Fast lenses for night action shots

rlx wrote:

Wow. I like that dance video!

Super!

For a long video sequence of a 2m tall frame I would try a manual f/1 lens. The focal length is your choice. The focal length has no effect on the DOF if one keeps the same framing (but the distance to the subject changes). Of course the background looks more blurry with the longer lens.

I know these are going to be 2 very stupid questions, but...

1) If we are talking about framing, why are we talking about apertures rather than focal lengths? I would think that focal length is crucial to determine how to fit a 2m tall person into my shot, while aperture is just about lightning and how blurry I want my background to be.

2) If background looks more blurry with longer lens, why do you say that focal length has no effect on DOF?
Isn't blurry background = shallow DOF? Or am I missing something?

For short video sequences or stills I would try an AF lens with AF-C wide or zone tracking or AF-S if you can use backbutton focusing and keep the focus on your moving subject up to date. I feel manual would do but with fewer keepers and a bit more work.

For short video sequences or stills I would try an AF lens with AF-C wide or zone tracking or AF-S if you can use backbutton focusing and keep the focus on your moving subject up to date. I feel manual would do but with fewer keepers and a bit more work.

Oh yes, I didn't use AF-C with tracking last night and I highly regret it.
On my next post I'm going to post some of the pics I took and one of the take-aways is that I need to study the AF system of my camera better