On Thursday 10 April 2014 11:18:50 Rob Z. Smith wrote: > In principle yes. To see how much AF is out I just take a shot focused on a > 45 degree angled ruler and then see how far away from where I focused the > actual image focus is. An alternative is to adjust focus until both AF and > Live View focusing come to the same point, this works as Live View > (contrast adjust) focusing does not suffer from the same errors. > > All this is very easy. I find the difficulty, for which some personal > judgement is required, is deciding what is a consistent and useful AF to > calibrate against as the actual focus point AF achieves with a lens varies > according to whether it is focusing in or out at the time focus lock is > achieved and how fast the lens is moving i.e. how far it has had to spin > the lens. This is the real problem and I don't see how software based > utilities are likely to help me with that.
Thank you for the detailed description. I will try this. If there is any insight worth sharing, I come back. > > -----Original Message----- > From: Wolfgang Mader [mailto:[email protected]] > Sent: 10 April 2014 12:04 > To: [email protected] > Subject: Re: [Darktable-users] Off-topic: Calibrating lenses > > On Thursday 10 April 2014 11:00:58 you wrote: > > Yes I certainly do bother with calibration. Some lenses don't need any > > at all but other, actually very good, lenses never achieve sharp > > results without it. > > > > I don't use any form of software tool for the adjustment though, that > > would seem an unnecessary complication. At least on the Pentax systems > > I use, it may be different for other brands. > > So you simply shoot, say, a ruler and check if there is back or front focus > and then adjust? > > Rgds, > > Rob. > > > > -----Original Message----- > > From: Wolfgang Mader [mailto:[email protected]] > > > > 1) Do you bother with camera/lens calibration? > > 2) Is there a tool I can run on Linux for the task? (I am on Canon, > > but this might be interesting for others and hence other brands also.) > > > > Thank you. > > Best, > > Wolfgang > > > > > > > > This email is confidential and is intended for the addressee only. If > > you are not the addressee, please delete the email and do not use it > > in any way. Please note that any views or opinions presented in this > > email are solely those of the author and do not necessarily represent > > those of the company. NHBC reserves the right to monitor all email > > communications. 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NHBC is authorised by > the Prudential Regulation Authority and regulated by the Financial Conduct > Authority and Prudential Regulation Authority. NHBC Building Control > Services Ltd, registered by guarantee in England with Company No. 01952969. > Registered address: NHBC House, Davy Avenue, Knowlhill, Milton Keynes MK5 > 8FP. NHBC Services Ltd registered by guarantee in England, No 03067703. > Registered address: NHBC House, Davy Avenue, Knowlhill, Milton Keynes MK5 > 8FP. If you make a claim under a Buildmark policy your personal details > will be stored and processed in accordance with the Data Protection Act. > Your personal details may be passed to others involved with your claim such > as the original builder, or a consultant or remedial works contractor that > we may employ in connection with your claim(s) and matter ancillary to your > claim(s). Other than disclosure provided for in this statement, we will not > pass any data about you to any other party without your permission unless > we are required to do so by law. > > ---------------------------------------------------------------------------- > -- Put Bad Developers to Shame > Dominate Development with Jenkins Continuous Integration > Continuously Automate Build, Test & Deployment > Start a new project now. Try Jenkins in the cloud. > http://p.sf.net/sfu/13600_Cloudbees > _______________________________________________ > Darktable-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/darktable-users ------------------------------------------------------------------------------ Put Bad Developers to Shame Dominate Development with Jenkins Continuous Integration Continuously Automate Build, Test & Deployment Start a new project now. 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