Sony a77 vs Nikon D3100

This is a full comparison between the cameras Sony a77 and Nikon D3100. We compare them by looking at the categories you see below.

Manufacturing

Sony a77 is manufacturered by Sony but Nikon D3100 is from Nikon. Both Sony and Nikon are well known brands though.

Sony a77 were released 2011 and Nikon D3100 was released 2010. That is a 1 years difference. In tech, this period can be of interest since technology is always improving, etc.

Camera Released
Sony a77 2011
Nikon D3100 2010

Type of camera

Sensors / crop factor

These cameras have different sensors. Sony a77 has a "Sony APS-C"-sensor while Nikon D3100 has a "Nikon DX"-sensor, and their difference in sensors will also affect the crop factor and experience focal length. See the table below.

Camera Focal length, 50mm f/1.8 **
Sony a77 75 mm
Sony APS-C sensor
Crop factor/focal length multiplier by * 1.5
Nikon D3100 75 mm
Nikon DX sensor
Crop factor/focal length multiplier by * 1.5

** Experienced focal length when using a lens such as a common "50mm f/1.8"

Learn more about crop factor and focal length multiplier here:
Camera selection can affect the focal length (Sony)
Camera selection can affect the focal length (Nikon)

Resolution

Sony a77 has a 24 MP (Megapixels) resolution while Nikon D3100 has 14,2 MP. If we break down this in more detail this is the data behind the numbers:

Camera Megapixels
Sony a77 24 MP
24000000 pixels
6000 x 4000
Nikon D3100 14,2 MP
14155776 pixels
4608 x 3072

Sony a77 has a 70 % larger resolution than Nikon D3100. This could give you more details in the picture but also a possibility to crop more in the pictures, afterward while editing the pictures, if needed that is.

ISO range

Sony a77 has a larger ISO-range than Nikon D3100. Sony a77 has an ISO range that stretches from 100 to 16000 while Nikon D3100 has 100 to 12800.

Camera ISO Range
Sony a77 100-16000
Nikon D3100 100-12800

Autofocus and lens compatibility

There is a big difference between these two cameras. Sony a77 has a built-in autofocus motor but Nikon D3100 does not. If you want to be able to use autofocus on Nikon D3100 there is a need for having an autofocus motor inside the lens. We really encourage you to look closely at our lens compatibility charts at the links below.

Here is a complete overview of which lenses work with each camera:
Lens compatibility chart for Sony a77
Lens compatibility chart for Nikon D3100

Pictures per second

Depending on what you are shooting the FPS, or frames/pictures per second, can definitely be of interest. Sony a77 can shoot up to 12 pictures per seconds and Nikon D3100 can shoot up to 3 pictures per seconds.

Camera FPS (Frames per second)
Sony a77 12
Nikon D3100 3

Ability to record movies

It is becoming more and more popular to record movies with digital cameras.

In this case, both Sony a77 and Nikon D3100 can shoot movies.

Weight

The weight of the camera can be an extremely important factor, especially if the camera is about to be used, or carried around, for several hours at a time.

Sony a77 weighs 732 gr (equal to 1.61 lb) which is 45% heavier than Nikon D3100 and its 505 gr (or 1.11 lb).

Camera Weight
Sony a77 732 gr
1.61 lb
Nikon D3100 505 gr
1.11 lb

Sony a77 vs Nikon D3100 Specs

Below you will find the complete and detailed technical specs for both Sony a77 and Nikon D3100, next to each other. Each category of data is a link to an article covering the subject, giving you a deeper understanding so you can better understand the strengths and weaknesses of the two camera models.

Product
Sony a77
Nikon D3100
Name Sony a77 Nikon D3100
Manufacturer Sony Nikon
Release Date and Price
Sony a77
Nikon D3100
Release Year 2011 2010
Release Date 2011-08-24 2010-08-19
MSRP 1399 USD 699 USD
Buy it today
Camera Type
Sony a77
Nikon D3100
Camera Type SLT DSLR
Sensor
Sony a77
Nikon D3100
Sensor Size APS-C (approx 23.5 x 15.6 mm) APS-C (approx 23.7 x 15.5 mm)
Also known as "DX"
Sensor Type CMOS CMOS
Resolution 6000 x 4000 pixels 4608 x 3072 pixels
Megapixels 24 MP 14,2 MP
Image Processor Bionz EXPEED 2
Image
Sony a77
Nikon D3100
ISO Range 100 - 16000 100 - 12800
White Balance Presets 8 12
Custom White Balance Yes Yes
Image Stabilization Yes
(Sensor-Shift)
No
Image Stabilization CIPA Rating 0 stops 0 stops
Uncompressed format RAW RAW
Optics & Focus
Sony a77
Nikon D3100
Autofocus Motor Yes No
Autofocus Phase Detect
Multi Area
Selective Single Point
Single
Continuous
Face Detection
LiveView
Contract Detect (sensor)
Phase Detect
Multi Area
Selective Single Point
Tracking
Single
Continuous
Face Detection
LiveView
Focus Points 19 11
Lens Mount Sony A

See Compatible Lenses
Nikon F

See Compatible Lenses
Focal Length Multiplier APS-C Sensor (1.5x)
1.5x multiplier
Example:
24 mm becomes 36 mm
50 mm becomes 75 mm
100 mm becomes 150 mm
200 mm becomes 300 mm
DX / APS-C (1.5x)
1.5x multiplier
Example:
24 mm becomes 36 mm
50 mm becomes 75 mm
100 mm becomes 150 mm
200 mm becomes 300 mm
Screen & Viewfinder
Sony a77
Nikon D3100
Articulated LCD Fully articulated Fixed
Screen size 3” 3”
Screen dots 921000 230000
Touch screen No No
Screen type N/A TFT LCD monitor
Live view Yes Yes
Viewfinder Type Electronic Optical (pentamirror)
Viewfinder Coverage 100% 95%
Viewfinder Magnification 1.1× (0.73× 35mm equiv.) 0.8× (0.53× 35mm equiv.)
Viewfinder Resolution N/A N/A
Photography features
Sony a77
Nikon D3100
Frames per second 12 fps 3 fps
Minimum Shutter Speed 30 seconds 30 seconds
Maximum Shutter Speed 1/8000 seconds 1/4000 seconds
Built-in Flash Yes Yes
Built-in Flash Range 12 meters 12 meters
External Flash Yes Yes
Self-Timer Yes Yes
Time-lapse No No
Metering modes Multi
Center Weighted
Spot
Multi
Center Weighted
Average
Exposure Compensation +/- 5 (at 1/3 EV, 1/2 EV steps) +/- 5 (at 1/3 EV steps)
Videography features
Sony a77
Nikon D3100
Video recording Yes Yes
Video format MPEG4
H.264
AVCHD
MPEG4
Video resolution 1440 x 1080
1920 x 1080
1280 x 720
1920 x 1080
Built-in Microphone Yes Yes
Built-in Speakers Yes No
Storage
Sony a77
Nikon D3100
Memory Card Memory Stick Pro Duo
SD/SDHC
SD/SDHC
Connectivity
Sony a77
Nikon D3100
HDMI Output Yes Yes
Microphone Port No No
Headphone Port No No
Wireless Yes
Eye-Fi Connected
Yes
Eye-Fi Connected
Remote Control Yes (Optional) Optional
GPS Yes
Built-in
Yes
Optional
Body & Dimensions
Sony a77
Nikon D3100
Enviromentally sealed Yes No
Battery Battery Pack Battery Pack
Battery Details Rechargeable NP-FM500H battery & charger
Lithium-Ion EN-EL14 rechargeable battery & charger
Battery Life (CIPA) 470 shots N/A
Width 143 mm 124 mm
Height 104 mm 96 mm
Depth 81 mm 75 mm
Weight 732 gram 505 gram