There are many features to digital (or film) cameras that will determine to quality output. Your Optio 230 is a decent little camera but quite frankly the MACRO stinks.
MACRO is not the zoom. Macro is the close-focusing capability. For tank shots this is crucial. You will want to find a camera with the ability to focus close. Minimum focusing distance should be anywhere from 0.5" - 5". Not that you will get a half inch away from things in the tank always but, many times you can catch shots of fish right next to the glass.
Zoom range will help for all occasions. All digital cameras will list a lens equivilent to 35mm. Example: 5.0mm-15.0mm (38mm-114mm equivilent to 35mm). In 35mm (standard film) terms, 50mm is equal to the view of the human eye. It is simply multiplication from there..................100mm is 2x the human eye, 200mm is 4x human eye and so on and so forth. Digital cameras however will advertise a 3x optical zoom or 4x optical zoom etc.. This is the zoom range..........if I have a camera that will zoom (equivilent) from 38mm-114mm............114 divided by 38 equals 3, you have a 3x optical zoom.
Optical zoom vs. Digital Zoom - Optical zoom is where the lens is actually moving back and forth away and toward the image sensor...........true zoom. Digital zoom is the point where you have exhausted your optical zoom and you are now multiplying the size of pixels..........the more you zoom in on a pixel, the lower the image quality. Digital Zoom = Poop.
Flash or No flash? Depending on if you use flash or not will determine the way a photo looks as well. If you like the way "no flash" photos look you will have to look at a camera with good ISO EQUIVILENTS. If you want good flash pics..........you may want to splurge for a camera with external flash capabilities. Reflections are a bear with built in flashes on the cameras unless you are very close to the tank (not completely true in all cases). If you have an external flash, you are putting the flash up higher to reduce the chance of getting reflections in your shot. This is the same reason that you may have "red-eye" problems...........flash is too close to the lens and reflects the blood in your retina.
ISO equivilents are more important than most people think. ISO is film speed. ie: 100, 200, 400, etc.. If you have a camera that only shoots an ISO equivilent of 100 (very common), you are not going to get good low lighting shots. You will want a camera with the capability to change to ISO 200, 400, 800, or even higher depending on how high-end you go. Just as with film, the higher the ISO..........the worse the grain gets. It is all a comprimise.......... not quite as good of a grain quality but, you can at least the picture is bright.
Usually the higher-end camera you get.............the better the metering (way the camera reads light off of the subject) system as well as better auto focus systems.
Mega-Pixels are not everything in this world. The amount of pixels a camera has will determine the maximum print output. Somewhat of a good rule to go by is: 2megapixel=5x7, 3megapixel=8x10 however, 4megapixel=better 5x7s and 8x10s
If you have a high-megapixel camera, it will also leave you room to play with. If you plan to crop a photo you need extra resolution to still get good output from your crop.
Manual Adjustments are a whole other advantage. Many of the cameras simply have automatic adjustments to do everything for you. These can work pretty well in a lot of cases but, the camera does not know what you are trying to achieve. If you have the ability to change exposures by F/STOPs or SHUTTER SPEEDs, you can obtain a multitude of effects. Digital cameras are still cameras and that is how they should be used to get the best results.
f/Stops are one of the most important factors in photography to obtain the correct amount of lighting, as well as controlling depth-of-field and sharpness. f/Stops are another word to measure APERTURES. An aperture is an opening in the lens that controls the amount of light that can reach the film or digital sensor. This amount of light is measured in f/Stops. ie: f/2.8, f/4, f/5.6, f/8, etc.. The smaller the number, the larger the aperture (opening). This enables you to shoot a fast picture since it is letting a lot of light in quickly, however, it also makes for a short depth-of-field. The depth-of-field is the frontmost focused point of the photo to the furthest point of focus in back. If you want to increase the depth-of-field (I often do), you must then start setting the camera to the larger numbers (smaller apertures) and this will give you more area of focus. Confusing.........isn't it?
Shutter Speeds can help you obtain more effects in a different way. If you are trying to stop the action of a fast fish (or race car for that matter), you will have to make sure that your shutter speeds can freeze the frame. Also if you are trying to show speed you may want to slow down the shutter speed a little bit to get a little motion blur on the moving object to give a sense of the speed. It is going to take some practice.............believe me, I have lots of it ahead of me.
I can go on more if you want..........................It all depends on what you are looking to accomplish. Let me know if you have any other questions.
