I have a canon digital rebel and I've been shooting with it for about a year now. I'm going to Yosemite latter this month and I want to improve my metering readings. Every time I go shooting I never can get the correct exposure setting. I never seem to spot meter correctly. I often use a polarizing filter but I think that does more harm then good. Should I buy a gray card or a handheld meter. Though handheld meters are quite expensive.