Digital Outback Photo
- Photography using Digital SLRs

Workflow Technique #043

PTLens Plugin: Lens Distortion Corrections

review note by Uwe Steinmueller

 
 

As a fact of life all (even the best lenses) show distortions. These distortions are specifically noticeable at the wider angles and if your subject shows straight lines.

There are some Photoshop plugins on the market that do a nice job to correct some distortions. But there are only very few solutions that are based on camera/lens profiles. One of those solutions is DxO Optics Pro. Unfortunately DxO Optics Pro shows a couple of shortcomings in its current incarnation:

  • Not cheap
  • Works not with current raw converters
  • JPG only (means 8 bit only)
  • Limited cameras and lens profiles
  • No PS plugin

Here the PTLens solution by Thomas Niemann shines:

  • Free
  • Works with Camera Raw 2.2 and Capture One 3.5
  • is 16 bit capable
  • Quite a collection of camera/lens profiles available (huge effort by Thomas Niemann!)

     
Brands and some camera models


Lenses for the 10D and 300D

  • Works as PS plugin

Note: PTLens uses the Panorama Tools library to do all the mathematical calculations.

How to use

Download from this page and follow installation instructions. The use is easy. If the image has the right EXIF information about the camera and focal length you see this dialog:


PTLens dialog

You then select the lens and the dialog will show the lens parameters for correction.

 

Note:To show the differences we use the symbol to indicate that a mouse over will show the previous or original image (move the mouse cursor slowly in and out of the image).

Here is a sample:


after correction

Extreme Fisheye

This is a sample shot by Jack Flesher with the 1D Mark II and the 15mm Fisheye lens:


After

Note: Jack and Thomas told me that the profile for the 15mm and 1Ds is beyond the limits what PTLens can correct.

More Profiles

Thomas is permanently adding new profiles (see his calibration page).

Our editorial member Jack Flesher took a lot of test shots to support the Canon 1Ds and Canon 1D MarkII.

 
New profiles created with Jack's help

DOP helps to improve products for the digital workflow

We hope you realize that we at Digital Outback Photo are not just looking towards the market and review products. We (with the help of excellent supporters) help to make products better or even initiate new products (e.g. EasyS sharpening). The collaboration of Thomas Niemann, Jack Flesher and DOP is a good example. But we also left our mark on most third party raw converters.

 
Now Version 4.1
 

PTLens is now in version 4.1 with even more profiles.

Here is a photo from our trip to Mendocino:


1Ds + 70-200mm f/2.8 + 1.4x tele extender

When we viewed this image we really thought our lens or extender were broken. Then our friend Jack Flesher helped Thomas Niemann to profile the 70-200mm f/2.8 + 1.4x combination (FYI he used his own lens and extender and not ours!).

Here is the shockingly positive result:


Corrected with PTLens

We are glad that our lens seems to be ok. On the other side we also realize that the 1.4x extender produces very strong lens distortions. We don't really need to worry about this anymore as PTLens does a great job fixing thes distortions.

The next shot was at 28mm with the Leica Digilux 2:


Courthouse in Santa Barbara with Leica Digilux 2


Fix with PTLens 4.1

Conclusion

Get PTLens, it is free.

 

Version 5.0 adds a Vignetting correction

The new version 5.0 also adds a vignetting correction tool. We hardly need this kind of correction (maybe we use more tele lenses and also only top glass).

Read our full review here.

What about Mac users?

Mac users can buy at a reasonable price LensFix from here.

 
 
 
 
   

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