Sony a7 vs Nikon D3100

This is a full comparison between the cameras Sony a7 and Nikon D3100. We compare them by looking at the categories you see below.

Manufacturing

Sony a7 is manufacturered by Sony but Nikon D3100 is from Nikon. Both Sony and Nikon are well known brands though.

Sony a7 were released 2013 and Nikon D3100 was released 2010. That is a 3 years difference. In tech, this period can be of interest since technology is always improving, etc.

Camera Released
Sony a7 2013
Nikon D3100 2010

Type of camera

Sony a7 is a Mirrorless camera while Nikon D3100 is a DSLR camera. More information about their differences will come soon.

Sensors / crop factor

These cameras have different sensors. Sony a7 has a "Sony Full Frame"-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 a7 50 mm
Full-frame sensor
No crop factor/focal length multiplier
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 a7 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 a7 24 MP
24000000 pixels
6000 x 4000
Nikon D3100 14,2 MP
14155776 pixels
4608 x 3072

Sony a7 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 a7 has a larger ISO-range than Nikon D3100. Sony a7 has an ISO range that stretches from 100 to 25600 while Nikon D3100 has 100 to 12800.

Camera ISO Range
Sony a7 100-25600
Nikon D3100 100-12800

Autofocus and lens compatibility

There is a big difference between these two cameras. Sony a7 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 a7
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 a7 can shoot up to 5 pictures per seconds and Nikon D3100 can shoot up to 3 pictures per seconds.

Camera FPS (Frames per second)
Sony a7 5
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 a7 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.

Nikon D3100 weighs 505 gr (equal to 1.11 lb) which is 7% heavier than Sony a7 and its 474 gr (or 1.04 lb).

Camera Weight
Sony a7 474 gr
1.04 lb
Nikon D3100 505 gr
1.11 lb

Sony a7 vs Nikon D3100 Specs

Below you will find the complete and detailed technical specs for both Sony a7 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 a7
Nikon D3100
Name Sony a7 Nikon D3100
Manufacturer Sony Nikon
Release Date and Price
Sony a7
Nikon D3100
Release Year 2013 2010
Release Date 2013-10-16 2010-08-19
MSRP 1699 USD 699 USD
Buy it today
Camera Type
Sony a7
Nikon D3100
Camera Type Mirrorless DSLR
Sensor
Sony a7
Nikon D3100
Sensor Size Full Frame (approx 36 x 24 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 X EXPEED 2
Image
Sony a7
Nikon D3100
ISO Range 100 - 25600 100 - 12800
White Balance Presets 10 12
Custom White Balance Yes Yes
Image Stabilization No No
Image Stabilization CIPA Rating 0 stops 0 stops
Uncompressed format RAW RAW
Optics & Focus
Sony a7
Nikon D3100
Autofocus Motor Yes No
Autofocus Contract Detect (sensor)
Phase Detect
Multi Area
Center
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 117 11
Lens Mount Sony E

See Compatible Lenses
Nikon F

See Compatible Lenses
Focal Length Multiplier Full frame
No multiplier
Example:
24 mm remains 24 mm
50 mm remains 50 mm
100 mm remains 100 mm
200 mm remains 200 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 a7
Nikon D3100
Articulated LCD Tilting Fixed
Screen size 3” 3”
Screen dots 1230000 230000
Touch screen No No
Screen type Xtra Fine LCD TFT LCD monitor
Live view Yes Yes
Viewfinder Type Electronic Optical (pentamirror)
Viewfinder Coverage 100% 95%
Viewfinder Magnification 0.71× 0.8× (0.53× 35mm equiv.)
Viewfinder Resolution N/A N/A
Photography features
Sony a7
Nikon D3100
Frames per second 5 fps 3 fps
Minimum Shutter Speed 30 seconds 30 seconds
Maximum Shutter Speed 1/8000 seconds 1/4000 seconds
Built-in Flash No Yes
Built-in Flash Range N/A 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 a7
Nikon D3100
Video recording Yes Yes
Video format MPEG4
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 a7
Nikon D3100
Memory Card Memory Stick Pro Duo
SD/SDHC
SD/SDHC
Connectivity
Sony a7
Nikon D3100
HDMI Output Yes Yes
Microphone Port Yes No
Headphone Port Yes No
Wireless Yes
Built-In ( with NFC and wireless control via PlayMemories Mobile app)
Yes
Eye-Fi Connected
Remote Control Yes (wired) Optional
GPS No Yes
Optional
Body & Dimensions
Sony a7
Nikon D3100
Enviromentally sealed Yes No
Battery Battery Pack Battery Pack
Battery Details NP-FW50 lithium-ion battery and charger
Lithium-Ion EN-EL14 rechargeable battery & charger
Battery Life (CIPA) 340 shots N/A
Width 127 mm 124 mm
Height 94 mm 96 mm
Depth 48 mm 75 mm
Weight 474 gram 505 gram