Wednesday, February 17, 2010

Project 61

The final project in artificial light is a strange one, I am not really sure what the objective is other than to try using a camera's built in flash or an external flash gun.  Almost all modern cameras have built in flash with TTL metering as a standard, perhaps this section dates back to an earlier age.

On the other hand my 5D2 is a new camera that does not have built in flash, however, I have a number of external  Speedlites that I use whenever I need extra light.  These TTL with the camera and allow flash exposure compensation as well as full tilt and swivel.  I also have a remote transmitter and off camera cable to move the light to more or less any position I wish.  Although recently I have been experimenting with low end studio flash, combining several speedlites in umbrella stands and with softboxes/light tents provides excellent control for still life, particularly for smaller subjects.  I originally purchased the speedlites as fill flash for wedding photography and portraiture, but have been pleasantly surprised by their versatility.

For this project I have decided to explore the function of a single camera mounted 580 EX, with a efw different subjects to illustrate some of the basic principles of flash usage.

My first pair of images is of my CD collection with the flash facing directly forwards

There is a strong unpleasant reflection from the CD cases caused by the forward facing flash.  This is a problem with shooting a very shiny surface

Tilting the flash upwards by around 60 degrees greatly improves the image and produces a much better lit image.

The next image is of a new plant sitting in a window, first of all with no flash

The image is clearly just a silhouette.  Adding flash does not change the background exposure but illuminates the foreground.  However in the following image I am square on to the window and the flash is reflected directly back

Moving around by a few degrees to change the angle eliminates the reflection and greatly improves the image

The lesson is to be very careful of any reflective surface square on to the camera.   A similar image pair enhanced by the addition of fill flash is the following image of my cat sitting on her cat tree, and not very sure about this strange flashing thing.  Again the background exposure does not change as I have not changed the exposure on the camera between shots

There is a little reflection here, but it is not too noticeable.  The next image pair shows the problem of forward facing flash, the creation of harsh shadows

Bouncing the flash of the ceiling, produces much softer more balanced light

Once again, the exposure on these two images is identical, all that has changed is the angle of the flash gun.

My final two images are of some glass on the top of a shelf.  The direct flash creates harsh shadows, but also unpleasant reflections.  Pointing the flash upwards completely changes the image

Changing the angle of the flash is a great tool, however, it only works when there are conveniently positioned surfaces (preferably white or grey) to bounce the light off.  Otherwise it is necessary to take the light off the camera.  My favorite approach to this is that taken by underwater photographers, in which the flash is positioned on articulated arms and attached to the camera via a sync cord.  The following image is the same set up that I use, housing and strobes, although this is not me in this case

This enables the light to be positioned arbitrarily within the limits of the cord length.  The water provides support for the weight of the strobes, this would not work on land!

Project 60

As anticipated this proved to be an extremely frustrating project to complete, although ultimately quite a lot of fun and definitely very educational.  Although the learning so far is to never attempt to photograph a highly polished surface ever gain unless threats of violence are involved.

I selected a small stove top espresso coffee maker with a highly chrome finish.  First of all I placed it onto a black felt surface and too a simply shot as a starter

Canon EOS 5D2, 50mm, f/8, 1/60s, ISO 100

The camera was fixed on a tripod and I used a couple of 11W low energy florescent lights on extensible arms as lighting.  These are quite bright but without any modification created a very ugly shine on the coffee pot.  Over the next few shots I have continued to use these lights, either directly, or bounced off the ceiling of my studio.  Keeping the aperture at f/8 and ISO at 100, I had a variation in shutter speed from 1.60s to 8s, depending upon the lighting position and intervening diffusion material

My next move was to place the coffee pot in a light tent that already own, this was easier than using tracing paper, but would achieve the same thing without waste.  This is the result

The reflection of the light is very much improved and the tonal gradation in the reflection is much better, however the blue floor of the tent is clearly visible as is the tripod.  My next move was to try and get rid of the blue mat, but also to light the tent to create a softer reflection on the top of the coffee pot

I have also adjusted the camera angle for a lower aspect, again trying to improve the reflections.  At this stage I have not tried to hide the camera yet and both it, the tripod and I am clear in the reflection.  In the next image I have covered the opening in the light tent with tracing paper and cut a hole for the camera

This is much better, but I did not like the black felt reflected in the coffee pot, so in the next image changed to a white surface:

This is very much better, however, the camera is still visible in the reflections - PHOTOSHOP

At this point I have progressed a long way from my first image and spent much time and effort playing with tripods and bits of paper.  However, the result is still far from what I would want, the reflection is still intrusive and it is clear that the pot is inside some sort of a tent.  

I think the biggest improvement that I could make at this stage would be to replace the surface under the coffee pot with something translucent and to light from below in such a way as to blow our the background.  An infinity curve could help here.  I would also look at add a light tent with a spherical rather than square shape to reduce the reflections.  Moving from continuous light to far more powerful studio flash might gain more control and again enable me to blow out the background.

Sunday, February 14, 2010

Book Report: Light Science and Magic

It has been a while since I wrote a book review, I haven't stopped reading, just stopped writing.

I have to say that this is one of the best books I have read on the subject of photography, it is not a casual nor easy read, but the information contained inside is invaluable.  I have read it from cover to cover, but this is probably not the best way to approach this volume.  It is in essence a cook book for lighting, providing recipes for lighting virtually all types of object and situations.  Starting very simply with a single light and perhaps a reflector it deals with solid objects, discussing how to light different surfaces, depending upon their reflectivity and light absorption properties.  It moves onto a very comprehensive study of lighting the human face, working from a single light through to 4 or more lights.  It then works through a number of "impossible" situations.

I cannot say that one read is sufficient for this book, however, having read through it I now know where to go back for detailed information on lighting any object.  It has proven exceptionally useful in this 6th chapter of AoP, on which I am currently working.  A particularly interesting item for me was the fact that using a polarizing filter can dramatically change the property of reflection from certain surfaces; I had never thought to use a polarizer in the studio.

My only warning for those reading this book is that it could prove to be very expensive.  I recently purchased a low cost studio lighting kit, with 2 400J lighting heads and soft-boxes, after reading this book I now realize that I should have double this (Ideally and assuming I had the space to store and deploy it properly.  Anyway, a great book and very useful reference for the future.

Project 59

Following on from the last project on filling shadows and managing contrast I kept the lighting rig together to do a couple of shots of a bunch of tulips for a pair of picture frames in the house.  I used two lights, one as the main light and the other as the background by shooting the tulips in front of a soft box.  I then supplemented this with a reflector to the right of the tulips for fill and a small one directly in front but below to reflect some light up into the tulips.  I made two photographs this way, a close up and a wider angle shot.  This was also a chance to try out a 2nd hand 180mm Macro lens I just bought

EOS 5D2, 180mm, 1/125s, f/11, ISO 100

EOS 5D2, 180mm, 1/125s, f/13, ISO 100

As I started packing away the lights I decided to retain one and use the tulips as the subject for project 59, concentrating the light.  I placed a snoot over the single flash gun and then attached a honeycomb grid to further concentrate the light.  My light was now acting like a search light with a very narrow focused beam off light:

EOS 5D2, 58mm, 1/125s, f/4, ISO 

This has dramatically altered the image, now I have sharp black shadows and only a small part of the frame is illuminated.  However, in this image the flowers were too small, so I moved in a little more and doubled the light intensity

EOS 5D2, 82mm, 1/125s, f/5.6, ISO 100

The tulips are better lit now, but the background is very distracting, so I changed the set by putting the flower vase on a black felt mat and hanging a black cloth behind.  Hopefully I would be able to completely isolate the tulips

EOS 5D2, 93mm, 1/125s, f/58, ISO 100

After some experimentation, I got the above shot.  This required pushing the light to full power, 2 stops more than with the last image which was under exposed.  I also wanted more DOF in the tulips.  This image really accentuates the colours of the flowers and the contrast between the red and the green.  I am giving serious thought to photographing a bunch of tulips such as this for my assignment 4, there are so many details and angles available within these flowers.

Project 58

For this project I selected a potted plant, an "Anthurium Dakota", possessing large leaves casting significant shadow if not releived.  I set up the still life on my work table using a single diffused flash gun and a Lastolite reflector as shadow fill device, rather than using white card and tin foil (which I did not have at the time).  The image below shows this setup at the every end of the process, when I had positioned a second diffuser to the rear of the plant to create a high key final image.

I set my camera on a tripod with an 85mm prime.  Flash power was set for an exposure of 1/125, f/8, ISO 100.

The first image is taken without the diffuser on the light

This image has very crisp hard shadows, the shadow caste by the plant pot is particularly siginificant.  The light has also created bright reflections from the plant pot and the shiny leaves of the plant.  Adding the diffuser to the light created the following image:

Now the shadows are much softer and the lighting of the plant pot is far more even and pleasing to the eye.  for the next image I have added my reflector, but simply with the white surface of the diffuser, so only partially reflecting the light

This has reduced the shadowing and in particular lightened the green of the leaves in the rear of the plant.  For the next image I have brought the reflector much closer.  The difference is subtle but the shadows in the upper part of the plant have brightened slightly.  

Covering the reflector with a silver surface yielded the following image

In this case the image now has some reflections on the side opposite the light and I would say that this has not improved the image.  The softer shadows caste by the white surface have a more pleasing quality than those created by the silver surface.  My final adjustment is to the background.  The background I have used is a white sheet of felt covering the bookcase behind the camera. This has rendered grey in the images as it is not strongly illuminated.  I have replaced that background by a second flash gun with a large soft box in front

This has improved the background, however, the line where the background meets the base board is distracting - so 5 minutes in Photoshop and

This is admittedly a slight cheat, but I do not have an infinity curve!  There is still much room for improvement as the plant is overexposed.  The plant itself is shiny and not very absorbent of light and so a difficult object to light.  A third light would improve things as it would enable the shadow to the right of the plant to be diminished more than the reflector is capable of

Tuesday, February 9, 2010

Project 57

Once again using Ganesha as my subject I have taken a series of images from different lighting angles.  My camera was fixed in position relative to the subject on a tripod.  As I did not have a convenient way to position the light above the subject other than to hold it I used a cable release to fire the camera shutter.  Once again my light source is an Elinchrom D-Lite 4, 400J monoblock with a 52x52 cm softbox to modify the light.

The first three images are taken with the light to the left steadily moving around to the side of the statue

Next I brought the light to the right of the subject and shot the following images from varying angles

In these sequences the image becomes progressively darker as less light is reflected towards the camera and once the light is almost at 90 degrees to the camera the statue begins to lose definition and 3 dimensionality.

I then moved the light to directly behind the statue

A number of things have gone wrong now.  First of all I have a tremendous amount of flare as the light is pointed directly at the camera and so I am getting a lot of internal reflection in the camera.  I think I could reduce this by angling the light or repositioning the camera at an angle to the light and also by reducing the light intensity.  Secondly I would ideally want to move the statue further back into the frame and lower the camera a little to avoid having so much of the table in the frame.  Then I could make a better attempt at a silhouette.

I then positioned the light just behind, on top of, and slightly in front of the statue to create the following sequence

The slightly behind image has picked up the edges of the statue very well, however, the light is too low in the image, which could be easily corrected by raising it.  The light directly above has created deeper shadows, with the light light in front slightly relieving these.

Subjectively I think the first image with the light placed just to the left of my shooting position produced the best balanced image, however, this was the best managed shot.  It provides the best depth, although it is not very dramatic.  The shots with the light almost fully to the right of the statue or just slightly behind and above catch the edges of the statue and create the most dramatic and moody images.

Project 56

My subject for this project is a bronze statue of the Indian God Ganesha, offering plenty of relief and fine detail, it is an ideal object to work up some lighting experiments.  The only thing it lacks is colour, the whole statue is bronze.  I placed the statues against a black felt background to avoid reflections and focus attention onto the statue.

My light source is an Elinchrom D-Lite 4, 400J monoblock with a 52x52 cm softbox to modify the light.  I placed the camera to the front of the statue pointing slightly downward and the light at about a 30 degree angle away to the left.  I established the exposure using a handheld flash meter.

The first image is taken without the softbox mounted on the flash head and includes no post processing modifications:

Canon EOS 5D2, 50mm, f/9.5, 1/125s, ISO 100

I then attached the softbox and obtained the following image

Canon EOS 5D2, 50mm, f/3.5, 1/125s, ISO 100

One immediate difference was that I had to open the aperture out to f/3.5 to account for the light absorbed by the softbox.  Otherwise the effect is very much as expected, the lighting is more even and the shadows far less pronounced, all in all a much softer image.

Sunday, February 7, 2010

Project 55

Having studied Physics to postgraduate level the inverse square law is very well know to me, but this was a fun exercise and reinforcement is a useful educational tool. .  For this exercise I placed my primary lighting tool, a 400W Elinchrom studio flash head, on a lighting stand pointing out of my patio window.  I used the naked flash gun without any device to modify the light, trying to create more or less a point source.  I then measured the distance into the communal garden of m apartment complex and using a flash meter with radio control of the flash head started to take measurements of the light.

My neighbours must be starting to wonder what I am up to, watching a guy walk backwards onto the lawn occasionally firing a large flash gun at himself.  As suggested in the text I set the exposure meter to ISO 100 and 1/25s.  The following chart shows the measurements:

The curve is a classic exponential curve, reflecting the fact that the light intensity is falling of at the square of the distance.  In effect every doubling of the distance drops the light by 2 stops.  This is only obvious with relatively close and small point sources.  In fact the exact same is true of the sun, however, as the distance from the sun is so huge, any change we can make in our distance from it is infinitesimally small and not detectable.

Project 54

I have been looking forward to this project as night photography has long interested me, although I admit that I have done very little, guess I never had the patience.  I have tried a few shots in the past, this is from 3 years ago overlooking the Singapore financial district and taken from my hotel window.  I specifically asked for a high room in the hotel looking in this direction.

Canon EOS 40D, 17mm, f/5.6, 1/5s, ISO 800

Canon EOS 40D, 17mm, f/2.8, 1/13s, ISO 800

Canon EOS 40D, 17mm, f/2.8, 1/6s, ISO 400

These images were particularly challenging as I did not have a tripod with me, so required a steady hand , wide aperture, high ISO, and the benefit of an image stabilized lens.

However, for this exercise I have set out to capture a variety of images from Munich's city center.  I have already posted a number of early evening and night shots for my 3rd assignment and so will not repeat these images in this blog.  My first sequence were taken from the Nockherberg a small hill overlooking the city.  My hope was to get some long range shots of the city, however, the elevation was not high enough and trees obscured most of the view, compounded with the fact that falling snow had greatly reduced the visibility.  Instead, I determined to create a few long exposures of moving traffic from the vantage point of a bridge.  A particular challenge at night is setting the correct exposure, many different exposures can work for the same scene depending upon the effect desired.  A higher exposure can provide details of the buildings, but tends to reduce the impact of the lights, especially with the strong lights from traffic.  In each of the following images the background becomes progressively darker:

Canon EOS 5D2, 105mm, f/4, 4s, ISO 100

Canon EOS 5D2, 105mm, f/11, 15s, ISO 100

Canon EOS 5D2, 105mm, f/11, 10s, ISO 100

Each image has merit, but I find the darker final image more visually interesting due to the contrast (these images are all as taken, (no editing).  I moved on from this location to a slightly busier junction overlooking the Munich technical museum (the illuminated building in the background).

Canon EOS 5D2, 105mm, f/22, 6s, ISO 100

Canon EOS 5D2, 28mm, f/22, 8s, ISO 100

My next subject matter consists of a few of the spotlit historical buildings in the city center.  These were all taken around dusk to maintain a blue sky in the background.  The first 3 images are of the Rathaus, the town hall of the city in the central square of Marienplatz.

Canon EOS 5D2, 24mm, f/11, 1s, ISO 800
(In this image I have chosen a narrow aperture to maintain DOF, but then selected a high ISO as I wanted to capture the people in the image to some extent.  A longer exposure at ISO 100 would have produced a better quality image but lost the people completely)

Canon EOS 5D2, 24mm, f/5.6, 1/2s, ISO 800

Canon EOS 5D2, 24mm, f/22, 8s, ISO 400
(This image used a very narrow aperture to try and keep the foreground and background in focus to provide a more dramatic perspective.  The  WB is some way off, however and the sky has a purple caste)

The next two images are of a large church on Odeons Platz to the north of Marienplatz.  These were taken on a different day in which the cloud cover was broken creating a much more interesting background to the images.

Canon EOS 5D2, 24mm, f/8, 6s, ISO 100

Canon EOS 5D2, 65mm, f/8, 3.2s, ISO 100

The next few images are pictures of everyday life taken at night in the shopping district and of a local cinema.  The first image is a telephoto image of the crowds walking along the main shopping street, very experimental for me at least - the focus is not good, but I like the fact that all the people in the shot are oblivious of the camera.

Canon EOS 5D2, 200mm, f/2.8, 30s, ISO 1600

The next image is one of our local supermarkets.  I have set the WB to the light inside the store, leaving the outside very blue.  Setting WB to the outside light made the interior glow a fierce orange.  I feel that the blue exterior emphasizes the cold and snow on the ground.

Canon EOS 5D2, 17mm, f/16, 3s, ISO 100

Canon EOS 5D2, 24mm, f/16, 4s, ISO 100

My final two nighttime images are attempts at capturing the weather, in this case heavy snow, using either street lighting or car headlights as the illumination of the scene.  As I was using a long telephoto for the images and wanted to capture the streaks of the falling wno, I had to use an exceptionally high ISO of 3200, however, the latest generation of digital SLR's can handle this with fairly acceptable results.

Canon EOS 5D2, 420mm, f/5.6, 1/10s, ISO 3200

Canon EOS 5D2, 65mm, f/5.6, 31/180s, ISO 100