David Mathre Photography

Welcome to my Images of the Day Photo blog. My goal is to post images from each day of the year going back to 2006 when I got my first DSLR camera. Images I post on Google+ are also forwarded to this Photo blog. I am a retired chemist that worked nearly thirty years in the Pharmaceutical industry. I took my first DSLR camera on a road trip across the United States, and became hooked, with my new passion becoming a photographer. I now spend all my time traveling and taking pictures. Since then I have visited over 50 countries, many on Semester at Sea voyages. My photographic interests include travel, the natural world, landscapes, and photographic techniques. I always want to learn something new and the only way to become better is to learn from mistakes.

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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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One Response to “26-July-2012”

  1. David H. Brooks says:

    Rib-bit!

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