Main
Model
Price
Advantages
launch
Announced
Body type
Camera subcategory
Sensor
Effective pixels
Max resolution
Sensor size
Sensor type
Processor
Image ratio w:h
Other resolutions
Sensor photo detectors
Image
ISO
White balance presets
Custom white balance
Image stabilization
Uncompressed format
JPEG quality levels
Boosted ISO (minimum)
Boosted ISO (maximum)
Photography features
Minimum shutter speed
Maximum shutter speed
Aperture priority
Shutter priority
Manual exposure mode
Subject / scene modes
Built-in flash
Flash range
External flash
Flash modes
Continuous drive
Self-timer
Metering modes
Exposure compensation
WB Bracketing
AE Bracketing
Screen / viewfinder
Articulated LCD
Screen size
Screen dots
Touch screen
Screen type
Live view
Viewfinder type
Viewfinder coverage
Viewfinder magnification
Videography features
Resolutions
File Format
Microphone
Speaker
Videography notes
Optics & Focus
Autofocus
Digital zoom
Manual focus
Number of focus points
Lens mount
Focal length multiplier
Physical
Weight (inc. batteries)
Dimensions
Environmentally sealed
Battery
Battery details
Battery Life (CIPA)
Storage
Storage types
Connectivity
USB
HDMI
Microphone port
Headphone port
Wireless
Wireless notes
Remote control
Other features
Orientation sensor
Timelapse recording
GPS
GPS notes
Samples
Videos
Summary
The D7100 has more number of focus points than the Nikon D3400: 51 vs 11. More number of focus points means less risk of losing focus lock during tracking a moving subject.
The D7100 display is better as it offers more number of screen dots 1,228,800 in compare to 921,000 dots of the Nikon D3400 display. The higher dot count display is better for reviewing images on your camera.
The Nikon D3400 is produced with built-in Wi-Fi which will help the photographer to transfer pictures wirelessly from a camera to a laptop. The Nikon D3400 battery life is better in compare to the D7100 battery life. According to CIPA standards the camera owner will be able to capture 1200 shots with the D3400 and only 950 with the D7100. The Nikon D3400 weighs 395g which is 370g lighter in comparison with the weight of the D7100. The D7100 can utilize optional accessory GPS devices. Recording GPS data can be useful if the camera owner is a traveller, to be able to go into the image metadata and find out exactly where a photo was produced.
Taking into account the above-mentioned differences the Nikon D7100 will become the best choice. Check the lowest price on Amazon.