AFMA Focal results for 5DSR and 600II +/- 1.4XIII

[Vern]

Spent part of today recalibrating my 5DSR with the 600 II +/- the 1.4X III. I had not been pleased with results with the 1.4X (see bird portrait thread), so I thought I'd redo the AFMA today. Had to work in doors b/c of weather, so the distance was a little tight for the 840mm (13.5 m). The bare 600 gave excellent results, but the astigmatism values with the 1.4X were poor compared Focal's average user results. I attach the results from Focal (hope you can read the info on each). I'd appreciate expert users of Focal and perhaps this combo to comment on whether my results w the 1.4X III are really "poor" compared to typical users. This is my 'go to' combo for avian pics, so if I have a bad 1.4X, it would be good to know.

I'm not sure that the astigmatism factors are the critical readout, but I do know I have not been too happy with the results in the field. That said, the results today did change the AFMA from -6 to -1, so that could be the whole problem.

 

[AlanF]

I am not sure whether the FoCal results on astigmatism are meaningful given your somewhat unsatisfactory indoor tests. Instead, print off charts from the Bob Atkins site that have concentric rings and perpendicular sets of lines. Test shots of those will tell you whether the lens is astigmatic.

 

[Vern]

I am not sure whether the FoCal results on astigmatism are meaningful given your somewhat unsatisfactory indoor tests. Instead, print off charts from the Bob Atkins site that have concentric rings and perpendicular sets of lines. Test shots of those will tell you whether the lens is astigmatic.

Thanks Alan - I will take a look at that site and follow-up on those results. I think the first step is to have a sunny day and repeat the AFMA outdoors.

 

[YuengLinger]

Not sure if this is relevant enough to be meaningful, but with my 100-400mm II + 1.4x tele, my AFMA value is +12, the most for any lens registered.

 

[AlanF]

I am not sure whether the FoCal results on astigmatism are meaningful given your somewhat unsatisfactory indoor tests. Instead, print off charts from the Bob Atkins site that have concentric rings and perpendicular sets of lines. Test shots of those will tell you whether the lens is astigmatic.

Thanks Alan - I will take a look at that site and follow-up on those results. I think the first step is to have a sunny day and repeat the AFMA outdoors.

I have just looked at some calibrations I did this morning and all my past data. FoCal has some really neat features. It stores all your old data and when a new version comes out, it reanalyses all your old data in some hidden files. So, I can compare all my lenses on past and present bodies. All of my expensive lenses are in the "green" above average category. All of them are stated to be above average astigmatism, but looking at the data I can see at the correct AFMA the astigmatism is excellent but deteriorates either side - Focal uses the median value to state the astigmatism relative status.

 

[AlanF]

Not sure if this is relevant enough to be meaningful, but with my 100-400mm II + 1.4x tele, my AFMA value is +12, the most for any lens registered.

My 100-400mm II on the 5DS R has a low positive AFMA. But, on my 5DIV, the AFMA goes from 0 to +11 with both of my 1.4xTC IIIs, and the quality of fit drops significantly. How is your QoF affected?