Yeah man you do round your back as well as start with you ass to high. Get lower to start and take a little bit wider stance. Also on the way down don't do a straight leg deadlift, bend your knees and drop your ass and go back down the same way you came up. You are putting a lot of undue pressure on your lower back.
Hey Mate, In my personal experience with the deadlift, as is mentioned above keep your lower back straight and shoulders back, also i can't really see how wide your stance actually is but it seems to be too narrow. I would personally leave the pride at the door and start lifting at a much lower weight and ensure your technique is absolutely perfect, just my opinion, hope that helps.....
Feet hip to shoulder width apart. You look way narrow.
Where do you feel your feet? You should feel the weight on you heels. Just rock back a bit before lifting. Shoulders might be too far forward. Retract scap. Push through heels, pull shoulders back, hump he bar.
If you are having difficulty straightening your back, your posterior chain is probably really tight. Try adding a PNF hamstring stretch into your warmup. I find a lot of individuals can suddenly really clean up their deadlifts if they just do that. Also, try some donkey kicks and whatever the opposite of that is (I can't remember the name) to get everything at your hip joint warmed up.
Like others have said, your form really needs to be cleaned up. Forget the plates, belt, and straps. You need to practice deadlifting an empty bar until you can do it perfectly, and then start working your way back up.
spread your feet abit more (gives you a stronger base) and arch your back inwards yours was outwards.If yo struggle to arch in just look up the back normally arches to suit then just glimpse the mirro to check your doing it correct.
Notice that when you put the bar down you're basically doing a stiff leg deadlift. You should be trying to emulate the pull in reverse when putting the bar down. Lose the mixed grip with the straps or lose the straps. Really focus on keeping the chest up and the upper back tight throughout the lift. Try and get tighter at the bottom before you lift and squeeze the bar off the floor to try and hold that arch. As for stance width, thats entirely up to how you are strongest, some people pull well from a narrow stance like yours, others prefer wider.
I think it could do with being abit wider as his feet are almost touching giving him a shit base,I can imagine hes fighting balance at the same time. But your right its all personal preference. Yeh lose the straps Ive allways felt its taken half the lift away,as I build alot of my tension through my grip (also personal preference)