Well, that sounds complicated… and it kinda is!īut this is THE solution for an unrecognized objective that has no chance of being recognized. But if it is not: no contacts on the lens or old lens, it will obviously be necessary to note frame by frame the aperture when shooting! This can even be extended to f/16, but the sharpness may need to be adjusted on a case-by-case basis if the diffraction does too much damage.Īttention: if the opening is present in the exifs, no problem to find the raw to be processed with such or such preset. For example, from f/4 or f/5.6 to f/11 the corrections will be identical, so only one preset will be necessary, which could have the name “(Brand)_50mm_f5-6_f11”. This means that we can generally group certain openings. This done, we create a new partial preset that we will name for example “(Brand)_50mm_f2”.Īnd we start again for each raw corresponding to the other more closed diaphragms…īut it is generally possible to reduce the number of cases very seriously: the vignetting generally decreases fairly quickly and the sharpness improves. On the other hand, the other settings are to be repeated, generally by decreasing them. In principle, the distortion correction is the correct one. Once this preset has been saved, open the next raw (taken at f/2 for example) and apply the preset that has just been created. This preset will be named for example: “(Brand)_50mm_f1-8” When all these corrections are made, you can then create a partial preset that you save in the preset editor. PhotoLab allows you to take this into account with the Edge Offset slider which will accentuate the sharpness going towards the edges. The important point to note is that most often a lens has maximum sharpness in the center, and this sharpness decreases towards the edges/corners. ![]() ![]() This step can be done with the raw target (for example if the paper has a pronounced grain), but it can then be refined with a more detailed photo, for example that of a road map or similar. Finally it remains to make the correction of sharpness: tool Unsharp Mask - Intensity / radius / Threshold.Then we move on to vignetting correction: Vignetting tool - Manual / intensity / medium.So we correct the geometry of the image with the Distortion - Manual / barrel pincushion / fisheye tool as appropriate and the intensity slider. Normally (usually) the distortion is constant regardless of the aperture used. We start with the correction of the distortion.This step is to be done with the raw taken with the most open diaphragm (f/1.8 for example). This must be repeated for each of the openings of the diaphragm. ![]() A pattern must be photographed at a reasonable distance, for example a grid of black lines on a large white sheet of paper (with uniform lighting!). ![]() The only realistic possibility is to make your own profile as follows, it being understood that this is reasonably possible only for a single focal length lens, and not for a zoom: far too complicated! I think there is no valid “software manipulation” method to use a lens profile A to apply a lens B!Įxcept in the special case of almost identical lenses, for example a new version of a lens without modifying the optical formula.
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