Exposure Comp

This one is for danthro.

Here are shots of the lobster weathervane with the camera set to aperture priority (auto shutter speed), and using exposure compensation.

F 5.6 ... 56 mm ... 1/1000 sec

[no exposure comp]

F 7.1 ... 56 mm ... 1/500 sec

0.67 step exposure comp

F 7.1 ... 60 mm ... 1/320 sec
1.00 step exposure comp

Though the aperture was wide open the first shot was too dark - no detail. Even the sky seems gloomy.

In the second shot I upped the F-stop to increase depth of field. All things being equal the camera would have reduced shutter speed to obtain the same exposure as the first shot
[higher F-stop = smaller aperture, which is a little counterintuitive but Wikipedia provides an explanation].

I didn't want another dark shot, so I set exposure comp to +0.67. This increased the amount of light captured by the camera, showing detail on the lobster and building while still keeping rich colour in the sky.

In the third shot I upped exposure comp once more (my camera does it in steps of a third of a stop) but this time although there was yet more colour in the building the sky and clouds started looking blown out.

All these photos are straight from the camera, simply resized to reduce download time.

I went with the middle shot as my Goldilocks shot - the other two were really used to bracket it and ensure that I calibrated correctly. The composition in the last shot is a little sloppy: if it were a keeper I'd rotate and crop it to remove the lower left distraction.

Depth of Field

Back on the topic of the Nikkor 18 - 200, here's a shot showing depth of field at extended zoom:

F 5.6 ... 200 mm ... 1/60 sec

These are the same shot. The first image has been compressed to save bytes. The second image is a crop; if you click on it you will see it at 100% relative to the original.

This shot was taken on a windy day - I missed the moment when the leaf was fully vertical but am nonetheless impressed by the lens's auto-focus working with the moving target.

Having used the lens for a couple of months now, I really like the large aperture bokeh at extended zoom, though the narrow depth of field does require precise attention to focus, as the following shots show:

F 5.6 ... 120 mm ... 1/160 sec

Despite the shorter zoom, the area of sharpest focus is at the intersection of bricks between the leaves. Ho hum... boring.

F 5.6 ... 200 mm ... 1/200 sec

This time the leaf is in focus and the brick blurs slightly. Once again an uncompressed crop to show the detail at 100%.

Somerville Throne

Outside the Davis Square post office today, a well-branded portaloo. Not of particular technical note, but entertaining.

Of note - good depth of field with a large aperture at 55 mm zoom.

F 5 .. 55 mm .. 1/320 sec

original jpg

Nikon 18 - 200 mm Lens

Before the next exotic trip I want to get to grips with the new lens. Yesterday I took it for a spin, and here are the results:

All photos Nikon D70, Nikkor 18 - 200 mm lens.

Busa Farm, Lexington MA USA

This sequence was taken standing on the same spot, using the same f-stop (aperture priority), in bright daylight (auto white balance). The original full-size photos are hosted by Pixamo.

Of note: very crisp focus, bokeh increases dramatically with zoom. Almost no bokeh at wide angles.

F 5.6 .. 150 mm .. 1/1250 sec

original jpg

F 5.6 .. 80 mm .. 1/1250 sec
original jpg

F 5.6 .. 26 mm .. 1/2000 sec
original jpg