From a regular snapshot to a decent one

Recently I was enjoying a party together with a group of friends. And there was a moment when they asked for the photos. It was evening, in a quite dark room, so there was not much options for lighting: I had to use flash or I had to crank the ISO up to 6400. So I have chosen for flash.

I started with one flash with omnibouncer, placed on the camera, directed 45 degrees towards the ceiling. iTTL mode did the job well, the only thing I had to do was to reduce the flash power by 1,5 stop, to balance a little bit with the background lighting. The result was, well, as expected:

The faces are well exposed, but the effect is rather disappointing: the scene is flat, shadows on the faces rather uniteresting.
But then I saw the possibilities to redo the scene with another lighting setup. Since I had 2 flash lights I decided to place them in the room according to the scheme shown below:

The light sources were SB-900 and SB-910 speedlight flashes, with omnibouncers, directed 45 degrees towards the ceiling, slightly above the model, both in the iTTL remote mode. They were triggered by the built-in flash of my camera. As previously, I adjusted the power of the flash by -1,5 stops - to show a little bit more background. I knew that the photo would be slightly underexposed, but I would be able to easily correct it in the post processing. The result was (in my opinion) much better:

Now I have separated the model from the background (look at the left shoulder of her and the top of the hair). Next to that, thanks to the light source on the left side of the camera I got the interesting shadow on her face, giving much more shape to it than on the first photo.
Of course, there is still a dozen of things to be improved (composition, background, white balance of the flash, just to mention some) - it is still a snapshot, after all.
But the learning is that it is always worth trying something else than on the camera flash. The setup cost me about 5 minutes but opened plenty of new possibilities of exposing the scene.

First photography DIY project of 2014 accomplished

Recently I have started the DIY project, which should end in the big (1x2m), sturdy  frame with detachable light diffuser or reflector, depending on the used fabric. The project is finished, and the result looks quite nice:

Front side

Back side

To check the quality I took several shoots using different materials: a shoot-through umbrella, a diffuser and the combination of two. All shots have been taken with the light source placed 1 meter from my face. I have used one SB-900 speed light flash, working in iTTL mode. I have compensated the light strength of the iTTL by -2 stops. The photos are not super sharp, because I had to operate the setup alone, using the remote trigger. So the lens focus was locked and I tried to keep the same distance from the camera during consecutive shots:

Shoot-through umbrella

Diffusser

Shoot-through umbrella + diffuser

First photo is the least successful in my opinion (let's not discuss quality of the model :-)). Note the blemishes on the chick and relatively high contrast around the ears. Second picture, taken with the screen only improves the blemishes.

The combination (putting the speed light behind the umbrella and the screen) produces the results which are to me most pleasant with respect to the softness of light. The idea of combining both light modifiers comes from Joe McNally (one of his online courses). Just to give an idea of the setup:

The diffuser gives a slightly warm color cast comparing to the umbrella, but it is not a big problem.

I have ended up with the budget for the whole project of about 70 EUR. Not bad, I'd say, considering the final effect.

Exploring the limits of my gear - Nikon strobes and the iTTL system

Couple of months ago during the portrait shooting session I have noticed quite annoying fact that I couldn't control the light strength of one of the speedlight flashes used for the lighting setup. In this particular case it was the rim light that was causing problems. I have set the strength of this flash to be +1.7 stops above the default strength determined by the iTTL system. Since this light was too strong, I have reduced it by 1 and then 2 stops, but without any result. The exposure corrections were neglected by the system. Due to the time pressure I didn't investigate it, just moved the light stand a bit further away and obtained the required exposure in this way. But the questions remained:

- why did the system bahave like that?
- how can such behaviour be circumvented?
- how do I know such limits in advance next time?

Due to the other activities I couldn't answer all those questions till this weekend.

I had suspected that the problem with this flash was related to the distance between the flash and the subject. I thought that when the distance is too big, iTTL fires as much light as it can and gives up the control possibilities. To prove it I have tested the system with a simple setup, sketched below:

When the subject is properly exposed by the flash it looks like shown below:

The test was straightforward. I selected a number of distances between the subject and the flash. For each distance I took the series of shots, with the relative exposure of the flash set to -3, -2, -1, 0, +1, +2, +3 stops. For each shot I observed if the flash exposure correction had effect. I did the observation based on the shot but also taking the histogram into account. To illustrate what I mean look at the two tables below, showing the situations where I had full control over the exposure and where I had the control over the exposure from -3 to +1 stop.

First the situation where I had full control over whole range of exposures (distance from the subject to flash was 0.9m):

Exposure	Histogram

It is clearly visible that the flash can produce enough light for the whole range of the exposure corrections.

Then the situation when the control is no more possible above +1 stop  (distance from the subject to flash was 2.9m):.

Exposure	Histogram

So indeed, my assumption was right: if the distance between the subject and the flash grows, the iTTL narrows the range of the relative exposures that can be used. For my measurements I have got the following results (for SB910, set at ISO 100, zoom 24mm):

Distance	0.9m	1.9m	2.9m	3.9m	4.9m	5.9m	6.9m	7.9m
Control	-3..+3	-3..+2	-3..+1	-3..0	-3..0	-3..-1	-3..-3	-3..-3

So the lesson learned is that one can manipulate the distance between flash and the subject as long as loosing of the relative exposure control is acceptable. Which answers my second question: to have the control back over whole range of exposures, one has to move flash closer to the subject.

How far? I found that iTTL can give quite accurate hint about the distance (provided you have SB-800, SB-900 or SB-910 flashes). Here is the procedure:

1. Connect the flash to your camera (either directly or by using the flash release cord)
2. Setup your flash to work in TTL or TTL BL mode, depending on your needs (or planned exposure)
3. Setup the zoom of the flash for the value you intend to use (either by the flash settings or by using the lens zoom, if applicable), required ISO to be used (this one needs to be set in the camera) and the aperture (again, either in the flash or in the camera).
4. Note that the distance scale of the flash shows the range of the distances where the flash will expose the subject properly.
5. Now change the relative exposure of the flash (example for SB-910):

6. Observe that the maximal distance changes with the relative exposure (here an example for the reading for relative exposure +1.3 stops:

The maximal distance together with the exposure correction can be interpreted as a maximal distance at which the exposure can be corrected from -3 up to the value set. In the presented picture, if the subject is at 2.4m from the flash, the exposure can be corrected between -3 and 1.3 stops. Setting it above 1.3 stop will not have effect on the exposure (the exposure will be the same as for +1.3 stop).

Note that it is not exact math, rather indication. I have noticed, for instance, that while iTTL indicates that I can control exposure up to -2 stops at the distance 7.7 meters, I was able in fact to do so at the distance less than 6.9 meters. But for the values -1 to +3 it matches my experimental results quite accurately.

So for the next time I have to remember:

- Check the distance between the subject ant the flash,

- For this distance validate the ranges of exposure correction that will make sense. 

- Don't waste time on trying to go above maximal exposure correction. It will not work.

Extend multiple flash setup applications - cheap and efficient

Sometimes (well, probably more often than I would like to) I experience the situation when the system that I thought and use during my photography assignments doesn't work as I expected. This happened during my last portrait shooting.

The problem I had was manifestated with the close-up portraits:

Since I was using the iTTL system of Nikon, it was required that all three light sources needed to be in the line of sight of the master flash, placed on the camera. The problem was with the rim light source (C). Since it was a strip softbox (30x100 cm) and it was quite deep (30 cm), the flash unit placed at the rear side of the softbox was not always reachable by the master flash. There are several options to solve it (at least that I came with in the first instance):

1. Put the omnibouncer on the master unit to create the broader light bundle used for controlling other flashes
2. Use a radio frequency wireless trigger
3. Don't come so close to the subject (for example by using a lens with a longer focal length)

The first option helped a bit, but didn't solve the problem completely. To be honest, it was required anyway, to control the base light (A) in a reliable way.
The second option is nice, but I don't have a wireless trigger and my budget for photography is for this year really, really up.
Third option is the probably something I'd love to try, if I had a proper lens. I was shooting with the 24-70mm lens. If I had a lens with a longer focal lenght (e.g. 70-200) that would solve my problem. And I think it would also create a lot of new opportunities for the composition of a close up portrait, but alas - something for the future.

There is actually a fourth option, coming from the observation that iTTL is a one-way control system, where the master unit sends the control signals in the form of short light pulses. So the basic light principles, like the reflection of light apply for these signals. The solution was born. I simply put a highly reflective surface ensuring the light from the control unit reaches the remote flash. Something like on the picture below:

Now the best part. The "high reflective surface" was a silver foam that is used to protect the windscreen of a car from freezing. To buy in the Netherlands for 2 or 3 Euro.

The result: 100% efficiency in the controlling of the rim light.

School portrets season is over - learnings and looking forward

The shooting of portraits for the Polish school in The Hague for 2012 is finished. Today I sent last photos for printing. As each year I try to put a new challenge on the area of photography and to experiment with something new. After all, it should be fun for everyone, including a volunteer photographer.

So this year I was using 3 light sources for the first time, building a classical setup: base light in front of the subject, left or right, background lighting to lit the background and the rim light coming from the  side, slightly behind the subject:

The light sources I have used for the setup were as follows:

- Base light (A) Lastolite's EzyBox Hotshoe 76x76cm powered with SB-900 in iTTL mode

- Background light (B): SB-600 placed on a boom arm behind a Lastolite's Tri grip diffuser. SB-600 set in manual mode on 1/4 of maximum power.

- Rim light (C): self-made 30x100 cm softbox with SB-900 set in iTTL mode.

The setup was controlled by the SB-910 flash placed on the camera.

The light setup was partially dictated by the background:

It felt more naturally to put the background light to the right letting the light travel along the lines formed by the orange clouds. So is the main light was placed also left to the photographed subject.

Before shooting I needed to decide whether to use a laptop and shoot in tethered mode or not. Finally I decided not to do so, mainly due to the number of children and the expected crowd and hectic during the session.

So what were the challenges this year? Here the list of most important ones:

1. Place the rim light efficiently to create the desired result,

2. Determine the limits of iTTL system and learn how to use it in such situations,

3. Learn how to deal with iTTL when there is no line of sight between the master flash and the remote units (and not ruin your budget),

4. Streamline the workflow during the session and during the post-processing efficiently so it doesn't take ages to come to the photos.

5. Fine tune the light setup to let children shine on a portrait (some information about it in my previous post)

6. Place the larger groups in front of the background of a limited size.

In coming posts I will take each challenge one by one and describe what I did to overcome it.