[RogerrDalTx]

I usually hang out over at photo.net in the Pentax forum; it's a MUCH smaller community and easy to keep up with. But now and then I have a question that requires a bigger audience and you guys always come through.

One of the new k-7 features is automatic lens correction. Per a review I read that it works in camera for jpg but can also be done when shooting raw with the new and included Pentax "Digital Camera Utility version 4". Which is some variant of Silkypix 4. Have any K-7 owners played with raw file lens correction yet? I'm very curious how well it works to automatically correcting barrel distortion on the wide end of the DA*16-50 or DA 21 limited. I'm pretty well rooted in Lightroom 2.5 for about 80 plus % of my raw conversion and post processing: And go to CS3 / NIC and some portrait software as needed. I almost bought a copy of DxO Optics Software (about $170) a little over a year ago to get the automated lens correction from raw (Their demo is really, really cool) but I feel their Pentax support is lacking so I opted not to make the investment. Automatic lens correction is something Canon added a while back to their free photo professional software and I think it makes a lot of sense to correct inherent lens design compromises.

Specifically I want to automatically correct barrel distortion on a couple of my wider Pentax lenses rather than having to individually take a shot into CS3 and "eye it". It would also be nice to be able to "unfish" shots from my DA 10-17 as the DXO software can automatically do on some Canon / Nikon lenses. There is also a nice little $25 utility called PT Lens that does optical correction, but it has no built in Pentax lens profiles so it's all manual for us and I want to do this automatically in raw conversion without "eyeing" and guessing at each correction. Preset lens profiles provide a nice starting point.

I'm thinking the lens info is in EXIF data in my K20d's raw files so if the desktop software has the lens profiles it should work Who's played with the lens correction feature for their raw files in the new K-7 PENTAX Digital Camera Utility 4? Is the correction process automatic or do you have to "eye it" and adjust sliders? If it works well I wonder if Pentax will make the new software available as an upgrade to owners of earlier bodies. Thoughts?

[Labuzan]

PDCU4 don't use automatic corrections send by the K7. Only K7 software can use it.
With PDCU4 you have to do corrections maually. It's crasy !!!
DPreview send us a false information.
K7 is built to create good jpg directly and effectively JPG are very goods.

I use only hi jpg quality **** with corrections and forget RAW

For PTLens, you can use the K20 corrections w/o problem (same sensor size). It's correct.

[flyer]

The data for lens correction is embedded in the RAW picture and can be used by PDCU4. But it doesn't de-fish the 10-17 as the distortion is voluntary with this lens.

It works pretty well, but sometimes doesn't completely eliminates CA and purple fringing.

[Labuzan]

Don't work !
I own K7 and Pentax 18x250.
All RAWs exported by PCDU4 are w/o lens correction.
Only K7 software apply lens corrections.

When i open RAW (PEF or DNG) with PCDU4, picture is corrected.
But, if i modify somewhat (exposure or white balance) corrections disapears instantaneous and jpg export is w/o corrections.

I already spent a lot of time to undertand Whyyyy
One idea ?

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Last edited by Labuzan; 10-06-2009 at 03:09 AM.

[RogerrDalTx]

Well the response to my question has not been the definitive answer I hoped for. I got the chance to play with the PCDU4 software with several of my k20d pef and dng files with various lenses. The lens correction does NOT seem to be profile driven nor automatic. It appears to be all slider based, though the vignetting does have a default value. Anyway distoration correction is not automatic, not does it come with preset lens based starting points. So while the software appears significantly improved over version 3 it have no benefit to my workflow to warrant adding it. I guess when I need this feature I'll keep going to PTlens after lightoom conversion from RAW. Thanks /Roger

[Labuzan]

So while the software appears significantly improved over version 3 it have no benefit to my workflow to warrant adding it. I guess when I need this feature I'll keep going to PTlens after lightoom conversion from RAW. Thanks /Roger

I agree for the poor improvement of PCDU4 except for ergonomics which is better.
May be PDCU 5 accept automatic K7 lens corrections ?

[mysticcowboy]

There's a Photoshop plugin, PTLens that can programatically correct lens distortion and CA. It's done on a profile basis, as I understand the K-7 does. If a lens is not in the database there's a straightforward method for creating a profile. I'm using it with my K20D and the 18-250 lens as well as the Sigma 10-20. Not affiliated in any way. Just a happy camper.

There's also a stand alone version if you don't have Photoshop, though when I bought my copy it didn't handle raw files. PTLens also allows for manual control, which is straighforward, but I find that I rarely need to. It runs on Windows and Intel Macs running X.5 or better.

It gets regularly updated and includes the standalone application, Lightroom/Aperture/iPhoto/Photoshop plugins or an external editor. It supports all Pentax DSLRs that have been released and all lenses with a multiplier of 1.5 or less, but not old 645 lenses.