lowkick Loc: Connecticut

I'm sure someone in UHH land has the answer to this, but I can't figure it out. I have a Sigma 100-400 Sport lens and a Sigma 150-600 Sport, as well as the 1401 1.4x teleconverter. The teleconverter works fine with the 150-600, but I'm having problems getting it to work properly with the 100-400 Contemporary. I understand that the lens, at 400mm, will have a minimum aperture of f9, but I can't get it to close down even more. I've even tried it in manual and it won't allow me to set the aperture smaller than f9. I looked up the compatibility chart for the lens and the 1401 teleconverter is compatible with both lenses. My question is, what does the designation that I circled in red mean on the chart? The AF is obvious, but what does the *6 and *4 designate? Could this be a clue to why I can't set the focus in manual or get it to close down past f9 in AF?

Any advice would be greatly appreciated. My next option will be to wait on hold for who knows how long for tech support from Sigma.

MT Shooter Loc: Montana

Refer to note 6 at the bottom of the page

SuperflyTNT Loc: Manassas VA

It looks like those numbers reference footnotes. AF indicates it auto focuses but the 4 and 6 are the caveats in the notes.

lowkick Loc: Connecticut

Now I feel stupid. I never thought to look to the bottom of the page. I've never seen footnotes denoted in this fashion and I thought this was some kind of photo tech speak that I was not familiar with. Thanks for picking up on it and pointing me in the right direction.

lowkick Loc: Connecticut

Thanks.

lowkick Loc: Connecticut

Let me ask you a question about this 1.4x teleconverter. The footnote says, "*6 When it is attached to cameras that are compatible with AF at F8,focus accuracy is not ensured on the telephoto side at the focallength scale more than 200mm."

I'm using it with a Canon 7D MII, and the teleconverter was sold as being compatible with that camera and the 100-400 Contemporary lens. I understand that the use of the converter costs me 1 stop, but the lens itself is f5-f6.3, so with the converter it would be f8-f9 at the 400mm end.

If the 7DII is compatible with AF beyond f8, which it is, does that mean that footnote 6 doesn't apply to my situation?

MT Shooter Loc: Montana

The 7Dii is AF compatible to F7.2, effectively, as I recall. Not sure at what focal length the 100-400 goes past F7.2 but I would guess around 270mm or so with the TC. In general it is never a good idea to use a TC on any variable aperture zoom lense.

lowkick Loc: Connecticut

Wouldn't that mean that advertising the 1.4 teleconverter as compatible with the 100-400 lens is actually false advertising because it is only compatible through a portion of the lens's range?

MT Shooter Loc: Montana

Hence the *6 qualified. Its PARTIALLY compatible, as clarified by the note.

lowkick Loc: Connecticut

Thanks for your help!

MT Shooter Loc: Montana

Anytime

SuperflyTNT Loc: Manassas VA

What it’s saying is if you have a camera that will focus at f/8 it might not be accurate once you zoom out past f/8. I don’t know Canon but generally most of the better DSLR’s have focus points that will focus at f/8 but usually the number is limited.

All that being said I don’t think anybody has been able to tell you why you can’t get smaller than f/9.