Studio Flash with AF540FGZ

[Michael]

Can Somebody please help me with thes questions.
When I use the af540fgz in studio and set it on manual at what length do I set the zoom on the flash. Maybe I should ask this. I want to take some studio portraits with either an shoot through umbrella or a softbox. I want to use the 540 off camera and fire it with catus 4 triggers. Do I use the 540 on 85mm zoom as this is the higest gn of 54 or do I change the flash zoom. I will meter the output with a flash meter
Secondly when metering with a incident flash meter. Do I point the dome of the light meter towards the flash or towards the camera position

[spyglass]

Hi Michael,

There are two directions that most things can be approached from. With flash lighting you can work from an objective to a conclusion, or you can work from a conclusion to an objective. If I had to use an analogy I would liken it to a horse and cart. You can have set number of horses and build your wagon and load to work with the capability of the horses, or you can have a wagon and load and add horses to deal with the burden of the load. You will have to forgive me for the western analogy... I was watching Clint Eastwood last night - "A fist full of dollars" for about the 100th time.

The easiest way is to determine what you need to accomplish with the photo. If you are taking a portrait, you may decide that an aperture of f8 or f11 would be needed to ensure that you have decent depth of focus throughout the subject. You know that the camera's shutter speed has to to be set to 1/125th sec so that it is in sync with your flash duration. Your wagon is build and loaded. Make sure you enter the ISO and shutter speed into your flash meter.  

Now you need some horses (lighting) to deal with your burden (lighting requirements). Start with your main (Key) light first. You will hold your flash meter up against your subject and aim it at your flash. You will make adjustments to the flash power OR the distance of the flash to subject until your flash meter provides you with a reading that matches the aperture setting you are using. (remember that light intensity changes by the square so every time you double the distance you half the power, and every time you half the distance you double the power).

If you are going with a single light setup you are ready to take your photo. If you are going with a two light setup I would suggest that you take a test photo to see and get a good feel for what your key lighting is doing for you. Make adjustments until you are reasonably happy. The two most common lighting styles are Rembrandt & Broad. (Rembrandt lighting is probably the most widely used. Broad lighting tends to flatten features - great for subjects with narrow faces, deep features, long or pointed noses).

For the second light source simply repeat the same procedure. The only difference will be the light level you set. Generally photographers use a 2:1 lighting ratio for basic portraits. This means that your Main (Key) light will be twice as strong as your Fill light. So if your aperture is set at f11, your Main (Key) light is setup for an exposure of f11, you would want your Fill light to be set to f5.6. I would also suggest that  you take a test shot with just your Fill light on to get an idea of what it will offer.

Now with both flash units ready take your first shot. See what the effect of the two light sources working together offers. Remember that a reflector or piece of white card can work wonders for a secondary Fill source (you will often see one placed under of the face to fill the neck and reduce the under chin shadow).



Hope this helps.  


Spyglass

[Michael]

Hi Michael,

There are two directions that most things can be approached from. With flash lighting you can work from an objective to a conclusion, or you can work from a conclusion to an objective. If I had to use an analogy I would liken it to a horse and cart. You can have set number of horses and build your wagon and load to work with the capability of the horses, or you can have a wagon and load and add horses to deal with the burden of the load. You will have to forgive me for the western analogy... I was watching Clint Eastwood last night - "A fist full of dollars" for about the 100th time.

The easiest way is to determine what you need to accomplish with the photo. If you are taking a portrait, you may decide that an aperture of f8 or f11 would be needed to ensure that you have decent depth of focus throughout the subject. You know that the camera's shutter speed has to to be set to 1/125th sec so that it is in sync with your flash duration. Your wagon is build and loaded. Make sure you enter the ISO and shutter speed into your flash meter. 

Now you need some horses (lighting) to deal with your burden (lighting requirements). Start with your main (Key) light first. You will hold your flash meter up against your subject and aim it at your flash. You will make adjustments to the flash power OR the distance of the flash to subject until your flash meter provides you with a reading that matches the aperture setting you are using. (remember that light intensity changes by the square so every time you double the distance you half the power, and every time you half the distance you double the power).

If you are going with a single light setup you are ready to take your photo. If you are going with a two light setup I would suggest that you take a test photo to see and get a good feel for what your key lighting is doing for you. Make adjustments until you are reasonably happy. The two most common lighting styles are Rembrandt & Broad. (Rembrandt lighting is probably the most widely used. Broad lighting tends to flatten features - great for subjects with narrow faces, deep features, long or pointed noses).

For the second light source simply repeat the same procedure. The only difference will be the light level you set. Generally photographers use a 2:1 lighting ratio for basic portraits. This means that your Main (Key) light will be twice as strong as your Fill light. So if your aperture is set at f11, your Main (Key) light is setup for an exposure of f11, you would want your Fill light to be set to f5.6. I would also suggest that  you take a test shot with just your Fill light on to get an idea of what it will offer.

Now with both flash units ready take your first shot. See what the effect of the two light sources working together offers. Remember that a reflector or piece of white card can work wonders for a secondary Fill source (you will often see one placed under of the face to fill the neck and reduce the under chin shadow).



Hope this helps. 


Spyglass

Spyglass, Thanks for that. I do not realy have a problem with the setup. The problem is I do not have any studio stobes. I am using the AF540FGZ pentax flash. Now according to the manual the GN number is 54 at 85mm. Do I set this on my flash and diffuse through a shoot through brolly or softbox or do I set it to a different zoom length. If I understand the workings of the pentax flash the wider the zoom the less directional is the light.

[spyglass]

Hi Michael,

I think you have a good understanding of the effect of the beam adjustment of your flash. When used with a light modifier the modifier will ultimately control the distribution of light and the factory guide number will not be relevant to f stop and distance, etc.

A softbox and an umbrella were not designed with hotshoe type flash units in mind. A studio strobe will throw light in over a 180 deg half sphere. A hot shoe flash is generally a lower powered device and uses a much narrower light spread to channel the available light onto the subject and be as efficient as possible with the light energy that it has. One is a big shot gun the other a small riffle. Other than that they are both short duration high intensity light sources.

Placement of the flash within the umbrella will probably be as or more important than the beam width adjustment of the flash. Moving in tends to yield less spread (basically like creating a smaller umbrella). The larger the umbrella the large the light spread.

There is a very easy test you can do to get a feel how your light source is working with your "shoot through" translucent umbrella. Take an underexposed picture of your umbrella. You will be able to see the light distribution. If you see that the center is a hot spot and the outer region is quite dark, widen the beam adjustment of your AF540FGZ to try and offer better source distribution. If the center is still overly hot (bright) in comparison to the outer region move the AF540FZ father back out of the umbrella. If you find that spill becomes a problem make a cardboard diverging snoot on the end of your flash.

If you search on the net you will see many photographers that are using hot shoe flash units with shoot through umbrellas have a reflective back to the umbrella opening (creating a brolly box). This reintroduces the rejected light energy back into the umbrella.
Some photographers intentionally place their strobe deep into their umbrella to create a poor mans beauty dish effect (going for a small round source).

At the end of the day the only rule is that there are no hard fast rules that could ever cover every aspect of photography. It is mathematical in its science, but emotional in its application.

Sorry if I have repeated information that you already know, just trying to cover everything off. Sometimes understanding the question is much more difficult that the actual question (purely self induced by the person wanting to help).  
 
Hope this helps,

Spyglass

[Michael]

Spyglass
Thanks for the explanation. It will certainly help me. I am more of a nature and landscape photographer, but would like to move to portraits and I still have a lot to learn for studio photography.

[spyglass]

No problem Michael,

The wonderful thing about this hobby is that it supplies us with endless challenges, and has so many different directions to explore. It is nice to have several irons in the fire. I love landscape and nature photography, working with natural lighting, etc. But I also enjoy product and studio type photography and the control that artificial lighting offers. So many people get intimidated or put off with flash & strobes. There is a little learning curve, as with anything, but once you get a foot hold it can be very exciting. This hobby is all about painting with light. Being able to control light gives you a lot of power and influence with your photos.

I still remember the first flash photos that really blew me away. The photographer was taking pictures of a bicycle racer. He was seated in the back of a pick up truck that was driving ahead of the racer. The flash illuminated the bike a rider and the light fall off offered a frame like quality. Because both the bike and photographer were moving at the same rate their reference to each other was basically stationary. But the background was wonderfully blurred in a tube like manner (motion blur accentuated by the light fall off). I cut the photo out and pinned it to my wall, where it stayed for several years. I have always wanted to try that shot. One day I will. (I might not use a bike, maybe a motorcycle or car - you never know). Thanks for reminding me.

I would love to see your results Michael,

Spyglass