You need to rethink the statement that 400 speed film would allow for greater depth of field. The speed of the film has nothing to do with DOF directly. DOF is controlled by the aperture size. Indirectly, the faster film would allow the same exposure with a smaller f-stop, which would allow a greater DOF. Of course, this in turn would negate the advantage of a faster film increasing light exposure to the film.
Film types and speeds
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You need to rethink the statement that 400 speed film would allow for greater depth of field. The speed of the film has nothing to do with DOF directly. DOF is controlled by the aperture size. Indirectly, the faster film would allow the same exposure with a smaller f-stop, which would allow a greater DOF. Of course, this in turn would negate the advantage of a faster film increasing light exposure to the film.
Folks,
When I write "I do not remember, what I am trying to say is that "I do not remember."" No inferences. No innuendos. Just a failure of memory! And, I still do not remember.
What I do remember is that all cameras have limitations. And I DID NOT REMEMBER WHAT THE LIMITATIONS WERE ON THE REEFMASTER'S CAPABILITY IN THE AREA OF FILM SPEEDS WERE. It would do no good to suggest using ISO 400 film if the camera's settings were topped off at 200!
Now, Scorpiofish, you might rethink how a camera works. At a given shutter speed, the higher the ISO number the greater the lens can be stopped down. The more a lens is stopped down, the greater the depth of field (= depth of focus= how much is in focus).
Let me give you an example for a 20mm lens when you are focusing on something at 3 feet: if you choose to use ISO 100 film and you choose a shutter speed of 1/100, you might then have an f stop of f/4 and the depth of field would be 2.17 ft to 4.58 ft.
Now, let's take the same lens, same focus and use ISO 400 film: now, we will keep the shutter speed the same (1/100) and, thus, we can stop the lens down a factor of 4 to f/8. The depth of field becomes 1.75 ft to 10.5 ft!
In other words, when we replace ISO 100 with ISO 400, at the same focused distance and shutter speed, we go from having a total distance of 2.41 feet in focus to having 8.75 feet in focus. That will make it more likely that what you are shooting will be in focus.
This is a standard precept in photography.
Joewr...
When I write "I do not remember, what I am trying to say is that "I do not remember."" No inferences. No innuendos. Just a failure of memory! And, I still do not remember.
What I do remember is that all cameras have limitations. And I DID NOT REMEMBER WHAT THE LIMITATIONS WERE ON THE REEFMASTER'S CAPABILITY IN THE AREA OF FILM SPEEDS WERE. It would do no good to suggest using ISO 400 film if the camera's settings were topped off at 200!
Now, Scorpiofish, you might rethink how a camera works. At a given shutter speed, the higher the ISO number the greater the lens can be stopped down. The more a lens is stopped down, the greater the depth of field (= depth of focus= how much is in focus).
Let me give you an example for a 20mm lens when you are focusing on something at 3 feet: if you choose to use ISO 100 film and you choose a shutter speed of 1/100, you might then have an f stop of f/4 and the depth of field would be 2.17 ft to 4.58 ft.
Now, let's take the same lens, same focus and use ISO 400 film: now, we will keep the shutter speed the same (1/100) and, thus, we can stop the lens down a factor of 4 to f/8. The depth of field becomes 1.75 ft to 10.5 ft!
In other words, when we replace ISO 100 with ISO 400, at the same focused distance and shutter speed, we go from having a total distance of 2.41 feet in focus to having 8.75 feet in focus. That will make it more likely that what you are shooting will be in focus.
This is a standard precept in photography.
Joewr...
I am so confused...will some please write the book Underwater Photography for Dummies. I have never taken any classes on photography and my underwater pics aren't that good, and I have used 100 and 400...have no idea what the f/stops are for or how they relate...
Arggghhhhh....... I need a camera with a digital touch screen that I can touch the object I want to photography, using sonar it calculates the distance to source and sets everything just right...
Arggghhhhh....... I need a camera with a digital touch screen that I can touch the object I want to photography, using sonar it calculates the distance to source and sets everything just right...
Syruss,
Before I write an exposition of photography, let me suggest a book on photography in general: "National Geographic Photographer's Field Guide." My copy dates back to 1981, but I believe that I have seen more recent editions...
It will explain the basics of photography, including the relationship of lens opening (aperature opening) to depth of field, focal length of lens to depth of field, film speed etc. It is well-written and not "too technical".
There is a small section on u/w photography, but I can suggest other books after you finish that one.
Joewr...
Before I write an exposition of photography, let me suggest a book on photography in general: "National Geographic Photographer's Field Guide." My copy dates back to 1981, but I believe that I have seen more recent editions...
It will explain the basics of photography, including the relationship of lens opening (aperature opening) to depth of field, focal length of lens to depth of field, film speed etc. It is well-written and not "too technical".
There is a small section on u/w photography, but I can suggest other books after you finish that one.
Joewr...
Syruss...there are several good books out there covering underwater photography. There are also several online sites that will get you started.
One of the easiest to understand is by a friend of mine, Dave Read. He can describe all that technical stuff so even dummies can understand it!
Plus, you never had to leave your monitor. Check it out... http://www.daveread.com/uw-photo/
One of the easiest to understand is by a friend of mine, Dave Read. He can describe all that technical stuff so even dummies can understand it!
Plus, you never had to leave your monitor. Check it out... http://www.daveread.com/uw-photo/Originally posted by Dee
Syruss...there are several good books out there covering underwater photography. There are also several online sites that will get you started.
One of the easiest to understand is by a friend of mine, Dave Read. He can describe all that technical stuff so even dummies can understand it!
So now I am a dummy huh Dee.... Okay I have seen my pics and I think that qualifies me. I just looked at some online pics at the below url and wow are they good!
http://www.sonic.net/~jmp/photos.shtml
Obviously I still have some training to go. I will check out that site.
P.S. Joewr thanks for the advice I might have to look for that book!
Hey...you're the one who mentioned dummies! I learned alot from Dave. He takes it slow and breaks everything down into sections so you are trying to learn everything all at once. One of the most inportant things to learn, no matter what kind of camera you use is composition. His tutorial on it is excellent. He also shows you how to critique your own photos to find out just WHY it didn't turn out like you wanted!
So from one dummie to another....try it!
The original quote I referenced stated
"That is because it has been a long time since I have seen one up close and personal! I also indicated that, if it can take 400, I would recommend it because it would allow for greater depth of field at a given shutter speed. "
While your followup is correct, your original statement makes no mention of stopping down the aperture. Your original statement might confuse someone. Merely changing from 100 to 400 will not effect the DOF without stopping down the aperture.
If one goes from say 200 to 400 speed, stays at the same shutter speed, stops down one f-stop, you get the same exposure with increased DOF.
One may alternately go from 200 to 400 speed, keep shutter speed and aperture constant and gain on the exposure without effecting DOF. This is often why 400 is recommended in point and shoots with limited strobe power or in low light situations.
My point is you cannot do both.
"That is because it has been a long time since I have seen one up close and personal! I also indicated that, if it can take 400, I would recommend it because it would allow for greater depth of field at a given shutter speed. "
While your followup is correct, your original statement makes no mention of stopping down the aperture. Your original statement might confuse someone. Merely changing from 100 to 400 will not effect the DOF without stopping down the aperture.
If one goes from say 200 to 400 speed, stays at the same shutter speed, stops down one f-stop, you get the same exposure with increased DOF.
One may alternately go from 200 to 400 speed, keep shutter speed and aperture constant and gain on the exposure without effecting DOF. This is often why 400 is recommended in point and shoots with limited strobe power or in low light situations.
My point is you cannot do both.
Scorpiofish,
In my very first post on this thread on 8/23 I wrote that a higher ISO would allow one to stop down the lens at a given shutter speed and that that would allow a greater depth of field. Go back and check it out.
Then on 11/13 I wrote that at a given shutter speed a higher ISO number would allow for a greater depth of field.
Now, are you saying that on 11/13 I had forgotten what I wrote on 8/23 (and have known for over 45 years) and I was suggesting that folks not adjust the aperature at a given shutter speed? And that I would not know that that would lead to overexposure? Give me a break!
What I was assuming was that they were using a camera that was "automatic" and that it would adjust the aperature at a given shutter speed, thus giving them greater depth of field.
Joewr...
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