I saw this deal from B&H, im pretty sure its the same as a samyang 14mm, which is highly reviewed. Its very tempting as a ultra wide astrophotography lens.

Vivitar Series 1 13mm f/2.8 Ultra Wide Aspherical Lens VIV13MMP

[Na Horuk]

I asked the member and he gave permission that I upload the profile. He made it for K-5IIs, I think, but it should work equally well on all 16MP Pentax cameras, and probably others as well. He used the Adobe Lens Profile Creator. The problem with my specific copy of the Samyang 14mm is that it is slightly decentered, so the CA is not uniform, but is stronger on one side than the other. But the profile works well for distortion and vignetting.
To install, just download the attachment, unzip the file, put it in the lens profiles folder (Its in your Personal folder\AppData\Roaming\Adobe\CameraRaw\LensProfiles\1.0 , at least on modern Windows, not sure about other OS, feel free to gugl it). Then open Lightroom, Develop a photo, Lens Corrections, choose Profile, check Enable Profile Corrections, in the Make drop down menu select Pentax, find Rokinon 14mm. And now its applied to the photo!
You can thank John for making this profile And please post your thoughts if you try it! Here or in the Samyang lens club

Attached Files

Rokinon 14mm F28 profile for Pentax IIs.zip (1.3 KB, 57 views)

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Last edited by Na Horuk; 12-04-2014 at 09:53 AM.

[T Evergreen]

Na Horuk, thank you for posting the profile and John for creating it.

I have Windows 8.1 and found the Lens Profiles inside Lightroom 4.4, but unfortunately I couldn't get the new profile to work after adding it to the others already there. It simply doesn't show up among the lenses when I run Lightroom. I'm using a Pentax K-50, so don't know if the profile is camera specific as it was made for a K-5 II.

In any event, when looking at the text of the profile and comparing it to other profiles, I noticed there was some data at the beginning and end of the 14mm profile that doesn't appear in those already in Lightroom. In addition to using it as it was downloaded, I removed the additional text and then added it to the other profiles in Lightroom, but it still didn't work. It simply doesn't appear among the list of other lenses when I run Lightroom.

Any thoughts on my problem?

One other thing I noticed was that the Rokinon 14mm profile is quite a bit smaller than the other lens profiles already included in Lightroom.

[saladin]

Just got an email from B&h. They have been told by their supplier that this lens is discontinued and therefore cannot meet my order. So, i have a credit to use or get a refund.

[Na Horuk]

Any thoughts on my problem?

I use this profile on cameras that are not K-5IIs, so that shouldn't be the problem. But I have an older version of LR - LR3 (updated to 3.6, I think?), maybe it is not compatible with LR4. I don't know, maybe someone else can confirm.

Just got an email from B&h. They have been told by their supplier that this lens is discontinued and therefore cannot meet my order. So, i have a credit to use or get a refund.

Oh wow. Wonder if this goes only for the Vivitar, or for all the Samyang 14mm versions.

[T Evergreen]

Na Horuk, thanks for the follow-up.

This morning, I was able to track down information on installing correctly the lens profile you posted in this thread and it works in Lightroom 4.4.

There was a thread on Flickr about installing the profile in Lightroom 4. Basically, you don't want to add the profile to those that come with Lightroom. Rather, you add it in the "Lens Profiles" folder you find at C:\Users/your user\AppData\Roaming\Adobe\CameraRaw\LensProfiles. Just drop the new profile in the "Lens Profiles" fold, there's nothing else to do.

As I mentioned earlier, I did remove some characters at the beginning and end of the profile you posted. I simply removed what came before "<x:xmpmeta" at the beginning of the profile and "x:xmpmeta>" at the end. Not sure if removing the text was necessary, but the profile works that way.