Perfect lens

The Sigma ART 105/1.4 lens - which I consider to be an optical masterpiece - works very well on my Canon EOS 1V HS camera from year 2000.

There was the thought of that perhaps the AF isn't working too well, because it is a brand new lens but an old camera. Especially when we speak about autofocus and a third party lens maker, things can sometimes go erratic. Or even malfunctioning. But it didn't.

The lens has perfect AF behavior - and the Fuji Acros 100 reveals perfect sharpness even when the lens is used wide open at the extreme aperture of ƒ 1.4. It really is an achievement. For me, the lens is the "replacement" for the Canon EF 85/1.2 L II lens.

I never had that lens, Daniel had it. And my other EF 85/1.8 USM lens I gave to Sal daughter Carla, so that she would enjoy a really bright lens (compared to her slow zoom). But ever since, I kind of missed a real portrait lens. I had the funky EF 50/1.2 L and the excellent EF 135/2 L - which for my taste is a bit too long for portraits.

 

Filling an important gap

So, not until recently I finally filled the gap with the Sigma ART 105/1.4 lens. It is of course huge. Like really really huge. But due to the excellent AF and optical performance - it is a simply stellar lens. And doesn't have any of the drawbacks the classic Canon EF 85/1.2 L II has. Fringing is less, sharpness is higher, and AF is very consistent.

 

Managing the funky AF with Canon EF 85/1.2 L II lens !

The Canon EF 85/1.2 L II is not so stellar in that regard. You have to activate the single AF point in your Camera, several times and listen to the AF behavior. If it "settles in" - then you can take a photo and likely hit the right sharpness.

But if you use it by just shooting right off, then you will have a lot of inconsistent AF behavior. Sometimes your images will get slightly back focused, sometimes front focused. Which at aperture ƒ1.2 means everything. Slightly misfocus ruins the entire photo, because the depth of sharpness is extreme shallow.

The only way to get around it, is to activate the shutter button and pre focus your subjects several times (at exactly the same spot) and listen to the AF until it "settles down", e.g. the AF isn't correcting it's position anymore: Then you get a better keeper rate. At least that is my experience with the Canon EF 85/1.2 L II lens.

You have to use single point AF !