Spacecom 16mm f/1.4 2/3″ C Mount Pyxis on Pentax Q
The Q with its tiny sensor needs very large aperture lenses to shine, does this classic 85mm equivalent do the trick?
This 16mm f/1.4 lens is equivalent to an 89mm on full frame making it an classic portrait/mid telephoto focal length. Now the f/1.4 * 5.5 crop factor equivalent aperture of f/8 might not sound impressive, the shorter physical focal length means the lens has a much closer minimum focal distance, meaning you can actually get shallower depth of field than you can on the full frame with an 85mm f/1.4 since you can focus mere inches away, but you will have tighter framing in that circumstance.
Spacecom must be using some OEM lens, or maybe is the OEM for this 16mm f/1.4, I think the Pentax 5 MP 16mm f/1.4 2/3″ is actually the same lens based on what I can tell from the specs, but I could be wrong. The pricing on this Spacecom was more affordable for similar specs so I ended up with it, even though it doesn’t look as nice as the Pentax with its red stripe.
Getting down to business, the lens is nicely made with all metal exterior construction, decent looking AR coatings. Both the front and rear elements have multi layer coating on them. Focus is smooth, but loose feeling and makes a light scraping noise, I think the mechanism used for tightening it down with the locking screw.
There are locking screws for the aperture and focus ring, I will probably take these out, but are great if you want to prevent an accidental focus change. The aperture ring has nice click stops so probably doesn’t need the locking screw. The lens caps were very cheap plastic slide on caps that could be replaced with something better. This type of lens is often designed to be used on a video camera 24 hours a day so caps are not necessary other than to protect in transit.
The lens is on the large side compared to the Q standard zoom, but is well sized. I think any smaller and it starts to be more difficult to manual focus. The filter threads are 49 mm, with a nice star shaped 10 bladed aperture (it is wavy and changes shapes at various apertures). Focus is from a nice close 0.2 m (7.9 inches), compared with about 0.85 m (2.8 feet) for most 85mm lenses. Weight is noticeable but not heavy at 200 g, very nicely weighted with the dense little Q camera. The lens retails for approximate $190 US.
This lens claims to have 5 MP resolution, whatever that means. The manufacturer doesn’t advertise how to they came to this number, and they also claim 145 LP/mm across the frame, but they don’t state at what contrast. I will comment on how it performs at the end.
Lets get on with the review:
Comments on the Results
This lens has flat resolution and sharpness across the frame. This lens performs about the same at f/1.4 as the Pentax 02 prime at 15mm f/4.5. The lens is good at f/1.4 for close up and available light photography, and by f/2 or f/2.8 it is at good levels for the Q, for MTF50 we are resolving about 155 lp/mm and for MTF20 about 240 lp/mm. So I think the camera holds up to the claim of 145 lp/mm across the frame. Even wide open it will hit this for MTF20. The 5 MP claim is for a 2/3″ sensor.
Distortion is negligible.
Lateral CA is slightly noticeable. Longitudinal CA is fairly noticeable which will lead to some purple fringing.
The lens is susceptible to veiling glare and aperture ghosting. There is maybe a bit of a white balance shift from f/1.4 to f/2.8, that the AWB will take care of automatically, but you might notice it in RAW. It isn’t too significant, just something to be aware of.
I measured the corrected focal length to be 16.1mm based on 1:197 magnification.
Pros and Cons
- Resolution across the frame from f/2
- Surprisingly good at f/1.4
- Subject isolation good for sensor size
- Longitudinal CA
- Focus ring too loose
I was immediately pleased with the images, and the lens should be decent at HD video at all settings (want about 1080 LW/PH for HD), and makes a nice classic portrait lens on the Q. Just remember you won’t get the same object separation at a distance like you would with a full frame 85mm f/1.4, but up close this lens shines and you will get a lot better depth of field control than either kit lens at about the same focal length. It actually performs fairly similar to what an 85mm would on full frame (susceptible to flare and longitudinal CA).
The lens doesn’t have the flare performance of the Pentax lenses, but definitely excels at sharpness, resolution, and minimum focus. This is a great mid telephoto lens for the Q if you enjoy manual focus. Much better than other older manual focus lenses like the Pentax 110 18mm, and any of the VGA C mount lenses in that range, and the short minimum focus helps showcase one of the benefits of smaller sensor photography (short focal length lenses focus closer so your telephotos can focus very close)
Spacecom JHF16M-5MP 2/3″ 5 MP Fixed Focus Lens (16mm) on BHPhoto in the US to support the site.
You need a C mount to Q adapter as well!
Gallery images have some sharpening (have to with Q) and some have minimal exposure adjustments, like some of the flare shots.