However, the first photos were a shock because rel. low-contrast subjects were recorded in overcast weather. However, such a thing does not go with this lens! In such an extreme telephoto focal length, also constructed as katadioptisches system, the transmittance as well as the modulation transfer are very low. As a result, under unfavorable reception conditions, a sinking, slightly out of focus looking image.
The motives must therefore be taken in good weather and illuminated ideally from the sun to reflect a sufficient subject contrast. A monopod and very short shutter speeds are helpful, as well as many trips should be undertaken in order to achieve a high hit rate. Then, the images have to be reworked on the PC. (These conditions apply, however, to other, expensive extreme focal lengths ...)
Practicing with the lens and observe some rules, it is perfectly adequate for occasional "extreme telephoto photography" - so a "good".
