Measuring exposure

The brief for this exercise is to produce four to six images deliberately under or over exposed and give the reasons for doing so.  To a degree the effect of under or overexposure is affected by the metering mode you are using.  My camera has multi segment; centre weighted and spot metering modes.

As an example here are three shots at the same aperture but with different metering modes.

DSC01820-2

F2.8 @ 1/125 ISO 200 Multi segment metering

 

DSC01821

F2.8 @ 1/160 ISO 200 Centre weighted metering

 

DSC01822-2

F2.8 @ 1/250 ISO 200 Spot metering

As can be seen there are small differences in shutter speed.  To further illustrate the point I used the same shutter speed and aperture but just altered the metering.

DSC01823

F2.8 @1/125 ISO200 Spot metering

DSC01824

F2.8 @1/125 ISO 200 Centre weighted metering.

 

DSC01825

F2.8 @1/125 ISO 200 Multi segment metering.

Again the difference is only small but there are variations in the white of the door frame.

I probably use centre weighted more than the others but do use spot metering a lot as well.

The exercise asks you to produce four photos either under or over exposed and I was not sure whether “produce” means take new shots or find existing shots – so I did the former.  These then are ones I have shot previously unconnected with the coursework:-

DSC09984-3

Overexposed by one stop to compensate for the rather poor lighting.

DSC07129-2

Underexposed by 2 stops to compensate for bright light on water.

DSC03856-2

Under exposed by just under 5 stops on a very sunny day to get the tower in silhouette.

DSC06949-2

Overexposed by a stop to bring out the figure at the bus stop.

 

 

 

 

 

 

 

This is a shot I did specifically for the exercise:-

DSC01829

I’m not a great fan of ornaments and I particularly dislike this one. But I wanted to highlight the light play on the surface, so massively overexposed by 5 stops to subdue its environment.

This is the first subject of five ranged photos.  Its an old wax seal belonging to (or acquired by) my grandfather.  I decided to use spot metering on the face of the seal.

DSC02472

Measured exposure

DSC02473

Measured exposure -1/2 stop

DSC02474

Measured exposure + 1/2 stop

DSC02475

Measured exposure – 1 stop

DSC02476

Measured exposure + 1 Stop

Of these I think the plus one stop photo works best as it brings out the detail of the carving in the seal.

The second set is of a hanging bird chime and light.  Again not one of my favourite objects, but I thought it would be a useful subject for the exercise.  I used my tilt shift lens for this as I just wanted the right hand side with the chime in focus.   I underexposed by one stop (and used that as the “base” shot) to see if I could get a bit more detail in the clouds and also I wanted to see if any alteration to the exposure affected the bracketing.   It did not appear to, with the camera taking the minus one stop as the point from which the other bracketing adjustments were made.

DSC02502-2

Measured exposure (set at minus one stop)

 

DSC02503

Measured exposure minus half a stop.

DSC02504

Measured exposure plus half a stop.

DSC02505

Measured exposure minus one stop

DSC02506-2

Measured exposure plus one stop

Of these shots I think the minus half a stop (or minus one and a half stops taking into account the existing adjustment) is the one I prefer as it gives a bit more cloud detail but does not completely subdue the red of the chime.

The next scene was the interior of a garage.  I thought it would give a good indication of the effects on bracketing on the shadows.

DSC02492

Measured exposure – no adjustment.

 

 

 

 

 

 

 

 

DSC02493

Measured exposure minus half a stop

DSC02494

Measured exposure plus half a stop

DSC02495

Measured exposure minus one stop

DSC02496

Measured exposure plus one stop

In this case I’m torn between two images.  I like the plus one stop version as it brings out most of the objects in the garage, but possibly at the expense of an y atmosphere – it is a more “clinical” shot.  I also like the minus half a stop shot as this creates the atmosphere – you know stuff is there but you are not sure what it is.

The last subject I chose was a school roof, with a development site in the background, viewable from our landing window.  The site is about a mile away so atmospherics play a part in the quality of the image.

DSC02482

Measured exposure no adjustment.

DSC02483-2

Measured exposure minus half a stop

DSC02484

Measured exposure plus half a stop

DSC02485

Measured exposure minus one stop

DSC02486

Measured exposure plus one stop

The minus half a stop shot gives, I think, more substance to the roof and still provides plenty of detail, the plus one stop gives a more washed out look and the overexposure takes away any dynamism, such as there was, from the scene.   Overall I think I prefer the measured exposure without any adjustment as it provides sufficient foreground and background information.  What the exercise demonstrates is that relatively small adjustments to exposure can have significant impact on the aesthetics of a shot.  I’m lucky in that the camera I use can easily be set to adjust exposure (and also bracket exposures) but also give a pretty clear indication by means of the liveview viewfinder what effect such an adjustment will have.  My main use of bracketing is for scenes with both heavy shadows and highlights so I can merge exposures to cater for this.

 

 

 

 

 

 

 

 

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s