Maximize DOF

[Krystal]

Hello,

I'm new to this forum and had a question on DOF and infinity. I have been doing landscape photography for about 2 years now. My equipment is a Canon Rebel 350 D SLR, and have the 28-135 IS and the 70-300 IS lenses. I'm still having issues with DOF and I'm trying to understand the rules. I know about the 1/3 rule and also focal lengths. I printed out the calculator for setting focal lengths to aperature setting to get max DOF. Problem is sure you can estimate the focas point if it is 10-30 ft, but after that who knows.

My question is if your closest focal point is more than 30ft (meaning the first 30 ft is not in your compostion) and you have your aperature set to 11 or 16 and larger can you set the lens to the infinity mark and get everything from the 30 ft to infinity in focus? Is there an instrument you can get to measure length since my lense will not do that for me? Lets say my focus point has to be 60 ft in front of me to get the 30 ft of foreground to infinity in focus. I'm wondering if there is something to help estimate that 60 ft mark.

Thank you for any help,

Krystal

[jdepould]

Lenses used to have scales to tell you your DoF. Most new ones don't. If you're down at f/16, you're pretty safe. I'd focus a little closer than infinity, then chimp to taste.

[kencaleno]

All depends on the aperture you are using,for instance,with your zoom on the 18mm setting and F11(Hyperfocal distance will be 1500mm(5 feet)) all will result in acceptably sharp rendition from 750mm (2 feet six inches) to as far as you can see. To help, here is a chart showing hyperfocal distances for both 18-55 zoom and 70-300 zoom.