So I've decided to take a step up for my film making , thats why I'm looking for a good camera especially for video.
Canon 1300d (t6) / nikon d3500 / dji osmo x3 ?
Which one of above is good for shortfilms , travel videos , slow motion etc ?
Note that I have no experience with any of these cameras, but I hope my thoughts can be useful regardless.
What type of content am I making? You already know you want to make travel videos and short films, as well as being able to shoot in slow motion... So personally, I would choose the camera that has the best portability, that allows maximum creative potential (more on that in a second), and can shoot at high frame rates.
What camera will allow me to best express my creativity? If you love gimble shots, then the Osmo is your only choice here. But if you prefer Depth of field and the looks you can get with various lenses, then go for one of the DSLR options. If you want the slowest slowmo possible with the options you have, then (according to my brief research) the Osmo will get you to 120 fps while the other two only go up to 60.
Do your research!!! Look at as many reviews and as much test footage as you can. Pay attention to the features and limitations of each model (each of them have pros and cons). Find out what accessories you'll need to get (and how much they'll cost). If at all possible, see if you can test the same or similar models. Figure out what you'll need to do regarding audio (you'll almost certainly need additional audio equipment for any of these models)
Narrow down your options. The biggest decision you'll have to make is between Osmo-style filmmaking and DSLR-style filmmaking. If it comes down to the DSLRs, it seems to mostly come down to your preference between Nikon and Canon as (at least on the surface) they seem like a pretty even match (once again, do your research!)
My personal pick would be one of the DSLR options because that's the type of filmmaking I do. You may find that the Osmo is better for your needs. All of them look to be decent cameras for their price and target markets. In the end, it's up to you and what you want and need most.
@triforcefx gives good advice.
One factor he didn't mention is variety of shots. The DSLR's take external lenses. You'll be able to (eventually) buy lenses from fisheyes to superzooms. With the Osmo the lens you have is the lens you have. I'd say, if you go the osmo route to go for the Osmo+ for the 3x zoom.
There are other good options in that price range, like the Lumix G7. The Lumix is an MFT camera so, it and its lenses are smaller/lighter than a DSLR.
I'm so confused about this from past few months , i did my research found out that osmo has gimble plus it has 4k and 1080at 120 fps . But these DSLRs just have 60fps not even 4k. I can't decide what to do ?
4k is, to be quite blunt, unimportant and largely something pushed by camera and TV makers to get people to buy new 4K gear.
You might have heard of this little $300 million movie called Avengers: Endgame. Like the rest of the Marvel movies its CGI and mastering was done at 2k. The future 4k home release will be an upsample.
The Osmo may be 4k, but it's tiny little 1/2.3-inch sensor is going to have much less light sensitivity and more noise than the APS-C sensor in the T6. The Canon T6 records 1080p video at 35mbps, while the Osmo records 4k at 60mbps. This means the Osmo is recording four times the pixel resolution in less than twice the data rate. This means OSMO footage is going to have a lot more compression artifacts than the Canon. 120 fps footage at 60 mbps? That's pretty low quality.
I realize this is throwing more confusing technical data at you, but the point is to not get hung up on buzzwords like resolution and frame rate. Resolution and frame rate are not indicators of quality. That's going to rely more on sensor size, lens quality and compression rate.
Again, I recommend you look at the Panasonic G7. It's a bit more expensive than the T6 or Osmo (about $50 USD), but you get 4k recording, an MFT sensor (larger than the Osmo, smaller than the T6) and a 100 mbps bitrate.
So should keep the osmo aside and focus on dslr?
Unless you're absolutely in love with gimble shots, I would focus on DSLR/mirrorless. I agree with @Triem23 that you should look into the Panasonic g7... It is (in my opinion) the premier camera in it's price range. There's always stabilization and gimble options to look at later.
I'd go so far as to say a DSLR/mirrorless camera will turn you into a better filmmaker than the Osmo ever will.
Okay then , I'm going for the dslr !