Tuesday, December 6, 2016

Fujian 35mm f/1.6 CCTV Lens on m4/3 camera- Test and Thoughts


I was thinking a lot about these widely offered CCTV lenses on ebay and other webshops.
Available in 25mm,35mm and 50mm with apertures of about f/2 these low priced lenses look nice bargain for low light photography and producing nice blurred background in portraits when used on a micro4/3 cameras..
However,the CCTV lenses,especially the cheap ones are not meant/designed for serious HQ photography and the presence of various optical flaws is guaranteed.
The expensive large aperture alternatives from Olympus and Panasonic are out of my reach,so the thoughts bellow are not based on comparison between totally different class lenses.

In terms of design I found the 25mm and 35mm pretty unattractive and looking as a toy.The 50mm one is too long for easy portraiture and requires to stay far from the subject. I already have the SMC Pentax 50mm f/2 and the Helios 58mm f/2 lens,so there was no need for another 50mm lens.
Then came this new version of the 35mm lens and I liked it from the first look. Very compact with a good lens looking form.The previous version has looked like a piece of tube to me.
At the time of purchasing this lens was offered only from one seller on ebay.I bought it for $30 with two extension macro rings and CCTV to m4/3 mount adapter included.

Knowing from different reviews that this CCTV lenses produce pictures with very soft corners,I was also attracted from the fact that this new version is described as APSC compatible,which gave me some hope that on a micro4/3 camera this effect will not be so noticeable.Read about that below...


Let's start with the pros-
Full metal body. In comparison kit lenses like the Olympus 14-42 entirely made of plastic,look like toys and cost 10 times more.The metal body of this lens even not machined on the highest level gives really nice feel on the construction and definitely brings some more trust in its reliability.
As you can see from the pictures,all needed markings are engraved on the body.
 This is a manual operation only lens so it has full manual mechanical aperture ring(big plus in many cases) and manual focusing ring. Both rings operate very smoothly and consistently.Twisting the focusing ring is tight but not so much to be uncomfortable and prevents unwanted de-focusing.
There are markings only for the full f stops. The focusing ring has nice relatively short rotation which allows quick focusing and nice smooth operation in videos.
 The minimum focusing distance is 50cm.Not very good for macro use,but don't forget that this lens comes with two macro rings ready for use.
The center sharpness is really good and in my tests beats the Olympus 14-42 kit lens with much.

The aperture ring is this with the f markings.There are some grooves on its sides.
The focus ring is this with the distance scale and the grooves above it.
To sum up-the zone with the 35mm f1.6 marking is stationary and is used for indication of the two aperture and focus ring rotation.

The C mount to micro4/3 adapter is well machined and fit pretty well on different cameras,without gaps.
Locks well on my cameras.Blends with the camera body quite well and does not look bad at all.


Another really attractive feature is the 12-blade aperture.
The advantage of this-rounded out of focus lights(bokeh) even with the aperture closed.
Another great feature is the click-less aperture ring without defined positions.
Great option for video shooters.Allows easy and precise adjustments of the aperture while filming possibly undetectable by the viewer.
The front filter thread is 37mm compatible.

Here is a close look at the aperture blades.
Not perfectly symmetric,but with great final result.



Below is a size comparison with the Olympus 14-42 lens and SMC Pentax 50 lens(without adapter).
The Fujian lens in the center is also without adapter.

A look at the diameter and max aperture of the lenses.

Here the Fujian and Pentax are with partly closed apertures,easy to check the expected bokeh shape.
6 blades on the Pentax lens vs 12 on the Fujian.

IMO well looking on different cameras,compact and not distracting.



Cute on the E-PL5.


Here we start with the disadvantages of using a very low priced lens with large aperture designed for different devices-CCTV security cameras.
Above is an example picture taken with the Fujian 35mm.
Center sharpness is great-quite descent for most users in most cases.
The corners on other side are not well rendered. Blurred with a kind of whirlpool effect.
Taking series of test shots on an improvised test chart I found my copy of the Fujian 35mm to suffer from de-centering at its largest apertures,f/1.6 and f/2.
I mostly use it at the reasonable good f/2.8 and f/4.
If you like to shoot videos handheld,camera bodies with build in stabilization compensate the shaking easily on short FL lenses like this. 

Samples
I see no real difference between f/1.6 and f/2,so I skip f/1.6 in some of the examples.
Click on the images to see them fullscreen.

The larger the aperture,the narrower sharp zone with circle shape.
Most images are taken before sunset and there is not much green at that time of the year.

Depth of field in portraits at f/2.8 with a m4/3 camera.
Click on the pictures for larger view.



Macro shots with one extender.


Pictures at different aperture.f/2  1/800s  ISO 160
f/2.8  1/640s  ISO 160
f/4  1/320s  ISO 160
f/5.6  1/200s  ISO 160
f/8  1/125s  ISO 250
f/16  1/125s ISO 5000

Shape of the Bokeh effect at different aperture.



Some test chart shots.
Remember,just don't expect too much from this type of lens.
Edit-After some more tests with Panasonic G6's focus peaking,I found that the lens itself has no problem with the corner sharpness. The corner rendition is quite sharp.The actual problem of the lens is that the center and the corners are in focus at a different point,even at f/8. If I intentionally focus on an object in the corner,it is sharp,but then the center is soft/blurred/out of focus.
The focusing zone is like a corona that expands its diameter from the center to the corners depending on the focus point. (I will try to do a video for better demo)

f/1.6  1/320sec
f/2  1/320sec
f/2.8  1/250sec
f/4  1/160sec
f/5.6  1/80sec
f/8  1/30sec
f/16  1/2sec -corner to corner sharp,but diffraction limits picture quality a lot.


Video test
Aperture test-testing the exposure difference at each aperture marking on the lens.


Manual focus test at f4


Aperture priority test, auto ISO

Who will enjoy using this lens?
People that understand the limits of using a low priced product and know how to take the best out of their gear. People that do not expect too much from a cheap lens.
This lens is a great option to train your manual focus skills; To test if the shallow depth of field at large aperture suits your way of shooting; To learn more photography techniques using different aperture values(especially if you were using only small aperture kit lenses; For example shallow depth of field allows you to blur distracting/ugly background,bringing the whole attention to the main subject of the image.
The lens is good for people that like art looking photos and don't expect corner to corner tack sharp images.

For me sacrificing the corner quality,but taking low light videos more easily also worth it.
With everything said,I would not recommend the lens to people seeking very high optical quality represented in corner to corner sharp images.It should be avoided by landscape photographers unless their goal is initially giving the scene more artistic look(which in our days is quite easy to do in computer software).
The performance on f/2 and f/2,8 can't match dedicated lenses and more especially the more expensive ones-usually all large aperture native lenses for the particular mount are quite expensive. The vintage Helios 58mm and Pentax 50mm lenses beat the CCTV lens with much in terms of optical performance. But they are full frame lenses and the comparison with a lens dedicated for much smaller sensors is hard.
Let me know about your experience with CCTV lenses in the comments don't forget-practice and understanding the gear is the way for improvement and enjoying the photography.


What's positive:
+Compact; Simple but effective barrel design;Looks well on different cameras;
+Solid metal feel; Stable focus and aperture ring with smooth 'fluid' rotation;
+Not limited to the regular f/ stops;
+Great for practicing manual operation;
+Enjoyment to take some low light photos,some nice portraits and videos with precise focus pull;

What's negative:
-It is hard to tell what aperture is set without looking at the f ring;
-As expected from a cheap lens(and not only) apertures of f/1.6 and f/2 are hardly managed and we can see various flaws-distortion,chromatic aberration,overall loss of sharpness,blurred corners,slight decentering;
-Simple anti-reflective coating;Bright light at certain angle may cause overall purple tint of the scene;
-Using  sun hood is a good idea;
-Vignetting is not as noticeable as expected,yet I can test it only on micro 4/3 sensor; On a APSC sensor there should be more vignetting and corner softness;
-I don't see any difference between f/1.6 and f/2 on a m4/3 sensor camera from my tests so far;
 Don't have a way to test it on a larger sensor and comment; Cameras measure the same amount of light and select identical settings for both apertures;

Thanks for reading.I hope you found some useful info.
Your comments are welcome-share your thoughts of using CCTV lenses.

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