Exercise 4: Shutter speed- or why 1/1000th of second really matters

I'm not sure why but I really struggled thinking about photographing something for this topic. Sure I could have photographed varies moving objects like buses which would fill the frame (see below) but i wanted to do something slightly different with the cliche which would get the message (and picture) across in a more obvious, yet subtle way. It finally dawned on me... if there  is one subject  that has been photographed to death to appear creamy and still in one frame, and forceful, even violent, in the next, it is most surely water. The sea is a few miles away, and then some, from the big Smog so I thought I'd try photographing fish swimming in a tank with an air bubble volcano.... I think the result was a success.

First the obligatory bus shot:

Yes, there is a bus in this picture. but all you see of it are the lights. I took it on a very narrow aperture (f32) and low ISO and kept the shutter open for 10 seconds... the results, a Waterloo bridge devoid of traffic and people except for the lights of the cars and buses. Tell tell sign of the bus... the streak of light in the top right hand corner. There we go, movement and light all in one!



The actual pictures:
The pictures were taken at an ISO of 800 and automatic aperture. Most of them resulted in an aperture of f1.8 but certainly as the shutter speed decreased, the camera compensated by reducing the aperture value accordingly  in order to maintain an exposure value of . some observations were expected, brighter photographs as the shutter speed decreased, less detail and blurring. A little less expected was the illusion of speed. The rate of air  flow was constant, so the increase in the number of bubbles, at first gives an impression of increased air flow. Not so, it seems what happens is that the shutter is open long enough to capture more bubbles without distortion, of course this reached a threshold between 1/250 sec and 1/60 at which point distortion restored the old assumptions.

Photo 1:

1-TV4000 or 1/4000th of a second exposure. This resulted in a clearly defined bubble column and almost no fish! atmospheric shot but not much detail.

Photo2:

TV1000 or 1/1000th of second shutter speed.
A lot more detail and the  fish are clearly visible. Bubble column remains static and frozen in time. the shutter speed is now slow enough to capture the light escaping from the top of the tank which creates a ghostly flame effect

Photo3:

 Tv 250 or 1/250th of a second shutter speed.
Again a lot of detail but fish are still sharp and the bubble column, remains fairly distinct, but if you look at the two previous photographs it seems like more bubbles are now present in the column... not so, the rate of air being pumped in to the tank is fixed all that seems to have happened is that the shutter is now open long enough to catch more of the bubbles in the column.

Photo4:

TV60 or 1/60th of a second shutter speed.
At this speed we now start to see movement. the fish are becoming less sharp, and the bubbles appear to have taken on a more elongated shape, no longer round, most definitely cylindrical.

Photo5:

TV15 or 1/15th of a second shutter speed:
The bubbles are gone, in their place an eruption of air. The fish are loosing definition and form, well at least the fancier versions with flowing tails. The less flamboyant ones, the ones that can stay still remain in fairly clear detail.

Photo6:

 TV1" or 1 second shutter speed.
the illusion is complete. we now have air flowing up the stream at an impossible speed  given the dimensions of the tank. the highlights are blown out and the fish are disappearing before us, a few indistinct colours and shapes remain, ghostly fish but the escaping light has changed shape from flames to a halo.

Exercise 3: Focus at different apertures

This turned out to be a strange exercise and definitely did not yield the results that I had expected. The brief here was to take the same picture with the same focus point at different apertures (widest, middle and smallest aperture) I used a 50mm prime and took 4 photographs at f1.8; f5.6; f11 and f22. We were asked to ensure that the shutter speed adjust accordingly so as to ensure an even exposure value across the photographs. I decided to shoot in Aperture priority and set the ISO to automatic. Shutter values were, respectively 1/4000; 1/400; 1/100 and 1/500. ISO remained constant at 100 except for the f22 shot where the camera increased ISO to 200.

Despite the even exposure I was expecting to see some drop in brightness, but the camera performed very well, certainly at a causal glance there is very little difference in brightness to the images. I was expecting softness away from the focus point, what I wasn't expecting was the lack of sharpness at the focus point when the lens was wide open and also when the lens was at it's smallest aperture. I had always assumed that at it's widest aperture, while most of the image would be soft, the focus point would be sharp and detailed. Not so. I deliberately chose to shoot trees on southbank from across the river. The f1.8 and f22 photos are surprising soft and lack detail even at the focus point, while the f5.6 and f11 photos are crisp and clear across the whole photograph, not just at the focus point. what is  nice about the f1.8 shot is that the branches in the foreground are nicely out of focus and it mimics the way the eye will hone in on on the specific point of  view. It detracts less from what is being observed. What was also surprising was the level of chromatic aboration which disappeared as soon as the lens was stepped down to f5.6

It's hard to tell from the resized images, but at full size at 100% you can read the names of the boats and the signs on the buildings in the f5.6 and f11 photos, whereas at the extremes in the aperture range the signage is difficult to distinguish clearly.  Photographs below with focus point marked as a red dot:

Exercise 2: Focus with a set aperture

For this exercise we had to photograph a scene with depth. It was suggested  that we photograph a wood or a row of cars as an example. Living in London, planted forests are in short supply and photographing cars on a street filled me with  a sense of emptiness so i thought I'd create my own depth scene, et voila, I introduce the mini-hedgerow, admittedly not the most dense but sufficiently "row" like to get the idea across!

The brief was as follows:

1. Find a row (see above) 
2. Make sure the lens is set at its widest apeture
3. Take 2/3 photos each focused on a different point 
4. Once processed  compare the photographs and see how the sharp focus draws the eye  to the subject and lets it stand out against it's surroundings. 

I'm not sure i like the first 2 photographs; there  is too much foreground out of focus and makes me feel quite queasy. The third one, on the other hand, strikes a balance- the green pin is sharp (pun unintentional!) and there is sufficient foreground blur to draw the eye to the subject but not displace it, and the background remains un-distracting too!

Exercise 1

First off, exercise 1 has been done but it seems rather underwhelming. let me explain, I took my camera down to the local park, took a couple of pictures of the pond using different  focal length, having already tried this exercise out  in a different context, i.e. coming to grips with the focal length difference that the crop factor creates on the same lens compared to a full frame camera, I expected a similar effect to occur here which is that the greater the focal length the less of the "view" you capture and the larger it looks. Indeed, that is exactly what I saw. There, done. Next time I'll try zooming out as i press the shutter speed.....