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12-19-2013, 01:15 PM - 1 Like   #1
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Samyang 16mm f/2

I can't believe no one has yet posted still samples from the new APS-C Samyang lens that goes by the (less than elegant) full name of Samyang 16 mm f/2.0 ED AS UMC CS. I'll be going to discuss and demonstrate my first impressions, although I haven't had too much real-world experience so far. I'll do this in serial form, so let's begin with a sample shot and then some general observations.

K-5II, f/8, 1/350, ISO 100, RAW converted in ACR 8.2


I tried to shoot a subject that is too boring to be stolen if I post a link for the full size. The lens did very fine, with the small branches against the sky (a stress test for any lens) sharp into the extreme corners. The full size sample is here:
https://www.dropbox.com/s/hl2yozyg2tid98j/1312164268.jpg
Although flare resistance was identified as the weak point of the Samyang 16mm in the Lenstip test, the sun in the frame does not cause any major problems. More to follow!

12-19-2013, 01:57 PM   #2
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Not unexpectedly, the lens is quite big and heavy. (If you want the details, the full specs are in the Lenstip test.) After the first few test shots, I knew why. Every optical design has its compromises, but in this case there are not too many; bulk and weight is the price for that. The few compromises that I noticed so far are a relatively high amount of distortion and somewhat more ghosting/flare than with the best Pentax lenses. The latter is probably due to a less refined coating technology and also to the complex construction (13 elements in 11 groups).
The infinity mark is approximately correct, although not quite spot-on. Infinity appears to be perhaps half a millimeter before the mark. The focusing ring can be turned beyond infinity and is marked accordingly, so perhaps the effective infinity setting changes with temperature. There is some kind of close-range correction: the back lens group moves forward while turning the ring towards the close end, while at the same time the front group moves ever so slightly backward. In line with that complex design, the MFD is only 20 cm; I haven't yet used it. The focus throw is very long. Interestingly, although the lens is bright and very sharp wide open, I found it more difficult to focus than most of my other lenses (and I tend to be an all-manual guy with a lot of practice). However, this impression may have to do with the temptation of using the lens in low light. I'll post a few test shots shortly, but to put it in a nutshell: the Samyang 16mm is totally usable at f/2 and VERY sharp from f/2.8 onward.
12-19-2013, 03:04 PM - 2 Likes   #3
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First test: the LP/CD shelf

In order to put the results of this test into perspective, let's compare the Samyang 16mm to the smc Pentax-DA 15mm f/4 Limited--a fine lens by any standards.

First, the full frames at f/5.6.

Samyang 16mm:


DA 15mm Limited:


Note that the light is different: it was getting dark and there is less daylight involved in the 15mm shots. I adjusted the colour temperature accordingly. So you cannot draw any conclusions concerning colour rendition. The Samyang has noticeably more distortion (but I had no difficulties in correcting it 100% in Hugin; once a Lightroom/ACR profile is available this can be done during RAW conversion).

Now the details: 100% crops for various f-stops. I don't post the Samyang shot at f/5.6 because there must have been some motion blur. As I am interested in the real-world possibilities of a lens rather than its theoretical performance, all samples are treated to get the best out of them: ACR's CA auto-correction and a little sharpening (a lot more would be possible without overdoing it).

The sharpening/NR setting is the same throughout:
Sharpening
Amount: 40
Radius: 0,6
Detail: 50
Masking: 0

NR
Luminance: 0
Color: 5
Color Detail: 50

Samyang 16mm, f/2, center crop:


Samyang 16mm, f/2.8, center crop:


Samyang 16mm, f/4, center crop:


Samyang 16mm, f/8, center crop:


As far as I am concerned, there is no relevant difference in the center between f/4 and f/8. Some diffraction is already visible at f/8 (or there was again some motion blur--the wooden floor in my livingroom is not very solid).


DA 15mm Limited, f/4, center crop:


DA 15mm Limited, f/5.6, center crop:


The DA Limited is remarkably sharp even wide open. I think there is no clear winner.


Now for the extreme corners. The Samyang is a little weaker in the lower left corner, so I chose that corner for the samples. This--or better than this--is what you can expect from a good sample.

Samyang 16mm, f/2, corner crop:


Samyang 16mm, f/2.8, corner crop:


Samyang 16mm, f/4, corner crop:


Samyang 16mm, f/8, corner crop:


At f/2 you see the effects of vignetting (not too bad; at f/2.8 vignetting is less than with the DA 15mm Limited at f/4). Sharpness is quite good at f/2 and very good from f/2.8 onward. It gets better until f/8 where it is beyond any doubt.


DA 15mm Limited, f/4, corner crop:


DA 15mm Limited, f/5.6, corner crop:


Ouch! The Samyang is much sharper at f/2.8 than the DA 15mm Limited at f/5.6. This is what the weight is for.
Stay tuned for more.
12-21-2013, 09:40 AM   #4
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Second test: treescape

This is the uncropped frame:

Samyang 16mm, f/2.8


At f/2.8, very little vignetting is left.


100% crop from the extreme right edge:

Samyang 16mm, f/2


Samyang 16mm, f/2.8


Samyang 16mm, f/4


Samyang 16mm, f/5.6


Not bad for a very wide angle lens. Interestingly, the left edge seems to be a little sharper at close to infinity (different from the behaviour in the shelf test).


100% crop from the extreme left edge:

Samyang 16mm, f/2.8



100% crop center:

Samyang 16mm, f/2


The wide open shot, whether in the center or at the edge (above), has practically no LoCA. Awesome!


Up to now, pretty much everything was just great. Now let's go hunting for problems. What about flare resistance with the sun inside the frame?

f/5.6


Now that's really bad. But... wait a moment... this is from the FA 31mm Limited and not from the Samyang!

Samyang 16mm, f/5.6, cropped to the same FOV as the FA 31mm Limited for comparison


This is not so disappointing after all. What I want to demontrate with these shots is not that the FA 31mm Limited has a problem (it is a great lens in every respect, no doubt about that) but that you can get bad results from just about any lens under some conditions. A single sample for ghosting/flare is just a matter of coincidence. Change your angle by just a few degrees and the results will be quite different. A verdict on ghosting/flare resistence should be based on extensive real-world experience rather than a formal test. That said, if you compare the two shots you will find that the overall loss of contrast is less with the FA 31mm Limited.
BTW, in my opinion something similar can be said of bokeh tests. I can get you a bad bokeh from just about any lens (such as, for example, the Voigtlander Apo-Lanthar 125mm f/2.5 which, justly, has a great reputation overall for lovely bokeh).


Last edited by wkraus; 12-21-2013 at 09:50 AM.
12-21-2013, 10:25 AM - 1 Like   #5
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CA uncorrected

For those of you who are interested in the uncorrected CA, here's the extreme left edge from the Samyang and then from the FA 31mm Limited (same position and angle, but different FOV). Both samples have the upper half uncorrected and the lower with ACR auto correction:

Samyang 16mm, f/4



FA 31mm Limited, f/4


Nut surprisingly, the Samyang has a little more CA than the FA 31mm Limited, but very little for its FOV. In both cases it is very well handled by ACR’s auto correction (which BTW appears to work better than in Photoshop CS5, although the later ACR updates may have improved things).

A second comparison, this time with the DA 15mm Limited, without correction:

Samyang 16mm, f/5,6


DA 15mm Limited, f/5,6


The DA 15mm Limited has more CA, but also of a kind that is easily corrected. However, contrary to what many people seem to assume, CA correction does not improve sharpness but reduces it (at least according to what I have seen with my lenses). Want to test it? Convert a corrected and an uncorrected image to black and white and compare sharpness.
12-21-2013, 10:57 AM - 2 Likes   #6
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Close range performance and bokeh

Despite what I said above about bokeh test, here's a test shot. The focus distance is approximately 50cm.

The uncropped frame:

Samyang 16mm, f/2.8



Bokeh, 100% crop, close to the center:
Samyang 16mm, f/2.8


Edge performance, 100% crop, left edge:
Samyang 16mm, f/2.8


Very nice bokeh for a really wide angle lens. The close range is very well corrected. There is no apparent field curvature (the same goes for all tested distances).

A few more observations from my experience so far:
Colour rendition seem fine to me but with a green/cyan tendency. As I shoot RAW only, this is no problem for me. At the same f-stops, the Samyang is a little darker than the Limited lenses I used for comparison. I assume this has to do with the auto aperture regulation (I just used the A setting so far). I made the same observation with my Voigtlander Apo-Lanthar 125mm. The focusing is very smooth with a very long throw--about 150 degrees. It might be a little stiffer for my taste (I'm used to the Voigtlander 58mm and 125mm MF lenses). As for build quality, there is nothing to complain about. The lens caps are rather flimsy.

Bottom line: this is a wonderful lens that equals or outperforms lenses of twice or three times its price. Optical compromises are minimal; the only real issue I found so far is a ghosting/flare resistance that falls short of the best Pentax lenses. As I said above: the main compromise you have to accept is bulk and weight.
Since there haven't been any comments so far: if you are interested in more samples and/or test please tell me so. Otherwise, I'll leave it at that.

Last edited by wkraus; 12-21-2013 at 11:09 AM.
12-21-2013, 11:14 AM   #7
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Great tests, thank you! I think this is a great option for a UWA lens on APS-C. I'd prefer it over the 14mm personally.

12-22-2013, 07:22 AM   #8
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Great review! I have just ordered the 16mm

I also like the 24mm very much...are you familiair with that one too?

Cheers Marcel
12-22-2013, 05:15 PM   #9
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I ordered one too. The Rokinon version. This will be my third Rokinon lens. They are good. Can't understand the price difference between the main and re-branded brands though. The Rokinon is 379, the Samyang is 399 and the Bower is 469 at B&H. My impression is these are identical lenses with different branding.

Larry
12-23-2013, 09:01 AM   #10
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QuoteOriginally posted by Fookus Quote
Great review! I have just ordered the 16mm

I also like the 24mm very much...are you familiair with that one too?

Cheers Marcel
No I'm not, are you? It sure looks tempting.

I just made a small experiment using the sensor shift on my K-5II (as explained here) to see how it works with the 16mm. Using the maximum up and down shift results in an effective sensor area of 24 by 19 mm.

Samyang 16mm, f/8, sensor shift, aligned and blended in Photoshop CS6, distortion corrected in Hugin (approximately only)


At f/8, the image circle is quite generous with no visible vignetting (once you remove the hood). This means that if and when Pentax offers that FF camera you might also use the Samyang 16mm for a 22 by 22 square format with the FOV of a 40mm lens on the Hasselblad. IQ is great too:

50% (approx.) crop near center


50% (approx.) crop near lower right corner


Oh, and I forgot: the metallic red ring on the lens must fit real nice with the new HD Limiteds!
12-28-2013, 04:36 AM   #11
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Vienna, Ringstrasse in early morning sunlight

K-5II, Samyang 16mm f/2, 1/250, f/8, ISO 80, distortion corrected in Hugin, PPed in PS CS6


See also here: https://www.pentaxforums.com/forums/122-lens-clubs/137335-samyang-lens-club-28.html#post2628252
01-03-2014, 07:52 AM   #12
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Looks like this lens i have been searching for landscapes. Thank u so much doing this test!
01-04-2014, 11:05 AM   #13
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Looks like this lens best aperture is f5.6. F8 would have been better for landscapes use. Other thing i not happy to notice is distance scale, there is nothing after 1meter. I would like to see 2 and 3 meters also or more. Like in 16mm f5.6 focus on 2.3m then focus should be sharp enough starting from 1.3m in theory...i would use f8 to just make sure anyway and focus in the middle of those 2m and 3m marks almoust always.

Maybe i just continue landscapes with my tamron 17-50, i am still happy with that lens...
01-04-2014, 05:33 PM   #14
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Thank you for the review...I was checking out this lens. Does it have an "A" setting? Or is this a full manual lens; stop-down metering?

Again, thank you!
01-05-2014, 06:24 AM   #15
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QuoteOriginally posted by marosari00 Quote
Thank you for the review...I was checking out this lens. Does it have an "A" setting? Or is this a full manual lens; stop-down metering?

Again, thank you!
You're welcome! It does have the A Setting, just as the other Samyang lenses for Pentax mount do.
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