As others have mentioned the Depth of Field is vary narrow at 1.8. This gets more narrow the closes you get so fine focusing becomes key. If you find you are getting quite getting what you were hoping to get in focus then you may also need to practice your manual focus skills.
I find it best to go about it like tuning a guitar. Get the subject in focus, go a little bit beyond that and bring it back in to focus again.
Also, try focus bracketing if you are having problems. Simply put, take a photo when the indicator dot is lit. Also take one focusing a little to either side of where the indicator lights and make note of which of the three (you can do more if you like) gives you the better result.
I find the one I pick varies from lens to lens, but the good news is I have 3 to pick from 
__________________
Nikon D700/D90/F100 - 24-70 2.8, 70-200 2.8 VR, 105mm f/2.8G VR Micro, 18-200mm VR, 70-300mm VR, 50mm 1.4, 1.7X TC, Tamron 17-50mm, Sigma 150-500mm, Tokina 12-24mm, SB900/SB-800, Gitzo GT2331 Tripod w/ ball head, Manual Focus - Nikkor 80-200mm f/4, Vivitar 1 70-210mm (Komine) f/2.8, Nikkor-Q 135mm 2.8, Nikkor-H 28mm f/3.5
Last edited by Cuchulainn; 12-02-2008 at 03:22 PM.
|