[DanielT74]

I've hoarded 4 ultrawides and thought I'd give them a kind of a rigorous test before letting some go. So today I took them out (forgot the Sigma 10-20/4.5 at home - damn!) and here are some initial impressions (with pics to follow).

at f8:

1. They are all decently sharp in the centre with Pentax having a slight edge.
2. In the corners Samyang's edge increases especially over the Sigma. DA is still pretty good.
3. CA especially present in Pentax and also in the Sigma, mostly blue fringing, it is practically absent on the Samyang.
4. Distortion is lowest on the Sigma, seems pretty good (I don't have such a great eye for it) on the DA and funny on the Samyang - some parts of the image are not distorted and some are significantly distorted.

Note that there was a compounding factor - the exposure times were not exactly the same.

at f13 there is not much between the lenses as Sigmas CA disappear. I guess distortions are same as above.

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Last edited by DanielT74; 04-19-2011 at 06:08 AM.

[Lowell Goudge]

some images would be nice, also you should consider removing distortion from the samyang using software.

the reason I suggest sample images, is that I also have the samyang (AKA vivitar) and I could then add the sigma 10-20F4-5.6 into the comparison.

I have noted when shootinig with the samyang the edge sharpness, lack of vignetting, even with full frame (PZ-1) , and have had no issue taking distortion out of the equation using PSP X3.

[Ash]

Good points Daniel, leading to a good overall performance by the Pentax, a mixed one from the Sigma and characteristic one from the Samyang.

Indeed images to highlight these impressions would assist a lot.

[Lowell Goudge]

one point to note on the sigma and samyang, these are both full frame lenses, so they are designed to cover a lot more, and it should be expected that they out perform the pentax over a cropped sensor.

[DanielT74]

Thank you for your comments, folks. I don't have paint shop pro (if this is what PSP is) but I have photoshop cs3. I also heard that PtLens is pretty good for distortion.

Here come the pics (Sigma followed by Samyang followed by Pentax):

[DanielT74]

https://www.pentaxforums.com/forums/newreply.php?do=newreply&noquote=1&p=1472299

[DanielT74]

The album is here: https://picasaweb.google.com/103430830473331312618/20110419UltrawidesTest?au...nuoGZLg&pli=1#

[Lowell Goudge]

Daniel

thanks for the images

With respect to distortion, maybe the best way is for one of us that has distortion correction software to attempt to fix each photo, and then evaluate distortion based upon the relitive difference in correction.

for that, we really could use a brick wall or face on a square building.

[LowVoltage]

It seems all three of these lenses, plus the missing Sigma and Tamron's 10-24mm, all get respectable marks in formal and informal reviews.

I was positively blown away by how well the ultra-wide Vivitar/Samyang 14mm performed. Photozone.de has a nice breakdown of that lens' strengths and weaknesses.

One upon a time I considered the Samyang as a possible alternative to the Pentax DA 15mm because it cost less and the sharpness could not be be beat. Unfortunately, the pure size of the lens is pretty much a deal breaker for my taste. Unless somebody wants to lend me one to try out for a season (or three!) I don't see myself hauling one around just to see if I can get used to it.

Still, it's pretty tempting. The only other big knock against the Samyang 14mm would probably be its high distortion. I've seen reviews measuring the distortion figures twice as high as the other lenses in this test group at their widest angles. Then again, as others have pointed out, it's an issue that can be largely alleviated in post-production. For me, the devil on my shoulder is saying "...but the sharpness! Oh, the sharpness!"

[Lowell Goudge]

It seems all three of these lenses, plus the missing Sigma and Tamron's 10-24mm, all get respectable marks in formal and informal reviews.

I was positively blown away by how well the ultra-wide Vivitar/Samyang 14mm performed. Photozone.de has a nice breakdown of that lens' strengths and weaknesses.

One upon a time I considered the Samyang as a possible alternative to the Pentax DA 15mm because it cost less and the sharpness could not be be beat. Unfortunately, the pure size of the lens is pretty much a deal breaker for my taste. Unless somebody wants to lend me one to try out for a season (or three!) I don't see myself hauling one around just to see if I can get used to it.

Still, it's pretty tempting. The only other big knock against the Samyang 14mm would probably be its high distortion. I've seen reviews measuring the distortion figures twice as high as the other lenses in this test group at their widest angles. Then again, as others have pointed out, it's an issue that can be largely alleviated in post-production. For me, the devil on my shoulder is saying "...but the sharpness! Oh, the sharpness!"

I own 3 current samyang products, the 85F1.4, the 14F2.8 and the 8mmf3.5 fisheye.

None of them will ever compete against pentax for size, and on the two UW products, the non detachable hood is a bit of a killer, in terms of size, as is the snap over cap. I am quite sure a much more compact cap could be made, but.....

[Jimfear]

I've been looking in to the Samyang 14mm a little but haven't been able to get my hands on one to try it yet. Seems like a good performer aside from the distortion.

How is the focusing? Smooth and good? Compared to Pentax manual focus lenses.

Does anyone know how it compares to the K/A15/3.5?

[DanielT74]

From little experience that I've had with Samyang, it is excellent except for the distortion. If you can correct the distortion or are not bothered, it is fantastic value for money. The detail and the absence of CA are amazing.



100% crop:

[DanielT74]

You can see the distortion in the concrete benches in the red building pictures above. Samyang while correcting the perspective quite amazingly (in my uneducated view) has very bent benches.

Also check here:





If someone is using PTLens or other distortion correction, here are the links to full-size pics, maybe you can correct them and post for us to see?

https://picasaweb.google.com/103430830473331312618/20110419UltrawidesTest?au...90859051621682

https://picasaweb.google.com/103430830473331312618/20110213MelbourneCBDUltra...26990509616178

https://picasaweb.google.com/103430830473331312618/20110419UltrawidesTest?au...82027829985922

I don't mind the size that much. The k20d doesn't fit into my jeans pocket.

One day when I get rich and spoilt I will get myself a Leica M10 (or more likely an M1000000 ).

[yyyzzz]

Samyang14 is just amazing in terms of resolution, especially border resolution. But DA 15 allows filters. My only minor gripe with the Samyang is that the focusing throw is a bit too long for a 14mm lens. DA15 is about right.

[DanielT74]

So what do you use for distortion correction, yyyzzz?