Pentax O-GPS1 GPS Unit Review

Features
Handling
Performance
Verdict

The Pentax O-GPS1 is a GPS unit that mounts on the hot shoe of the latest Pentax cameras including the Pentax K-5, Pentax K-r and Pentax 645D. It provides standard GPS tracking info that it adds to the exif data of the image, along with a compass and navigational aid, that are viewed on the camera's LCD and an Astrotracer feature to track stars.

Pentax O-GPS1 Features

The O-GPS1 is nothing much to look at - just a relatively bulky box shaped gadget that you slide onto the camera's hot shoe. It's powered by one AAA 1.5v battery housed in a chamber accessed on the right of the unit and has a blue LED light indicating it's on and connected. The battery light blinks orange when its power is low.

Key Features

• Records Latitude, Longitude, Altitude, Time (UTC), Direction
• 50 tracking channels
• GPS accuracy 10m RMS
• Compass with accuracy of ±5°
• Dimensions approx. 49.0mm (W) x 33.0mm (H) x 59.5mm (D)
• Powered by 1x AAA battery

The Navigation feature lets you input destinations (it comes preset with nine Pentax International service centres) and you can then use that for planning photo based orienteering events.

The compass lets you record the camera's direction when shooting, and also records the altitude, which will no doubt come in useful for architectural and travel photographers.

The longitude and latitude data can be transferred to photo maps, so when importing into Lightroom or uploading to your ePHOTOzine portfolio, the map positions are transferred and your photos will appear in the correct position on the map.

The compass shows magnetic north so is ideal for astro-photographers and it's this aspect that the unit really shines. It has an Astrotracer feature that utilises the camera's anti-shake feature to adjust the sensor in sync with stars so they remain in a fixed position as solid points in the photo, making night sky photography easier.


Pentax O-GPS1 battery chamber - seen here with zinc chloride battery. You should use Alkaline - this was the only battery to hand in the photo studio so is just for illustration.

Pentax O-GPS1 Handling

The unit slides onto the hotshoe and has a lock that stops it slipping off and ensures solid contacts are made between connection pins. If you bought an early version of one of the compatible cameras and are still running on the original firmware you will need to download and install a firmware update before you can use the O-GPS1. The K-r and 645D need V1.10 and the K-5 will run on V1.10, but performs better on V1.12. You can find updates here. Firmware updates for Pentax digital SLR cameras.

The unit has just an on / off switch and is controlled through the camera's menu system. When the firmware upgrade is made there's an additional GPS menu item. It's here where you select Electronic Compass, Simple navigation or Astrotracer.

There's also a calibration option which involves turning the camera through 360 degrees in all three directions: left to right, clockwise / anticlockwise and up and down. The instructions are pretty basic and sometimes you see the OK calibrated note before you've completed all three rotations. I couldn't find whether that meant it had actually incorrectly set ok or whether the extra data wasn't needed.

When using AstroTracer there's a second Precise Calibration, but the instructions don't say whether this has to be done after each shot or each time the unit is turned off, so you're left guessing.

Also one help video that Pentax Japan created shows the user not letting go of the camera and backup instructions suggest you should keep hold with both hands. Try rotating a camera more than 360 degrees without letting go!! I can only assume this is purely a safety aspect, so you don't drop the camera, but clarity would be good. The demonstrator on the video only rotated about 320 degrees. So my tests may not be precise if the calibration wasn't done right, but the OK confirmation was seen at all times.

Pentax O-GPS1 Performance

To work correctly the unit must first connect to three or more Satellites and starts searching as soon as it's switched on. The blue light flashes to indicate on and searching. It goes constant when it's located the satellites. According to the manual this should take a few minutes, but it can take much longer and isn't ideal if you want to take quick shots and record the location. The device needs to be on and ready... and then it's draining the battery, so not ideal.

The unit may not connect indoors either. I was only two meters from a window at my desk and the unit would not connect. So it's no use for pinpointing locations for architectural and travel photographers who shoot mostly interiors. You could take a shot outside of the building with the unit coupled before you go inside, but that's not ideal.

I went for a wander around Worksop and took photos along my route. When importing the photos into Lightroom it's automatically placed them all on the map and the locations are quite accurate. This is a great time saving feature, but nothing new -  Nikon, Canon and Sony each have a GPS unit. What's different with the Pentax one is the AstroTracer which we'll come to in a moment.

But first how about turning your camera into a compass with a lovely looking graphical display? It seems quite accurate and could help if you get lost while out and about.


Likewise the navigational device will come in handy for those who like that sort of thing. It's pre programmed with all the Pentax service centres and you can add, save and load destinations. Then when reselected the unit will tell you the direction and distance.

Pentax O-GPS1 Preset Destinations list

Pentax O-GPS1 Select Preset Destination

Pentax O-GPS1 Destination manager

Neither of these are features that rock my boat, but they seem to do the job effectively so we'll skip along to the highlight - Astrotracer. As soon as I heard about this feature I was keen to test.

Astrotracer can be set to a specific exposure time so when the shutter is fired it will keep the shutter open for that preset time. And while the shutter is open the camera sensor adjusts position so it keeps aligned to the stars. This means the stars will stay still, but the static earth elements, such as trees and buildings, will become blurred.


This was one of the hardest things to get the hang of as I couldn't seem to get the unit to follow and freeze stars as well as it's supposed to.

It's this mode that has the precise calibration and problems I had are mentioned earlier in handling.
Once the calibration is made, you can set a preset exposure from 1 sec to 5 minutes. The time depends on the focal length used. Wider angles provide static shots at longer exposures.

What is irritating when using the GPS unit for stars is the bright blue LED. Normally it's not an issue but in the dark it's extremely bright, especially being so close to the viewfinder. Also the LCD stays on at some points of the operation and it's all too much when youre moving your eye to and from the finder.


Two examples of using the Astrotracer - the left one is a 239sec exposure at f/8 with the lens at 16mm and ISO400. The right side is a 120sec exposure at f/6.3 with the lens at 16mm and ISO800. You can see the blur of the trees on the longer exposure and the stars are certainly sharper than they would have been with a standard exposure. I don't live in an area where I can get clear enough skies to take this to its maximum potential. Hopefully those reading the review who live in good locations and buy the device can post their shots on ePHOTOzine. We'd love to see them.

Value for money

If you have a smartphone many of the features of this GPS unit can be added for a few quid. If you prefer on-camera gadgets £229 for the Pentax GPS may seem expensive, but the Canon GP-E2 GPS unit is £300 and doesn't have an Astrotracer feature. Both are undercut with the Nikon GP-N100 GPS Unit - simple in looks and design, but just £109 providing you have a Nikon with the multi-port accessory. If not you'll need the Nikon GP-1 GPS Module at £199. Making the Pentax seem very good value.

Pentax O-GPS1 Verdict

I still can't fully make my mind up about certain aspects of this gadget. Without doubt, if it works correctly, the Astrotracer will be a superb feature for star gazers. I did manage to get sharper star photos, but mainly on shots under two minutes even though I used a wide angle on all shots which should be okay up to 300seconds.

The ability to record location helps for me as I tend to travel around and shoot lots of photos in a wide area of the location. I often forget where something was, so this pinpoints for future reference perfectly. Also when out in remote locations it can take minutes to pinpoint the place on a map. Here it's sorted out each time. But you can get that from less expensive units or even from a 1 to 2 quid app if you have a smart phone. You have to weigh up whether the convenience of this, that automatically adds the data to the photo in-camera, offsets the bulk and cost sufficiently.

I can't see the point of the compass or navigational aspects... if you want them you probably already have them on your phone.

Overall though Pentax owners can be pleased that they can buy a more versatile product than Canon and for less money.

Pentax O-GPS1 Pros

Multifuntional features ahead of competition
Unique AstroTracer feature
Great location tagger

Pentax O-GPS1 Cons

Sometimes long delay in finding satellites
Blue light too close to eye piece
Rear LCD on when using AstroTracer
Unclear instructions

FEATURES
HANDLING
PERFORMANCE
VALUE FOR MONEY
VERDICT