered by the smaller format (e.i. APS). I say
   

that the
 

DOF of these two identical images - is exactly the same. I say that
   

focal
 

length, aperure and focal distance determins the DOF.
   

This part is true, to an extent.
However, if you are going to use the same focal length, but change
formats, then really, camera to subject distance pretty much has to
change to be photographically useful.
Or, if you are going to change formats, but not camera to subject
distance, then you need to change lenses.
In theory, I think you are correct.

In practice, I find that I have to stop down a bit more on 6x7 to get
similar DOF as I get with 35mm, presuming a similar angle of view is
being done on both cameras.
 

IMO COF theories are somewhat subjective, because the point to
   

where a point
 

looks like a disc, depends on the degree of enlargement. I think
   

that the
 

smaller image, captured by a shorter focal length needs more
   

enlargement,
 

thus less appearing less sharp.
   

Well, yes. Of course.

William Robb



 

RE: DOF and angle of view or focal length (long)

[Jens Bladt]

Thanks DagT
>Both, depending on you priorities.  If angle of view is important you say
the first, if DOF is more important you say the >>>latter.  In addition, as
you say, the degree of enlargement also plays a part, along with
resolution/diffraction limits etc.

I guess it matters who is asking (digital or 35mm enthusiasts)
I have allways regarded DOF as sometihning like this: The speed of which
sharpness is decreasing - from the focal point - to both sides of the focus
point - further away towards infinity, and towards the camera. This "speed"
is determined by the physical, optical laws rather than a subjective opinion
about what is sharp and what isn't.
All the best

Jens Bladt
mailto:[EMAIL PROTECTED]
http://hjem.get2net.dk/bladt


-Oprindelig meddelelse-
Fra: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Sendt: 22. marts 2004 10:33
Til: [EMAIL PROTECTED]
Emne: Re: DOF and angle of view or focal length (long)


> Fra: "Jens Bladt" <[EMAIL PROTECTED]>

> Some of you people are very knowledgeable when it comes to optical
science.
> So, I would like to ask you this:
>
> On the internet there is an ongoing discussion about this subeject.
> Some say, that smaller formats have greater DOF (Photonet). They say that
in
> order to get comparable images, I must use shorter focal length to go with
> the smaller format, thus achieving greater DOF. They are using circle of
> confusion (COF) theories to support their point of view.

If you want the same field of view, that is correct.

> I (and Photozone) say, that smaller formats only show a part of the image,
> captured by a specific focal lenght. If I shoot the same scene twice with
> the same camera, same lens (focal length( and same aperture and focus
point,
> you will get identical images on let's say APS and 35mm film - that is for
> the part, that is covered by the smaller format (e.i. APS). I say that the
> DOF of these two identical images - is exactly the same. I say that focal
> length, aperure and focal distance determins the DOF.

If field of view is unimportant, that is correct.  The APS size sensor
simply crops the image.

> IMO COF theories are somewhat subjective, because the point to where a
point
> looks like a disc, depends on the degree of enlargement. I think that the
> smaller image, captured by a shorter focal length needs more enlargement,
> thus less appearing less sharp.

> What is right and wrong here?

Both, depending on you priorities.  If angle of view is important you say
the first, if DOF is more important you say the latter.  In addition, as you
say, the degree of enlargement also plays a part, along with
resolution/diffraction limits etc.

This image:
http://foto.no/cgi-bin/bildekritikk/vis_bilde.cgi?id=13611
is impossible to make with an APS size sensor, because of the combination of
shallow DOF and field of view.  This was made using a 28mm @ 1:2.0.  A
corresponding 18mm will not be able to make the large difference between COF
in focus and in the background. Compare images made with MF and APS formats
and this is much more evident.

DagT

RE: DOF and angle of view or focal length (long)

[Jens Bladt]

Thanks William, now I can sleep fimly again...:-)

>In practice, I find that I have to stop down a bit more on 6x7 to get
>similar DOF as I get with 35mm, presuming a similar angle of view is
>being done on both cameras.

Exactly my point - if I want change angle of view I can do to things:
1. Change focal length, which changes DOF
2. Change ditance to subject (move the camera), wich also changes the
conditions for DOF.
All the best

Jens Bladt
mailto:[EMAIL PROTECTED]
http://hjem.get2net.dk/bladt


-Oprindelig meddelelse-
Fra: William Robb [mailto:[EMAIL PROTECTED]
Sendt: 22. marts 2004 07:35
Til: [EMAIL PROTECTED]
Emne: Re: DOF and angle of view or focal length (long)



- Original Message -
From: "Jens Bladt"
Subject: DOF and angle of view or focal length (long)


> Some of you people are very knowledgeable when it comes to optical
science.
> So, I would like to ask you this:
>
> On the internet there is an ongoing discussion about this subeject.
> Some say, that smaller formats have greater DOF (Photonet). They
say that in
> order to get comparable images, I must use shorter focal length to
go with
> the smaller format, thus achieving greater DOF. They are using
circle of
> confusion (COF) theories to support their point of view.
>
> I (and Photozone) say, that smaller formats only show a part of the
image,
> captured by a specific focal lenght. If I shoot the same scene
twice with
> the same camera, same lens (focal length( and same aperture and
focus point,
> you will get identical images on let's say APS and 35mm film - that
is for
> the part, that is covered by the smaller format (e.i. APS). I say
that the
> DOF of these two identical images - is exactly the same. I say that
focal
> length, aperure and focal distance determins the DOF.

This part is true, to an extent.
However, if you are going to use the same focal length, but change
formats, then really, camera to subject distance pretty much has to
change to be photographically useful.
Or, if you are going to change formats, but not camera to subject
distance, then you need to change lenses.

In theory, I think you are correct.

In practice, I find that I have to stop down a bit more on 6x7 to get
similar DOF as I get with 35mm, presuming a similar angle of view is
being done on both cameras.

>
> IMO COF theories are somewhat subjective, because the point to
where a point
> looks like a disc, depends on the degree of enlargement. I think
that the
> smaller image, captured by a shorter focal length needs more
enlargement,
> thus less appearing less sharp.

Well, yes. Of course.


William Robb

Re: DOF and angle of view or focal length (long)

[keller.schaefer]

My rule of thumb is that when I use a lens designed for film cameras on the *ist
D, I get one stop less DOF as what is engraved on the lens.
Example for a 55mm lens: DOF indicator says "infinity to 9m" for f=11. On the
*ist D this will become "infinity to 12m" as indicated for f=8.

However, you get one stop more DOF than using the 'equivalent' focal length on a
film camera at the same aperture.

Sven



Zitat von [EMAIL PROTECTED]:

> > Fra: "Jens Bladt" <[EMAIL PROTECTED]>
...
> > Some say, that smaller formats have greater DOF (Photonet). They say that
> in
> > order to get comparable images, I must use shorter focal length to go with
> > the smaller format, thus achieving greater DOF. They are using circle of
> > confusion (COF) theories to support their point of view.
>
> If you want the same field of view, that is correct.
>
> > I (and Photozone) say, that smaller formats only show a part of the image,
> > captured by a specific focal lenght. If I shoot the same scene twice with
> > the same camera, same lens (focal length( and same aperture and focus
> point,
> > you will get identical images on let's say APS and 35mm film - that is for
> > the part, that is covered by the smaller format (e.i. APS). I say that the
> > DOF of these two identical images - is exactly the same. I say that focal
> > length, aperure and focal distance determins the DOF.
>
> If field of view is unimportant, that is correct.  The APS size sensor simply
> crops the image.
>
> > IMO COF theories are somewhat subjective, because the point to where a
> point
> > looks like a disc, depends on the degree of enlargement. I think that the
> > smaller image, captured by a shorter focal length needs more enlargement,
> > thus less appearing less sharp.
>
> > What is right and wrong here?
>
> Both, depending on you priorities.  If angle of view is important you say the
> first, if DOF is more important you say the latter.  In addition, as you say,
> the degree of enlargement also plays a part, along with
> resolution/diffraction limits etc.
>
> This image:
> http://foto.no/cgi-bin/bildekritikk/vis_bilde.cgi?id=13611
> is impossible to make with an APS size sensor, because of the combination of
> shallow DOF and field of view.  This was made using a 28mm @ 1:2.0.  A
> corresponding 18mm will not be able to make the large difference between COF
> in focus and in the background. Compare images made with MF and APS formats
> and this is much more evident.
>
> DagT
>
>

Re: DOF and angle of view or focal length (long)

[William Robb]

- Original Message - 
From: "Jens Bladt"
Subject: DOF and angle of view or focal length (long)


> Some of you people are very knowledgeable when it comes to optical
science.
> So, I would like to ask you this:
>
> On the internet there is an ongoing discussion about this subeject.
> Some say, that smaller formats have greater DOF (Photonet). They
say that in
> order to get comparable images, I must use shorter focal length to
go with
> the smaller format, thus achieving greater DOF. They are using
circle of
> confusion (COF) theories to support their point of view.
>
> I (and Photozone) say, that smaller formats only show a part of the
image,
> captured by a specific focal lenght. If I shoot the same scene
twice with
> the same camera, same lens (focal length( and same aperture and
focus point,
> you will get identical images on let's say APS and 35mm film - that
is for
> the part, that is covered by the smaller format (e.i. APS). I say
that the
> DOF of these two identical images - is exactly the same. I say that
focal
> length, aperure and focal distance determins the DOF.

This part is true, to an extent.
However, if you are going to use the same focal length, but change
formats, then really, camera to subject distance pretty much has to
change to be photographically useful.
Or, if you are going to change formats, but not camera to subject
distance, then you need to change lenses.

In theory, I think you are correct.

In practice, I find that I have to stop down a bit more on 6x7 to get
similar DOF as I get with 35mm, presuming a similar angle of view is
being done on both cameras.

>
> IMO COF theories are somewhat subjective, because the point to
where a point
> looks like a disc, depends on the degree of enlargement. I think
that the
> smaller image, captured by a shorter focal length needs more
enlargement,
> thus less appearing less sharp.

Well, yes. Of course.


William Robb

DOF and angle of view or focal length (long)

[Jens Bladt]

Some of you people are very knowledgeable when it comes to optical science.
So, I would like to ask you this:

On the internet there is an ongoing discussion about this subeject.
Some say, that smaller formats have greater DOF (Photonet). They say that in
order to get comparable images, I must use shorter focal length to go with
the smaller format, thus achieving greater DOF. They are using circle of
confusion (COF) theories to support their point of view.

I (and Photozone) say, that smaller formats only show a part of the image,
captured by a specific focal lenght. If I shoot the same scene twice with
the same camera, same lens (focal length( and same aperture and focus point,
you will get identical images on let's say APS and 35mm film - that is for
the part, that is covered by the smaller format (e.i. APS). I say that the
DOF of these two identical images - is exactly the same. I say that focal
length, aperure and focal distance determins the DOF.

IMO COF theories are somewhat subjective, because the point to where a point
looks like a disc, depends on the degree of enlargement. I think that the
smaller image, captured by a shorter focal length needs more enlargement,
thus less appearing less sharp.

What is right and wrong here?


Jens Bladt
mailto:[EMAIL PROTECTED]
http://hjem.get2net.dk/bladt

Re: 88 degree angle of view and f/3.5, was Re: Pentax AF 18.5/2.8 for SLR

[Dag T]

På 30. des. 2003 kl. 14.13 skrev Rob Studdert:

On 30 Dec 2003 at 10:39, Dag T wrote:

OK, but if a 22.5mm FF lens has an angle of view of 88mm (a didn´t
remember those numbers), the FOV factor of 1.5 of the *istD should
indicate that a new DA lens with this angle of view would be a 15mm.
OK now I'm confused.

If the diagonal angle of view across an APS frame (almost the same as 
the *ist
D sensor) is 88° then this lenses actual FL would be approximately 
18mm.

If this same 18mm lens covered a 35mm frame it would provide a 100.5° 
diagonal
angle of view in that format.
One of us is confused, i´m not sure who :-)

 Doesn´t the field of view of your 15mm correspond to the field of view 
on a 22mm when used on the *istD?

A DA 15mm f/3.5 would be very interesting
Not for those of us who already own an SMCPA15/3.5, an 18/2.8 would be 
nice
though.
They have another patent application for that one...

DagT

Re: 88 degree angle of view and f/3.5, was Re: Pentax AF 18.5/2.8 for SLR

[Rob Studdert]

On 30 Dec 2003 at 10:39, Dag T wrote:

> OK, but if a 22.5mm FF lens has an angle of view of 88mm (a didn´t 
> remember those numbers), the FOV factor of 1.5 of the *istD should 
> indicate that a new DA lens with this angle of view would be a 15mm.

OK now I'm confused. 

If the diagonal angle of view across an APS frame (almost the same as the *ist 
D sensor) is 88° then this lenses actual FL would be approximately 18mm.

If this same 18mm lens covered a 35mm frame it would provide a 100.5° diagonal 
angle of view in that format.

> A DA 15mm f/3.5 would be very interesting

Not for those of us who already own an SMCPA15/3.5, an 18/2.8 would be nice 
though.

Rob Studdert
HURSTVILLE AUSTRALIA
Tel +61-2-9554-4110
UTC(GMT)  +10 Hours
[EMAIL PROTECTED]
http://members.ozemail.com.au/~distudio/publications/
Pentax user since 1986, PDMLer since 1998

Re: 88 degree angle of view and f/3.5, was Re: Pentax AF 18.5/2.8 for SLR

[Dag T]

På 30. des. 2003 kl. 01.02 skrev Rob Studdert:

On 29 Dec 2003 at 23:53, Dag T wrote:

Sorry, I lost you there, you meant 12,5mm?
No, 12.5mm FL lens on a 35mm frame provides a 120° DAOV or 110° HAOV.
OK, but if a 22.5mm FF lens has an angle of view of 88mm (a didn´t 
remember those numbers), the FOV factor of 1.5 of the *istD should 
indicate that a new DA lens with this angle of view would be a 15mm.

A DA 15mm f/3.5 would be very interesting

DagT

88 degree angle of view and f/3.5, was Re: Pentax AF 18.5/2.8 for SLR

[Dag T]

By the way, here´s one with a half angle-of-view of about 44.degree,  
and F-number of about 3.5":
http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=/ 
netahtml/search-adv.htm&r=1&p=1&f=G&l=50&d=ptxt&S1=6490101.WKU.&OS=pn/ 
6490101&RS=PN/6490101

That should about 88 degrees viewing angle.  They have hidden the focal  
length, you have too calculate it from the formulas, so it´s hard to  
say it is for FF or APS size sensors.

DagT

På 29. des. 2003 kl. 20.47 skrev Dag T:

Here it is:
http://appft1.uspto.gov/netacgi/nph-Parser? 
Sect1=PTO2&Sect2=HITOFF&p=1&u=%2Fnetahtml%2FPTO%2Fsearch- 
bool.html&r=16&f=G&l=50&co1=AND&d=PG01&s1=%22ASAHI+KOGAKU+KOGYO+KABUSHI 
KI+KAISHA%22.AS.&OS=AN/"ASAHI+KOGAKU+KOGYO+KABUSHIKI+KAISHA"&RS=AN/"ASA 
HI+KOGAKU+KOGYO+KABUSHIKI+KAISHA"

and there is no mention of a zoom.

DagT

På 29. des. 2003 kl. 20.39 skrev Leonard Paris:

I don't have the URL anymore.  Send it to me and I'll find it again,  
if I can.

Len
---
* There's no place like 127.0.0.1




From: "Jostein" <[EMAIL PROTECTED]>
Reply-To: [EMAIL PROTECTED]
To: <[EMAIL PROTECTED]>
Subject: Re: Pentax AF 18.5/2.8 for SLR
Date: Mon, 29 Dec 2003 19:34:08 +0100
I missed the part saying it's a zoom.
Do you have any chance to point me to the right paragraph?
Jostein
-
Pictures at: http://oksne.net
-
- Original Message -
From: "Len Paris" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Saturday, December 27, 2003 6:08 PM
Subject: RE: Pentax AF 18.5/2.8 for SLR
> A 10:1 zoom ratio. Would that likely be an Ltd lens?
>
> Len
>  * There's no place like 127.0.0.1
>
>
> > -Original Message-
> > From: Jostein [mailto:[EMAIL PROTECTED]
> > Sent: Saturday, December 27, 2003 6:47 AM
> > To: [EMAIL PROTECTED]
> > Subject: Re: Pentax AF 18.5/2.8 for SLR
> >
> >
> > Not being able to decipher patent language, my first guess is
> > Another Limited?
> > Jostein
> >
> > Quoting Alan Chan <[EMAIL PROTECTED]>:
> >
> > >
> > http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HI
>  
TOFF&p=1&u=%2Fnetahtml%2FPTO%2Fsearch- 
bool.html&r=16&f=G&l=50&co1=AND&d=
>  
PG01&s1=%22ASAHI+KOGAKU+KOGYO+KABUSHIKI+KAISHA%22.AS.&OS=AN/"ASAHI+KO 
GAK
>  
U+KOGYO+KABUSHIKI+KAISHA"&RS=AN/"ASAHI+KOGAKU+KOGYO+KABUSHIKI+KAISHA"
> >
> > Yours regards,
> > Alan Chan
> > http://www.pbase.com/wlachan
> >
> > _
> > The new MSN 8: smart spam protection and 2 months FREE*
> > http://join.msn.com/?page=features/junkmail
> >
>  
http://join.msn.com/?page=dept/bcomm&pgmarket=en- 
ca&RU=http%3a%2f%2fjoin
> .msn.com%2f%3fpage%3dmisc%2fspecialoffers%26pgmarket%3den-ca
> >
> >
>
>
>
>
> 
> This message was sent using IMP, the Internet Messaging Program.
>
>

_
Working moms: Find helpful tips here on managing kids, home, work —   
and yourself.   http://special.msn.com/msnbc/workingmom.armx

Stupid question: medfo WA lenses, angle of view and hoods.

[gfen]

I need to purchase a hood for my 645 45mm lens. Now, I'm just happy enough
purchasing a generic rubber hood for it, however, do I need to buy the
"wide angle" version, or would a regular hood be sufficent?

I wonder only because I'm sure on a 135 45mm lens, it wouldn't vignette,
but is the angle of view any different since it is a wide angle lens in
its intended format?

-- 
http://www.infotainment.org   <-> more fun than a poke in your eye.
http://www.eighteenpercent.com<-> photography and portfolio.

Re: Angle of View

[Shel Belinkoff]

Thanks for all the great answers to the question .

> > When it is said that a lens has a 
> > certain angle of view, where is the
> > point from which the angle is measured
> >  - film plane, somewhere inside the
> > lens, front element?

-- 
Shel Belinkoff
mailto:[EMAIL PROTECTED]
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Re: Angle of View - William Robb

[Gary L. Murphy]

On Mon, 22 Oct 2001 21:52:57 -0600, William Robb wrote:

Bill,

When I send email to you, it keeps getting bounced back or delayed. HAve any idea?

Did you get me PUG submission?






Later,
Gary
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Angle of View

[William Robb]

> > Date: Mon, 22 Oct 2001 14:22:02 -0700
> > From: Shel Belinkoff
> > Subject: OT: Angle of View
> >
> > When it is said that a lens has a certain angle of view,
where is point
> > from which the angle is measured - film plane, somewhere
inside the
> > lens, front element?

The angle of view is measured from the optical center of the
lens.
William Robb
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RE: Angle of View

[Anthony Farr]

- Original Message -
From: "Anthony Farr" <[EMAIL PROTECTED]>

> - Original Message -
> From: "Shel Belinkoff" <[EMAIL PROTECTED]>
>
>
> > When it is said that a lens has a certain angle of view, where is
> point
> > from which the angle is measured - film plane, somewhere inside the
> > lens, front element?
> > --
> > Shel Belinkoff
> >
>
> Rear nodal point.
>
> Regards,
> Anthony Farr
>

A minor correction is in order.  The rear nodal point is the point from
which the AOV is measured to the film.  The AOV to the subject (ie. in
front of the lens) is measured from the front nodal point.  The space
between the rear and the front nodal points can be thought of as the
province of the lens designer.  As John Francis says, 180 degree and
greater fisheye lenses appear to follow a different set of rules.

Regards,
Anthony Farr
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Re: Angle of View

[Anthony Farr]

- Original Message -
From: "Shel Belinkoff" <[EMAIL PROTECTED]>


> When it is said that a lens has a certain angle of view, where is
point
> from which the angle is measured - film plane, somewhere inside the
> lens, front element?
> --
> Shel Belinkoff
>

Rear nodal point.

Regards,
Anthony Farr
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RE: Angle of View

[Paul M. Provencher]

The angle of view indicates the area that will be included within the film
frame when the lens is focused to infinity.  The standard practice is to
give the angle of view based on the diagonal of the film format.  Since most
subjects are either horizontal or vertical, angles of view for these are
given in the lens data sheets. (AMPHOTO, Dr. Joseph D. Cooper, Honeywell
Pentax Manual, Chapter 3, page 2.)  The lens data sheets referenced in the
same chapter give, for example:

SMC Takumar 24mm f/3.5
.
.
.
Angles of view
Diagonal 84 degrees
Horizontal 74 degrees
Vertical 53 degrees

.
.
.

The Spotmatic II manual lists this lens simply as having an 84 degree angle
of view.

The useful angle of view depends on your application, I suppose.

ppro



> -Original Message-
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED]]On Behalf Of Shel Belinkoff
> Sent: Monday, October 22, 2001 5:22 PM
> To: Pentax List
> Subject: OT: Angle of View
>
>
>
> When it is said that a lens has a certain angle of view, where is point
> from which the angle is measured - film plane, somewhere inside the
> lens, front element?
> --
> Shel Belinkoff
> mailto:[EMAIL PROTECTED]
> -
> This message is from the Pentax-Discuss Mail List.  To unsubscribe,
> go to http://www.pdml.net and follow the directions. Don't forget to
> visit the Pentax Users' Gallery at http://pug.komkon.org .
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Re: OT: Angle of View

[Juan J. Buhler]

On Mon, 22 Oct 2001, Shel Belinkoff wrote:

> When it is said that a lens has a certain angle of view, where is point
> from which the angle is measured - film plane, somewhere inside the
> lens, front element?

Somewhere inside the lens. I don't remember how that point is called,
but suppose you have an equivalent pinhole. The point from which the
angle is measured will be the pinhole. 

j

--
---
 Juan J. Buhler | Sr. FX Animator @ PDI | Photos at http://www.jbuhler.com
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OT: Angle of View

[Shel Belinkoff]

When it is said that a lens has a certain angle of view, where is point
from which the angle is measured - film plane, somewhere inside the
lens, front element?
-- 
Shel Belinkoff
mailto:[EMAIL PROTECTED]
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