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%.

Others II

Another shot I really like from Photonodie, whom I found via play.blogger


It appeals to the African (bushbaby) in me.

And on the topic of my own work, the Prague/Czech photos are now in the gallery.

Others' work

Surfing around play.blogger when I should have been working today I came across this shot from the Idolos del Futuro blog:


Unfortunately I don't speak Spanish so have no idea what the story is about (and I hope the author doesn't mind my embedding the image here in a more easily viewable format).

Anyway, I like the energy and the colour... who knew two middle-aged men in suits could be so interesting.

Light and Timing

A couple of shots showing the challenge of contrast:

F 10 .. 18 mm .. 1/250 sec

F 10 .. 18 mm .. 1/400 sec

The first shot is a yawn: underexposed in the nearground, overexposed in the farground. Though it's not technically perfect I like the drama of the second shot, taken a few minutes later as a cloud sailed by. The result makes the buildings pop far more, and the faster shutter speed keeps the background from fading out.

In the Field: Exposure

The cathedral of St Vitus is an imposing Gothic edifice at the castle in Prague. It is vast and gloomy: a great setting for the Addams family, but a challenge to photograph on a very bright day. So I fiddled with the exposure and got the following set of photographs:

F 10 .. 24 mm .. 1/320 sec

F 7.1 .. 18 mm .. 1/500 sec

F 7.1 .. 18 mm .. 1/200 sec

Shooting a dark building against a bright sky is difficult... and the sky gets that weird wash-out of colour closer to the (invisible) sun. Adjusting the exposure almost completely erased (overexposed) the colour of the sky, though the building's detail was far clearer. None of them great shots. For these shots the only filter used was a (UV) skylight.

Turning around and shooting a light building with my back to the sun resulted in these shots, the first at the same settings as the final shot of St Vitus above:

F 7.1 .. 18 mm .. 1/200 sec

F 7.1 .. 18 mm .. 1/1250 sec

Amazing what a difference lighting and reflective surfaces make!

Depth of Field / Zoom

Here's a study in how the depth of field alters as one adjusts the zoom.

All photos were taken from the same spot, using a fixed aperture (F 5.6). The first two involved focusing in turn on neighbouring flowers to give a sense of the very narrow constraints on depth of field at 200 mm. Subsequent shots all focused on the forward flower.

Of note - when using the maximal zoom, exactly *what* you focus on is very important. At wide angles focusing anywhere roughly in the general area one wants will do. So no snapshots / action shots at great zoom.

F 5.6 .. 200 mm .. 1/160 sec

F 5.6 .. 200 mm .. 1/125 sec

F 5.6 .. 105 mm .. 1/160 sec

F 5.6 .. 56 mm .. 1/125 sec

F 5.6 .. 27 mm .. 1/125 sec

F 5.6 .. 18 mm .. 1/80 sec
original jpg