I tested a camera lens accessory for stargazing – and it wasn’t great

We took some impressive photos with the OPPO Find That’s a pretty long range, and as a very, very, very amateur astronomer, I wondered if OPPO’s lens kit would be a gateway to even more amateur astrophotography. Given the rise of brilliant camera phones, computational photography and special astrophotography modes, I wanted to investigate whether smartphones are finally overtaking the entry-level telescopes for casual sky observation.

Before bracing myself for the cold, I did some quick math to determine my expectations. “My Newtonian telescope has a focal length of 750mm, just bright enough to distinguish nebulae and galaxies, such as Andromeda, on a dark night with a 28mm lens (27x magnification).

OPPO’s lens kit certainly doesn’t have the same capabilities as a telescope – unless we throw some software zoom on top. The 230mm telephoto lens equates to about 10x zoom compared to the phone’s 23mm primary lens, or about 6.6x compared to 35mm, which is close to the human eye’s field of view. Digital zoom can take this even further, to around 40x, but software zoom doesn’t help capture the all-important light.

Are you using the astrophotography mode of your camera app?

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Additionally, the X9 Pro’s small 1/1.56-inch periscope camera sensor is approximately 0.4x smaller than an APS-C sensor and even smaller than the full-frame cameras typically used for amateur astrophotography. Not to mention that putting glass and mirrors in front of glass and mirrors is a recipe for reducing light capture and introducing artifacts like chromatic aberration and vignetting.

In short, I don’t expect the Hasselblad lens and Find X9 Pro combination to work wonders. But in combination with my standard equatorial mount I would at least have the benefit of stable long-term exposures (much sturdier than software-based astrophotography modes). But what can you see in the night sky with this setup? Well, moon craters are visible even through binoculars, so that’s where I started.

The exposure is perfect, but the field of view is relatively wide, even at 40x, which doesn’t come close to filling the field of view with the moon. So we have to crop and the combination of optical and digital zoom leaves a lot to be desired in terms of detail. The craters are there, but there are hardly any details. Disappointing, especially considering how clear the night was. I probably would have been better off trying to take a photo through my telescope’s viewfinder, which doesn’t bode well.

After seeing how disappointing the moon shots were with the telephoto extender, I shifted my focus to star clusters: the Pleiades and the stars in the Orion Nebula region (I think. It wasn’t easy to see exactly where the camera was pointed, even with my tracking mount, because the screen was essentially black).

While I’m quite impressed with the amount of zoom the setup can provide, I find the results disappointing – even though I didn’t try anything that came close to the bright, colorful photos you’ll see taken with top-level equipment. You can clearly distinguish the clusters, which is certainly a plus, and thanks to a little RAW editing you can make out quite a few stars. But even my cleanest shots are blurry; stars appear as round, processed blobs rather than twinkling points of light, and there’s not much to see in the way of red or blue color.

Unfortunately, OPPO’s camera app setup isn’t well suited for this type of photography. Although you can use manual controls for longer exposures, distance focus, RAW and high ISO settings, the results came out blurry and the photo is mirrored thanks to the extender. You’re forced to switch to OPPO’s Tele Lens Extender camera mode to improve focus, but then you lose manual control. The best I could achieve was a shutter speed of 10 seconds, which just wasn’t good enough to pick out many stars.

I was tempted to experiment with other camera apps and RAW stacking to see if I could achieve better results, but my gut feeling was that I would be wasting my time. What you really need for even basic level astrophotography is a nice, bright camera sensor and lens, solid long-range optics, and software options to make capturing and stacking images easier. After some experimenting, it’s clear that a telephoto extender on a smartphone isn’t going to get me there.

I was much more impressed photographing larger areas of the night sky with the camera’s larger primary sensor at the widest aperture – without a telephoto extender. The results were much more comparable to the Pixel’s astrophotography mode and previous photos I took using Samsung’s Expert RAW. I also took a moon shot by simply holding my phone up to the eyepiece of my telescope, which again wasn’t exactly stunning, but looks much better than the shot with the lens extender.

Telephoto extenders for smartphones are not a substitute for a good telescope or large sensor for serious astrophotography. For casual shots, a stable tripod and a primary camera lens (or mounting the phone to a telescope) will yield much better results. The Hasselblad lens is nice, but the stars remain largely out of reach. Live and learn.

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