Saturday, 12 February 2011

Project:Focus - Different Apertures

The aim of this exercise is to determine the effect of different apertures on the same scene.

I have tried several images for this exercise, but so far due to the flat overcast February light it has been hard to get the modelling required to clear define the areas of focus. These so far are the best set with a good clearly delinated areas of focus.

I tried to keep the same exposure, by using aperture priority, for each shot but once again was cursed by the changeable weather and light levels. Even using a tripod I wasn't quick enough as the clouds kept drifting across the sun... again and again...

I used the 50mm lens for this due to it's very wide range of f/stops from 1.4 to 22.

Image 1 clearly shows the small area of focus (marked within the yellow lines) with the fall off towards the lens clear in the lack of sharpness in the grass at the foot of the picture.

Project:Focus - Different Apertures
Image 1:
Focal Length: 50mm
Aperture: f/1.4

Image 2 shows how by moving to the middle of the available f/stop range that the area of focus has increased. Focus is improved towards the edges and corners but it is still clear that there are still areas where sharpness starts to degrade and makes it difficult to define separate blades of grass on the lower limit of the image.

Project:Focus - Different Apertures 2
Image 2:
Focal Length: 50mm
Aperture: f/5.6

Image 3. was taken using the limit of the range, in this case f/22. It can be clearly seen that even towards the edge of the image all details can be clearly seen and separate blades of grass are evident on the bottom edge of the image.

Project:Focus - Different Apertures 3
Image 3:
Focal Length: 50mm
Aperture: f/22

Thursday, 10 February 2011

Project:Focus - Set Aperture

The aim of this project is to determine the effects of a using fixed aperture when changing the point of focus.
Given the nature of the recent weather, the non-stop grey cloud giving a flat featureless light which has plagued me over the past month, I decided to move indoors for this project.

I set up a white panel to try and bounce available light back into the shot and soften the shadows I also set up the flash to one side to provide a small amount of fill.

Project:Focus- Set Aperture 1
Image 1 : 50mm f/1.4 1/40 ISO 100
Image1: I focussed on the smallest doll first, and was pleased with the way the narrow depth of field helped isolate it. Also the lack of focus wasn't that great as to completely lose definition in the other dolls.

Project: Focus - Set Aperture 2
Image 2 : 50mm f/1.4 1/50 ISO 100

Image 2: I moved the point of focus to the middle sized dolls and this helped to isolate them amongst the others. However I found this less pleasing given the subject matter than the Image 1. I do feel though that if you need to isolate a person or an item within a central position in a frame this would be a good option.

Project: Focus - Set Aperture 3
Image 3 : 50mm f/1.4 1/50 ISO 100
Image 3: This brings the background into clear focus but I feel it does not give the same feeling of depth as Images 1. and 2 which would be my preference.

Using a narrow Depth of Filed to isolate the main item in an image works well with static subjects. Using this technique to isolate foreground subjects and blurring the background works best. I would consider the best use would be to use this in portraiture, particularly to isolate the subject from  a distracting background.