Geotagging with YongNuo GPS receiver for Nikon D700 (GP-1 compatible)

I’ve always fancied the Nikon GP-1 GPS on-camera receiver for its ability to directly write geotagging information to a photo, including the Nikon .NEF RAW format, thus greatly reducing the complexity of the post-processing workflow involved when using an off-camera GPS logger like the Holux-M241. The Nikon GP-1 still costs around USD 200 which IMHO is a bit overpriced.

Off-camera vs. on-camera GPS for geotagging photos

An on-camera GPS receiver talks directly to the camera using a connection cable and writes the GPS data to the photo when it’s taken. Typically, an on-camera GPS receiver doesn’t have its own power source and is powered by the camera’s battery.

Off-camera GPS means that there’s no direct connection between the camera and the GPS logger. An off-camera GPS logger logs your current position in regular intervals to an internal storage. That’s why they’re called GPS loggers. Many units are capable of storing several days of data even when they’re set to log the current position every few seconds. Using off-camera GPS loggers involves a post-processing workflow to store the GPS information in the photo’s metadata (EXIF header). Off-camera GPS loggers always have to use their own battery.

Yong Nuo (or YongNuo) GPS receiver N-918

I wasn’t ready to shell out 200 bucks for the Nikon GP-1. Instead, I had a look at the on-camera GPS units offered on eBay and the most listed, Nikon GP-1 compatible models are the YongNuo N-918, the JJC JC-36, and the Phottix Geotagger One GPS. According to the description, they’re all compatible with the Nikon D3, D3X, D200, D300 and the Nikon D700. I decided to go for YongNuo’s GPS unit because, at least judging from the images, it appealed most to me visually. Not a very sophisticated approach I know, but due to the lack of technical data that was all there was left.
It also carried the lowest price tag: USD 105 including free shipping from Hongkong to any common destination.

The N-918 comes with a wired remote control that can be plugged into the side of the N-918 GPS unit. The remote features a hold mechanism for bulb exposure.

On the outside, the N-918 looks well built. It has a green LED on top that indicates whether GPS data is received or not. A fast blinking (3 times a second) LED indicates that there’s no GPS signal. A slow blinking LED (once a second) indicates the unit is receiving GPS data. The N-918 has a data cable that has to be plugged into the 10-pin terminal on the Nikon DSLR camera. Once it is connected, the N-918 just works like the original Nikon GP-1. Fortunately, there’s an alignment mark on the plug so plugging it in is a quick and easy job.

Be prepared to wait at least 40 seconds until you gain an accurate position fix before you shoot your first photo after switching the camera on. Once the camera is on, the GPS signal is tracked continuosly, unless you enable the “auto meter off” option in the GPS menu. I looks like the GPS unit goes to some kind of hot standby mode if the “auto meter off” option is enabled as it only takes a couple of seconds to regain a position fix. Enabling this option saves a ton of battery life but don’t expect to get a dead accurate position fix within the first few seconds after re-activating the exposure meter, especially if you moved away from your previous position in the time between. The N-918 showed pretty much the same accuracy as my Holux M-241 off-camera GPS logger. As usual with GPS devices, tall buildings will have a negative effect on accuracy.

The LCD on top of the camera and the one on the back indicate if a Nikon-GP 1 (-compatible) GPS unit is connected.

In the GPS menu of the camera, the last position and the current UTC from the GPS satellites time are displayed. You can choose to automatically sync the camera to the GPS time in the menu.

Just like the Nikon GP-1, the YongNuo N-918 doesn’t have an internal compass, thus no heading is provided. If you’re looking for a GPS unit that provides heading information, you may want to have a look at Easytagger.

As with the competition, the built-in flash is unable to fully pop up as it’s being blocked by the GPS unit mounted on the hot shoe.

Uncovered internals

I was unable to determine what GPS chipset was used in the YongNuo N-918. Both, the antenna and the GPS controller don’t have any markings on them. I wasn’t not too impressed about the soldering job of the cables on the circuit board but the rest looks okay.

Verdict

For half the price, the YongNuo N-918 offers everything the Nikon GP-1 does. The communication between the GPS unit and my Nikon D700 works flawlessly, in fact, the N-918 operates the same way the GP-1 does. Accuracy in the open is up to standard but don’t expect any GPS device to be 100% accurate amongst tall buildings because it just doesn’t “see” enough satellites. There’s one quality issue with the YongNuo GPS unit: The data cable plug can’t be tightened to the camera’s 10-pin terminal. There’s something odd with the thread on the plug. Fortunately, the plug attaches securely anyway just by pushing it in.

The GPS “auto meter off” option in newer Nikon DSLR cameras reduces the power consumption of an on-camera GPS unit. However, just like with any GPS device, the time to get an accurate position fix can be significant.

Further reading

If you want to know more about the slightly more expensive Phottix Geotagger One GPS unit you may want to head over to John Biehler’s blog and read his interesting comparison between the Phottix Geotagger and the Nikon GP-1.

More about the GPS “auto meter off” setting found in Nikon DSLRs. They also sell their own Nikon compatible GPS unit at a reasonable price and it seems they know what they’re talking about.

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