26-July-2012

Bullfrog in a Pond at the Sourland Mountain Preserve in New Jersey.

Recently there have been a lot of messages on the internet regarding some users of the New Nikon D800/D800e camera having issues with autofocusing. Specifically, that the left autofocus sensors are not focusing accurately. I tested my D800 with a test chart — comparing the CAM3500FX contrast based autofocus system with the Live View phase based autofocus system. I did not find any significant difference between right, left, and center contrast based autofocus, all being equivalent to the Live View based focus.

Rather than spending a lot of time testing each lens, I took the camera out to the local Sourland Mountain Preserve and took the following images of a Bullfrog. The images were taken with the D800 an a 500 mm f/4 VRII lens. The lens was mounted on a tripod, and the images taken in “Mirror up” mode to minimize vibration. I was approximately 20 feet away from the bullfrog, which is near the minimum focus distance for this lens. The lens was wide open (f/4) which means a very narrow depth of field in sharp focus. I did the same shot with the head of the frog in the left, center, or right most autofocus sensor, each time re-focusing from infinity. If anything the image from the left sensor was the sharpest. I think the softness for the image from the right sensor is due to vibration.

Bullfrog in a Pond at the Sourland Mountain Preserve in New Jersey. Image taken with a Nikon D800 and 500 mm f/4 VRII lens (ISO 800, 500 mm, f/4, 1/800 sec). Left focus sensor. (David J Mathre)
Bullfrog in a Pond at the Sourland Mountain Preserve in New Jersey. Image taken with a Nikon D800 and 500 mm f/4 VRII lens (ISO 800, 500 mm, f/4, 1/800 sec). Left focus sensor. (David J Mathre)

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Bullfrog in a Pond at the Sourland Mountain Preserve in New Jersey. Image taken with a Nikon D800 and 500 mm f/4 VRII lens (ISO 800, 500 mm, f/4, 1/800 sec). Crop of image taken with the left focus sensor. (David J Mathre)
Bullfrog in a Pond at the Sourland Mountain Preserve in New Jersey. Image taken with a Nikon D800 and 500 mm f/4 VRII lens (ISO 800, 500 mm, f/4, 1/800 sec). Crop of image taken with the left focus sensor. (David J Mathre)

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Bullfrog in a Pond at the Sourland Mountain Preserve in New Jersey. Image taken with a Nikon D800 and 500 mm f/4 VRII lens (ISO 800, 500 mm, f/4, 1/800 sec). Center focus sensor. (David J Mathre)
Bullfrog in a Pond at the Sourland Mountain Preserve in New Jersey. Image taken with a Nikon D800 and 500 mm f/4 VRII lens (ISO 800, 500 mm, f/4, 1/800 sec). Center focus sensor. (David J Mathre)

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Bullfrog in a Pond at the Sourland Mountain Preserve in New Jersey. Image taken with a Nikon D800 and 500 mm f/4 VRII lens (ISO 800, 500 mm, f/4, 1/800 sec). Crop of image taken with the center focus sensor. (David J Mathre)
Bullfrog in a Pond at the Sourland Mountain Preserve in New Jersey. Image taken with a Nikon D800 and 500 mm f/4 VRII lens (ISO 800, 500 mm, f/4, 1/800 sec). Crop of image taken with the center focus sensor. (David J Mathre)

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Bullfrog in a Pond at the Sourland Mountain Preserve in New Jersey. Image taken with a Nikon D800 and 500 mm f/4 VRII lens (ISO 800, 500 mm, f/4, 1/800 sec). Right focus sensor. (David J Mathre)
Bullfrog in a Pond at the Sourland Mountain Preserve in New Jersey. Image taken with a Nikon D800 and 500 mm f/4 VRII lens (ISO 800, 500 mm, f/4, 1/800 sec). Right focus sensor. (David J Mathre)

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Bullfrog in a Pond at the Sourland Mountain Preserve in New Jersey. Image taken with a Nikon D800 and 500 mm f/4 VRII lens (ISO 800, 500 mm, f/4, 1/800 sec). Crop of image taken with the Right focus sensor. (David J Mathre)
Bullfrog in a Pond at the Sourland Mountain Preserve in New Jersey. Image taken with a Nikon D800 and 500 mm f/4 VRII lens (ISO 800, 500 mm, f/4, 1/800 sec). Crop of image taken with the Right focus sensor. (David J Mathre)

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Author: David Mathre

I am a scientist by training (Eckerd College, BSc; Caltech, Ph.D.). I worked for 27 years as a Chemist in the Pharmaceutical Industry developing processes to manufacture medicines for human and animal health. I now spend my time as a photographer and world traveler. My interests in photography include the natural world, wildlife, landscapes, skyscapes, and seascapes. I have traveled to over 50 countries over the last 10 years, often on Semester at Sea voyages. While at home in New Jersey, I spend time on a home renovation project and expanding my wildflower garden/meadow.

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