Hi guys, Sorry for bothering you again with this subject, being a beginner I'm a bit of a numb skull. I have a sigma lens with a f5.6 what will the size be with a 1.4x converter . And the second question is I have a sigma lens with f6.3 what would the size be with a 1.4x converter. I don't want to pass f8 as I would loose auto focus. And I don't want to waste my money as I need it to be auto focus. Thank you all. Pete.
You will lose 1 stop of light with a 1.4, 2 if you had a 2.0. This is because you extended the length of the lens with this added barrel. At 6.3 will be effectively as dark as using it at 8 without the converter. Hope this helps.
So it looks like I can use a teleconverter then. Hopefully. Just as I have notice the stop working at f8.
Hi guys, Well I purchased a 1.4x converter, only a cheap one so I didn't was my money if it didn't work . And it works just fine it even worked up to f11, can't understand how, but mainly at f9. So shortly a better quality teleconverter will be purchased. Thanks all for your help. Pete
