What is ISO, aperture and exposure?

George Farmer

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aaronnorth said:
Thanks George,

would faster shutter speeds for photographing fished used as they are fast?
Yes.

This is where full tank shots get tricky, as generally the tank lighting may not be sufficient to give you a fast enough shutter speed. 1/125 sec. is normally enough to freeze most fish.

Cranking up the ISO will help, as you have learnt by now (hopefully), but image grain can be an issue.

Also increasing the aperature will help, but you lose important depth of field, essential for ensuring all the tank is in focus.

This is why flash guns are commonly used by the more serious 'scapers/photographers.

A remote flash is positioned above the tank, sometimes using a light box, to ensure all light goes downwards and into the water. So shutter speed is fast (freeze fish movement), depth of field is good (smaller aperature) and ISO is low (better quality).

My next photography purchase will be a decent flash gun and remote cable. It takes aquatic photography to a new level. All the CAU guys use them, Neil Hepworth, Amano (lots of them!) and a couple of guys on here (Dave Spencer for one).

Another option is to simple get as much light as possible above the tank. I've used 8 x HO T5 + T8s before now.
 

aaronnorth

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A quick test! If i was photographing a fish, would the following settings be used:

low aperture - f/2.8 - picks up fine detail
fast shutter speed 1/60 sec or quicker?
ISO 200 as i have bright lighting, but i want a fast shutter speed

how would the pic come out? :) :? :(
 

George Farmer

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f/2.8 = great for shooting fish and blurring background.

1/60 sec. = ok for slow moving fish, or if you're really good, you can 'pan' (follow the fish with the camera and shoot).

ISO 200 = fine with most cameras.

But composition is also VERY important...
 

aaronnorth

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so composition is when you try to get all the elements like lighting,depth, and put it into rule of thirds and everything makes it eyecatching.

i have drawn these lines on:

006_13-1.jpg


is that correct?
 
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