How do you remember the relationship with aperture, iso, and shutter speed

[Vic Vinegar]

I use a Canon 40D with a 50mm lens and I use AV (aperture priority). Since I'm still learning the relationship between shutter speed, aperture, and ISO in terms of the amount of light captured, I take a picture with many different settings and then choose the best one and delete the rest. It's hard to remember what ISO is best with what aperture and shutter speed for any given brightness. So the only solution I have is to take like 20 pictures of the same thing with different settings. Is there a way to record the settings used in the picture? By the time I put them on my PC I don't know which exact ISO or aperture I used for what.

edit: I forgot to add that the shutter speed is picked automatically and what I am doing is picking different apertures and ISOs. But when I move on to manual I'd like to be able to do it properly.

 

[480sparky]

The data is saved as part of the image file. Camera model, shutter speed, aperture, ISO, time & date and a bunch of other information is automatically saved for you. You just need the right software to read it. Check what came with the camera.... usually it will at least give you that much information.

If you're using Av mode, why the need to take 20 shots?

 

[480sparky]

............edit: I forgot to add that the shutter speed is picked automatically and what I am doing is picking different apertures and ISOs. But when I move on to manual I'd like to be able to do it properly.

So if the exposures are identical when in Av mode but just a different shutter/aperture combination, why the need to take 20?

As for shooting in Manual mode, it's a matter of choosing two of the three variables (ISO, shutter & aperture) that fit your needs, then accepting the third one that's needed to create the 'correct' exposure.

For instance, if you're shooting a landscape using a tripod, you can lower your ISO to reduce noise, choose the aperture needed for depth of fiend and lens sharpness, and use whatever shutter speed necessary to expose the image properly.

If you want to use a low shutter speed to allow a moving subject to intentionally blur to create the illusion of motion in the image, you choose a slow enough shutter speed to achieve that, and make one of two choices after that: 1. A low ISO and open aperture to throw the background out of focus and isolate the subject, or 2. A high ISO and smaller aperture in order to gain more depth of field.

 

[Designer]

By the time I put them on my PC I don't know which exact ISO or aperture I used for what.

What is your editing software? Most have the capability to read the EXIF, as it is known. If yours does not (odd) then go on the internet and find one you can download.

 

[Vic Vinegar]

When I said 20, I meant with different f stops and different ISOs per f stop. So the number of pictures of the same thing on the card is about 20 give or take when I'm finished. As for the software, it came with a CD but I didn't install the CD. I just use Picasa since all I really enhance is the lighting. I didn't know the CD had that sort of software on it.

 

[Braineack]

picasa can still tell you the camera settings of your pictures.

Viewing EXIF data in the Properties panel - Picasa and Picasa Web Albums Help

 

[unpopular]

First of all, I never change ISO unless I need to. If you're changing ISO a lot (and not using auto-ISO) then I can get that it would be very complicated.

I like to use ISO as close as possible to my cameras native ISO, which is 200 on both my Sony and (I think, anyway) Fuji. If I need less exposure, I consider ISO like a "boost in sensitivity" - which it is. It's not really an exposure control, because it does not affect the amount photons on the sensor, it's more of a camera setting. (back to ISO in a bit)

Now that I have ISO tucked away in the corner, it's a little easier to think about shutter and aperture. Here it's a simple give/take relationship. If you stop down one whole unit (f-stop) then you must increase exposure time by a factor of two in order to get the same result. This is because each f-stop is calibrated to cut light by half. If your background is as sharp as you want it, but your meter is reading two "equivalent values" (EV being equivalent to one stop, twice as "bright") under what it should be, then you need to decrease your shutter time by a factor of four. (i.e. from 1/250 to 1/60). If your hands are too shaky to shoot at 1/60, then you'll need to open up the lens by one stop (say from f/5.6 to f/4) and decrease your shutter speed to 1/120.

So it's all about give and take. Now, back to ISO.

Sometimes you have no choice but to adjust ISO and introduce some degree of noise. I worry about this less with my fuji being that it is a pretty good performer in low light. On my a700 DSLR on the other hand, I need to be more careful. What is an acceptable level of noise is up to you.

ISO will literally turn up the signal off the sensor before it is converted into digital data. It is a very similar process as turning up the volume on your stereo. So when you do that, everything will become more exposed when increased, and less exposed when decreased.

So let's say that on that shot you couldn't hold at 1/60 the background looked perfect at f/4. Your only option would be to increase ISO. Don't worry too much about what ISO numbers mean, it predates digital and using it this way is kind of silly anyway.

What you need to worry about is that every time you double the ISO, you're sensitivity doubles as well. This will allow you to cut the exposure time in half while keeping the aperture the same (or stopping down once and keeping the shutter time the same if need be).

But again, I tend to think of ISO as a last resort option. Many modern cameras are a lot more flexible in this way, though, so maybe you might find it useful to adjust it more frequently. But for me ISO is just something I don't think a whole lot about until the sun starts to set.

Still, it might be beneficial if you first learn aperture and shutter speed and get a good feel for exposure equivalences before trying to balance a three-way teetertotter.

 

[unpopular]

PS - sorry if that was too complicated. feel free to ask any specific questions and I will be happy to clarify.

 

[Braineack]

do not fear iso.

 

[astroNikon]

Learn to use your built-in Light Meter ... at the middle of the bottom of your viewfinder, or bottom left of your LCD to balance out your exposure.

Then you adjust Aperture, Shutter, ISO depending upon what you want to do.

For instance, if you know you need to use f/1.8 then that becomes fixed.
If you are shooting something that does not move, then you have some leeway, if it's moving then you need a faster shutter speed, say 500
Then you may adjust ISO to get the light meter to 0

==>

 

[Braineack]

learn the triangle.

learn the stops of light.

learn the jazz flute.

 

[astroNikon]

learn the triangle.

learn the stops of light.

learn the jazz flute.

rats, I thought it was Jazz Saxophone.
I knew something didn't work right.

 

[480sparky]

..........learn the jazz flute.

I can already play flute, and have played in a jazz band.

I'd rather learn more ways to prepare bacon.

 

[Vtec44]

Lighting is never the same so I don't usually remember the settings or need to. I typically shoot at a certain range of aperture, and the shutter speed is whatever it is to avoid motion blur and give me the correct ambient light. The ISO is for overall exposure. So, I never remember the exact settings but I know what I want to create and will adjust the settings accordingly.

Basic shutter speed values I try to remember: 1/5-1/10 if I want to play with shutter drag, around 1/60 if I want more ambient light, 1/100-1/200 studio, 1/4000-1/8000 for full sun. The values will never be exact but are just starting points for my shooting style.

 

[AKUK]

@Patrick McGuirk, As recommended above, you need to learn the Exposure Triangle. Once you understand the relationship between the variables you can control your exposures and even the look of your images with ease, through very quick mental calculations. Knowing your F-Stops inside out will also aid this, as it is a part of the Exposure Triangle.