What are the best settings on Nikon D90 for outdoor portraits?
I want to play with my camera. I know I should set my ISO to 200. Approx an hr before sunset is best for lighting.
Can I achieve the same quality of photos in Auto mode as I can in Manual? What way of saving my images to the SD card is best?
There's a lot of missing information in your ""best settings"".it would be best if you take a beginners course to understand your camera.
"best settings" for outdoor portraits is a delicate dance between light, depth of field, composition.
Ill provide a few general guidelines to try to help.
1. Use a longer focal length to isolate the subject. You don't want the background to distract from the subject. I. E. 90mm
2. Use a large aperture, i.e. F/2.8 or f1.8 or the smallest number available (try shooting in av mode). This will minimize the depth of field, throwing the background out of focus. Again this is done to isolate the subject.
3.To support number 2. The subject should be as close to the camera as possible. Te background should be as far away as possible.
3. Notice the light. Portrait lighting typically has a main light, rim light and a fill light. This can be accomplished with some small reflectors or flash guns.
4. Balance the exposure with your shutter speed and iso.
Example. I'm using a 50mm f1.8 lens. I set the aperture to f2. The subject stands 1.5 meters away. Trees are in the background, 20 meters away. The sun is my main ligt at 5pm in the afternoon. The sun is in front to the side of the subject. I use my camera flash set at a low setting as my fill light. I'm choosing not to use a rim ligt because i don't have the lights for it, so i choose to shoot from a lower angle.
I have a D90 and practically shoot everything in auto, I get good results. But I would use 400 instead of 200. I have never seen good quality using the 200 ISO, not even when I used 35mm. Use the RAW setting. This helps keeps original color/pixel quality
Get a light meter. The meter will help definitely help outdoors.
Question/Comment: "What are the best settings on Nikon D90 for outdoor portraits?"
Answer: There's no such thing. It all depends on the lighting and what you want to achieve.
Q/C: "I know I should set my ISO to 200"
Answer: Not really. You can set it to whatever you want. It just depends (see above)
Q/C: "Approx an hr before sunset is best for lighting."
A: No it isn't. It just depends on what your subject is. Although admittedly sunrise and sunset are nice times.
Q/C: "Can I achieve the same quality of photos in Auto mode as I can in Manual?"
A: Sometimes. It may better, worse, or the same. It really depends.
Q/C: "What way of saving my images to the SD card is best?"
A: Are you referring to which format? Again it depends. If you want the pictures automatically processed, then jpeg is better. If you want more control over the final look of your photos, then something like RAW might be better.
Due to the number of misconceptions you have, I strongly recommend getting a book on photography from the library. It will explain a lot. And it can be fun reading about stuff.