Tuesday, January 18, 2011

Comparing Lens Correction Profile Software

Last week I did a comparison of Ultra Wide Angle lenses. What I didn't discuss was how do different RAW converters and their Lens correction profiles help a typical 16-35mm image? This time using the different Lens Correction software I own, I compare DxO Optics, Photoshop CS5/Lightroom ACR engine, PTLens, and also for reference an uncorrected 14mm prime image.

Wide Angle Lens Compared

I should mention first that some of the crops look smaller than others. This is to show what happens when lens correction is applied and how much of the original image is lost. Photoshop/Lightroom loses the most, and frankly is not all that impressive compared to the others. However it does some of the CA and distortion correction, but at a huge cost of the field of view.

Lightroom/Photoshop via Adobe Camera Raw shows some limitations here. In the stock profiles, the images are still exhibiting strong CA and requires further intervention. This particular lens has a lot of lens variations, so when the settings were tweaked a little further, the results were much closer to what PTLens produces.

PT Lens does a pretty good job of fixing both distortion and CA. It also loses only a minor amount of the original field of view. it however has some alignment issues still so it's still not perfect.

DxO Optics is by far the best one. This is what equalizes the 16-35 with a prime lens like the Samyang 14mm in this respect. The field of view of course is different but it does show that with the right software that some of the problems that a zoom lenses exhibits can be fixed very well with software. It doesn't mean that it can replace a good prime, but what it does show is that if you want to use a zoom lens like the 16-35mm there are options to improve it without too much sacrifice to image quality.

Overall, the most economical choice is PTLens especially if you use Photoshop in your photography workflow, however DxO is clearly the superior choice here. The caveat with DxO Optics is that there's no third party profiles that can be added like Adobe Lightroom. Lightroom's approach is far more open and has a community of contributors that have created profiles for various lenses. From a general RAW processing point of view, I prefer DxO Optics about 80% of the time and because of that, I recommend it's Lens Correction Profile for problematic images. Also DxO Optics does a far superior job with perspective correction and control over Lightroom or Photoshop. Geometry seems far less distorted and closer to what I'd expect from a tilt-shift lens.

DxO Optics can be purchased directly from their web site available in two versions, the Standard ($169 USD) and the Elite ($299 USD) Editions. The Trial Version can be download here for a limited period of time with no limitations or watermarks.

Adobe Photoshop Lightroom can be purchased directly from their web site for $299 USD and the Trial Version can be download here which also offers no limitations or watermarks.

PTLens can be found online at their web site for $25 USD. Comes with a standalone application and also a plug-in for Adobe Photoshop.

4 comments:

  1. I wanted to thank you for this excellent read!! I definitely loved every little bit of it.Cheers for the info!!!! & This is the perfect blog for anyone who wants to know about this topic.
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  2. Hi!
    I bought a new samy 14mm/2.8 lens last week. I try to make a 360 degrees panorama photo, but it didn't successfull. :(
    I try picture processing with dxo, and stich with panorama maker 5, but it was no good. :(
    Can you help me what to do, please!
    Thanks: kovacslaci88 @ gmail.com

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    Replies
    1. Unfortunately the problem is in the lens choice in this case. A 14mm is not ideal for doing a 360 degree panoramic because of the amount of distortion that is naturally part of that focal length. It's why you have to be very careful about making sure your camera is level when using this focal length as it doesn't take much to distort everything. A decent 360 panorama photo should be done with something like a normal lens like a 50mm which has the least amount of distortion.

      The other part you need to do is find the parallax point of the Samyang (formerly or incorrectly called the Nodal point). This is the the precise point where the image inverts before it hits the sensor on the camera. Calibrating for this with the Samyang would be difficult. (instructions on how to do it may be found here: http://dgrin.smugmug.com/gallery/2114189_sdwC9K/ )

      Lastly if you are going to use the Samyang for 360, you will need to overlap your images quite a bit (I would say around 50% of the last image at least.

      I'll email these to you as well.

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