Bluetooth GPS Receiver AK-4N for Nikon DSLR In Review

With the compact Bluetooth receiver from Aokatec, camera-internal geotagging can be done without cables. Together with a Bluetooth GPS receiver, the module connected to the Nikon D300 for testing.

AK-4N on the Nikon D300

The 10-pin connector connects to the Nikon D200, D300 (s), D700, D2x, D2xs, D2Hs, D3 and D3x cameras as well as the Fuji S5Pro GPS receiver. This makes internal geocoding possible with “right” cameras. Not just like previous tests on camera phones.

The solutions offered by Nikon (MC-35 or GP-1) are cable-based and therefore not really handy in use. Especially with the MC-35 adapter cable it quickly turns into a tangle of cables.

Aokatec wants to do better here. The connection to the GPS receiver is made using Bluetooth. The AK-4N module to be connected to the camera is small. 26mm x 18mm x 12mm the manufacturer indicates.

The GPS module occupies the accessory socket. These also connect the remote control of the shutter button. Therefore, the existing remote control cable can not be used together with GPS recording. There is a small jack socket available. For this purpose, however, a new, to Canon cameras (1000D, 500D, 300D, …) compatible trigger cable is needed.

Technical specifications:

• Range: 10 meters
• Pair time for first: 30 seconds
• Time to connect: 3 seconds
• Transfer rate: 1 record per second
• Average power consumption: 10mA
• Price: about 100 EUR

Bluetooth GPS receiver

Fortuna Clip-On and AOKA AK-4N

With the purchase of the camera-side receiver, but it is not done. You also need a GPS receiver that sends the received satellite data via Bluetooth. Previously, these devices were often used to navigate PDAs from Palm. I still have a Fortuna Clip-on GPS Bluetooth mouse. I use this for this test. A disadvantage of two independent systems are two separate batteries. As a user, you now have to monitor both the battery of the camera and the battery of the GPS receiver. That’s not a problem with the camera. But with the logger, which is usually stored in a bag, that can be problematic.

Pairing the triad

Nikon D300 GPS display

Here I was absolutely positively surprised. GPS mouse placed on the window and turned on. Insert the BT receiver into the accessory socket. Turn on the camera. After a short wait; significantly shorter than the 30s indicated by the manufacturer, the GPS symbol flashed on the display of the D300.

Sign that there is a connection to the GPS but no valid signals are yet to be delivered. The receiver also masters the BT pairing with code (0000) of the Fortuna GPS mouse. A short time later, GPS reception was also present and the display changed to a continuous signal.

GPS settings on the D300

 Nikon D300 system menu GPS

The submenu GPS is available in the system menu.

Nikon D300 GPS hibernation

Hibernate mode allows you to select whether the light meter should go to sleep after a certain period of time (ON) to save power or whether it should be disabled when the GPS receiver is connected (OFF). Meaning makes hibernation in my opinion only if it is a directly connected GPS device. The Bluetooth GPS mouse receives here even with the camera off satellite data. In this case, after a restart (regardless of whether it is from idle state or switched off), only the BT radio connection must be rebuilt. The lengthy GPS fix is ​​eliminated. The additional power consumption by the AOKA receiver is low.

Recommended setting: Sleep ON

Nikon D300 position

Another menu item is Position. This is only active when the GPS receiver is connected. Latitude, longitude, altitude, compass bearing and UTC (world time) are displayed here.

Aokatec has dispensed with a compass despite the defined mounting position on the camera. Therefore the bearing field remains empty. An improvement for the next version?

test round

This variant had to complete the 13 km test. Even if no recorded track comes out. You can already see that the card looks a bit “naked”. Since the test candidate does not output a track, I have also decided not to include the Garmin reference track. Due to the missing track, no presentations are possible, as shown in the geotagging book starting on page 77.

The positions on the map should not decide on the quality of the AK-4N. After all, this one is not responsible for GPS quality. He passes only the data to the camera which he gets from the Bluetooth GPS receiver. The position quality depends solely on the quality of the BT mouse used.

Practical test during city sightseeing

In addition to the standard round I tested the AK-4N extensively during a city tour in Munich. In the course of this city tour photos were taken, as is usual for a traveler on vacation. Attractions from the outside, visit of churches and museums.

At the end of the tour, the disillusionment came. Only about 60% of all images had geo information in the Exif data. Many pictures from churches, but also some outdoor pictures did not contain any data.

Here is a logger clearly in the advantage. Although the track breaks in buildings. By interpolation of the downstream software, it is possible to determine missing positions at least approximately. From my experience with loggers, I know that this always works quite well for churches or museums. The image inside is assigned to a coordinate near the entrance. Not perfect but still better than no position.

As an improvement, the manufacturer should think about saving the last position. This can then be used until a current position is available again.

During the city stroll, the receiver also once slid out of the camera jack. Luckily, this happened near the camera bag. The AK-4N then fell back into the bag. From other users I’ve heard of lost modules while hiking. Why did Nikon thread the accessory jack? An improvement for the next AK-4N version should include a mounting option for this thread. Or at least one kind of safety line.

Recorded Exif data

Of course, the camera can write the supplied GPS information in JPG, TIF and RAW files. The recorded data goes beyond mere position information. Here is an excerpt from an internally georeferenced picture. Read out using GeoSetter.

Exif data with GPS information

Conclusion AK-4N

The enthusiasm of quick and easy coupling quickly gave way to disillusionment. If there is no GPS signal when recording, you have no chance to install the position later. But the worst thing I felt was that the receiver could easily slip out. You always have a bad feeling. Is he still there? And with new devices, plugs are always tighter. How should that be later? Also I appreciate the possibilities which a track offers for the presentation of the pictures. This path is missing here.

I can only recommend this option of geo-imaging to landscape or nature photographers who have secure GPS reception and do not need tracks. All others are better served with a cheap logger and some rework on the computer.

I like that:

• No rework on the computer
• No danger to the image data. The entry is made 100% according to the specifications of Nikon
• Deviations between GPS time and camera time are irrelevant

I do not really like it that much:

• In addition, a Bluetooth GPS receiver is needed. Surcharge about 40-50 €
• In addition to monitoring battery of the GPS receiver
• Danger of losing as there is no possibility of security
• Flash correction button difficult to access when the module is plugged in
• No track for additional presentation options
• If no GPS reception, then no position; no interpolation or storage of the last position
• Existing cable releases can not be used.

[Update 23.04.2012]

The AK-4N version for the 10-pin Nikon accessory socket is no longer available. There is now a version for the USB socket of the Nikon D90 or D5000. New is the storage of the last position before the demolition of the GPS signal when entering buildings. The AOKA AK-N90 costs about 100 euros. Due to missing camera I can not test this Geotagger myself.