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Exposure calculation



 
 
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  #1  
Old April 16th 08, 07:08 PM posted to rec.photo.equipment.large-format
Max Perl
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Posts: 281
Default Exposure calculation

When you use a view camera for macro work you have long extention on the
bellows.
You then need to compensate for the lost light to calculate a proper
exposure.
Does somebody have an easy way to calculate the exposure compensation?

I am using a 6x9 Linhof and want to play with a 5.6/100 Componon-S.
I guess you don't compensate down to 1m? ......but from here and closer?


Max


  #2  
Old April 16th 08, 08:25 PM posted to rec.photo.equipment.large-format
Howard Lester
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Posts: 36
Default Exposure calculation

"Max Perl" wrote

When you use a view camera for macro work you have long extention on the
bellows.
You then need to compensate for the lost light to calculate a proper
exposure.
Does somebody have an easy way to calculate the exposure compensation?


Calumet Photo used to (still does?) sell an inexpensive (under $10)
"close-up calculator." It consists of a square about 1-1/2" on each side
(one face is black, the other white), and a "ruler" that you place on the
ground glass. You place the small square piece up against your subject. With
the "ruler" you measure the size of the square as its image appears on the
ground glass and you read directly in f/stops the amount of extra exposure
required.


  #3  
Old April 16th 08, 09:59 PM posted to rec.photo.equipment.large-format
Max Perl
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Posts: 281
Default Exposure calculation


"Howard Lester" skrev i en meddelelse
news:nYqdnaeYm4VXz5vVnZ2dnUVZ_veinZ2d@dakotacomip. ..
"Max Perl" wrote

When you use a view camera for macro work you have long extention on the
bellows.
You then need to compensate for the lost light to calculate a proper
exposure.
Does somebody have an easy way to calculate the exposure compensation?


Calumet Photo used to (still does?) sell an inexpensive (under $10)
"close-up calculator." It consists of a square about 1-1/2" on each side
(one face is black, the other white), and a "ruler" that you place on the
ground glass. You place the small square piece up against your subject.
With the "ruler" you measure the size of the square as its image appears
on the ground glass and you read directly in f/stops the amount of extra
exposure required.


Then it must be this one?

http://www.calumetphoto.com/item/CC9201/


  #4  
Old April 17th 08, 12:21 AM posted to rec.photo.equipment.large-format
Howard Lester
external usenet poster
 
Posts: 36
Default Exposure calculation


"Max Perl" wrote

Then it must be this one?

http://www.calumetphoto.com/item/CC9201/


That's it!


  #5  
Old April 17th 08, 12:27 AM posted to rec.photo.equipment.large-format
Nicholas O. Lindan
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Posts: 1,227
Default Exposure calculation

"Max Perl" wrote

Does somebody have an easy way to calculate the [bellows extension]
exposure compensation?


http://www.salzgeber.at/disc/

--
Nicholas O. Lindan, Cleveland, Ohio
Darkroom Automation: F-Stop Timers, Enlarging Meters
http://www.darkroomautomation.com/index2.htm
n o lindan at ix dot netcom dot com


  #6  
Old April 17th 08, 03:43 AM posted to rec.photo.equipment.large-format
____
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Posts: 534
Default Exposure calculation

In article ,
"Max Perl" wrote:

When you use a view camera for macro work you have long extention on the
bellows.
You then need to compensate for the lost light to calculate a proper
exposure.
Does somebody have an easy way to calculate the exposure compensation?

I am using a 6x9 Linhof and want to play with a 5.6/100 Componon-S.
I guess you don't compensate down to 1m? ......but from here and closer?


Max


A held calculator with this formula and then you can make your own
"dummy stick"


Indicated F/stop (Use a light meter) * Bellows Extension (Use a ruler)
____________________________________
Focal Length (Of the lens)


= Effective F/stop.

--
Reality is a picture perfected and never looking back.
  #7  
Old April 17th 08, 04:01 PM posted to rec.photo.equipment.large-format
Max Perl
external usenet poster
 
Posts: 281
Default Exposure calculation


"____" skrev i en meddelelse
...
In article ,
"Max Perl" wrote:

When you use a view camera for macro work you have long extention on the
bellows.
You then need to compensate for the lost light to calculate a proper
exposure.
Does somebody have an easy way to calculate the exposure compensation?

I am using a 6x9 Linhof and want to play with a 5.6/100 Componon-S.
I guess you don't compensate down to 1m? ......but from here and
closer?


Max


A held calculator with this formula and then you can make your own
"dummy stick"


Indicated F/stop (Use a light meter) * Bellows Extension (Use a ruler)
____________________________________
Focal Length (Of the lens)


= Effective F/stop.

--
Reality is a picture perfected and never looking back.


Thank you!
I will try this!


  #8  
Old April 17th 08, 04:04 PM posted to rec.photo.equipment.large-format
Max Perl
external usenet poster
 
Posts: 281
Default Exposure calculation


"Nicholas O. Lindan" skrev i en meddelelse
...
"Max Perl" wrote

Does somebody have an easy way to calculate the [bellows extension]
exposure compensation?


http://www.salzgeber.at/disc/

--
Nicholas O. Lindan, Cleveland, Ohio
Darkroom Automation: F-Stop Timers, Enlarging Meters
http://www.darkroomautomation.com/index2.htm
n o lindan at ix dot netcom dot com


Thank you!
I will try out the formular!


  #9  
Old June 6th 08, 06:07 AM posted to rec.photo.equipment.large-format
MangroveRoot
external usenet poster
 
Posts: 7
Default Exposure calculation

Max Perl wrote:
When you use a view camera for macro work you have long extention on the
bellows. You then need to compensate for the lost light to calculate a
proper exposure. Does somebody have an easy way to calculate the
exposure compensation?


I am using a 6x9 Linhof and want to play with a 5.6/100 Componon-S. I
guess you don't compensate down to 1m? ... but from here and closer?


Would I be right in the belief that this question, and the solutions to it,
would be applicable to formats other than "large",
should one care to do such a thing?

(I do extremely little (haha) macro work, and my largest camera is a 645,
and while that and my old 35mm are pretty clunky, they still are advanced
w/r/t many large-format camera, correct? And, of course, my DSLR does
everything but procreate. So I doubt I will *need* to know this.
But it would be nice to know if it applies, and, if so, how to do it.)
  #10  
Old June 6th 08, 03:19 PM posted to rec.photo.equipment.large-format
otzi
external usenet poster
 
Posts: 25
Default Exposure calculation

I am surprised that no one has responded, yet. I'll be the duffer.

With a flash, a doubling of the distance from flash to subject is a 4 fold
reduction in illumination that's 2 stops. So in the same vein a doubling of
the bellows extension from say 150mm to 300mm would necessitate a 2 stop
increase or 4 fold increase of light requirement getting to the film..
Therefore a partial extension say 1/2 way would be 1 stop increase and so
on. Rough as guts but it is quick and gets you in the ball park (where ever
that is) to the nearest 1/2 stop. This does require one to mark by big fat
texta or neat biro on tape or mearly tape measure the increase in bellows
extension.

If you are new to macro, keep watch on the lighting so that the lens is not
so close to the product that it casts it's own shadow.



"MangroveRoot" wrote in message
news:KC32k.2583$Yw1.410@trndny02...
Max Perl wrote:
When you use a view camera for macro work you have long extention on the
bellows. You then need to compensate for the lost light to calculate a
proper exposure. Does somebody have an easy way to calculate the
exposure compensation?


I am using a 6x9 Linhof and want to play with a 5.6/100 Componon-S. I
guess you don't compensate down to 1m? ... but from here and closer?


Would I be right in the belief that this question, and the solutions to
it,
would be applicable to formats other than "large",
should one care to do such a thing?

(I do extremely little (haha) macro work, and my largest camera is a 645,
and while that and my old 35mm are pretty clunky, they still are advanced
w/r/t many large-format camera, correct? And, of course, my DSLR does
everything but procreate. So I doubt I will *need* to know this.
But it would be nice to know if it applies, and, if so, how to do it.)



 




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