Reviews > Lighting > Headlamps - LED > Princeton Tec Corona > David Sowards-Emmerd > Field Report

Field Report - Princeton Tec Corona
October 27, 2004

Backpacking Background:
I began backpacking semi-frequently about four years ago, soon after moving to California. I generally take weekend (1 night) trips, and occasionally take 3-4 day trips. Most of my backpacking experience is at moderate altitude, 6,000'-12,000' (1,800-3,650 m), in conditions ranging from dry desert to hail/heavy snow in the mountains. In winter and spring I split time between Southern California (SoCal) deserts and snowshoeing/skiing/snowcamping in the Sierra/Cascades. Summer and fall I tend to stick to the high country. I have reduced my packweight down to less than 50 lb (23 kg) over the past year - including food/water and a bear barrel. I'm trying to include more mountaineering, climbing and bouldering in my trips.

Product Description:

Manufacturer's Specifications:
Weight (w/ 3 AA Alkaline batteries): 227 g / 8 oz

Specifications (as measured by tester):
Weight (w/ 3 AA Alkaline batteries):231 g / 8.15 oz
Weight (w/o batteries):158 g / 5.57 oz
Color: Yellowish green

The Corona is a 8 LED headlamp powered by 3 AA cells. Of the 8 LEDs, 1, 3, 5, or all 8 can be used at once, and for each of these modes, there is a choice between low power, high power, and strobe. For a more detailed description, see my Initial Report.

Field Use:

Sept 4-6, 2004
Location: Horton Creek BLM campground, Bishop, CA
Conditions: Unseasonably cool, around 75 F / 24 C during the day and probably 50 F / 10 C at night.
Elevation: 4500' / 1370 m

On this car camping trip, I used the Corona frequently for digging things out of the car in the dark, and for general use around camp: figuring out which beer was which, cooking over a fire, operating the handle-less water faucet with needlenose pliers, and figuring out which boulders to hurt myself on the next day.

Sept 18-19, 2004
Location: Vogelsang, Yosemite National Park, CA
Conditions: 20 - 40 F / -7 - 4 C on Saturday and remained below freezing during the day on Sunday (water bottles half froze overnight)
Description: 19 mi / km loop with 2,000' / 600 m elevation gain
Elevation: 8,500-10,500' / 2,600-3,200m

Since it was pretty cool out, my wife and I headed to bed pretty early. I used the Corona for light during the last bit of cooking and for reading a bit before heading to bed. During the night I got up, put on the Corona for a bathroom run (forgot my bottle), and found we had received a nice dusting of snow.

Oct 2-3, 2004
Location: Island Lake, Desolation Wilderness, Eldorado National Forest, CA
Conditions: Cloudy, 60 F / 16 C on Saturday with about an hour of rain Sunny and cooler on Sunday
Distance: 8 mi / 13 km roundtrip with 1200' / 370 m elevation gain, and more hiking with the pack top converted into a hipsack.
Elevation: 7,000-8,200' / 2,100-2,500 m (plus day hike to 9,500' / 2,900 m

On this trip, I just used the Corona around camp and in the tent, nothing out of the ordinary.

October 13-17, 2004
Location: Dusy/Palisade Basin via Bishop Pass, South Lake Trailhead, Inyo National Forest, CA
Conditions: Sunny and 60F / C to 12'' / 30 cm of snow, snowing, below freezing and strong winds.
Elevation: 9,800'-12,300' / 3,000-3,750 m (plus day hike to North Palisade at 14,242' / 4,341 m)
Description: 10 mi / 16 km hike in with ~3,000' / 900 m of elevation gain to get to base camp.

On this trip, we got up at 5:30 am each morning, so I had a good 30-45 minutes of darkness where I needed the Corona for morning chores before the sun came up, in addition to cooking dinner in the dark after 12 hour hiking days. Around camp, I wore two hats, a tighter fitting fleece skull cap and a looser fitting wool cap. To help preserve battery life (it generally dropped to around freezing when the sun went down) I positioned the Corona between these two hats to keep some warmth from escaping. In the tent at night, I hung the Corona with a biner from a loop in the tent, which worked nicely for providing an area light inside the shelter. When sleeping, I kept the Corona close by in my bivy sack to keep the batteries warm.

I also carried the Corona along on a successful summit attempt of North Palisade, just in case we summited early enough to try a longer traverse and hit two more peaks before descending - lucky for my knees this wasn't the case.

Saturday night, the snow started falling, and approximately 1' / 30 cm had fallen by noon. The epic hike out was very slow due to routefinding in the storm and since the start of the hike mean negotiating 2.5 mi / 4 km of snow covered boulders. It took over 14 hours to hike out, so the last few hours of the trip were in twilight and then darkness. The Corona was just barely adequate for following the very snow covered trail (huge drifts), and we had to backtrack a few times to find the correct way out. A narrower or focusable beam would have been very helpful here. However, the overall light output was very high, and the beam lit up the other side of Long lake and Bull lake - however this was mostly just a glow. I used the Corona on the 8 LED setting on low power mode (no visible difference at this point) for the hike out, whereas for use around camp, I generally used either 1 or 3 LED mode, usually on the low power setting. I used one freshly charged set of 3 NiMH batteries for this trip, and did not bring spares (since one hiking partner had several extra AA cells for his camera).

General Observations:

The headband is quite comfortable, the curved shape helps and so does wearing a hat under it! Also it's not uncomfortable when reading at night with my head back on makeshift pillow. So far, the Corona doesn't show any wear or visible damage. I haven't dropped or otherwise abused the Corona, it has just been banged around in my pack.

The Corona provides plenty of light for anything and everything around camp. The beam shape of the LED is visible when using just one LED. Using more LEDs effectively rounds out this shape and the beam becomes very smooth with very few features. When reading, even in 1 LED mode on low power I generally use the side of the beam for reading - but I personally don't need all that much light to read. I'm able to operate the light (and still could distinguish which button was which) with thick WindStopper fleece gloves on, although it does take some doing. I'm able to wear a hat 'over' the Corona, so that the battery pack is somewhat insulated from the outside cold (and gets some warmth from my head) while at the same time the LED module is still sticking out from under the hat.

Water Resistant?:

The manufacturer describes the Corona as water resistant, but don't elaborate any further on this. I took this to mean that it'll work just fine in the rain, but don't submerge it underwater. To check this, I took the Corona in the shower with me for about 5 minutes, and tried out all the various settings on the shower head. Before the shower test, I made sure the seal on the battery pack was clean and would seal well. The light didn't short out and I didn't notice any other problems (e.g. decreased light output). The only downside was the wet headband afterwards.

Quirks:

• When turning the Corona on, if the button is held down for more than a second or so, then when released, the light ends up in 5 LED mode instead of 8 LED mode. This is not the case for any subsequent clicks of the button though. When turning on with gloves, this means I'm not sure what power setting I'm on.
• When turning the light off (through cycling through modes), after the last click (before turning off all LEDs), all 8 LEDs flash once (quickly) after releasing the buttons - this flash only appears to happen in this exact scenario and is easily repeatable.
• The LEDs seem to be focused in slightly different areas - namely the single LED points in a different direction than the 3 LED row. I initially noticed this when switching modes, but it's also clearly visible by examining the which angle the 'wire' is best visible in the LEDs (when off).

Basic Light Output Comparison:

Below is a photo table comparing the light output of the Corona and the different beam shapes on the different modes. Freshly charged NiMH cells and the alkaline cells that were bundled with the Corona were used. All photos were taken in manual mode at f/6, one second exposures, ISO 100 setting with a Nikon Coolpix 995. Both the light and camera were placed 5' / 1.6 m from the wall, and the horizontal distance across the photos is approximately 4' / 1.3 m. The alkaline batteries do put out noticeably more light than the NiMH batteries as claimed by the manufacturer, and I'm curious to see how Lithium AA cells compare. In the Photo below, the left column is the Corona's output on low power with NiMH cells, on 8, 5, 3, and 1 LED modes (top to bottom). The middle column is the same setup except that the Corona is on high power and the right column is the same setup with the Corona on high power but with fresh alkaline cells. The blueish hue of the LEDs becomes less apparent as more LEDs are used - this is very noticeable with the naked eye as well as in the photos.

Potential Concerns:

What happens if one LED burns out or is damaged (more likely)? This should never happen, but would all the lights be useless, or are they LEDs wired in parallel, or sets of parallels (each line of LEDs wired in parallel) such that some modes/LEDs would still work? I'll email the manufacturer about this and include the response in my final report.

Wishful Thinking:

I would really like to see a multi-LED light that allows the plane of the LEDs to be changed to focus the light instead of the fixed positions, allowing one to effectively stack the light of the LEDs (and focus for different distances) instead of just creating a wider beam. However, this would make the lamp setup/circuitry more fragile, hence the wishful thinking.

Further Testing:

The Corona will still see several backpacking trips, generally snowy, over the next four months, as well as a 9-day road trip to the Eastern Sierra, CA and a weeklong trip to MI over the holidays. Additionally, I'll supplement the cold weather testing using my freezer and try to see how long it'll keep shining. Finally, I may still use it as an additional bike light for my daily commute after the upcoming time change.

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Reviews > Lighting > Headlamps - LED > Princeton Tec Corona > David Sowards-Emmerd > Field Report