What are some of the best DSLRs to buy under ₹30,000 ($500)?

In that price range, and even a bit more, Pentax is easily the best performing DSLR.

Pentax is somewhat of a sleeper DSLR (sleeper meaning that it performs much better than public opinion. Kind of like an beat up car with a 600 HP engine under the hood) in that they have great performance and features, it's just that they have no where the marketing campaign of Canon or Nikon, so they are often overlooked. Because of Canon and Nikon's massive marketing budgets, and the fact that they're both the most used DSLR by professionals, people falsely believe that since Pentax or Olympus, or Sony aren't being used by pros that they're somehow inferior or not good enough. When in fact, there's the beginning of a movement away from DSLRs to mirrorless by pros who primarily do portraiture or commercial work where the auto focusing speed of a DSLR just isn't a requirement. Photojournalists, sports and wildlife photographers are a few types that will need to go with a DSLR, but may find the need to add a mirrorless to their arsenal for certain jobs such as when shooting in low light hand held. Some mirrorless cameras like the extremely popular Sony A7R II, are very useful for low light work because they have 5-axis in-body image stabilization that allows for using shutter speeds that are literally impossible with a DSLR. Plus they're rather inconspicuous which allows the photographer to be hidden to have less of an affect on what's going on.

So with that in mind, you have a few options:

In mirrorless, take a look at the Sony A5100 and A6000. Both are very good cameras offering all of the capabilities and features of a DSLR, but with some added features only found on mirrorless. They're smaller and lighter. The big deal with these cameras is that you can use any lens from any brand via lens adapters. This is one of the reasons they're so popular with pros because a pro can just buy the body and an adapter to use their current set of glass without having to invest tens of thousands in a new lenses. Again, the only down side is that they're not so good for sports or fast moving subjects.

In the DSLR market, the Pentax K-50 has the best specifications of any entry-level DSLR. Compared to the Canon T series (T4, T5, T5i, and T6), and to Nikon's D3xxx series, the Pentax K-50 has a faster AF system, faster shutter speeds, and faster continuous shooting. All Pentax DSLRs are weather and dust proof to a very high standard. Canon and Nikon does have weather sealing but only in their upper end cameras. Even so, C/N weather sealing isn't anything like what you'd find in a Pentax. Go to an electronics expo and you'll often see at the Pentax both a fish tank with one of their DSLRs weighted down at the bottom fully functional; they're that good.

Probably the biggest advantage that Pentax has over C/N is their in-body image stabilization (IBIS). This allows you to shoot 3.5 stops lower ISO or slower shutter speeds than a DSLR without any kind of stabilization. Canon and Nikon put their stabilization inside their lenses, so you must buy specific lenses, and not all of their lenses have stabilization. With IBIS, every lens you use is stabilized, even $20 used lenses from the 70s.

Between the three, Canon does have the best video capabilities, especially if you add the Magic Lantern firmware upgrade. But for stills, the Pentax K-50 with it's advanced features, incredible build quality and super-ease of use, it is the best DSLR at the sub $500 price point.

Pentax K-50.

There are very few.

The Pentax K-50 is probably the best camera in its class on paper, but may be just outside your budget.

Fortunately for you, dpreview.com has a list of cameras in your price range and a brief review of each of them.

http://www.dpreview.com/reviews/2016-round-up-inte...

Of those, I would pick the Olympus PEN E-PL7.