I'm thinking of buying entry level DSLR Nikon D3500. I haven't used DSLR before, so I'm not sure if it is a good decision to buy DSLR. I would like to know if with this camera I can shoot portraits with blured background such as on the new smartphones with two cameras. Another thing I want to know if buying DSLR is good for beginners in photography and amateur photographers and is it worth the money.
I'm new in this community, so I'm not sure if this is the right place to ask this question.
If you read the other answers, it should be apparent that the qualities you seek such as (a) better portraits and (b) the desire to have a blurred background ... aren't really one thing, but a combination of many factors.
There are some nuances but the short answer is ... portraits do not require advanced DSLRs (so entry level is fine) but... there are nuances to consider. I discuss these below.
The advantage of the DSLR isn't that the camera is 'better' per se, but rather that it allows interchangeable accessories (such as lenses, lighting, etc.) to create the right conditions in order to capture the results you want.
Much of this is based on the knowledge & skill of the photographer. Buying a more expensive musical instrument doesn't make a person a better musician... learning music and practicing makes a person a better musician. The camera can't propel you forward ... but a camera with limited capabilities might hold you back.
If I buy a better guitar than anything Peter Frampton uses ... I will still not be a better musician than Peter Frampton (nowhere even close). His knowledge and skill in that area of music is legendary and mine ... not so much.
Better portraits
We're getting into a subjective area, but flip through portraits you like and try to notice why you like them. Inspect the posing of the model, the composition of the frame and how foreground or background elements are used. Check out the lighting (especially check out the lighting).
My personal thoughts are that:
The above is my priority list. A different photographer might give you a different order. I don't get to hung up on brand names or equipment. Loads of companies make fantastic cameras. It is possible to select a camera that may not be ideal for a particular type of photography ... and it is possible to select a lens that isn't ideal.
Blurred Backgrounds
Ultimately the ability to have one thing in sharp focus and another thing far out of focus (to make that thing blurry) is based on an idea called the Depth of Field (you'll often see this abbreviated as DoF).
If my subject is 10 feet away and I point the lens at the subject, we'll need to focus the lens on the subject. In reality we are adjusting the focus for a 10 foot distance. If something is not precisely 10' away... suppose something is 9'11" or 10'1" -- will being fractionally nearer or farther make a difference? Probably not when you consider the ratios... 10' = 10 x 12 inches or 120 inches away. So a 1" difference works out to a difference of just 0.8% (not even 1%). But what if a lens was focused to 10' and something else was 100' away... now the difference is more significant.
DoF is the idea that there's a range of distances at which you will judge the subject to be ... more or less ... acceptably focused (I didn't say perfectly focused). How you judge this will also be affected by how closely you inspect the image.
There are a few factors that ... when added together ... affect the overall depth-of-field.
This include things such as:
Focal length of the lens where short focal length lenses tend to produce much broader depth of field and very long focal length lenses tend to produce much narrower depth of field.
Focal ratio of the lens. The focal ratio considers the size of the physical opening in the lens through which light may pass. But instead of being a simple diameter ... it is expressed as a ratio of the lens' overall focal length divided by that physical diameter. If a lens with a 100mm focal length has an aperture opening 50mm across than that lens has a focal ratio of 2 ... since 100 ÷ 50 = 2. That would be expressed as f/2 (the 'f/' is short-hand for focal ratio). If we adjust the opening so that it has a diameter of 25mm then the focal ratio becomes f/4 because 100 ÷ 25 = 4. One take-away is notice that the lower-focal ratio example (f/2) had the larger physical diameter opening in the lens (50mm opening on a 100mm lens). If the lens had a very tiny opening (a pin-hole) then all the light has to pass through just that one very tiny point. Such a lens would have and extremely large depth-of-field. If you use a lens with a very large opening, the photons have a choice of many different paths through the lens. This reduces the overall depth-of-field.
Subject distance is another factor. If a subject is very far away a lens needs to be focused to near the infinity point. Of course everything in the background is even farther ... so also focused to near the infinity point. Since there isn't much difference ... the background seems to be more or less just as well focused as the subject. Foreground subjects might appear blurry. But if the subject were close to you... and the background was quite far away, the background will probably appear to be more blurred. As a photographer I rarely place a subject against a wall for a portrait shoot... unless that wall is extremely interesting and will add to the overall value of the shot. Better to pull them away from the wall so that the wall can fall begins to get farther outside the depth-of-field.
All of these factors have to be combined... each one simply influences the overall depth of field. None of them completely rule the depth of field.
A camera with a long focal length lens using a very low focal ratio and a subject placed somewhat close to the camera with a background placed much farther away ... will result in strong background blur. Doing the opposite ... short-focal length lens, high focal ratio, and a more distant subject ... will produce very large DoF and you won't notice much blur in the background.
Other Considerations for Blur
There is a term used in photography called 'bokeh'. This term refers to the quality of the blur... not the strength of the blur.
Once upon a time, Canon produce a particular 50mm f/1.8 lens that had merely 5 aperture blades inside the lens and these were not well-rounded blades. This means the opening in the lens was a pentagon instead of a circle. As points of light blur, they blur with the geometry of the aperture opening. This means that as pentagons overlap pentagons it created a rather strange effect ... the quality of the blur was not very smooth. It was somewhat jagged ... jittery ... almost nervous looking. It did not evoke emotions of peace and beauty that will add to the effect most photographers were going for.
Canon replaced that lens with a lens that has identical optics (not similar... identical!) But that newer lens has 7 aperture blades instead of 5 and the blades on the newer lens do a bit better w.r.t. to being more well-rounded. This produces a more circular opening and the results in images produce a much better quality in the background blur (the blur appears more smooth).
The lenses are optically identical and they have identical focal ratios. But one lens produce a poor quality blur. The other produces a higher quality blur.
This is what the term 'bokeh' is meant to convey... the quality (over quantity).
This means that even if you combine the conditions such as focal length, focal ratio, and subject distance (relative to background distance) to try to maximize the background blur... it is possible to have a blur ... but a blur that you may not enjoy.
Summary
It's not the camera, it's the lens.
If you want a cheap and good option for shooting portrait pictures, you should definitely purchase in addition to a DSLR, a 50mm f/1.8 "nifty fifty" lens. Do expect to spend $100-$200 for the lens.
50mm is about optimal for portraits, because the relatively long 50mm focal length on crop sensor cameras is long enough to obtain blurred background while being short enough that the distance to the subject need not be excessive.
At 50mm, the kit zoom probably has f/5.6 aperture. A nifty fifty has f/1.8 aperture, which is more than 3x the difference. Three times the background blur with a nifty fifty.
Even an expensive (and heavy and large!) zoom (17-55mm f/2.8, $700-$1000) cannot match a nifty fifty (50mm f/1.8, $100-$200).
Also, the f/1.8 aperture is useful in low light no flash situations: the f/1.8 collects 9.68x the amount of light than the f/5.6 (@50mm) zoom.
Is an entry level DSLR going to shoot nice portrait pictures? By itself, no, absolutely not.
It's easy to make the joke that the camera by itself just sits there and doesn't take pictures at all, being an inanimate object and all. Of course, we know what you actually mean, but there's really some truth to that. A DSLR is by nature a flexible tool, and that includes the flexibility to get bad results as well as good ones. So, in a very real way, whether you get nice pictures is up to you, not the camera.
If you put some time, effort, and brain-power into learning how to operate a DSLR and to understand fundamental concepts about light and composition, you can absolutely get better results with a DSLR (entry level or above) than with a phone camera.
However, if you just want to snap pictures without learning anything or working for each shot, a high-end smartphone is guaranteed to produce results you'll be happier with 99% of the time.
Spending your money on a DSLR (or other interchangeable lens camera) and hoping that that alone will produce good photographs is a recipe for frustration and disappointment.
You say:
Another thing I want to know if buying DSLR is good for beginners in photography and amateur photographers and is it worth the money.
and fundamentally, to answer this, you need to know if you want to actually be a beginner in photography — that is, someone who is starting on the path to something bigger. Do you want to be an amateur in the true sense of "someone who does something because they love it"?
If the answer is yes, then it's probably worth quite a bit of money (and in fact, I'd suggest starting beyond so-called "entry level" cameras — see Are there disadvantages to a prosumer camera for a beginner, aside from cost?).
On the other hand, if you mean "someone who doesn't know much and doesn't care to" (a dabbler, perhaps), then without even knowing your financial situation I can say that no, it would not be worth the money.
Yes, low-end DSLRs can get you nice photos. But it depends a lot on the photographer, not just the camera.
The main thing to keep in mind for blurry backgrounds is the ratio between two distances:
The further the background relative to the subject, the blurrier the background.
Also, the bigger the aperture opens, the more pronounced the effect. The size of the opening is represented by the f-stop. The smaller the number, the wider the aperture (harder to focus). So f/16 will give you a much sharper overall picture than f/4. Much of the time, f/8 is pretty sharp all around, and if your lens can reach it, f/1.8 will give you good subject isolation with a blurry background. But you’ll need to experiment to see what you like.
I had an entry level for years (Canon 550D) and I have taken really good shots on it. Although lenses are important, I would like to enumerate a few other factors (sorted from the most important to the less important) that will influence on your results
The subject: This is by far the most important of all. Your cellphone can make a much better picture than your camera if you point it to the right subject. I have wasted a lot of time taking pictures of not so interesting subjects and thinking about saving money to buy a better camera until I finally discovered that it is a much better investment to spend that money on short travels to parks with view-sights and animals, or neighborhoods with cute streets and interesting people, etc etc.
Light and weather conditions: Remember the park I said you should go? If you really want good results, you should check the forecast, go really early in the morning or maybe after rains, it depends on what you want, but this the right conditions will add the right "life" to your photos
The lenses: You may be in the right place but maybe the right light you want is something that just doesn't occur naturally. Or maybe you want to be much closer to some animal, or to take a much wider picture. For this, you have the lenses. An f/4 outside in a clear day can make really good pictures, but an f/2.8 will let you work under more severe light conditions. However, an f/4 is much lighter than an f/2.8 and this may allow you to make longer journeys. An 70-200mm will make you fell amazed on how much close you can get to some subjects and a 16mm will let you make excellent wide photos. And good lens are forever. They will always do their job and you can sell them well if in good condition. They are an instant change in possibilities: you change the lens, everything changes
How you use your camera and lenses: You have to know your equipment. To know where are the button, the limitations, which possibilities do you have and so on. After upgrading for a better camera, you will feel for a while that you were more capable with your old camera until you get to know your new one
The camera: Finally, the camera. In my experience, a better camera gives you a better ISO, better shutter, more durable components, more functionalities, more photos per second, etc. Not necessarily a better sensor, for example. The better camera will make it easier for you to go further, but if you don't have what I told you above, there will be not a lot of difference in your results.
Best thing I can recommend in order to achieve maturity as a photographer so you finally feel that your entry level camera is limiting you is to go outside and take pictures. Just go out for it every weekend and you will start to understand the places, the lights, your equipment. After that, the day will come where you will know exactly why you need a better camera and what camera you need. And you will probably keep the entry level, because they are good anyway.
A DX sensor has a crop factor of 2/3. You are presumably talking about the 18-55mm kit lens. For portrait work, you'd likely use it at its long end, giving you about 83mm equivalent focal length with an aperture of 1:5.6. That will give you the same depth of field as an 1:8 aperture setting on a 35mm film camera with the same kind of effective focal length which is quite discernible but not terribly strong. You'll want to arrange your scene appropriately so that the background is indeed some distance away.
The computational blurring on a smartphone aims to emulate the visuals of quite smaller depth of field, namely larger sensors/aperture. If your viewing device ends up being a smartphone, you'll not likely be able to appreciate the much more natural action of optical object isolation (but due to camera and lens parameters, more subtle) over computational approaches, particularly since the small display scale increases the perceived depth of field.
If you are going for print, things will look different already, however.
Is it worth the money? It depends on your purpose. If you don't intend to throw further money at the problem of doing portraits (namely buying a suitable prime lens or a less basic zoom lens), you'd likely be better off with a 15-year old Sony DSC-R1. It has about the same sensor size, goes to 120mm equivalent at 1:4.8 aperture. Its age has definite implications for handling (no image stabilisation, so tripod wanted), speed, storage media, convenience, autofocus, sensor resolution (10MP) and sensitivity (ISO400 is where noise starts) and so on. But for your principal criterion of a small depth of field at reasonable image quality in portrait situations, it will deliver more than the D3500 with a kit lens, but you will be left without an upgrade path.
Of course, analog cameras will deliver effortlessly in that category at quite cheaper secondhand prices but handling film is a hassle in comparison. Even if you do want to end up using film, learning your photographic skills using digital first is going to save you a lot of time and money.
To summarize: you want to throw money at a problem. The direction you are planning to throw it in is a good starting point but you'll need to throw more in that direction before achieving your goals. Partial goals may be achieved cheaper by throwing in a different direction first and thus getting a good idea how and where to throw larger wads of money for best effect at some later point of time.
Buying your learning gear preowned often means that as you develop a good idea where you want to be heading for real, the gear retains most of its resale value. Newer gear often is more supportive with regard to getting good results with moderate effort, however.
