Isolating images with a black background

[Ardy]

I am sure you all know how to do this but I havent a clue (in more ways than this one).

I have just come back from Lembeh and although generally happy with the results I am unable to take fish shots in the water column and have them come out with a black background. This was easy with my old film set up.

What I am doing/using: e520 with 50mm macro lens. shooting manual at F18 F20 or F22, 1/80th sec. This has resulted in shots with the background exposed as if it was at a lower F stop. Almost forgot I have 100asa set.

I understand that there are issues due to the sensor size but that aside how the hell do I do these simple shots.

I hope you are not going to say 'select the background in PShop etc etc' I am already pissed with the amount of time I am spending on the laptop.

 

[dhaas]

Ardy,

F-stop only controls exposure of the foreground, i.e., the part lit by your flash. BACKGROUND is TIME, as in shutter speed.

Earlier in the day and later afternoon boost your shutter speed to whatever the maximum it can synchronize with your flash (Not sure of your particular model it's in the manual I'm sure.)

UPDATE: Olympus's site says 1/180 so there's your fastest shutter speed.

This should result in the background being so underexposed to be black, even in daytime and make your flash lit subject "pop out".

Good luck!

David Haas

David Haas Underwater Photography

 

[herman]

1/80 is your problem. Crank it up as far as you can go, I use 1/1000 or 1/2000 if I want a black background.

 

[dhaas]

As Herman suggests 1/1000 or higher will work also but ONLY if you are shooting MANUAL flash settings.

If you have a TTL type system hard wired the camera will still only fire at the MAXIMUM shutter speed no matter what you set on your camera's dial.

EXIF data would confirm this.

Good luck getting the effect you want!

dhaas

 

[herman]

Manual camera mode (user controlled shutter speed and F-stop), not manual flash, background is uneffected by flash/strobe. If you are shooting UW you should forget using any kind of programmed modes and stick strickly with manual.

 

[Ardy]

Hi GUys thanks for the info.
I shoot, at the moment, only on manual with a slave strobes triggered by an optical cable. I will try upping the shutter speed and 1/1000 would be interesting to see if the flash can synchronise in manual at that speed which my old film set up could not do.

 

[herman]

Hi GUys thanks for the info.
I shoot, at the moment, only on manual with a slave strobes triggered by an optical cable. I will try upping the shutter speed and 1/1000 would be interesting to see if the flash can synchronise in manual at that speed which my old film set up could not do.

Here are a couple of examples of shots taken in manual. The first was taken at 1/100 and the second was taken at 1/2000, both were taken at the same distance, strobe power and F-stop. If I had decreased the speed to 1/80 or so, the background would have been lighter. Is this the kind of effect you are trying to achieve?

Here is another thread you might find useful.
http://www.scubaboard.com/forums/underwater-photography/214500-help-manual-camera-settings.html

F-8 1/100

F-8 1/2000

 

[fairybasslet]

Very nice Herman. Thanks for the info

 

[gravity]

those that are telling you shutter speeds of 1/1000 or more are referring to point and shoot cameras. point and shoots typically use an electronic shutter and can sync with the strobe at speeds of 1/1000 or faster. dslr's typically use an actual shutter and sync at slower speeds. my experience is that even shooting manual (which i always do as i don't have ttl) you still cannot sync over the maximum sync speed without having lighting abnormalities, which is typically in the 1/180-1/300 range depending on the camera.
Either way, you should be able to get a black background by using the fast end of your sync speed and your lowest iso.

 

[gravity]

when you shoot exceeding your max sync speed, sometimes it will work, other times the lighting will by clipped by a shutter that is opening or closing while your strobes goes off, other times your shutter will not match up with your strobe going off at all and you will end up with an all black picture. for consistent results don't exceed your max sync speed, again not an issue if you aren't shooting an dslr.