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Sunday, 26 February 2012

Ltl Acorn 6210 MC and Bushnell 119467 - Review - Part 4

Back to Part 3 - First Impressions and Case design

Fig 20  Bushnell 119467 showing main PCB and the
back of the IR LED Array at top left
Infra Red LED Arrays and Power Consumption:

Following on from the last part of this review, I wanted to quickly compare how the two different approaches to achieving invisible or no glow IR LED's impacted on battery performance, and coincidentally find out how the cameras performed at low temperatures.

Test conditions and set up: 
Each camera powered by 4 New Energizer Industrial Alkaline cells each measuring 1.62 volts.
SanDisk SDHC 4GB memory cards.
Cameras set on time lapse to take
1 still image every 60 seconds.
Fig 21  Bushnell 119467 IR LED VArray
Both cameras were placed in a deep freeze for
9 hours at a temperature of -24C

After 9 hours each camera was switched off and then switched back to test position.
The Bushnell failed to operate and was switched off and removed from freezer.
The Acorn showed the flash screen but not the normal operating screen and was switched off and removed from freezer.
Both cameras were taken to the bench, opened up, and batteries and cards removed.
They were then left to acclimatise to room
Fig 22  Ltl Acorn 6210 IR LED Array
temperature for a further 9 hours.
Battery cells were tested on removal.
The Bushnell cells measured 1.23 volts each and after a 9 hour recovery were 1.38 volts each.
The Acorn cells measured 1.43 volts each and after a 9 hour recovery were 1.5 volts each.
Card analysis showed that the Bushnell had taken 85 images and had stopped operating after 1hour and 18 minutes; and the Acorn had taken 539 images and had continued to operate for the full 9 hours.
Both cameras worked normally after the 9 hour recovery period.

Fig 23 Ltl Acorn 6210MC night range test.

Conclusions:  Bushnell made a big mistake in deciding to use a 40 x 850nm LED array and make it invisible  by putting a black filter in front. The current consumption when shooting infra-red is approx' 1050mA compared to the Acorn with its 28 x 940nm LED array which consumes less than half that at approx' 500mA.  No wonder Bushnell say you should use Lithium AA cells in low temperatures!

Fig 24  Bushnell 119467 night range test.
Fig's 23 and 24 show the night illumination range from the two cameras. The three posts are at 20 (6.1), 30 (9.15) and 40 feet (12.2 meters)
The results from both cameras are very similar although the Bushnell image quality is superior.

When I started this test I wasn't sure what to expect. The conditions were fairly harsh considering the cameras were taken from 20C room temperature and plunged into -24C but I truly didn't expect such a difference in performance between these two cameras.

Even the Bushnells daytime operating current is nearly 100% greater at 250mA as against the Acorns 150mA so it's obvious to me that if you want battery economy, the Acorn is a clear winner.

Fig 25  Reference test card
taken with Olympus E 620

Test card bench tests:

I know you are waiting for me to get these cameras outdoors and see how they perform in a working environment; but  first I carried out tests using cards on a desk top at 1.5 meters to get a controlled idea of the image quality.

All the images are crops of the centre of the frame and are full size when opened.

Both trail cameras were set at 5MP.

The image in Fig 25 was taken with an Olympus E 620 to use as a reference.

Images in Fig's 25, 26 and 27 are as they left the camera, other than cropping.

Fig 28 shows the Bushnell image after correction for brightness and a green colour cast.

Fig 26  Acorn 6210

The Bushnell images are clearly superior to those produced by the Acorn and I've shown the corrected file in Fig 28  to illustrate this.

I've noticed that the same brightness/colour issue exists  right at the start of Bushnell videos, and that the camera corrects itself after a fraction of a second. Maybe the camera's automatic exposure adjustment just isn't capable of keeping up with the trigger speed. Whatever the reason, it's a shame that it takes the edge off what are otherwise, good quality image files.

Judge for yourselves by opening the four images up in a slide show and comparing them.

Video sound level:
One last item for this post is video sound levels. The  short clip below is a comparison of video and sound levels from the Bushnell Trophy black flash camera with internal colour viewer model #119467; and the Ltl Acorn 6210MC.

The video sound track from the Acorn is about twice as loud as that from the Bushnell.

Fig 27  Bushnell 119467
Fig 28  Bushnell 119467
after correction

The next part of this review will cover Trigger speed and Sensitivity, plus side by side working examples from the real world.

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This web site is about the wildlife, particularly the mammals, of the Glen Affric National Nature Reserve area in the north west Highlands of Scotland, UK; and the equipment I use to search for them, which is chiefly trail cameras.

I provide a technical support and parts service for the Ltl Acorn range of cameras and the income from this provides for the upkeep of this site and the purchase of cameras for my own surveying.

I hope you find the site useful and informative; and please contact me if you have any questions that I haven't already covered.