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Most digital single-lens reflex cameras (digital SLR or DSLR) are digital cameras that use a mechanical mirror system and pentaprism to direct light from the lens to an optical viewfinder on the back of the camera.

The basic operation of a DSLR is as follows: for viewing purposes, the mirror reflects the light coming through the attached lens upwards at a 90 degree angle. It is then reflected three times by the roof pentaprism, rectifying it for the photographer’s eye. (Note that the diagram below incorrectly shows a non-roof pentaprism.) During exposure, the mirror assembly swings upward, the aperture narrows (if stopped down, or set smaller than wide open), and a shutter opens, allowing the lens to project light onto the image sensor. A second shutter then covers the sensor, ending the exposure, and the mirror lowers while the shutter resets. The period that the mirror is flipped up is referred to as “viewfinder blackout”. A fast-acting mirror and shutter is preferred so as to not delay an action photo.

All of this happens automatically over a period of milliseconds, with cameras designed to do this 3–10 times per second.

DSLRs are often preferred by professional still photographers because they allow an accurate preview of framing close to the moment of exposure, and because DSLRs allow the user to choose from a variety of interchangeable lenses. Most DSLRs also have a function that allows accurate preview of depth of field.

Many professionals also prefer DSLRs for their larger sensors compared to most compact digitals. DSLRs have sensors which are generally closer in size to the traditional film formats that many current professionals started out using. These large sensors allow for similar depths of field and picture angle to film formats, as well as their comparatively high signal to noise ratio.

The term DSLR generally refers to cameras that resemble 35 mm format cameras, although some medium format cameras are technically DSLRs.

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Canon EOS
Canon EOS Rebel T3 12.2 MP CMOS Digital SLR with 18-55mm IS II Lens and EOS HD Movie Mode (Black)
by Canon
Ranking has gone up in the past 24 hours 448 days in the top 100
4.8 out of 5 stars(221)

Buy new: $549.00 $499.00
91 used & new from $399.00

(Visit the Best Sellers in Digital SLR Cameras list for authoritative information on this product's current rank.)


Nikon D5100
Nikon D5100 16.2MP CMOS Digital SLR Camera with 18-55mm f/3.5-5.6 AF-S DX VR Nikkor Zoom Lens
by Nikon
Ranking has gone down in the past 24 hours 405 days in the top 100
4.5 out of 5 stars(260)

Buy new: $849.00 $699.00
52 used & new from $575.00

(Visit the Best Sellers in Digital SLR Cameras list for authoritative information on this product's current rank.)

Nikon D3100
Nikon D3100 14.2MP Digital SLR Camera with 18-55mm f/3.5-5.6 AF-S DX VR Nikkor Zoom Lens
by Nikon
619 days in the top 100
4.6 out of 5 stars(391)

Buy new: $649.00 $549.00
80 used & new from $429.00

(Visit the Best Sellers in Digital SLR Cameras list for authoritative information on this product's current rank.)

Canon EOS
Canon EOS Rebel T3i 18 MP CMOS APS-C Sensor DIGIC 4 Image Processor Full-HD Movie Mode Digital SLR Camera with 3.0-Inch Clear View Vari-Angle LCD (Body Only)
by Canon
Ranking has gone up in the past 24 hours 450 days in the top 100
4.6 out of 5 stars(401)

Buy new: $699.99 $618.94
35 used & new from $573.00

(Visit the Best Sellers in Digital SLR Cameras list for authoritative information on this product's current rank.)

Nikon D800
Nikon D800 36.3 MP CMOS FX-Format Digital SLR Camera (Body Only)
by Nikon
Ranking has gone down in the past 24 hours 97 days in the top 100
4.5 out of 5 stars(36)

Buy new: $2,999.95 $2,999.00
4 used & new from $2,999.00

(Visit the Best Sellers in Digital SLR Cameras list for authoritative information on this product's current rank.)

Nikon D7000
Nikon D7000 16.2MP DX-Format CMOS Digital SLR with 3.0-Inch LCD (Body Only)
by Nikon
602 days in the top 100
4.5 out of 5 stars(417)

Buy new: $1,199.95 $1,199.00
52 used & new from $999.99

(Visit the Best Sellers in Digital SLR Cameras list for authoritative information on this product's current rank.)

Canon EOS
Canon EOS 60D 18 MP CMOS Digital SLR Camera with 3.0-Inch LCD (Body Only)
by Canon
Ranking has gone up in the past 24 hours 619 days in the top 100
4.6 out of 5 stars(328)

Buy new: $999.00 $899.00
63 used & new from $780.00

(Visit the Best Sellers in Digital SLR Cameras list for authoritative information on this product's current rank.)

Canon EOS
Canon EOS Rebel T3i 18 MP CMOS Digital SLR Camera and DIGIC 4 Imaging with EF-S 18-135mm f/3.5-5.6 IS Standard Zoom Lens
by Canon
Ranking has gone up in the past 24 hours 406 days in the top 100
4.6 out of 5 stars(401)

Buy new: $999.99 $949.00
45 used & new from $840.00

(Visit the Best Sellers in Digital SLR Cameras list for authoritative information on this product's current rank.)

Nikon D5100
Nikon D5100 16.2MP CMOS Digital SLR Camera with 3-Inch Vari-Angle LCD Monitor (Body Only)
by Nikon
Ranking has gone down in the past 24 hours 405 days in the top 100
4.5 out of 5 stars(260)

Buy new: $749.00 $599.00
28 used & new from $479.00

(Visit the Best Sellers in Digital SLR Cameras list for authoritative information on this product's current rank.)
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