You can put your 40D in P mode as well. In my opinion though, that would be waste... what's the point of having a DSLR if you shoot in P mode?? The results are still better than with P&S, but for me at least it sounds super dumb thing to do. Maybe just shoot with a 1Ds mark3 on Auto mode... [:P]
Originally Posted by Oren
Agree...you are funny! actually you made me feel better as this is how I feel...why get this capable camera and use it as P/S?
Maybe Nikon does something different/better, but I think I can learn and think like a photographer if I use my brain and skills....it's just that it is taking me longer, LOL. I have been reading up this weekend a bit, it is somehow coming better together but it will be a long time before I will say with a certainty that the picture I took looks good because I intentionally made it that way or the other.
I need some help with ISO...any web pages that would explain well use of which ISO (on digital SLRs) in relation to aperture and shutter speed. I know it may sound basic, but I could use some tutorial. Thanks for your help and making me laugh []
Keep having fun, and it will all fall into place.
Aperture, ISO, and shutter speed are all related to each other in terms of light.
ISO is sensitivity to light (from the sensor/electronics standpoint, used to be the type of film)
Higher ISO is more sensitive, in proportion to the number. With a given amount of light, higher ISO will provide a brighter picture, lower ISO a darker picture.
Aperture is how large the shutter opens, expressed in a ratio to the focal length, or f/x.x. We often forget that the number is actually related to the focal length ratio, and just say '2.8' or '4' or whatever, when in fact it's actually f/2.8 or f/4.0. So, the 'larger' the short hand number, the smaller the actual aperture is. The aperture is the diameter of the opening. The light that can pass through the aperture is proportional to the area of the opening, which will be proportional to thediameter squared. So, what this means is, that everytime the aperture doubles, the light increases by a factor of 4. So, f/4 is twice as 'wide' as f/8, in terms of the diameter of the aperture. However, it lets in 4 times the light.
Shutter speed is how long the shutter is open. The amount of light passed is directly proportional to the length of time. 1/50 of a second lets in twice as much light as 1/100 of a second.
So all three of them can be manipulated to get the correct exposure, in terms of how much light, to capture the information. However, as you're learning, it's not just about how much light, because if it were, we could simply set the thing to 'Auto', or adjust a single parameter, and so long as we got a good exposure, everything would be fine.
But....
ISO changes the signal to noise ratio (and in film changes the resolution with different sizes of film grain). If you want to get into it with Daniel, he'll explain to you that changing the signal to noise ratio can also effecitively change the resolution too...
Aperture changes the depth of field (how quickly things get out of focus as you move away from that perfect distance which is 'in focus')
Shutter speed changes how much blur there will be due to motion of the camera or the subjects. You usually don't want motion blur induced by the camera (but sometimes you might), and you may or may not want motion blur created by subject movement.
But, you almost always want the correct amount of light
I'd suggest playing with the aperture and shutter speed with the Av and Tv modes, and maybe doing so with different ISO settings and see what happens. Manual mode is probably worth messing around with too. And check out the histogram!
Colin, thanks so much for taking your time to explain it so clearly. I really appreciate it. Are there any guidelines as to what ISO should be used with what aperture and SS---on average, before I learn what I am doing. I often make my shutter "stop", which makes me think I am not setting speed properly and I do not know how to assess it. I would like to know what are the "average" numbers to go by. What I am doing now is take a picture in idiot mode, take a look at numbers and try to duplicate settings in either P, TV or Av or M, but I cannot be as creative then and histogram is way off, in addition I am not getting the same "reaction" from my camera. Maybe there is something wrong with it in "creative" modes? I suspect it is rather "operator error" [
ISO is the same (conceptually) whether film or digital. I often explain it by drawing a complete analogy with a water bucket and a hose:
"Fill up a one-gallon bucket with water. The wider you open the faucet, the faster the bucket fills."
The one-gallon bucket is similar to the amount of light your sensor needs to see for a proper exposure at ISO 100. The faucet opening is comparable to aperture, and the time needed to fill the bucket is shutter speed.
A half-gallon bucket becomes ISO 200, quarter-gallon is ISO 400, etc.
Does that help connect the dots?
We're a Canon/Profoto family: five cameras, sixteen lenses, fifteen Profoto lights, too many modifiers.
ISO is the same (conceptually) whether film or digital. I often explain it by drawing a complete analogy with a water bucket and a hose:
"Fill up a one-gallon bucket with water. The wider you open the faucet, the faster the bucket fills."
The one-gallon bucket is similar to the amount of light your sensor needs to see for a proper exposure at ISO 100. The faucet opening is comparable to aperture, and the time needed to fill the bucket is shutter speed.
A half-gallon bucket becomes ISO 200, quarter-gallon is ISO 400, etc.
Does that help connect the dots?
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this is great analogy! thanks so much! i am finally getting this stuff [
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