I confirm the comment left by another person: I had the opportunity to use the Canon 60D 70-300L on, and mounted on a Panasonic GH3 compares the level of pique.
I could also compare the Nikon 70-300 VR mounted on a D7100, and there seems to dive significantly better on the Panasonic.
The construction is of good quality, not at the same level as that of an L series certainly, but it is discreet, lightweight and compact.
Finally, the development is very fast (slower than the Canon 70-300L but faster than the Nikon 70-300VR), and you can edit at any time to develop.
Important for lovers of macro-photography or proxi: I used a reducer bushing to secure this objective windscreen macro Nikon 5T.
The studding Nikon have been manufactured in 52 and 62mm diameter, and 5T and 3T are the only achromatic studding of moderate power (1.5 diopters, while the 500D Canon already has a power of 2 diopters, and Marumi have a capacity of 3 or 5 diopters).
The objective diameter is 67mm and the windscreen nikon 5t is only 62mm. Excellent surprise: although the diameter of the windscreen is less than 5mm, everything works perfectly and there is no degradation in the corners, no vignetting.
Clearly, with this arrangement, can be photographed at all focal lengths with the front lens less than 60 cm from the subject, with remarkable results.
In conclusion, very long lens compact, versatile and very good optical quality.
