Bursting Balloons !

Bursting Balloons !
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Sunday, August 29, 2010

What is Fill-Flash?

I've seen various opinions of what 'fill flash' is . My thoughts are that it is when the ambient is the main light source and you only want to lift the shadows with a small amount of flash .
As you underexpose the ambient and use more flash you start tending toward 'fill ambient' where the flash is the main light source and you 'drag the shutter' to expose some of the background as well .
So I just thought I'd share the graph I just made showing the relationship between exposure , TTL flash and TTL-BL flash since Nikon defines TTL-BL as "Balanced fill flash" .

As we see TTL flash maintains the same output regardless of where you have the ambient exposed - it doesn't know or care how well you have the ambient exposed - it thinks it is the only light source .

This is why we need to dial in more negative flash compensation when we use TTL flash and the subject is already properly exposed .
TTL-BL on the other hand 'watches the meter' and in situations where they meter evenly [ a centralized subject filling the middle of the frame ] TTL-BL will back off to the equivalent of TTL -1.7 stops to simply act as 'fill flash' .
As we under-expose the ambient TTL-BL steps in and starts to take over control of the exposure of the subject .
The graph I've shown is the result of some controlled tests I did using a flash meter to determine the difference in their output in varying situations .
Ok well I've been doing more tests and calculations on the subject to try and figure out why we lose so much power as we start going into auto-fp mode and think I just worked it out .
Auto-fp flash logically must stay on for longer for slower shutter speeds .
Let's take 1/1000th sec first , the flash must start 'pulsing' before the first curtain opens - then it must last for 1/280th sec [ if that's how fast the curtain moves ] but once the first curtain reaches the other side it must stay open for the duration of the slit that still has to close !
At 1/1000th sec let's say that slit is 1/4 of the frame = another 1/1120th of a second.

Now we look closer at the slit at speeds closer to normal sync .
1/320th shows a much larger slit [ 3X the size of 1/1000th?]
Now after the first curtain moves across the frame [ 1/280th sec] the flash still has to remain on until the second curtain is closed which will now take 3X as long as at 1/1000th = 3/1120th = 1/370th sec extra  !

This would explain why the first drop into auto-fp mode gives us so much less power than 1/2000th .
When I fire the SB24 at 1/16th on the D90 at 1/250th sec I don't see the curtain starting to close yet though sync speed is back at 1/200th .
This means that when the flash goes into fp mode it is doing so over 1/280th sec plus the 1/250th sec that the rear curtain takes to close cutting the total power in half [approximately ] .
So auto-fp would have to push out around half as much power over twice the time as opposed to around 1/250th sec shutter travel at 1/4000th sec - not counting the power before and after the pulse .

So essentially different shutter speeds would vary how long auto-fp stays on , and how much power it pushes out over that time period resulting in the differences we see between 1/250th and 1/2000th in auto-fp mode !

Friday, August 27, 2010

another backward video :)

auto-fp flash power tests

This afternoon I did some tests to compare the power of auto-fp to normal flash . I used a solid white wall and kept the flash set at 1/1 full power and also made sure I kept the ambient level [which  was very under-exposed ] the same , to simulate a situation where we would keep our ambient settings in the same place while reverting to auto-fp mode .
I aimed to get the same histogram in each shot and it was interesting how much difference a few cm made when I made adjustments .

This is what I aimed for :

After each change in settings I moved the camera until I got the same histogram and then measured the distance to the flash head so I could calculate the power difference compared to normal flash .

F25        1/200th normal flash               195cm
F22        1/250th auto-fp mode             68cm  =  1/8th of normal flash power
F16        1/500th                                88cm =    1/5
F11        1/1000th                              120cm =  1/2.6
F8          1/2000th                              136cm = 1/2
F6.3       1/3200th                              120cm = 1/2.6
F5.6       1/4000th                              112cm = 1/3

My conclusion is that due to the way auto-fp works even though the flash head suggests the same working distance at any of these settings when in auto-fp mode it appears that the combination at 1/2000th sec yields the greatest output , after which the curve drops off again .
Since auto-fp flash behaves as a continuous light the slower the speed the more energy it requires ! So faster shutter speeds mean that light is 'switched on' for shorter times , not counting the short period before the shutter opens and after it closes that it will need to be on . This should also result in faster charge times .
In other words , when you revert to auto-fp mode stay away from the the slower speeds and aim for 1/2000th sec and the aperture that gets you the results you want to get the most flash power possible in this mode .

The results :

Wednesday, August 25, 2010

Auto-fp power loss

I've read varying opinions on how much flash power you have in auto-fp flash mode at high shutter speeds .
This weekend I will devise a test to see what results I get .
The distance info reported on the flash head suggest you have a little over 25% of the power of normal flash [ 2 stops less ] but many are reporting 2.3 to 2.6 stops less power .

Saturday, August 14, 2010

New Casio FH100 compact

I just bought a new compact - I wanted something easy to carry with a wide angle lens and after doing a little research ended up with the Casio EX FH100 with a 24 mm wide angle [ - 240mm tele ] and the ability to do high speed video .
I'm really enjoying this video mode !

Monday, August 9, 2010

Fuji F31fd high iso samples

The last 6 meg camera made by Fuji still sets a standard for high iso from a compact . They used their brains back then and stayed at 6 meg but made a larger sensor for better light gathering .
Tonight I did some test images at varying iso's which shows why the newer 14 meg compact sensors still can't catch up - they have too many megapixels and the dots are so small they can't gather enough light at high iso's .

Unfortunately "megapixels sell" or rather "A lack of megapixels doesn't sell " so they have to keep making compacts with more megapixels because people think the bigger numbers mean better image quality and the manufacturers exploit this idea to make people think they need to replace their camera because a 'better' model with more megapixels must be better .....

These images are slightly underexposed which exaggerates their noise .

And a few with different lighting

Thursday, August 5, 2010

Nightclub photography

We all have different views on how things should be photographed - auto , manual , with flash , without flash - on camera flash , off camera flash .....
But basically whatever gets the results you want is the right way and "Jr" - 'Mike Petrie Jr' of nikoncafe has allowed me to copy and paste his thoughts and experiences on nightclub photography :

I wanna start off by saying I by no means consider myself a guru of nightclub shooting. This is just going to be some information that I've learned along the way and some of my techniques. Please feel free to contribute, ask questions or flat out disagree with me. I think this should be a good learning process for any and all involved.

Nightclubs - Starting off

Before you even step into a club, you need to be savvy with a camera. Your non-professional modes aren't going to get you far. Generally speaking, you're always or should always find yourself in manual mode. If words like aperture, shutter speed, ISO, exposure bias, etc... all seem like foreign vocabulary, I recommend picking up a few books and getting more hands on training before considering this. Understanding Exposure is a great book to start you off. The newest edition can be found on Amazon.


Camera Body

Shooting in a dark club is difficult, walking in and using on board flash, a D40 and a kit lens may seem fine - but it's going to be a stressful night. Don't get me wrong, you can "make it work" if you know what you're doing... but your pictures are going to be noisy, flash exposure will be poor and your shots won't look very professional. The better your camera deals with noise and high ISOs, the better your pictures will be without needing to spend tons of time post editing. You don't need to be shooting FX (it wouldn't hurt) but I recommend at least using a camera that has an internal motor.


The faster, the better. The wider, the better. For the most part, you won't be shooting wide open, but being able to work with a fixed aperture throughout the focal range makes life A LOT easier and having the capability of dialing down to f/2.8 is always a plus. If you have the itch to shoot prime, make sure it's wide. That nifty fifty won't do you much good in a tight club. I rarely even use my 35mm f/2.
*For DX cameras, I recommend something beginning around the 17mm or 18mm range. I personally shoot with a 3rd party Tamron 17-50 2.8. FX shooters, I hear the 24 - 70mm f/2.8 works wonders in the club.


Lighting is THE MOST important aspect of club photography (in my opinion). Invest in at least one flash unit. There are many different techniques for shooting clubs and utilizing Nikon lighting, but that will be covered later in the thread. For now, you need to understand that some sort of flash unit is essential.


Pick up a lens hood and a filter for your lens. I call it "the drunk guard". You'd be surprised how much that small investment will help you out in the long run from people smashing into you and spilling drinks.

The basics - Every club is different, but here are general club settings.

Shutter Speed

I tend to shoot anywhere from 1/2 - 1/40th depending on the club and effect I'm trying to achieve. Dragging the shutter is very common in clubs so that you pull the right amount of ambient light into your lens. If you shoot too fast, your subject(s) will look like they are in a dark room... that's kinda boring.


As a general rule of thumb, when shooting with my flash unit, my aperture stays between 4.5 - 5.6 respectively. This DOES vary, but this is a nice starting ground.


More expensive Nikons handle light sensitivity better than others. I keep my D90 between 500 - 800 depending on my shutter speed. I've heard of FX users shooting much higher in their camera's ISO range.

Flash/Exposure Bias/Flash Power

Good luck. This will change every few minutes if you have a lot of strobes and are flipping from portrait to landscape style shots. There are SO man factors that play into these adjustments... the list is endless. One thing I can recommend is a diffuser.

A diffuser will soften light - the pure physics of something sitting between a light source and it's projected path will obviously scatter or hinder the light output in someway (think of clouds) and in turn will help your pictures. The biggest problem with a flash unit (on the hot shoe) is having such an intense amount of light coming from one super small area/on the same plane as your lens, so it's always going to have a little bit of the deer in headlight effect.

Now, shooting on the hot shoe is pretty normal and economical in these types of settings. I say economical because room is sometimes really tight. If you're shooting portrait on the shoe, you're going to get some type of side shadow no matter what you do. Even if you have a Gary Fong or some type of fancy shmancy diffuser, the location of the light source is still going to be coming from the side of the camera, period.

If you want to shoot with your flash in your hand, you have three options. Get yourself a TTL cord or wireless trigger and fire the flash that way. You'll still get to use your precious AF on flash assist light if it's not a slave. Another option is mounting a more expensive Nikon flash (SB 800 +) on your hot shoe and firing another flash in slave mode in your other hand. This is a great option - but a pain in a hot crowded club. Lastly, shooting Nikon commander is always an option... but you don't get to use the luxury AF assist light on your flash unit. You need to depend on the in camera illuminator. Womp Womp.

So, how do you fix harsh portrait sidelights with a single flash? Answer = flash bracket.

Post Production

Do yourself a favor, shoot in JPEG. Raw is incredible, but after thumbing through 200+ photos a night and not be able to batch process... you will be hating your job.