Basic ISO and other setting guidelines

[stanwelks]

I am new to DSLRs and just got a Canon XTI with a a Canon EFS 18-55mm lens.

1. When outside in sunny conditions, I have my xti ISO set to 100 or 200 though I am not sure what to set my exposure, aperture and focal length to.

2. When it is overcast, I am using an a range of 400-800, what about the exposure, aperture and focal length?

3. When shooting people at night, I am using 800, what about other settings?

Thanks!

[Franglais]

Good question. However the reply could fill a book. Let me just say what I do:

1. When outside in sunny conditions, I usually have the camera set to 400 ISO. If the camera is on a tripod I set the ISO to the lowest possible (100 or 200 ISO).

The focal legth depends on the subject:

18mm = Scenes when I want to "get it all in" or "tell a story". Great for tourism
24mm = When doing pictures of people in the street or at parties and I want to include a group. My favourite shooting distance is about 6 feet
35mm = Pictures of people when is isolate just a couple, still at 6 feet. I also use this focal length for buildings when I don't want them to look distorted by a wide-angle (problem of the 18mm setting)
55mm = Pictures of a single person, waist-up. Picking out details in a landscape

I like to have the aperture between f5.6 and f11 to get depth of field. I usually use Program mode so thecamera sets the shutter speed (high) as necessary

2. When it is overcast, I am using an a range of 400-800, what about the exposure, aperture and focal length?

See previous comment about the focal length.

I would use 400-800 ISO and try to keep the aperture at f5.6. I would watch the shutter speed closely. It should never be less than 1/ the focal length that I'm using i.e. if I'm using the lens at 55mm the shutter speed should not be less than 1/60s or I may get camera shake.

If your lens has IS then you can use a shuttter speed 3 stops slower i.e. 1/60 > 1/30 > 1/15 > 1/8 second but try to keep the camera stable just the same. HOWEVER if your subject is moving - something human beings tend to do - I never use a shutter speed slower than 1/60s (1/125s is more comfortable)

3. When shooting people at night, I am using 800, what about other settings?

When I shoot people at night or indoors (without flash) then I set 3200 ISO. With modern cameras there is noise but it's hardly noticable. I set the shutter speed at 1/60s or 1/125s (see previous point about subject movement). If I was using an 18-55mm like yours then I would leave the focal length at 24mm. The lens will be at it's maximum aperture (f4) which should be enough to get the picture. (If you zoom out to 55mm then the maximum aperture of the lens falls to f5.6 = 50% less light coming through)

I only use the built-in flash if I'm desperate, the results are rotten. With an external cobra-type flash, usually bounced, 800 ISO is good because the room lighting is illuminating the background to some extent and you don't have the impression that you're shooting in a cave.

[stanwelks]

Thank you soooo much for your detailed response! It is VERY helpful. I am about to go on a trip, what do you use when trying to capture motion like waves crashing, people surfing or even whales jumping out of the water?

Thanks!

[Franglais]

Thank you soooo much for your detailed response! It is VERY helpful. I am about to go on a trip, what do you use when trying to capture motion like waves crashing, people surfing or even whales jumping out of the water?

Thanks!

These are all subjects that require a fairly long telephoto lens. You cannot get close to the subject therefore you need a lens that reaches out and just takes a small part of the scene.

Your 18-55 at the 55mm setting is a moderate telephoto but not long enough for these cases. A 135mm even a 200mm would be a good choice. The most economical solution would be a low-end 55-200. An 18-200 would be more versatile, but it would replace the 18-55 as well.

Remember the rule: if you're shooting on a 200mm then you need a shutter speed of at least 1/200s. For things that are moving fast like most of the subjects you've mentioned, 1/500s might be better.

As all of these subjects are far away, depth-of-field is not going to be a problem. However (assuming you're using a 55-200) if the use the lens at its maximum aperture then you might get light falloff or unshaprness at the edges. I would use the lens at f8-f11 to make sure it's giving its best.

[stanwelks]

I will look into what you are recommending, though I will be leaving soon, so I may not be able to get one before my trip. Any general advice for shooting these types of subjects without a telephoto lens, using just what I have, understanding that it will not compare to a telephoto lens?

Thanks!

These are all subjects that require a fairly long telephoto lens. You cannot get close to the subject therefore you need a lens that reaches out and just takes a small part of the scene.

Your 18-55 at the 55mm setting is a moderate telephoto but not long enough for these cases. A 135mm even a 200mm would be a good choice. The most economical solution would be a low-end 55-200. An 18-200 would be more versatile, but it would replace the 18-55 as well.

Remember the rule: if you're shooting on a 200mm then you need a shutter speed of at least 1/200s. For things that are moving fast like most of the subjects you've mentioned, 1/500s might be better.

As all of these subjects are far away, depth-of-field is not going to be a problem. However (assuming you're using a 55-200) if the use the lens at its maximum aperture then you might get light falloff or unshaprness at the edges. I would use the lens at f8-f11 to make sure it's giving its best.

[Franglais]

I will look into what you are recommending, though I will be leaving soon, so I may not be able to get one before my trip. Any general advice for shooting these types of subjects without a telephoto lens, using just what I have, understanding that it will not compare to a telephoto lens?

Thanks!

Shoot as though you were using a telephoto lens (at least 1/500s shutter speed) so that the image is sharp. Use a low ISO (100 or 200) so that the images is "clean" with little noise. Set the lens at its best aperture so that the image is sharp all over.

Then crop. Use an editor like Photoshop or even MS-Paint and cut out everything except the center of the image where the subject is. If you're only making a postcard-size print or doing a web page it's surprising how good even a 800x600 pixel image looks.

[Loupey]

... I am about to go on a trip...

Then I suggest you cram like there is no tomorrow and shoot like crazy to get as much practice in as possible before you leave.

ISO, shutter speed, and aperture are three factors that change in unison to changing conditions. Even if you choose to let the camera perform some/all of these settings for you, you should at least understand the ramifications of those choices to determine if they will be helpful or detrimental to the look that you are trying to achieve.

Go out and shoot, shoot, and then shoot some more while changing everything and understand why the images came out why they did for every image.

[stanwelks]

How good of job will the XTI generally do if I shoot in P mode to let it select the shutter speed and aperture?

Thanks guys!