For beginners - Point and shoot flash

[Chris Bangs]

For those of you just getting started I will try to post some basic tips on underwater photography.

First lesson/Tip

Using the internal Flash on a compact camera ( Digital or film )

I will break it down based on my own decesion process when I do any dive. in a nutshell, suspended particles are your worst eneny and how should you deal with them in order to create a nice clear image!

Suspended particles produce what UW photographers call "backscatter", you have seen it! Those large bright blotches that appear in many photos shot with small cameras with internal flashes. In essence what is happening is the light from the flash bounces off the suspended particle and is reflected directly into the lens. The closer the flash is to the lens the more difficult it is to avoid getting this nasty backscatter in the image.

Your mission! Try to reduce the effect it has on your photos.

I will try my best to help.

Basics

The general rule of thumb is to shoot upward as the lighter background will reduce the effect of the backscatter. if the water is a bit dirty a dark background, be it water or reef will highlight the backscatter.

In bad conditions consider shooting macro if your camera or attachments support it, otherwise, do not use the flash and just try to shoot shallow with the sun behind you. Later you can correct the color in photoshop. there is a great "action" plug ( mandrake UW action )in that makes this a snap.

Good vis but some large particles still present, The flash can be used but any particles between you and your subject will produce large lighter bloches on the image. This is a game of chance hoping that most will end up in the dead space in the shot and not on the subject. again in such conditions try shoot so that the background is quite bright.

If the vis is so bad you have trouble seeing your buddy or even reading your guage, forget the camera and just have a good dive!

I appoligise if this is poorly written, I am just a photographer and not a "photojourlnist" Now you know why!

anyway, ask questions and I will try my best to help out.

Also, any suggestions as to what I should discuss next?

Chris

 

[f3nikon]

Good work. Thanks for sharing your photos. Now if I ever get around to scanning my slides I hope to share them also. Where were your clown fish photos taken?

f3nikon@excite.com

 

[Chris Bangs]

Ahh, scanning, what a pain, I have thousands of images in pelican cases waiting for me to get off my lazy bum and scan them, I am actually waiting for digital cameras to catch up with scanner resolution, then I will just use my bellows/slide copier to make the copies.

Anyway, all the anemone fish shots except the one in the "pink" anemone were taken on Guam. The pink one was taken on Okinawa.

Chris

 

[the_cat_keeper]

Also, any suggestions as to what I should discuss next?

Chris

How about writing something on using digital SLR for a new uw photographer with no technical know-how on photography? Most of my pictures were taken using trial-and-error. I tried to read about underwater photography on the web but the discussions are usually so technical that they are beyond my comprehension.

 

[Chris Bangs]

Hello Cat keeper

I agree, I also am involved in another "digital" forum but I like discussing photography and not all that interested in much of the tech talk about camera technology.

Anyway, first of all photography is photography, digital is only a different way to record the image period. A Digital SLR works exactly like a Film SLR, the difference is that digital SLRs add more exposure latitude, let you see you results instantly, and most important for underwater use, you can shoot more than 36 images at a time.

advantages of using a SLR are

A, the user can determine if the shots is in focus and focus on a specific portion of your subject

B, there are more lens choices and in most cases the optical quality of such lenses is far superior to fixed lenses on consumer cameras. for macro and wide angle this is even more true as "digital" zoom and Wide angle "adapters" do not even come close to producing the image quality of dedicated macro and wide angle lens

C, ( for good or bad ) most SLRs allow more user control over the camera functions

We all know the disadvantages

"big bucks and much bulkier set-ups"

Anyway, My first recommendation for someone wanting to make the SLR leap, is to get Jim Church's "Essential Guide to Nikonos Systems" This book it is available from most major booksellers. Although it was written based on using a Nikonos, 90% of the material is general photography and of course underwater techniques. I still refer to that book for strobe setting info.

feel free to fire away some specific questions you have on SLR usage.

 

[the_cat_keeper]

Hi, Chris,

will look for the book... and in the meantime, here's some questions (do you know what you are getting into, saying to fire away questions? )

On a digital camera, I can adjust shutter speed, aperture, ISO exposure and flash output to take a picture. I usually keep the exposure and flash output fixed, and adjust only the shutter speed and aperture. Is this the right way? Even with adjusting only 2 parameters, I feel like I am spending so much time in the water adjusting the settings.

I'm really confused :06: ... a friend uses only f2.8 and f5.6 underwater and the pictures turned out great. While I do trial-and-error with all the aperture opening and shutter speed that is available on my camera... and when the picture still looks dark, then I increase the exposure from ISO50 to maybe ISO100.

Thanks...

 

[Chris Bangs]

Hi

when using automatic settings Large apertures like 3.5~ 5.6 will produce sharp images as the camera will use faster shutter speeds, but at the cost of depth of field, in other words your subject may be in focus but the background and foreground may be a bit soft.

basically, when using a flash, shutter speed will only affect the natural light exposure.

Here is what I do for a normal shot where I want to use the flash to light a subject in the foreground and have expose the water in the background to get my desired hopefully blue color.

I first need to determine the proper shutter speed and aperture to expose the natural light properly. SLRs have a meter in the viewfinder that makes this quite easy. My goal is to set the aperture to give me as much depth of field as possible ( within my strobe power limits as well ) while still keeping the shutter speed at or above 1/60th to avoid motion blur due to subject movement and camera shake. this requires adjusting both the Aperture and shutter speed until the optimal setting is reached based on the light meter readings. Consumer digital cameras may have some kind of exposure indicator

Once I have that set I then set the strobe power based on the aperture as well as how far the subject is away from the flash ( max 2 M/6 ft ) . real close use less power, farther away, requires more power. this may take some practice to learn your individual strobe exposure settings.

Shutter speed is used natural light exposure. in the case of underwater photography it is usually set to properly expose the background, and in most cases it is used to properly expose the water in the background. The flash exposure is controlled either by the aperture or manual strobe power setting, depending on your camera and strobe, combinations of both these settings can be used to give you more latitude in exposure settings.

Anyhow, with digital this is much easier to dial in than with film because you can preview your results and make adjustments on the spot

 

[the_cat_keeper]

I see, that's where I've gone wrong... I kept assuming that I should use a faster shutter speed to avoid "blurring" (is there such a word?) the pictures, and using strobe to get to the right exposure... No wonder most of my pictures look so dark!

Another question, since you brought up the use of the strobe... I read somewhere that there is a particular speed the strobe operates at, and I should synchronize the camera shutter speed with the strobe. I checked the spec of my strobe and did not find mention of a speed. Have I misunderstood?

Also, what exactly does it mean by "Through-The-Len strobe control system? Is a TTL camera one that tells the strobe how much light is required automatically?

Thanks again...

 

[Chris Bangs]

This is called sync speed, in reality it is based on the fastest shutter speed that can be set when using a flash , ( 1/90th to 1/250th. most mid level SLRs sync at 1/125, high end cameras may sync at 1/250).

Why is this true if the flash duration is 1/5000th or faster. Well, the shutter works like a curtain, and the flash must fire when it is fully open, if the flash fires too early or too late only a portion of the frame will be exposed to the flash output. older cameras and newer mid level cameras need more fudge factor. the high end cameras that can sync at higher speeds have better electronics and mechanisms to control the flash firing time.

anyway, most if not all cameras that have automatic features, know when the flash is connected and if you set a speed too fast, the camera will default to the fastest sync speed.

hope this helps

sorry, in a hurry, will be back later

got a typhoon knocking on my door

 

[sbloomer]

Later you can correct the color in photoshop. there is a great "action" plug ( mandrake UW action )in that makes this a snap.

Pray tell, where can I get this action? I have searched using Google but to no avail. I use levels (manually) to do this with reasonable success, but if there's a faster wa to do it I'm all ears.