Went out to photograph some aircraft at Manchester today. Decided to fit my 1.4x converter. It was windy, raining so I was bent over trying to shield the lens. But could not get the converter to fit. Examined it and .the lens for damage or bits stuck in the mount but found nothing. Decided not to bother. Then suddenly the light became eliminated and I realised I was trying to fit it to an EFS lens instead of the 100 L. I should .have been fitting it to. Another super senior moment.