Probably a dumb post, but for older consoles, is the only way to submit a run done via capture card, or are there any other methods that are acceptable?

Want to casually speedrun a handful of games in my spare time, and don't want to shell out the money just yet for a capture card.

You can point a camera to the screen. That is also acceptable.

If you want to record runs, you could use a camera like SpiderHako is telling you ^^

But games like Super Mario Bros. (NES) is only a video required if you are below a time of: 5:21.00 So for some games having no video is acceptable, and some games accept image proof. (Check the rules to be sure!)