You probably know already that your aperture setting has a direct impact on what’s in focus. Shallow depth of field, or a low f-stop, creates more blur either behind or in front of your subject. Large depth of field, or a high f-stop, puts everything in focus.
Depth of Field Matters: Portrait photos work really well with a shallow depth of field, but you need to be extra sure the subject is sharp. Make sure the subject’s eyes are what’s in focus. You also will most likely want a shallow depth of field to emphasize this. There are a lot of pro portrait photographers who don’t use a tripod because they like to be fluid in their sessions. However, they’re probably using a 50mm portrait lens (i.e. not heavy like a telephoto lens) with shallow depth of field. They also have ample experience with moving around, stopping, and focusing. This takes practice.
Alternatively with landscapes, you want the entire image to be sharp. Although most might expect the f-stop to be f-11 or higher for landscape, pros know that the secret to landscape photography is setting the f-stop to a range between r-7.1 to 9. That’s the sweet-spot. If you’re not sure about how to set the f-stop, or how it affects Depth of Field, I recommend my Depth Of Field Secrets product.
Your ISO setting should be adequate for the lighting conditions. If a subject is in a poorly lit area, the shadows just won’t have detail.
ISO Settings: Increase your ISO to 200 for situations like cloudy days and 400 for indoors or subjects in motion. The darker the lighting, the higher your ISO should go because you need to allow that light in to capture details within she shadowed areas. Some of the shadowed areas can be lightened in post-processing software plug-in filters, such as Topaz Adjust. See tip #7 for details.