new TIMP article... "EXPOSURE = SHUTTER + APERTURE + ISO"

Tim

Tim

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in this article, i try to explain the three sided equation that makes up exposure. i try to break down aperture/ shutter speed/ and ISO then put them back together so it all makes sense. you can view the article at:
http://www.themagicinpixels.com/articles.aspx

i welcome your comments on this article and would love to have a discussion on it...
 
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Very nice discussion, Tim. No matter how many times I review the "Photographic Triangle", I find I think about it in new ways.

I've been swearing to myself since I bought my DSLR that one day I was going out in the field and shooting a ton of "test" images showing how each setting affects a picture (such as taking a still shot on available room light starting at ISO 100 and working up ot ISO 800, or starting at 1/300 shutter speed and working my way up). I read a couple photo books that basically did that, and it's always stuck with me as a way to visualize how the settings affect an exposure and why, creatively, you want to use one setting or another (for instance, changing shutter speed when taking a shot of a fountain can either give you a frozen view of individual water drops, or a foamy "in motion" type of effect if you use a slower shutter speed). Just another thing to add to my "to do" list.
 
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Nice article.

Except that depth of field should link to another article, since it's not just related to aperture, but focal length as well.

"you see Simba, your digital camera sensor can only record so many ISO speeds, and ISO speed is related to shutter speed, and shutter speed to aperture, and aperture to depth of field, which is based on lens focal length, and the size of your lens is based on aperture, and that is why they are all connected in the great photographic circle of life"
 
"rlongenbach" said:
Nice article. Except that depth of field should link to another article, since it's not just related to aperture, but focal length as well.
Click to expand...

agreed, but that was a primary article meant for the beginner level. there will be a follow up article on depth of field coming in the future. i appreciate your advice and feedback.
 
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I know I know.... ;)

It gets too hard to try and explain the basics without going further. Sometimes it's best to leave it like it is.

Guess that's why Canon has a "green" button on the 5D dial for shooting modes. Better than the icons on mine I never use.
 
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great article, seemed to sum it up just as a novice would want to here it many books you would read try to elaberate to much. And I know when I first got my DSLR that would have been great but instead I got a book and ended up a bit confused
 
Hello Tim and everybody! New member here! Tim, I've followed your photo blog and now TMIP for several months now. It is very inspiring! I'm also saving these tutorials you're creating! They're wonderful!

I had a question about the last example in this article. When shooting SE at night with a tripod, I understand the reasoning behind ISO 100 (I assume you want the smallest ISO possible on this shot to reduce noise as much as possible). I understand also that you want a small aperture to sharpen as much of the picture as possible. But I didn't follow why f/8 would be selected instead of f/11 or f/16, if available. Is this to hit the lens' sweet spot? (You mentioned stopping down 2-3 steps from the lens' maximum to hit the sweet spot, so a lens that goes to f/16 would have a sweet spot of f/8 or f/5.6?)

Thanks for the great site! I've read several books and I think this stuff is slowly starting to click a little for me!

Jim
 
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lenses, in general, have a sweet spot of between f/8 and f/11, based on what i have read. stopping down too far can actually cause the lens to lose sharpness and become soft again, similar to putting on eyeglasses that are too strong for your eyes.

when referring to "stopping down", a photographer goes from a lens' maximum aperture (meaning the smallest f/number which is the most wide open a lens can go). i think you may have read the example backward. a maximum aperture is f/2.8 or so, f/16 would be minimum.

welcome to the boards and thanks for the nice compliments.
 
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Am I reading the article correctly? The smaller the F-Stop, the more light being allowed in?
 
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the smaller the number the larger the aperture (diaphram) opening the more light as in f4 has 2x as much light as f5.6 if the shutter speed and iso don't change. as the number gets higher the aperture gets smaller allowing in less light as in f5.6 has half the amount of light as f4 and again as long as shutter or iso don't change
 
the smaller the number, the larger the opening, so yes more light going into the camera.
it's a reverse relationship... an f/stop of f/2.8 lets in 3 stops more light than f/8 (f/2.8 <-> f/4 <-> f/5.6 <-> f/8). it's a bit confusing at first.
 
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Thanks, Tim.

I'm trying to get a grip on these settings because I think that is what is hurting me when I try to take pictures in less than ideal lighting situations and the built-in flash doesn't suffice to fill in.
 
&quot;Tim&quot; said:
you can always raise the ISO up a bit also to get some help.
Click to expand...

True, that would probably be the best way. Flash photography has it's own little quirks with aperture v shutter speed changes, such as higher shutter speeds usually decrease exposure to the background (assuming you've got a high speed sync flash); but most dSLRs, even the prosumer ones will start at 1/60 sec for flash exposures in P mode, and with Canon's I think even the 5XX EX series you have to tell it high-speed if you want to go beyond 1/250 or 1/300 sec.

My favorite though has to be when my 30D is telling me in Tv mode at, let's say 1/250 sec, that there is no way it can get a good exposure with the maximum aperture, I fire the preflash, take the pic and it comes out fine.
 
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It's conversations like this one that lets me know really quickly that I don't know anything....haha

My problem was that I was using either the 'Auto' mode or the 'A' mode and when I was trying to take pictures of my house being built and there was a strong light coming from the background), the flash wouldn't fire so the shot came out dark and overpowered by the natural light coming from the background (outside light).

I just couldn't seem to get the right settings that would minimize the impact of that light.

I guess it's the same as trying to take a picture of something standing in front of a window.
 
That would probably have to involve either:

Spot metering (the D80 has this) away from the light source then locking the exposure (AE lock- * button on Canon cameras unless changed. But if you are firing a flash it will fire then too) or

Overriding the exposure with manual exposure compensation (rear dial on Canon cameras so long as the dial is on, the flash should compensate but you probably should do the first thing) or

Manual mode noting that the camera will think you are grossly overexposing the scene.


While the autoexposure systems are supposedly getting better and can recognize backlighting, I don't see that in real world results.
 
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Thanks Roger!

I'm going to have to dig out my manual for my D80 and figure out the spot metering and AE lock functions.
 
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Ray, just last week I discover the P mode on the top dial of your d80. So far, I love it, Its kind of like advanced auto or advanced point and shoot!! It lets you turn on your flash manually.
 
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Don't be ashamed of P mode. Heck even Tim's camera still has the P&S mode: Green box.
 
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Craig,

Thanks. I wondered what P for for. I had figured out that S was Shutter Priority, and A was Aperture priority, but really didn't notice what the P did. If it will let me force the Flash to fire then it will have it's uses. That was my problem. The flash wouldn't go off and all you'd get exposed was the very bright scenery that was outside the shot not the room I was trying to take pictures of.

I've been doing alot of experimenting before my trip to Disneyland. I've found the construction process of my new home seems to simulate alot of the lighting conditions that I encountered on my last trip to the parks. So, it's a good "training ground"
 
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