With Definite Focus, the company offers a system for the Axio Observer.Z1 that can be used not only for the research of cell cultures in many biomedical applications, e.g. cell biology, pharmacology, molecular genetics, developmental biology and the neurosciences, but also in basic research. The system has been specially designed for fluorescence applications and time-lapse experiments under live cell conditions. Definite Focus effectively counteracts drifting in the Z-direction. The microscopic image always remains in focus. Furthermore, preparation and waiting times in time-lapse experiments are markedly reduced. Since the introduction of the Axiovert 200 in 2000 and its successor, the Axio Observer, in 2006, hundreds of customers have successfully used these systems for long term time lapse imaging over periods as long as 72 hours. But increasing interest of integration of temperature impact on cell viability as part of the experiment put new demands on the ability of the imaging system to quickly compensate for temperature changes. Definite Focus helps solve this with its full integration into the workflow of the Axio Vision imaging workflow.