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Nautilus

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Could we (I) get some information on auto settings and and manual F stops while in manual A setting using a digital camera, and ISO settings and what happens at different speeds. Tell us why you would use a curtain setting in A and T manual modes.
Which camera do you use? :)
 

NaH2O

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Good questions Nautilus. I have been wondering about the ISO settings, and when I should be changing them. Could someone explain what A and T manual modes are? I always use aperature priority mode when I try to take macros, but that is because I don't know what the others do. I'm very photography challenged.

I use the Canon G3
 

Llarian

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Nautilus said:
Could we (I) get some information on auto settings and and manual F stops while in manual A setting using a digital camera, and ISO settings and what happens at different speeds. Tell us why you would use a curtain setting in A and T manual modes.
Which camera do you use? :)
Sure thing! I'll see if I can have something written up this evening. Too early in the morning to try right now. =)

Oh, and I shoot with an Olympus E-10.

-Dylan
 

Nautilus

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Nikki,
I used the G2 that I gave to my wife for her birthday until I got the 300D.
Can you get different lens for it? When I bought the G2 I thought I heard someone say you can get different lens for it!

Av is the abbreviation for Aperture value.
And Tv stands for time value.
 
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Mikeydog

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Camera Settings..

ISO: You want to try to set this as high as you can. This will allow you to shoot a higher shutter speeds under lower or low light (or smaller apature, see below for explaination). The downfall is that with many digital cameras the higher the ISO the more noise you photo will encure (noise is defined as rogue pixles in your pictures). I try to keep my camera up around 400 ISO, and I have no problems at all with noise, this gives me either 1 to 2 fstops (apature) or about 1/75 a second on my shutter speed. Whichever I prefer.

Apature Priority Vs. Shutter Speed: When shooting corals and other, farely non moving criters you probably want to shoot using Apature Priority. The smaller the apature (22 is smaller then 5.6) the more depth of field you will have in your picture. So if you focus on the center of a cluster of Zooanthids at apature 5.6 all the zooanthids within an inch (or so) of the center of the picture will be in focus, the farther out of the center the objects are the faster they come out of focus. The smaller the apature, lets say 11, the more zooanthids in that same picture will be in focus (maybe and inch and a half from the center of the picture). The down fall to shooting at smaller apatures is that, the smaller the apature the less light that is let into your camera CCD, thus you will need to shoot at slower shutter speeds to compensate for that (the camera will choose for you, unless you are in manual mode). And the problem with shooting at a slower shutter speeds, is that objects start to blur from movement. Most people can take a picture of a static object at a shutter speed of around an 80th of a second without any bluring from movement. However it becomes more difficult to do this when the object is moving, swaying or pulsing. You should always try to use a tripod that can help out a ton..

Anyway that is just a quicky answer. If you have any questions let me know

Mike
 

Llarian

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ISO: You want to try to set this as high as you can.
I'd really strongly disagree with that advice. The only time you should ever bump up ISO on a digital camera is when you need a faster shutter for a given aperature (usually wide open). Its not as bad as high-ISO film, but digital noise is ugly as hell, and while you might not care if you're just posting the image to the web, it becomes very very noticable if you happen to decide you really liked a particular exposure and want to blow it up to an 8x10 print. There are, of course, noise reduction algorithms, both in-camera and in photoshop, but they always will result in a loss of detail. (As does shooting at a higher ISO period, noise aside).

For anything other than fish, you can almost certainly get away with shooting with a tripod and the lowest ISO possible. (Most digital cameras except the true digital SLRs, have such a deep depth of field to begin with that you seldom need to stop down unless you're taking extremely close macros).

-Dylan
 

Mikeydog

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Llarian, I'm sorry I should rephase that you can bump up your ISO as High as possible, until noise appears, and then step down one (might need to play a little to figure this setting out). Most cameras will go upto 800, 1600 or even higher. So bumping up 1 or 2 ISO settings on most NEW cameras should not produce significant noise, if any at all.

I guess I just assumed people were asking about closeup pictures (macro). For those type pictures I would try to get the smallest apature (within reason, you probably won't get more than 11 and still keep the shutter speed up) with the highest shutter speed
 
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Nautilus

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Dylan,

I read my manual and understand most at the time I read it. Now when going out and doing some practice shooting I always start getting confused with the aperture size which effects the depth of field and then which value is smaller and which is lager.

I do a search and a web page says The aperture values F11.4 (smallest aperture), F6.8, and F4.0 (largest aperture) so how can 11.4 be smaller then 4.0 as I see it as 11.4 is the larger number. Do you guys have a chart or something for me or us to printout for the values?
I am just assuming that 4.0 is the amount the shutter opens so the smaller the number the larger the shutter hole is which has more light coming through? The higher the number say 11.4 the more the shutter is closed with less light coming in?
 

NaH2O

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Can you get different lens for it? When I bought the G2 I thought I heard someone say you can get different lens for it
My manual has a section on "Using Conversion Lenses (Optional)/Close-up Lenses (Optional)". It does indicate:

The Wide Converter WC-DC58 and the Tele-converter TC-DC58 for the PowerShot G1/G2 are not recommended since shooting problems may occur.
I believe Chuck uses the G2, and he takes some awesome photos. Maybe he can let us know if he has ever used a different lens.
 

Scooterman

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I have the G5, despite the purple fringing claimed problems (which can be avoided easily), it has advantages and great performance. I have a complete lens kit, filters all will fit the G3. One thing about digital photography over analog cameras, lighting is more crucial, indoors more so, the ISO ratios don't seem to slide on the same scale as in an SLR but the idea of thoes settings remains the same. If your doing a close-up, get a tri pod, take some time, use your manual functions, it takes practice. Unless your talking about a high end Digital SLR, or analog SLR your manual control isn't going to be the same on comparison, these cameras are for the most part snap & shoot, if you read the reviews of professionals you'll get that form most of them, not that some of these cameras are awesome & have a ton of features Analog cameras don't have. When your talking lenses, you can get a large variety of lenses for the SLR's, most digital cameras have optical lens zooming, & digital zooming, producing a combination of quality over zoom factors.
 

MtnDewMan

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I do own the G2 ... but use the stock lens. I think you can replace the lens if you use an adapter like this:

http://www.lensmateonline.com/G2start.html

My photos are very simple though. I don't do tooooo much with the camera to take my shots. It is much harder these days now that I am using 20000k bulbs, haven't taken many in a while actually. I guess I should get on that :)
 

Mikeydog

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Nautilus:
Aperture refers to the size of the opening in the lens that determines the amount of light falling onto the film or sensor. The size of the opening is controlled by an adjustable diaphragm of overlapping blades similar to the pupils of our eyes. Aperture affects exposure and depth of field.

Just like successive shutterspeeds, successive apertures halve the amount of incoming light. To achieve this, the diaphragm reduces the aperture diameter by a factor 1.4 (square root of 2) so that the aperture surface is halved each successive step. So the f-stop after f/4 will be (f/4 x 1/1.4) or f/5.6. "Stopping down" the lens from f/4 to f/5.6 will halve the amount of incoming light, regardless of the focal length of the camera/lense conbination. Because f-numbers are fractions of the focal length, "higher" f-numbers represent smaller apertures.

Soooo there you go. Kinda a dry definition
 

Nautilus

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Mikedog,

Yes it read just like my manual. I can't seem to grasp that part of it and it frustrates me to no end.

Mikeydog said:
Nautilus:
Aperture refers to the size of the opening in the lens that determines the amount of light falling onto the film or sensor. The size of the opening is controlled by an adjustable diaphragm of overlapping blades similar to the pupils of our eyes. Aperture affects exposure and depth of field.

Just like successive shutterspeeds, successive apertures halve the amount of incoming light. To achieve this, the diaphragm reduces the aperture diameter by a factor 1.4 (square root of 2) so that the aperture surface is halved each successive step. So the f-stop after f/4 will be (f/4 x 1/1.4) or f/5.6. "Stopping down" the lens from f/4 to f/5.6 will halve the amount of incoming light, regardless of the focal length of the camera/lense conbination. Because f-numbers are fractions of the focal length, "higher" f-numbers represent smaller apertures.

Soooo there you go. Kinda a dry definition
 

Llarian

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The aperature (F-stop) is a function. Literally defined, F is the focal length of the lens. So if you are using a 50mm lens, F/1 is a 50mm aperature. (Almost impossible to have a decent quality with.

So F/2 is a 25mm aperature, F/4 is 12.5mm, etc.

The "stops" typically are in 1/3 or 1/2 stop increments, which is why you see odd numbers. So F/4 would be one full stop darker (1/2 the light entering) than F/2. F/2.8 (a common one) is around 1/2 a stop darker.

Because we're usually talking about consumer (2/3" or smaller CCDs), depth of field is almost irrelavent, since lens focal lengths are usually less than 9mm true length. It APPEARS to be similar to a full-sized lens in total field of view because of the smaller image circle, but for calculating depth of field, which uses the true focal length, the dept of field is near infinite at anything smaller than a wide open or nearly wide-open aperature.

-Dylan
 

Llarian

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Oops, sorry, I goofed. Surface area, not diameter of the aperature.

F/2.8 is a full stop darker than F/2, F/4 is a full stop darker than F/2.8

If you think of a stop as doubling or halving the amount of light, that's the most important thing. The higher the F-stop, the less light and smaller aperature (because its a division function).

If you take a look at this site: http://www.sizes.com/tools/photoaper.htm
at the bottom is an aperature chart in 1/4 and 1/3 stop increments. The top line of each chart is a full stop from number to number. Hopefully that helps a little.

(Likewise, shutter is inverse to the surface area of the aperature. If I shoot at F/2, 1/250th of a second, I can get the exact same light, but a deeper depth of field and and slower curtain by shooting at F/2.8, 1/125th of a second.)

-Dylan
 

Mikeydog

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Basically the Lower the number the larger the Apature (more wide open the apature is that lets light into the camera to the CCD or imaging chip). The when you have your apature set wide open f4 or something like that you have the ability to shoot a picture in lower light situations because the dialiated open (much like your eye does in a dark room). Since your camera is receiving more light to the CCD you have the abililty to shoot at a higher shutter speed.

Example: I am shooting at a group of green mushrooms in my tank (maybe the size of a softball), all my lights are on, and my camera is on a tripod right up next to the glass. I focus my camera on the object, then look at my camera settings. If I want to focus on a single mushroom, the I set my apature Up to f4 or so. Then only that main mushroom will be in focus and the surrounding ones will move out of focus the farther they are from the middle of the picture. If I want more of the mushrooms to be in focus I stop down my apature to 11 or so. It is much like the you squint your eye to focus on more distant objects. By squinting you are forcing your pupil to diolate or close up.

As mentioned in my first post, the lower the apature (11 or whatever) the less light is let into the camera thus you have to shoot at a slower shutter speed, to expose the CCD to light for a longer period of time. That is where ISO can help by making the CCD more sensitive to light. But once again the downfall to that is if you set the ISO to high you will get noise (which is a side effect of a digital camera). You will have to experiment with your camera to see what setting will result in the best pictures.

I am by no means an expert or even close, so take my advice just as my 2 cents..

Thanks
Mike
 

Katchupoy

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Here is my two cents. let us make it in laymens term.

ISO = Light sensitivity. Look for the lowest you can afford or see. Canon has 50 ISO.
Why? ... Lowest is the clearest. Going up in ISO becomes noisier "BUT" more sensitive to light. Meaning it will become brighter and brighter even without using flash.

I usually go the lowest then bump it up a little if I dont want to use flash.

Aperture= Opening. F = to the size of the lense ; /2 is the opening divided in two.
Example = f/2 is equal 25 in a 50 mm lense.
In other words....
F/2 = big opening = 50mm/2= 25mm
F/11= very small opening = 50mm/11= 4.54mm (thats why 11 is smaller than 2)

Speed = self explanatory. Ex: 1/1000 = 1 over 1000 of a second. That is really fast.
1/15 = is slow, in fact that is the slowest I can take without tripod and without blurring.

Exposure:
Zero = center
+2 = bright
-2 = dark

All in all...................................................... let say that we want zero exposure, we can use two settings...

1)Big aperture/fast shutter speed... Ex: F/2 at 1/250 speed

or

2)Small aperture/slow shutter speed... Ex F/11 at 1/15 speed

Whats the difference?

1) Big aperture = small depth of field. Meaning.... clear object near you and blurry beyond the subject. Great for portrait.

2) Small aperture = big depth of field. Meaning clear object in front of you and beyond the subject. Great for landscape images.


LETS GO TO SETTINGS....

Aperture Priority = meaning, you set the aperture then it will set the speed.
Why use this? If you are looking for an effect. Example: do you want clear foreground and background? Then go to smaller aperture (f/11). Do you want clear foreground and blurred background? Then go to big aperture (f/2).


Speed Priority = meaning, set the speed and it will set the aperture.
Why use this? if you want to shot a sports event. Then you need to do a very fast shutter speed. (1/1000) If you want the best possible light / brightness in your shot without using flash? Then go to the lowest your hand can handle.(1/15) Sometimes i can go as low as 1/4 if i put it against the glass if im doing reef shots.


Hope this helps...
 
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Llarian

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Pretty much on the money.

One thing I'll mention. Casar mention "exposure" as a +/- value. That's usually what's referred to as exposure compensation. If I set it to +1, twice as much light as is metered will be let in. Ditto with -1, that's half as much. Its usually measured in +/- Ev on a camera.

This only applied in one of the auto modes, in full manual this does nothing. Basically you're telling the lightmeter that if it seems F2.8 at 1/125th of a second, to under/overexpose by a certain amount. This can be dangerous though, especically for doing anything involving motion in low light. If I set my camera for F/2.8, 1/125th of a second, I can probably catch a slow moving object. However, if I'm set to +1/3Ev or brighter because my light meter is giving me dark pictures, I don't know for sure how it'll change it. In the example I gave, the aperature is probably already wide open, so it'll slow down the shutter. Which means that slow moving object we were trying to capture is going to show up as a blur now, but we don't know why.

Be careful with Ev. Its useful in a lot of cases, particluarly since most digital cameras tend to overexpose a little. If you're willing to bring things out in photoshop after the fact, shooting at -1/3 or -2/3Ev isn't a bad idea. But it will yield darker pictures straight out of the camera, so you'll be required to post-process them at that point.

-Dylan
 

Scooterman

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I think most of this was pertaining to digital Non SLR's, which with all the neat gadgets, most of this being discussed won't pertain to them but the information is awesome!
 

Llarian

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Scooterman said:
I think most of this was pertaining to digital Non SLR's, which with all the neat gadgets, most of this being discussed won't pertain to them but the information is awesome!
No, it still very much applies. Almost every camera offers at least some control over the exposure, and I think all of them offer exposure compensation to adjust based on the lightmeter.

You may or may not have a full manual mode, but even my 6 year old 1.3MP Sony has aperature and shutter control.

The biggest thing to remember is that your true focal length is probably extremely small. A 2/3" CCD (Pretty standard size) will probably have a focal length of 9mm-35mm or so. (Equivalent of 36mm to 140mm on a full-frame 35mm SLR). What this means is that for the same field of view (lets say fully wide angle, so 9mm, or a 36mm equivalent field of view), your depth of field calculations are based on that tiny focal length and aperature. The net effect is that your depth of field is huge compared to 35mm, or even the digital SLRs.

I find myself almost always shooting at my widest aperature even with macros (for me, that's F/2.0). Anything much narrower than that, and there's no bokeh (out of focus effect) behind my subject, and the background tends to blend in to what I'm shooting at.

One advantage to the small focal length is that you can usually handhold at a much slower speed, since its not quite as prone to camera shake. The longer your focal length, the more smaller movements will show up.

(I'll stop rambling now, I think I lost track of what my point was.)

-Dylan
 
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