asiostygius wrote: spoupard wrote:
I tested my new to me 25-50 f4 on my IR converted Z50. I would say that, as wonderful as this lens is, it isn't very good for IR photography, at least at the short focal lengths. Zoomed to 50mm and it was pretty good, but any shorter and it produced horrific hot spots. These were all shot at 50mm.
The ratings for zooms area means [(shorter + medium + longer/3)]; for my 25-50/4 the only usable range is at 50mm too, as your findings Scott. Looks like a pattern for the lens.
I agree completely with your findings. As I stopped down, the hotspot grew in size and intensity. It was much worse at the short focal lengths of the lens. Thanks for posting the chart with your research. I'm going to save it for future reference, if you don't mind.
