I am a wildlife photographer mostly specialising in macros and I am researching buying a new camera to replace my D50. Either a D300 or a D700. High performance in low light levels and the ability to shoot in difficult, high contrast, conditions are very important to me. However I do tend to shoot alot of birds and other wildlife that (obviously) tends to be most comfortable when I am far away. My question is: In the opinions of this forum is the improved image quality that I get from having a full frame sensor worth the compromise in telephoto effect? All the lenses that I currently use are designed for full frame sensors so that is not an issue.