n00b aLeRt - A70 Powershot

[Digital Aura]

Hi! I've been reading some of these threads and on one hand I'm happy because -- YOU GUYS GIVE GREAT ADVICE AND KNOW SO MUCH!! But on the other hand I'm very unhappy. Because YOU GUYS KNOW SO MUCH and I feel so stupid now. hahaha
So please excuse my ignorance....
I've been pleased with the A70 results on auto mode but I want to learn what all the other settings do. I read the manual and tried experimenting but the auto is taking MUCH better photos than me. I guess it's because I lack the basic understanding of these key photo principles:
Shutter speed, aperture value, exposure, white balance, and ISO speed. Could someone be kind enough to explain these and there impact on my pictures? Or point me to a handy link that does!
Thanks so much! I'm just getting into this and can't stand the thought of using AUTO for anything!
- Digital Aura :)

[cA70]

I know how they work (kinda) but for explaining, i'll leave to someone else, i might just end up confsing you. But the best thing u cand i'm still doing is for the same shot, take it with different settings.

Then go home and with zoombrowser view the EXIF data (right lick properties) and see the difference in the 2. Mabey u had a quicker shutter speed, and it was alot darker, things like that.

And in manual, the little number in the top is a good indicator to getting a good shot, it tells you if its over or under exposed.

[Digital Aura]

But that's my point. What is over exposed! And how does it happen? I had it on auto! Quite right ... I can see some differences when viewing the properties in my zoom browser (which is quite nice software) but I don't know WHY or HOW to explain these differences because I don't understand the principles yet.
Wanna give it a try?

[cA70]

Under exposed is a picture that is to dark, over exposed is a picture that is to light.

I've only been shooting for about 3 months so i'm not as knoledgable as the people on this forum who have had years of experience and more of an understanding.

On the canon website, i found a place with 100's of definitions. Dont have a url handy though.

If you can find a link on previous posts to the canon online manual then thats where i found it and would be a good start.

[billh101]

Well, hopefully someone has a link that will explain these things in detail, but I'll throw a few basics out to you. The ISO is the sensitivity to light. Higher ISO numbers like 400 are very sensitive so they can properly expose in darker conditions, like on a clowdy day. A smaller ISO number like 50 is not very light sensitive, so you would need it to be bright out or use a flash. Lower ISO's are prefered though, because there is less "grain" and better quality.
The aperature controls how wide open the lens is to let light in. A higher aperature number like 22 is a very small opening that doesn't let very much light in (but gives you much more depth of field for your focus). A small aperature number (larger opening) lets more light in so you can shoot in more dim lighting, but has less depth of field.
The shutter speed controls how long the camera is going to collect light for the picture. If you are shooting action, you'll need a faster shutter speed, like 1/250th of a second, or more. Also, unless the camera is on a tripod, you need to make sure you are using a shutter speed fast enough that you can hold the camera still enough so you don't get blurry pictures. Maybe you can only hold the camera still for 1/60th of a second or a shorter amount of time (which would mean larger shutter speed number). Also note that the more you zoom in on something, the faster speed you need to hold the camera still.
So, that being said, it takes x amount of light to properly expose a picture, your aperature and shutter speed have to work together to come up with that amount of light. For example, lets say the camera is on ISO 50 and can properly expose a particular picture at F11 (aperature) for 1/125th of a second (shutter). Maybe you want to change one of these things to either get more depth of field or catch faster action. They go hand in hand. If you decide you need to speed up the shutter to 1/250, that will leave the shutter open for half the time, so you'll have to open the shutter up to a larger opening ( f 8 ) to compensate and still get the same total amount of light for the exposure.
I hope this explanation wasn't too confusing, is it all clear as mud now? ;-)
As for the white balance, I'll let someone else take that one. Basically, you have to tell the camera what is white so it can capture the colors accordingly. Different lights (sunlight, flourescent, etc.) have different colors. Our eyes and brain adjust for us so white still looks white, but we have to tell the camera to do so correctly. If someone has a good explanation of how to use white balance correctly, I'd like to see it as well. I've been shooting film for years, but not that long for digital.
Thanks,
Bill

[cA70]

Told ya someone with alot of experience woul give u a detailed one.

[Digital Aura]

hahaha! O JOY!
It's always better to hear it from actual people. Thanks so much guys. BillH I appreciate it!
Ca70 - thanks for pointing me as well...if you find that url please post it here.
I just went hunting but couldn't find it.

- Digital Aura :)

[Digital Aura]

I printed that off BILLH. That's handy!!! So ISO is controlled by aperture? They seem to be correlated! If i set ISO to 50 I could (theoretically) open the aperture to counter act that setting? is this right?

[cA70]

http://www.powershot.com/powershot2/why/glossary.html

Check out that link for all the info you need in regards to what they mean.

http://www.powershot.com/powershot2/customer/

That link is up one level of the first and gives u more to look into.

[cA70]

The way i work is is priority.

If u want a certain shutter or ap or ISO u go from there and get the others to work around it and expose the shot correctly.

Don't knwo if its the best way but it works for me.

[billh101]

Digital Aura wrote:
So ISO is controlled by aperture? They seem to be correlated! If i set ISO to 50 I could (theoretically) open the aperture to counter act that setting? is this right?
Well, the aperature doesn't "control" ISO, but those two things and shutter speed all impact each other. So if you set the ISO to 50 as opposed to a higher setting, then you do have to counter act that by either opening up the aperature wider (smaller number) or slowing down the shutter (smaller number.) Similar comparisons could be made to any of the three settings. If you change one in either direction from a correct exposure setting, then you have to change something else to make up for it. For example, an exposure of 1/60 second at f8 will let in the same amount of light as an exposure of 1/125 second at f5.6, or 1/30 second at f11, and so forth and so on. You just have to decide what settings are best for your shot. Do you need the faster shutter speed to stop the action, or do you need the smaller aperature for more depth of field? Hence the advantage of not using AUTO, so you can take control of these things rather than letting the camera guess.
Bill

[stopbath]

Your local library should have many great 'starting' books on photography. Browse through the books until you find a few that you like. Perhaps a skinny book that just quickly gives you the basics, and a thicker more involved book that has more detail. Use the quick guide to help you understand the relationships surrounding film speed, shutter speed, and aperture. Use the thicker book to augment that knowledge and help clear up any vague areas.

Read the books over and over if you need, borrow them again too. As your reading them, experiment, and try what they talk about. Take the book with you and take some pictures like what's in the book. This will give you working experience of what's in the book. Practice practice practice. Take lots and lots of photos. Experiment.

Photography is both a science, and an art. You should understand the science, so you can create the art.

Good luck, the time spent learning will be well spent. Hopefully, your walls will soon be adorned by some great photos.

[Digital Aura]

Thanks so much! You guys are great. This totally helps already!
So in simple application:
If I want to photagraph a moving object [say at ISO 50] then I have determined that I need to shoot with a higher shutter speed. (priority as CA70 puts it)
But I must also compensate by increasing the aperture so that I get enough exposure.
Likewise, if I were taking the shot on a dark, overcast day, I would determine that a high shutter speed is most important but I need to increase the ISO and maybe increase the aperture size even more (smaller number).
Does this sound right?

Thanks for the links and advice everyone. What a great forum.

- Digital Aura

[billh101]

I believe you are thinking on the right lines. You'll find that the shutter and aperature are the ones that you will change often. The ISO I don't change as often. I may go outside and if it's a bright sunny day set it on ISO 50 for everything I shoot at that time, or if it's dark and overcast, use a faster ISO and then just adjust the shutter and aperature as needed. But, you always have the option of changing the ISO any time you like as well if you find that you need a faster shutter speed or more depth of field than you are able to get with your current ISO setting. That's another big advantage of digital, you don't have to finish a roll of film and load a different one to change ISO.
Bill

[Digital Aura]

good points Bill!

[cA70]

ISO 400 (max on A70) and app of F2 would be the most effective DOF?

[billh101]

cA70 wrote:
ISO 400 (max on A70) and app of F2 would be the most effective DOF?
Did you mean F22 or F2.8? The higher the aperature number, the smaller the opening and the greater the depth of field. So, depending how much zoom you are using, at F22 your picture may be in focus several feet in front and several feet behind the object focused on. On the other hand, at F2.8 there may only be a few inches in front of and behind that will be in focus.
Bill

[cA70]

Osrry, i meant F2.8

I new there was a 2.x but couldn't rememeber what it was.

This is with the A70 and i have never got a good DOF unless is taken in macro.

[billh101]

Ok, 2.8, being the largest aperature opening (smallest number) the A70 has, will give you the least depth of field. If you want more depth of field, then you would want to use a smaller aperature opening (larger numbers.)
Bill

[cA70]

When i say good DOF, i mean effective (small).

And what i found out on the weekend is if you zoom in, the app hole is clearly visable from the outside, and its weird to see it open and close when you move it in and out of a light source.

The DOF isn't that good because it's not a top of the line camera, i can't have a subject 5 mtrs away and still blur the background.

What i was trying to get as is in the exact same light, a shot with ISO 400 would alow a quicker shutter (same app) than a ISO 50. Would the shutter also have an influence on DOF (same app)?

[billh101]

Well, the depth of field is impacted by the focal length of lens you are using and the size of the aperature. If you are shooting with a lens zoomed to any given length at the same aperature, you'll have the same depth of field on a $300 camera as you would with a $3,000 camera, the quality doesn't effect that. Of course, the lens on the $300 camera won't be as sharp to start with either. The shutter speed doesn't effect depth of field directly, only in the sense that you'll change the setting to account for changes you make in the aperature, which does control the depth of field.
Also, note that you have less depth of field when you are zoomed out to bring your subject in close. At wide angle, you have much more depth of field than at long telephoto zoom settings.
ISO 400 will allow you to use the fastest shutter speeds. However, the thing you have to keep in mind, is if you're on ISO 400 outside on a bright, sunny day, you may set your shutter as fast as it goes and still be letting so much light in that you wouldn't be able to get the aperature opened up to f2.8 to get a very narrow depth of field like you are trying to get. It all just depends on the lighting conditions to see what you can get by with.
Bill

[stopbath]

billh101 wrote:
Well, the depth of field is impacted by the focal length of lens you are using and the size of the aperature. If you are shooting with a lens zoomed to any given length at the same aperature, you'll have the same depth of field on a $300 camera as you would with a $3,000 camera, the quality doesn't effect that. Of course, the lens on the $300 camera won't be as sharp to start with either.

...

Bill

Correct but with a twist.

We've seen the "effective" focal length conversions for compact digital cameras. 5mm equates to something like 28mm on a film camera (or something like that).

Well, the depth of field is also part of that. The actual depth of field is greater on a compact, then that of a full SLR so that a compact's f8 may give the same depth of field as f22 on your film camera.

I wonder if f64 on a 4x5 is the close to f22 on a SLR?

[billh101]

stopbath wrote:
Correct but with a twist.

We've seen the "effective" focal length conversions for compact digital cameras. 5mm equates to something like 28mm on a film camera (or something like that).

Well, the depth of field is also part of that. The actual depth of field is greater on a compact, then that of a full SLR so that a compact's f8 may give the same depth of field as f22 on your film camera.

I wonder if f64 on a 4x5 is the close to f22 on a SLR?

I meant to compare apples to apples, so a $300 digital compared to a $3,000 digital with the same effective focal lengths. Throw a 35mm film camera into the comparision and it of course throws it off.

Don't know about the 4x5, I've never used one. I do have an old Mamaya Super Press 6x7 that I toy with once in a while, but I've never paid that much attention to it. I haven't ran a roll of film through it in a few years, it's more a collectable for me.
Bill