Tokina SZ 900mmPRO Reflex F11 MF CF Mirror Lens Review: A Comprehensive Analysis for Astro-photographers

As an astro-photographer, I have used several types of catadioptric optics, including telescopes and mirror lenses, over the past two decades. In this journey, I am continually surprised by the unique features of these systems, which introduce an optimal balance of performance, weight, and price for my practical work. The Tokina SZ 900mmPRO Reflex F11 MF CF mirror lens has emerged as a notable addition to this category, particularly for those seeking very high magnification capabilities in a portable design. After a year of extensive testing, I am excited to present a detailed review that combines my insights with key features and performance aspects of this lens.

Exceptional magnification power

The Tokina SZ 900mm f/11 mirror lens stands out prominently in the realm of astrophotography due to its exceptional magnification power. With an impressive focal length of 900mm, this lens allows photographers to capture stunningly detailed images and videos of celestial phenomena. For instance, it can easily reveal hundreds of craters on the moon's surface, showcasing the lunar landscape in remarkable clarity. Additionally, the lens is capable of capturing sunspots in details, providing a unique opportunity for solar observation that many other lenses struggle to achieve. This level of detail makes the Tokina SZ 900mm a valuable tool for enthusiast amateur Astro-photographers in a very compact size and reasonable price.

Dance of rising Supermoon light through clouds and high density parts of atmosphere results to image distortion atmospheric effects as captured through Tokina SZ 900mm f11 mirror lens mounted on Fuji Xt-2 camera body.

Shooting of the Sun

The lens also shines during other solar system events like planetary conjunctions and occultation, where it can document these astronomical occurrences with ease. However, the fixed f/11 aperture does present some limitations; it restricts the lens's performance to well-lit subjects.

About some limitations

When discussing the magnification of a super telephoto lens with a 900mm focal length, several limitations must be carefully considered by photographers. The sky rotates due to the Earth's rotation, so for such a long telephoto lens, the exposure time is typically limited to just ¼ second on current digital sensors. This duration is quite short, even for well-illuminated objects. For instance, when I attempted to capture the occultation of the red giant star Antares behind the moon, I noticed a blurry effect in the image caused by the sky's rotation during a brief ½ second exposure!

Specifically designed for Fuji sensors

The core uniqueness of the Tokina SZ 900mm f/11, compared to its rivals, lies in its impressive magnification of 18X due to its 900mm focal length. Specifically designed for Fuji sensors with a 1.5X crop factor, the effective focal length becomes 1350mm in practice (27X). This remarkable focal length enables much closer shots than other super telephoto lenses currently available. For example, when photographing similar events from the same distance, I was astonished by the magnification power of the Tokina 900mm lens compared to the Tokina 500mm mirror lens. The difference in magnification was striking!

Video time lapse of moonrise behind Milad tower as captured with Tokina SZ 500mm mirror lens mounted on Nikon D750 body.

The same object as above, captured through the Tokina SZ 900mm mirror lens mounted on a Fuji XT-2 camera body, shows a significant difference in magnification!

A compact telescope in the realm of astrophotography

This is a special lens with impressive outreach capabilities, making it suitable for use as a compact telescope in the realm of astrophotography. In my view, this lens is dedicated to capturing well-illuminated celestial bodies. Its mirror design ensures very low chromatic aberrations, especially for high-contrast objects like the moon and planets in a dark sky.

Careful considerations are essential for achieving a crisp photo with a 900mm lens. For this consecutive shot of the crescent moon, I used a ¼ second exposure time at ISO400 on my Fuji XT2 camera body. By setting the shutter speed to the upper limit of exposure, I aimed to capture as much light as possible without increasing the ISO, ensuring a cleaner, noise-free result.

Deep-sky astrophotography

While this lens is perfectly matched for my moon, sun, and planetary photography projects, I found it unsuitable for deep-sky astrophotography. The situation is somewhat complex in practice. A 900mm lens defines very high-resolution deep-field photos, but it requires a solid mount to point, guide, and track faint deep-sky objects like nebulae and distant galaxies. The images of these faint objects are very difficult to capture due to its slow aperture. Additionally, framing them indirectly with surrounding stars is challenging, as its high magnification and narrow field of view make it difficult to navigate toward the subject by jumping easily on stars.

Therefore, I prefer to use this lens for unique captures of well-illuminated objects, while opting for 600mm f8 SZ pro and 300mm f7.1 SZ pro mirror lenses in its family as a portable setup for deep-sky photography. However, if you can successfully point this lens at faint celestial objects, I recommend this little catadioptric telescope for sky shooting on all wide range of objects! Bear in mind that practicing manual focus skills is essential with all these super-telephoto manual focus lenses, and it is crucial for acquiring crisp results.

Conclusion

In conclusion, the Tokina SZ 900mm f/11 mirror lens stands out as a valuable tool for astrophotographers seeking high magnification in a portable design. Its impressive focal length allows for the capture of intricate details in well-lit celestial bodies, such as the moon and sun, revealing features like craters and sunspots with remarkable clarity. This lens excels during solar system events, making it an excellent choice for documenting planetary conjunctions and occultations. However, its fixed f/11 aperture presents challenges, particularly for deep-sky astrophotography.

Pros:

• Exceptional magnification power (900mm focal length).
• Compact and portable design.
• Low chromatic aberration for high-contrast objects.
• Ideal for well-lit celestial bodies (moon, sun and planets and Great for solar system events).

Cons:

• Fixed f/11 aperture limits performance for faint objects.
• Narrow field of view complicates subject framing.
• Less suitable for deep-sky astrophotography.

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