2 basic technical questions.
Bob
With that said, here are 2 ares which I am a bit puzzled.
1. I don't understand why anyone would use the aperture priority or
shutter priority selections on the camera. I understand what they are
used for, but it seems to me that the program mode would do the same
thing. For example, let's say you want a larger aperture for a smaller
depth of field. You could go to aperture priority and set it to F2.
The camera will then set the shutter speed automatically. Let's say it
sets it to 1/250. NOW, let's say you do the same thing in program
mode. The camera takes a reading and set's It to F8 at 1/15. To
achieve the same effect as the aperture mode all you would have to do
is shift it with the wheel to the desired range. Scroll the wheel down
and it will shift the fields as follows: F5.6 at 1/30 - F4 at 1/60 -
F2.8 at 1/125 - and finally to F2 at 1/250. Am I missing something? Is
there something the av and tv modes can do that the program mode
can't?
With that said, I can fully appreciate the value of the manual mode.
2. My next question, what exactly is exposure compensation? Again, I
know what it is but I'm a bit confused as to its functionality. Are th
next two statements true?
F8 at 1/125 +1ev = F8 at 1/60
Or
F8 at 1/125 -1ev = F11 at 1/125
In other words, can you achieve the same desired effect two different
ways? Is there any other reason to use exposure compensation other
than for convenience? And how does it actually compensate? Does it
physically stop up/down the aperture or is it more on the processing
side?
Sorry this post is so long winded. I would really appreciate anyones
expertise on these matters.
Thanks
Bob
Jim Nason
I will take the bait
> First of all let me state the obvious, I'm fairly new to photography.
> With that said, here are 2 ares which I am a bit puzzled.
>
> 1. I don't understand why anyone would use the aperture priority or
> shutter priority selections on the camera.
In scenics, portraits, or city scapes the single most important
exposure decison I make is aperature (ie controls depth of field and
image sharpness). So, I set the lens to what ever aperature I want to
use and leave it there. Its set.. won't move. If I take the standard
exposre I don't need to do anything else. The camera will pick a
shutter speed. I normally shoot from a tripod so shutter speed is of
little concern unless i am shooting moving targets. The +- exposure
compensation is convenient t in this scenario. In the Nikon world, +-
will affect the shutter speed not the aperature in Av mode. So, my
lens stays at f whatever and I compensate. Real quick for bracketing.
Also, I don't have t o guess at what is happening internally.
> I understand what they are
> used for, but it seems to me that the program mode would do the same
> thing. For example, let's say you want a larger aperture for a smaller
> depth of field. You could go to aperture priority and set it to F2.
> The camera will then set the shutter speed automatically. Let's say it
> sets it to 1/250. NOW, let's say you do the same thing in program
> mode. The camera takes a reading and set's It to F8 at 1/15. To
> achieve the same effect as the aperture mode all you would have to do
> is shift it with the wheel to the desired range. Scroll the wheel down
> and it will shift the fields as follows: F5.6 at 1/30 - F4 at 1/60 -
> F2.8 at 1/125 - and finally to F2 at 1/250. Am I missing something? Is
> there something the av and tv modes can do that the program mode
> can't?
Yes it works.. but look at all the steps you went through.. and the
subject has now moved...
>
> With that said, I can fully appreciate the value of the manual mode.
> 2. My next question, what exactly is exposure compensation? Again, I
> know what it is but I'm a bit confused as to its functionality. Are th
> next two statements true?
>
> F8 at 1/125 +1ev = F8 at 1/60
>
> Or
>
> F8 at 1/125 -1ev = F11 at 1/125
>
> In other words, can you achieve the same desired effect two different
Correct...
> ways? Is there any other reason to use exposure compensation other
> than for convenience? And how does it actually compensate? Does it
> physically stop up/down the aperture or is it more on the processing
> side?
Depends on the camera.