Exercise: Measuring Exposure Part 2

For this exercise we were asked to take 5 or 6 different photographs, and for each make 5 exposures arranged around the measured exposure.  The measured exposure was done using evaluative metering and the intervals were at 1/2 stop, providing a sequence of –1, –1/2, 0, +1/2, +1 stop.  In the sets below, this sequence is maintained, so for the portrait format, left to right, is –1, –1/2, then measured in centre and left to right bottom –1/2, –1.
For landscape format, then on left top is –1, left bottom –1/2, then measured in centre and right top +1/2 and right bottom is +1.
None of the images have been edited, as, for the purpose of this exercise I wanted to show these “as shot”.  They have been hand-held, so there are slight differences between individual images.

Above is a view of the old Naval College at Greenwich and the towering office complexes across the river at Canary Wharf.  I chose not to make a symmetrical view here, wishing to locate the office towers centrally between the clock towers of the college as I wanted to maximise the difference between old and new.  The measured exposure probably works best here, though the exposure at +1/2 stop also works.
 
This sign outside the Cutty Sark pub, along the river to the East of the Cutty Sark and the College, provided an opportunity to demonstrate the effect of meters adjusting black to a shade of grey.  For me, the best exposure is the one exposed at –1 stop as this gives the best black, though the grey brickwork is now slightly too dark.  In processing this image, I would retain the grey brickwork at the originally metered exposure.

An anchor provides the source of this subject.  Here, the most effective exposure is that given –1 stop compensation.  In the metered exposure, the shadow areas affected the calculation, allowing the brightly lit areas to be overexposed, losing detail in those areas.


Looking through the pillars of an old wharf at the office complexes in Canary Wharf, again, the measured exposure provides the best balance between the shadow and brightly lit areas, though the photograph taken at +1/2 stop provides slightly more detail in the shadow areas, but the highlights start suffering and the sky takes on a slightly washed out appearance.

Here, in this photograph of the Provost training aircraft from the 50’s, my preferred exposure is that indicated at –1/2 stop, though it actually looks brighter than the metered exposure.  The light was changing due to fast moving clouds and differed enough to cause this change of exposure.  I did not notice this at the time of taking, but I decide to leave this in as it still illustrates the purpose of the exercise.  Nevertheless, I was “caught out”.

Colourful pillars and geometric patterns at Stratford DLR station, provide the inspiration for this photograph.  The exposure with –1/2 compensation to me is the best one with the colours having improved saturation, without damaging detail in the shadows.

Exercise: Measuring Exposure Part 1

Lighter or darker

For this exercise we were asked to produce between 4 and 6 photographs which are deliberately lighter or darker than average and to explain why these were shot in that way.  Metering for these images was all in camera using evaluative metering.

ISO400, f/4.5, 1/30 sec +2 stops

I just loved the way that these two ladies, travelling on London’s DLR, maintained a separation between themselves and each maintained a totally disinterested “blank” look.  Both are protective of their bags, and also keeping to themselves with their encircling, joined hands denoting their space.  There is tension between them, clearly wishing to maintain the space between them.  I gave a +2 stop exposure here because of the bright daylight behind them, but I also wanted to burn out the view out of the window to give a starkness to the background which eliminates any distractions.

ISO 200, f/4.5. 1/180, +1 stop

These fun mannequin heads, I found at an outdoor market in Greenwich.  Here I needed to compensate for the backlighting, hence the additional exposure given of +1 stop.

ISO 100, f/8, 1/350, +1/2 stop

This and the next image I found by chance in Greenwich, but they were ideal to illustrate the point regarding the need to compensate positively or negatively depending on the subject.  The light meter is designed to work to an 18% grey average, so where there are tones which are at either end of the scale, then they will both tend towards a grey.  The Curlew Rowing Club plaque is light, almost white in colour, so standard exposure rendered it a murky grey.  I overexposed initially by 1 stop and then by 1/2 stop, selecting the latter as I lost detail in the higher compensation value.

ISO 100, f/8, 1/250, –1 stop

Here the plaque for the Globe Rowing Club, was a dark slate and the standard metered exposure rendered it a light grey, which it was not.  Applying compensation of –1 stop, brought it closer to how it was.

ISO 200, f/9.5, 1/125, +1/2 stop

Another backlit image, this of the MS Stubnitz, which is a converted East German freeze and transport vessel of the GDR fishing fleet, built in Rostock.  It is now, surprisingly an arts and music venue using the three converted cargo holds.  As it was backlit, even on a dull day, an extra 1/2 stop was of benefit, particularly in keeping whites ‘white’.

ISO 400, f/4.5, 1/180, –1 stop

A black monument to Chopin on London’s Southbank.  As it is black, the meter tends the exposure to a standard grey.  Even though I gave –1 stop compensation I feel this was not enough in order to achieve the rich black, however reducing the exposure further was likely to result in loss of detail.

ISO 1600, f/13, 1/30, +1 stop

The skateboard park in London’s Southbank.  I love this place, the graffiti is so vibrant and it is certainly not static.  Here I wanted to give greater vibrance to the graffiti and lightness in the dark areas at the expense of the outside, where I am comfortable that the spectators are reduced to light shapes.

ISO 200, f/6.7, 1/45, +1 stop

Stratford station.  Although overcast, this was very much like being inside a giant light tent and I wanted to keep the colours vibrant.  The silver of the train and the light grey skies, were pushing the standard meter reading to an underexposure, hence I applied a full 1 stop overexposure.

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TAOP Part 4: Light

Time to make a start on this part as I have very little time in which to complete part 4.  The introduction to this section in the course manual covers light as "the raw material of photography" and then leads on to "The intensity of light".  Here there is a general discussion of measuring the brightness of light and easily translating it onto a scale which can be used practically to provide the appropriate exposure when taking a photograph.  There is also a brief discussion of sensor sensitivity which is measured in ISO numbers as well as histograms.  These latter two subjects I will expand on further later in this blog.

Measuring Brightness

At this point I reached out for my little-used camera manual to remind myself what metering patterns are available.  Being rather lazy, I generally use what Canon refer to as 'evaluative' metering and this does seem to work well in most circumstances, though when working with speedlights, whether in the home studio or out in the field, I use a hand held meter.  As I have been using hand held meters for some time, I thought that I'd cover those off first.

Hand held meters

First of all, on of the major advantages of using a hand held meter is that it becomes possible to take incident light readings.  Why is this important and when should an incident light reading be taken?  An incident light reading measures the amount of light falling on the subject and this gives an accurate reading to be used in determining exposure.  Such a reading is independent of the texture and colour of the subject, which means that it is not necessary to make adjustments to take those into account.  It is appropriate here to touch on how meters are calibrated, regardless of whether they are internal to a camera or hand-held.  The basic principle which is adopted in metering the brightness of a scene is to reduce it to an 18% reflectance grey card.  This has considerable significance where the subject is predominantly at one or another end of the scale, ie either black or white.  A black surface will cause the meter to calculate an exposure some times up to 2 stops higher than required and a white scene, such as snow goes the other way and causes up to 2 stops  under exposure, giving rise to grey snow scenes.  An incident light reading is independent of these factors so more likely to give you an accurate exposure.

There are practical considerations, however, and it may not be possible to take an incident light reading in most circumstances, so I use it primarily for studio work, whether by flash or other light sources, and also portrait and close up work outdoors.  My first hand held meter was a Weston Master V, which is currently not working, however in doing this research, I discovered a company which repairs these meters, so I may well do so.  What did it look like, well, somewhat like this:

The white plastic attachment seen in this photo is called an "invercone" and it fitted over the area where the selenium cell receptor was located.  This is shown in the photo below.  Using the invercone was how incident light was measured.  Reflected light measurements were made without this attachment, pointing the receptor directly at the subject.

The hand held meter which I currently use is an Sekonic Flashmate L-308S, which is shown below:

The digital display and multiple functions, make this a very versatile tool despite being one of the cheaper models.  In the picture above, the white area is a "lumisphere" which is used for taking incident light readings in the same way as the Weston.  The main advantage of this type of lightmeter is its ability to take readings of flash output.

For metering small areas, referred to as spot-metering, I recall using at college a Pentax Spotmeter V which looked like this:



A rather strange device which incorporated a viewfinder which you used to find the "spot" you wished to meter.

In-camera metering

Reading the manual for my camera, the Canon EOS 5D mark II, I find the following on a page describing the Metering Mode:

Not a wonderful scan on my part, but it illustrates the point.  There are 4 metering modes, all with specific attributes, well described in the illustration.  I have a tendency to use the default which is the evaluative mode, but this is not necessarily the most appropriate in all circumstances.  Having said that, it all depends on how much you get to know your camera.  In theory, partial and spot metering will provide the best exposure values where you are looking to apply your own compensation, for the scene.  Evaluative does many calculations across a number of zones and it could well be applying compensation, so adjusting further may not make much sense.

As the course text suggests, different scenes require different treatment and an understanding of how the metering works in the specific camera in use so that appropriate compensation, if any is required, can be applied at the time of taking the image.