First visit to this astronomy/astrophotography blog? Well, firstly a warm welcome to you and thanks for stopping by. If you want to find out more about me and this blog, why not visit my introductory page at https://undersouthwestskies.blogspot.com/2025/01/welcome-to-my-new-astronomyastrophotogr.html You can also browse other posts by using the search bar or the blog post list on the right hand side and I'd really like to hear from you via the comment boxes. Drop me a tip, an observation or a question. Take care and clear skies to you. Steve
Samyang 135mm f/2 (Manual Focus) — My Go-To Wide-Field Astro Lens
If you love
photographing the night sky but don’t want to remortgage your house to do it,
then the Samyang 135mm f/2 could be your new favourite piece of glass. I like
to keep my setup simple, reliable, and travel-friendly and I’ve been using this
lens for more than two years, teamed with my Canon 800D; it’s my go-to
companion for wide-field astrophotography whether it be to frame a nebula or
sweep across the Milky way without lugging a telescope around.
After two
years of late nights, frosty fingers, and countless star fields, I thought it
was time to share my thoughts. What makes this lens such a hit among
astrophotographers? How does it perform? What are its strengths and pitfalls? And,
what are the trade-offs you should know before you buy? Let’s find out.
In this
review, I’ll:
- Walk through the key features
- Highlight the strengths
- Weigh up the downsides
- And wrap up with my honest
verdict
Overview
The Samyang
135mm f/2 is a bit of a cult classic in astrophotography circles — a
manual-focus, full-frame compatible prime lens that delivers serious optical
performance without burning a hole in your wallet. It’s available in several
mounts (Canon EF, Nikon F, Sony E, and more), and photographers often praise it
for its sharpness and contrast at a surprisingly modest price.
Think of it
as the astrophotography world’s version of a dependable old telescope — it
doesn’t boast flashy electronics or fancy features, but what it does
offer is clarity, consistency, and a ton of light-gathering power.
At f/2,
it’s a light vacuum, pulling in photons like a cosmic magnet. Even at
f/2.8, stars in the corners remain crisp and clean, with minimal chromatic
aberration or distortion. For me, it’s become a workhorse lens that simply
delivers, night after night.
Why It
Shines for Astrophotography
Here’s what I
think makes the Samyang 135mm such a gem for capturing the night sky:
1. A fast f/2 aperture — a real light
bucket.
Speed is everything in astrophotography. The faster the lens, the less time you
need to collect light — and that means fewer tracking errors, shorter subs, and
sharper stars.
2. Excellent corner-to-corner
sharpness.
Even wide open, stars stay tight and well-defined all the way to the edges.
Many lenses struggle with soft or warped corners, but this one keeps its
composure beautifully.
3. Great value for money.
Compared to astrographs or premium telescopes with similar optical performance,
the Samyang 135mm is an absolute bargain. You get premium-level sharpness at a
fraction of the price — ideal for beginners or anyone building a portable
setup.
4. Manual focus — an advantage, not a
drawback.
In astrophotography, autofocus is about as useful as sunglasses at midnight.
Manual focus gives you full control, and with a simple Bahtinov mask (you can
easily 3D-print or order one online), you can achieve razor-sharp stars every
time.
5. Plenty of compatible
accessories.
This lens is a tinkerer's dream. You can attach support rings, dovetails,
red-dot finders, guide scopes, ASIAir units — even a ZWO EAF focuser if you
want to automate your setup. These can be 3D printed – if you are lucky enough
to own one – or easily purchased off various shopping websites
6. Perfectly balanced focal
length.
At 135mm, you’re right in that sweet spot between wide-field and close-up
imaging. Large nebulae, Milky Way segments, star fields — it handles them all
beautifully. On crop-sensor cameras, the extra reach (around 200mm equivalent)
makes it even more versatile.
7. Impressively low chromatic
aberration.
Colour fringing on stars is minimal — a big win if you’re after clean,
natural-looking results, especially in narrowband imaging.
8.
Portable and travel-friendly.
Pair it with a small star tracker like the Sky-Watcher Star Adventurer, and
you’ve got a grab-and-go setup that can fit in a backpack. No observatory
required — just clear skies and a bit of patience.
9. When using a cooled astro camera (mono/colour) with filter wheel etc, the Samyang 135mm f/2 can serve as a fast, relatively “short‐telescope” field of view—great for large nebulae, wide star fields, Milky Way segments in narrowband or broadband. Because many astro-cameras have large sensors, the good corner performance is very useful.
Disadvantages
(a.k.a. “The Fine Print”)
No lens is
perfect — and the Samyang 135mm does have a few quirks worth knowing. Think of
these not as deal-breakers, but as “lessons from the field.”
1.
Vignetting at wide apertures.
At f/2, corners can lose up to 40% brightness. It’s nothing a good set of flat
frames (or stopping down to f/2.8) can’t fix, but it’s worth planning for.
2. Sample
variation.
Quality control can be hit or miss. Some copies are pin-sharp, others have
slight decentring or coma issues. Buy from a reputable dealer with a solid
return policy.
3.
Infinity focus quirks.
When used with astro cameras and adaptors, the lens doesn’t always hit true
infinity focus right at the mark (particularly when using M42/T2 adapters, it
seems). You may need to experiment a little with spacers or back-focus
distance.
4. No
weather sealing or stabilisation.
Not a huge issue for astrophotography, but if you’re shooting on cold or damp
nights, dew control is essential. A lens heater or dew strap is your friend
here.
5.
Focusing precision required.
At f/2, the depth of field is razor-thin. Even a hair off perfect focus can
soften your stars. Take your time, use Live View zoom, or better yet — a
Bahtinov mask.
6.
Middle-ground focal length.
Some users find 135mm to be neither wide enough for sweeping Milky Way shots
nor long enough for small galaxies. Personally, I find it a perfect
“in-between” — but it depends on your targets.
7.
Back-focus spacing issues (for astro cameras).
When used with filter drawers or adaptors, incorrect spacing can throw off
sharpness or infinity focus. It’s worth double-checking your measurements — the
devil really is in the millimetres.
8.
Heavier than you’d expect.
At first glance, it looks compact, but it’s got a bit of heft to it. Still,
when you balance it properly on a tracker, it’s more than manageable.
My
Verdict
After two
years of use, I can confidently say, that based on personal experiences, the Samyang
135mm f/2 must be one of the best bang-for-your-buck astrophotography
lenses out there. It’s sharp, fast, and remarkably capable for its price. A
compelling option for beginners on a limited budget who want a relatively fast,
high-quality lens.
Sure, it
asks for a little patience — careful focusing, calibration flats, and the
occasional bit of back-focus tinkering. But if you’re willing to put in that
small effort, it rewards you with breathtaking wide-field images.
To
summarise:
- Highly recommended if you’re using a DSLR or
mirrorless camera and are ready to get serious about wide-field
astrophotography.
- Excellent for astro-camera users, provided you dial in your
adapter spacing and calibration.
- Less ideal if you need autofocus, weather
sealing, or prefer ultra-wide or ultra-long focal lengths.
In short,
this lens is like an honest, hard-working friend — it doesn’t boast, but it
consistently delivers. It’s built for those who value results over bells and
whistles.
What
about you? Have you used the Samyang 135mm f/2 in your setup? What camera have
you paired it with — and what celestial wonders have you captured? I’d love to hear your experiences in
the comments below.
Until next
time — clear skies, steady mounts, and may your focus always hit infinity.
— Steve
If you are seeking a more detailed review of the lens then try this one - I take no responsibility for the website or any links from it - but I did find it an informative review - https://stellardiscovery.com/samyang-135mm-f-2-widefield-astrophotography/
