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Posts: 12,057
Registered: ‎12-07-2012

Re: Some lens correction questions

"... one only needs to worry about having the correct lens specific data installed in the camera if they want it used by the camera when producing .jpg files.  Is this notion valid?"


I admit I didn't read all the replies since most aren't accurate anyway and I don't use DPP so you may wnat to just stop reading this right now.  But the way it works is your camera settings are stored in a metagata tag file inside of the Raw file. Since you can not view or see or display a Raw file something has to happen. Well it does, your software converts it to a jpg but it doesn't know either how to display it.  So, it reads that metadata tage and uses it. This means whatever settings you made in camera will be applied to the jpg so it can be displayed.  It is true the Raw file is not changed and it never is but it has to be converted to show it. Raw is not an image. It is data which is just the luminosity collected by the camera.


The main benefit of a Raw file is its greater ability to edit it.  The range far exceeds a jpg.  All editors and/or converters are different in their conversion.  I prefer LR and PS because their 'adjustment' in conversion is more neutral.  More close to the actual Raw file.


EOS 1DX and 1D Mk IV and several lenses!
Frequent Contributor
Posts: 64
Registered: ‎02-13-2018

Re: Some lens correction questions

I completely understand that exact duplication cannot be assured when manufacturing the lens. However, I would think that what we're talking about here is actually a known design limitation that will exit in all such lens even if some (?slight) variation will always remain because perfect repeatability cannot be achieved.
Frequent Contributor
Posts: 64
Registered: ‎02-13-2018

Re: Some lens correction questions

@Waddizzle wrote:



With that said, you cannot use both the slider to apply correction and correction data from the downloaded lens catalog.  If you have downloaded lens correction data from Canon, just simply enable it.  Once you start adjusting the slider, you are overriding the Canon lens correction data, and applying your own.

Well now, this seems to me to be a profoundly important point that I never recognized after what I thought to be pretty careful study of the documentation (User Manuals).  What did I fail to notice in the Uer Manual?

In DPP4, when editing and the selection box called "Digital Lens Optimizer" optimizer is checked a slider is enabled and positioned at 50%.  While it did seem strange for me to start making adjustments absent any knowledge about the nature of correction associated with the "Lens Data" supplied by Canon the idea that one should keep their hands off, so to speak, this control was not at all apparent.  Fortunately, my bewilderment lead to asking about the slider.  No telling if I'd have ever figured it out without your help.  Thanks for that.
Honored Contributor
Posts: 6,223
Registered: ‎11-13-2012

Re: Some lens correction questions

[ Edited ]

The use of the slider controls the amount of DLO correction being applied. It allows you to fine-tune the image appearance. Depending on the subject more or less sharpness/correction may be desired. See pages 78-79 of the DPP PDF manual, as well as the following:



John Hoffman
Conway, NH

1D X, Rebel T5i, Many lenses, Pixma PRO-100, MX472, LR Classic
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