Friday, 22 May 2015

Camera Challenge 4: Triangle of Light - ISO

Littlest Thistle Camera Challenge 2015Katy at the Littlest Thistle is holding a Camera Challenge, a sort of photography workshop to help us understand our cameras better. After looking at aperture value and shutter speed, this month it's the turn of ISO speed. Once again I fished my trusty model, Bashful, out of the toy box to assist.

Assignment 1:

Fix the aperture value, change the ISO speed:


 I don't see much difference between the photos; the colours of the second appear brighter then the others, but numbers 1, 3, 4 and 5 all look the same to me. From the point of view of the technical specifications: as the ISO value increased so did the shutter speed; as the ISO value doubled the shutter speed also doubled, and produced the same effect ?!

Assignment 2

Fix the shutter speed, change the ISO speed:



Here there is a progression from dark to light, with the greatest contrast being beween the first two photos. Not only is the subjet, Bashful, lighter, but also the buildings outside in the distance become less clearly defined. This surprised me because I expected the background to be more defined the higher the aperture value.

I missed completeing last month's assignment on shutter speed, but tried to complete it last weekend. The cycle racing season has stared in earnest and there was an important race in my town last Sunday. Unfortunately I stopped reading the instructions too early so started at far too slow a shutter speed setting.

The start and finish were much too busy but I founld a good spot at a street corner, under some trees. The race was 9 laps of a 19 kilometre route. I arrived during the third lap, just in time to see, but not photograph the tete du cours. I did get the peleton but in the excitement forgot to change my camera setting!
arrival of the peleton
 For the next photos I reduced the shutter speed for each photo:
20 minutes later the leading group on the next lap

4 minutes later the peleton, this one taking the bend quite slowly,

this one taking it wider, and more quickly
 Then I moved onto a bridge over the railway, increased the ISO and shortened the shutter speed. I couldn't get any closer, and at this distance with an EF-S18-55mm lens there is little impression of speed; you can even see the spokes!
the head of the course

the head of the peleton, now two and a half minutes behind

the tail of the peleton: look at the cameraman!
 Next month I shall read everything before I start.

Thanks to Katy for setting the assignments, giving useful information and hosting the link up, to which I am now connecting.
 Littlest Thistle Camera Challenge 2015
Go over there to check on what other participants have snapped this month.

Happy snapping!

Marly.















3 comments:

Christine Barnsley said...

Hello Marly! I admire you for trying to improve your photography... I don't have the patience... just take a quick snap! Have a lovely weekend! :) x

Katy Cameron said...

Ah, now in fact you've learned a few things here without actually realising it :o)

In the first series, it was all about seeing the effect of increasing the ISO on the shutter speed, so with a fixed aperture as you increase the ISO, your shutter speed also increases.

Now in the second series it was all about seeing the effect of increasing the ISO on the aperture. In your first 2 photos, the limitations of your lens meant that your aperture couldn't go wide enough with ISOs of 100 or 200 in order to light the image correctly. By the time you get to the third photo it's able to give you an aperture that will work in harmony with the shutter speed and ISO to give a well lit photo.

As for grain, to be honest, these days the manufacturers of the higher end cameras have done so much work on the processors in the camera that photos don't show that much grain unless you blow them up to a very large size, although it still tends to be more noticeable on camera phones and compacts.

In the shutter speed challenges I get far more sense of speed in the close up pics at the start than the group ones on the bridge, looks like a fun day :o)

Ruth said...

Love your cycling shot of the guy in red, looks like you moved with him and got a lovely panning effect!