Advantages of DSLR:

• Less digital noise at high ISOs
• Faster shutter response (important for action shots)
• True through-the-lens manual focusing for close-ups & extension tubes & viewing action
• Slightly larger F-stops (for a price)
• Shallower depth of field to blur distracting backgrounds/foregrounds (see disadvantages)

Disadvantages of DSLR:

• Larger, heavier, bulkier than bridge cameras.
• Have to buy multiple lenses to get the range of focus
• Have to carry and swap out these extra lenses (camera bag – not just camera)
• Dust is more likely to get inside and on sensor when changing lenses
• Long zoom lenses are larger/heavier/very expensive with less zoom
• Shallower depth of field: harder to get both far and near objects in focus (see advantages)
• Have to be farther from the subject without special lenses (~ 2 feet with DSLR vs 3-5 inches with bridge)
• Shutter speed is limited when using flash
• Loud shutter release
• More expensive than bridge cameras
• Few have articulating LCD screens (this is changing)
• Because of the mirror flop they require a more stable thus more expensive tripod.

Digital Noise

This is the main advantage of DSLRs over bridge cameras.  Digital noise is like grain in film.  The colored specks you see in the image at right are digital noise.  I have deliberately chosen a very noisy picture to show what noise is. This picture was taken at ISO 400 with my older 2006 bridge camera. 

ISO is a number that represents how sensitive the camera is to light.  Said another way, it determines how well lighted the subject has to be to take the picture.  The higher the ISO the darker it can be around you and still take pictures.  On digital cameras you can vary the ISO setting.  If you use a bridge camera at normal ISOs (80-100) you aren't likely to have any problem with noise and it's plenty good for general photography.  But, as you go above 100 the noise gets progressively worse.  At 400 and above you are likely to get poor quality images (This is improving as the years pass). Whereas with a DSLR you can use ISOs of up to 1600 or even 3200+ and still get acceptable quality images. (This information is old, usable ISOs are higher in 2016 and increasing)  If you edit your pictures on the computer, there are programs such as NoiseNinja and others that help remove minor noise.  But, shooting action, such as sports, after dusk is one of the situations where a DSLR with a long lens has a clear advantage over a bridge camera.  And, if it's your intention to shoot a large proportion of your pictures in low light without flash a bridge may not be the camera for you.  That said, I took this shot of my grandniece's ballet recital from the back of a large auditorium with my 2006 bridge camera. 

Shutter Response

There's a delay between when you press the Go button on a camera and when the picture is actually taken. This delay is greater on non-DSLR cameras and people taking action shots are often frustrated by it.  The delay is less today (and still improving) than it was on early non-DSLR digital cameras, but DSLRs are still noticeably faster.  However, there's more than one way avoid this delay when using a bridge camera.  I'll only mention one here.  The delay is due to the camera having to figure out what F-Stop & shutter speed to use and (mostly) where to focus.  Point the camera at the location you intend to shoot and look at the settings the camera has determined (they're usually shown in the viewfinder), change the mode to manual and set the camera to those same values.  Now the camera doesn't have to figure them out, so it shoots about as fast as a DSLR (maybe faster).  If you want to shoot machine gun fashion (shooting picture after picture continuously while holding the shutter release down) the DSLR may (or may not) shoot faster -- maybe 6 vs 4 frames per second.  And, since you're actually seeing through the lens you can follow the action while the shutter bangs away which you can't do with a bridge camera.  Again, if your camera will be used primarily for sports/action photography you may be better off with a DSLR.   In this case I suggest you buy the camera body only, and get the best zoom lens you can afford.  As of 2010 bridge cameras can only shoot JPG images in this mode (called burst mode).

Trough-the-Lens Viewing

With a DSLR you're actually looking at the subject through the lens of the camera.  With a bridge camera you're looking at an image of what the camera sees, also through the lens, on a high resolution monitor in the viewfinder. For the majority of picture taking you won't notice the difference and even forget you aren't looking at the real thing.   But, if you do super close Macro photography -- if you want to fill the frame with a bugs eye -- focus becomes critical and you may want to do it manually instead of letting the camera focus automatically.  In this case you may need to see the real object clearly enough to focus sharply.  Bridge cameras have features to assist with this, but as of 2010 it's not like seeing the real thing.  Also, because you can remove the lens, you can put what are called extension tubes between the camera and the lens to create extreme close-ups.  This said, some truly spectacular macro photography is done with bridge cameras and some people argue it's actually better for Macro photography, partly because of the greater depth of field.  Extreme close-ups have a very shallow depth of field which can become a problem with DSLRs.

Shallow Depth of Field

Depth of field is the distance between the object nearest the camera and the most distance object that are both in focus.  Depth of field is a mixed bag.  Sometimes you want a lot and sometimes you want only a little.   Sometimes you want to make the objects in front or behind the subject go blurry so they don't detract from what you are trying to show.  In this case you want shallow depth of field.  In the picture at the right you can see the tractor and the closest words in the label are blurry. Other times you want everything you can get in focus, in which case you want great depth of field.  Greater depth of field is usually an advantage in Macro photography.  The greater depth of field you get with a bridge camera may compensate for the lack of through-the-lens viewing, because DSLRs have quite a bit less depth of field than bridge cameras making it hard to get that entire bug's entire eye in focus.

Discussion of DSLR Cons

With the bridge Panasonic Lumix DMC-FZ300 (and others) you get a zoom range of of 25-600mm and greater.  (Sony Cyber-shot DSC-HX400V reaches from 24mm to 1200mm.  If you could get such a lenses for a DSLR, which you can't, it would be too heavy to carry.)  To get a 28-500 zoom range with a DSLR you have to buy a wide angle lens and a long telephoto (and one or two more lenses to cover the midrange). A top quality 500mm telephoto from a major manufacturer like Canon can cost $6000 and the lens alone will weigh 8.5 pounds. But, you're more likely to end up with a 70-200mm zoom lens which can cost about $1600 and weighs about 4 pounds.  From a cheap lens maker this lens will cost $900.  Together these make for about 6 pounds of camera and lens. You can get a cheaper lighter lens in 70-200mm range but it won't have an F-Stop advantage over the bridge.  (It's almost certain if you are a DSLR user will never own a lens longer than 300mm.)  To get the wide end of the range 25mm you have to buy another lens.  If you want to get close to your subject (something the size of a Zippo lighter) you have to have a special lens.  All in all you can spend a small fortune on lenses.  Then, you have to carry these lenses with you when you plan to take pictures, and change them as the need changes.  And, when you take the lens off a DSLR you expose the inside of the camera to dust or trash blowing into it, and onto the sensor -- the heart of picture taking with a digital camera.

Whereas with a bridge camera  you can get a zoom range of 25mm-600mm+ all in one complete camera weighing less than 1.5 pounds, for about $450. That's about what the body alone of a DSLR weighs with no lens. And, the bridge camera lens is the manufacturer's lens (the lens on my bridge camera was made by Leica -- the prince of lens makers).   Also, with this lens you can fill the picture with that Zippo lighter.

Another advantage of bridge cameras is they can use flash at all shutter speeds.  This can be a real advantage if you want to present your subject against an all dark background.  An electronic flash is faster than any shutter speed.  This means you can set the shutter speed on your bridge to it's highest setting and the flash will still light the picture correctly.  There are two advantages to this.  1)  If the area around you is lighted, just not enough to take the picture, if you use a slower shutter speed this existing light will partially light your picture and give a ghost image of the surrounds and a blurry ghost image if you move the camera.  This problem is eliminated if you set the shutter speed high.  2)  You often see close-ups of insects or flowers where the background is dark.  This is a nice effect which you can get by using a shutter speed high enough the flash will only light the subject and the more distant background will go dark.  You can't do any of these things with a DSLR.  DSLRs use a special kind of shutter called a "focal plane shutter"  that limits the shutter speed you can use with flash.  I have a recent DSLR and the highest shutter speed that can be used with flash is 1/200 second.  A bridge camera can use it's full range of shutter speeds, as high as 1/2000 second or higher.  This will eliminate the ambient light in any interior shot and many exterior ones.  NOTE:  Some expensive DSLRs have a way to take flash pictures at higher shutter speeds, but it's beyond the scope of this article.

Because DSLRs have to flip up a mirror to take the picture and flip it back down afterward they make a lot of noise when you press the shutter release. This can be very annoying in some situations -- especially when you're trying to be inconspicuous. I remember once I was shooting a picture of a couple looking out at Niagara Falls from an elevated walkway using my SLR. When I tripped the shutter the couple, about 5 feet away, turned and looked at me. They heard it over the distant roar of the falls. The sound made when you shoot a picture with a bridge camera is artificial -- it's deliberately generated by the camera and comes from the speaker. It can be set to silent.  Also, if you are on a tight budget you can get by with a super cheap tripod like this one because there's no mirror flop.  You may have to use the self timer or a remote control or cable release for many shots (so you don't have to touch the camera) there's no reason for it to shake (strong wind gust maybe).  Bridge cameras don't move or shake so, as long as you don't touch the camera, it's not going to move.

It's becoming more common to put articulating LCD screens on DSLRs, but in 2011 many don't, and almost all bridge cameras do. This allows you to point the camera in one direction and see what you're shooting from and entirely different angle. You can shoot around corners, over heads in a crowd, under objects too close to the ground to see through the viewfinder, etc.

I'm 75 years old and have been taking pictures since I was 14 (actually 6, but I was 14 before I got anything more than a box camera). I had a wet darkroom in my home during my forties and have probably read a hundred or so books on photography.  All this isn't to say I'm a hotshot photographer, I'm not, rather it's to explain I'm not a newbie.  If you're going to devote much of your free waking life to photography, and are willing to tote a bag of gear and a tripod everywhere you go then by all means gear up with a DSLR, but before you do, get a good bridge camera and give it a try for a month or three so you'll know what you're really getting for all that pain.