S-II f/3 Ultra-Highspeed-Filter (4nm) – CMOS-optimiert

Unfortunately this is not possible. Our Highspeed Filters work only in the f/ratio-ranges mentioned on the products. This is due to the needed preshift to get them to work on fast optics. On slower optics the preshift will result in no or much less signal. Just check out the filter curves on our Whitepaper: https://www.baader-planetarium.com/en/downloads/dl/file/id/1794/product/0/whitepaper_narrowband_filters_on_astronomical_telescopes.pdf Please read also our blog post where the necessity of preshift is explained in detail: https://www.baader-planetarium.com/en/blog/preshift-and-further-information-concerning-baader-cmos-filters/ Furthermore please check out our Filter Selector Tool, in some cases it might be worth to switch to the wider 6.5nm Highspeed filters to cover f/2 and f/3 optics together, while this is not possible for the Ultra-Highspeed 3.5 / 4nm filters. For f/4 and upwards however you will always need the normal Narrowband filters. If you definitely only want to purchase one set of filters, it might be better to purchase the normal 6.5nm Narrowband filters, they "could" also work on f/3.3 and definitely will work fine on f/4