Strobe *too* powerful?

[kdietz]

shoot in manual.....f8 and 1/1000.....back off shutter speed if it's too dark

Karl

 

[Jcsgt]

Cole slaw lids make great diffusers. the milky white plastic ones. Or drink lids stacked.

Great idea! How would you attach them?

 

[Code Monkey]

I'm a little confused. I thought that shutter speed was supposed to alter the background when using a strobe rather than the foreground (keeping in mind, here, that all my knowledge is from reading-up rather than experience ). Does that not apply to macro photography or is there something else I'm missing?

Again, thanks for all your help!

 

[Doc Harry]

I'm a little confused. I thought that shutter speed was supposed to alter the background when using a strobe rather than the foreground (keeping in mind, here, that all my knowledge is from reading-up rather than experience ). Does that not apply to macro photography or is there something else I'm missing?

Shutter speed and aperature both control the amount of light reaching the camera's sensors. Varying either or both also has other effects such as darkening the background, increasing depth of field, etc. But the bottom line is that shutter speed and aperature control light.

If too much light is reaching your camera's sensors (overexposure), then:

(1) decrease the light reaching your subject (e.g., lower flash power, add a diffuser, get further back, mask the on-camera flash),

and/or

(2) reduce the amount of light reaching your camera's sensors (e.g., increase shutter speed, use a smaller aperature, use a lower ISO, etc.)

How you manage the solution depends on the interplay of all of the above factors. For instance:

-moving back may cause too much back-scatter with particulates in the water and so may not be an option
-increasing shutter speed may make your background too dark for your taste, so you'll need to modify other parameters
-increasing shutter speed may reach a point where it doesn't sync well with the flash
-using a small aperature may give you more depth of field than you desire

Play with the various parameters in various combinations, review your photos frequently to learn from your mistakes and keep playing! It's all a lot of fun!

I'm not an expert on underwater photography, so others chime in please!

 

[Tortuga Roja]

You have to remember that your camera and strobe don't "know" about each other. So, when you use Aperture priority, you set the fstop and the camera decides how to set the shutter by seeing how much light there is. But since it doesn't know that the strobe light is gonna be there, it guesses wrong. So you have to set the the aperture AND the shutter. That's why you have to shoot manual with a non TTL strobe. HTH

 

[Tortuga Roja]

Oh yeah, and plastic from a milk jug is good for a diffuser too. And a diffuser is a good thing to have on almost always.

 

[kdietz]

I'm a little confused. I thought that shutter speed was supposed to alter the background when using a strobe rather than the foreground (keeping in mind, here, that all my knowledge is from reading-up rather than experience ). Does that not apply to macro photography or is there something else I'm missing?

Again, thanks for all your help!

When shooting WA, the SS and aperture do control the background (ambient light) and the strobes light the foreground/subject....this gives balanced lighting. When shooting macro, all the light is from the strobes and that's why you should adjust shutter speed or strobe power/distance (you've already maxed out your aperture at f8) to control the light in the scene.

I agree with Mike about using any auto functions underwater. The camera gets fooled because it doesn't know that a flash is attached. Manual is the way to go. Shoot, review, adjust and shoot again. It won't take long and choosing settings will become second nature.

Karl

 

[MarkH]

When shooting WA, the SS and aperture do control the background (ambient light) and the strobes light the foreground/subject....this gives balanced lighting. When shooting macro, all the light is from the strobes and that's why you should adjust shutter speed or strobe power/distance (you've already maxed out your aperture at f8) to control the light in the scene.


Karl

I don't know much about digital cameras and from what I've been hearing, I have to ask: Why is a digital shutter so different from a film shutter? With film, you have to sync the shutter speed with the strobe, but in digital you don't have to? And is the flash duration so long with a digital strobe that you can use a higher shutter speed to cut out some of the flash? By the way, for a diffuser, I've used white plastic grocery bags held on with a rubber band. They do make the light a bit warmer, but I've realised it's hard to find a "homemade" diffuser that doesn't shift the colour abit. It's usually too small of a difference to notice though.

 

[kdietz]

I don't know much about digital cameras and from what I've been hearing, I have to ask: Why is a digital shutter so different from a film shutter? With film, you have to sync the shutter speed with the strobe, but in digital you don't have to? And is the flash duration so long with a digital strobe that you can use a higher shutter speed to cut out some of the flash? By the way, for a diffuser, I've used white plastic grocery bags held on with a rubber band. They do make the light a bit warmer, but I've realised it's hard to find a "homemade" diffuser that doesn't shift the colour abit. It's usually too small of a difference to notice though.

Film cameras have mechanical shutters and P&S digital cameras have electronic shutters...this allows them to be able to sync at any speed....there will be a point where the shutter is faster than the flashes full dump and the images will start to be dark

Digital SLR cameras are mostly all mechanical and most are limited to a max. of 1/250....some like the D70 have a combination of both and can sync at 1/500

Karl

 

[ScottB]

Just looked at the camera specs at http://www.dpreview.com/reviews/olympusc5050z/page2.asp

You have the ability to use exposure compensation of up to two stops plus/minus in 1/3rd stop increments.... try playing with that,


Quoted from dpreview.com's glossary:

"The camera's metering system will sometimes determine the wrong exposure value needed to correctly expose the image. This can be corrected by the "EV Compensation" feature found in prosumer and professional cameras. Typically the EV compensation ranges from -2.0 EV to +2.0 EV with adjustments in steps of 0.5 or 0.3 EV. Some digital SLRs have wider EV compensation ranges, e.g. from -5.0 EV to +5.0 EV.

It is important to understand that increasing the EV compensation by 1 is equivalent to reducing EV by 1 and will therefore double the amount of light. For instance if the camera's automatic mode determined you should be using an aperture of f/8 and a shutterspeed of 1/125s at ISO 100 (13 EV) and the resulting image appears underexposed (e.g. by looking at the histogram), applying a +1.0 EV exposure compensation will cause the camera to use a shutterspeed of 1/60s or an aperture of f/5.6 to allow for more light (12 EV).

Of course, as you become more familiar with your camera's metering system, you can already apply an EV compensation before the shooting. For instance if your camera tends to clip highlights and you are shooting a scene with bright clouds, you may want to set the EV compensation to -0.3 or -0.7 EV."

Take care,
Scott