Thread: Filter Offsets
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Old 19-10-2013, 09:11 PM
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RickS (Rick)
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RickS is offline
Join Date: Apr 2010
Location: Brisbane
Posts: 10,584
Hi Steve,

I find the offset calculation a bit of a crapshoot at slow focal ratios as you suggest. I do FMax focus runs on each filter in turn and toss any result that finishes with a HFD that looks out of whack. I do this several times and put this all in a spreadsheet and calculate the offsets for each run, delete any outliers, then average the offsets. Then I use a Baht mask and Bahtgrabber to check and tweak the results. This process takes a while but fortunately I don't have to do it often

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