I'm looking to upgrade from my Nikon 1 V2. The most challenging shooting situation I regularly face is taking videos and pictures (emphasis on videos) at my daughters' gymnastics competitions. They are indoors with mediocre lighting, and to photograph a vault or tumbling at just the right moment needs fast shutter. I'm not happy with the faster lens options on the Nikon 1, so I'm considering switching to the Panasonic G7. I thought to pick that one because it's said to be great for video (which is still the main thing I share from meets), the available 14-140mm f/3.5-5.6 lens ought to cover the range I need, and I hear good things about its ability to focus quickly and track. And camera and lens would fit into the approximate $1000 budget I'm aiming for.
What are some faster lens options for the G7 that I should consider? Maybe step down to the 14-42mm kit lens, and use the difference to invest in a fast 45mm prime? Am I correct that if my end product is an HD video, that the 4K video on the G7 gives me the option to shoot with a wider lens than I need, and still extract full HD-resolution video by cropping?
Thanks all!
I don't think I can answer most of this, but I'll say that you can usually get by with a much slower lens for video than stills. The reason is that some motion blur is acceptable in video, while, for stills, your goal is usually to stop motion.
From your post, it's not clear to me if your need for the fast shutter is for video or for stills. For video, it's generally recommended that you use a shutter speed double the frame rate. So, for 24p or 30p, you generally want to use 1/50s to 1/60s. For 60p, you generally want to use 1/120s. You can go faster than this if you want (for sports, for example), but only you can evaluate how the shutter speed affects the look of your video.
For video, with some gymnastics events, I think 24p or 30p video is actually fine. And with these, you usually use 1/50 or 1/60s shutter. But the issue is that perhaps with an event like vault, you may (or may not) want to shoot 60p with a 1/120s shutter, depending on the speed of the movement. 60p generally helps with very fast movement. I really have little experience with gymnastics events, so I don't know if 30p would be acceptable or not. And the G7 doesn't shoot 4k/60p (no other consumer camera except for the upcoming GH5 does either), so if you wanted 60p, you'd have to shoot 1080/60p.
You can absolutely crop the 4K video to 1080p or something between 4k and 1080p (and possibly downscale to 1080p afterward). I do it all the time.
But if you shoot 4K video at the recommended shutter speed, while it may look fine as a video, I'm not sure extracting frames from this would make good still images. There might be too much motion blur. The G7 does have a 4K photo mode, which usually has a faster shutter speed, allowing you to extract still frames from it. But it might not work well as a video.
If you want to use 1/50s or 1/60s shutter speed for video, a relatively slow lens like any of the f/5.6 zooms may work fine. If you want to stop motion at 1/500s (for either video or stills), you're likely going to need a fast lens. I would probably go f/2.8 or faster.
As an aside, regarding focusing, I might consider doing manual focus in video for events like BB and bars because you might be able to get the whole area in focus. For events like vault and floor, perhaps AF would be better. Again, I don't have much experience with this particular sport, so I can't say for sure. But I often decide manual focus vs AF depending on how much ground the person is expected to cover. If you're taking video of someone just swinging a bat or a golf club, there's generally no need for AF as you can get the whole area you need in focus without the need for switching focal points.
p.s. Panasonic cameras generally AF better in 1080p modes than 4K modes. That's likely to change with the GH5, but it's something to consider.
