The theme for this Assignment is "Flash at sunset". Shoot a person with a flash at sunset. This is a very popular assignment at photo schools with the opportunity to create very interesting images while learning a lot about flash. We will learn about guide numbers and gels. Print this out and take it with you.

What is a guide number? It is a number that rates the power output of your flash at a certain distance and aperture.

GN = Distance(in feet or meters) x F number


The guide number represents an exposure constant for a flash unit. For example, a guide number of 80 feet (24 m) at ISO 100 means that a target 20 feet (6 m) away can be fully illuminated with an aperture of f/4 (80 = 20 × 4) and a film speed of ISO 100.


For the same guide number and an aperture of f/8, the light source should be 10 feet (3 m) from the subject (80 = 10 × 8).

Guide numbers can be given in feet or metres, and are usually given for ISO 100 sensitivity.

138' (42 m) is the guide number of a canon 580ex II set at full power and 50mm, If you have a different flash look in the manual and you will find a table of guide numbers for different powers and flash zoom ranges.








Now that we know what a Guide Number is, Here is what your going to do:

1. Set the flash(idealy have the flash off camera) on full power, 10 feet away from the subject, and zoomed at 50mm.


2. using your guide number set your F stop. Basicly divide your GN by 10ft and thats the F stop you need to have a perfect flash exposure. So If the GN of the flash is 138' at 50mm, then 138' / 10ft = F13.8(F 14)
138GN = 10ft x f13.8 (f14) for a 580exII
(if you have nikon and have to shoot at 200iso, be sure you compensate for that with f stops, unless the GN table for Nikon flashes was made using 200ISO)


3. Sunsets are warm, you may need(I recommend it) a half or full CTO(color temp orange) gel to match the colors, the gel will take off a half stop or stop of light. Lower your F stop a full stop or 2/3rds to compensate.


4. Figure out the right shutter speed for the ambiant light. point the camera at the sky with the sun just out of frame and over expose one stop only adjusting shutter speed. That will give you a pretty good exposure for a cool looking sky. If the shutter speed is too slow, maybe lower the F stop a full stop then set the flash to 1/2 half power. you will get the same flash exposure but get to shoot at a faster shutter speed.


5. Shoot a picture. Play around with different color temp settings in camera and ambient exposures.


Here is a good example from the cover of the current tv guide.(they are using 2 flashes but you can do it with one and a fill card)















Guidelines (just to keep us all on track)
*SHOOT MANUAL on camera and flash
* Assignment is open from Sunday - November 9th Till November 23rd giving you 2 weeks.
* Only photos that have been shot within the assignment date range are allowed.
* No signup is required, participation is encouraged regardless of skill or equipment level (you do need a flash or auto fail)
* Photo size limit: 800px on the longest side
* Basically, photograph however you like and normally do…whatever photography is to you. As many (or few) bodies/lenses/formats//Post-processing as you’d like. Sticking to basic PP is encouraged, tho’.
* If you’d like, post brief but relevant photo information and note PP (if any) is done (*Free GIMP software*). Maintain EXIF data if possible.
* Keep comments on topic, constructive, and considerate.
* Have fun!

subscribed so I can find this later.. I have no idea how to really use my flash I always set it to ETTL and go.

#23?

This is right down my alley. I'm dying to learn how to best control my two flashes. I just need to find some models.

nice, someone ELSE posting assignments, and one I can learn from!!! Awesome!

(subscribed)

nice! right up my alley, i've done things like this before using flash on a shoe cord.
means i'll have to go find a model and a sunset now

This is what i came up with 4 years ago when i shot it for school.

Here is one of mine from a shoot last week. I love to underspose the sunset with the shutter, creates vivid colors.

I know this sort of sucks but, the "pan" was great, the flash was fired, it was at sunset and the result was sort of cool with the exception of overexposure, which is something the SD-14 I am using is almost impossible to avoid, minimum 1/200th second exposure with flash. Below is a pic without flash at 1/500th which I like a LOT better but I get the idea, my camera cannot keep up with me again...time to go shopping soon, EOS Canon 5d Mk2 with a stock of lenses and stuff...not until the motorcycle business improves a LOT though. It sucks to be a premier purveyor of fine Italian expensive bike right now....

about 100/th sceond exposure here.




about 1/500th here...if only my flash could keep up....so many "if only's with Sigma's SD14...so many.

This is from this weekends 900 mile road trip marathon. A much better use of flash at sunset for me, feel free to make suggestions, trying to learn this technique and it is way more difficult than I thought at first!