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. -----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. The recipient should check this email and any > attachments for the presence of viruses. 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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 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. The recipient should check this email and any attachments for the presence of viruses. The company accepts no liability for any damage caused by any virus transmitted by this email. NHBC, the National House-Building Council, is limited by guarantee in England, No 320784. Registered address: NHBC House, Davy Avenue, Knowlhill, Milton Keynes MK5 8FP. 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
