novice manual experiments

[jillR]

hi simon

thanks for your patience as i know what it must be like for you peeps who

have done all the hard work when a beginer comes along with silly questions.

jill

[Guest]

Completely the opposite Jill, I like nothing more than being able to help people with this sort of thing - one of the reasons I came up with the idea of the photo walks in the first place. Little did I know most of those attending would know more than me anyway and I'd end up being the one asking for help!

If you read the manual at all you got further than Mark did with his new EOS50D!

[mbird]

If you read the manual at all you got further than Mark did with his new EOS50D!

Cheeky

Manual now read 100%

Information retained 45%

Balance to be learned by playing 55%

[mbird]

thanks and ive now sussed how to set the ISO to

what does ISO mean ?

im sorry if im being lazy but i know you lads can explane it better than a manual

the 1st picky is of a duckling just behind mum and dad but you have to click to see it.

the second was my favorite due to the busyness and colour.

jill

Hi Jill

ISO stands for International Standards Organisation (or something similar) and is merely a reference to the speed of film. In the days when I was using my first 35mm SLR camera, film speeds were quoted as ASA ratings in this country. However, at some point over the last however many years, the UK version "ASA" was brought into line with the rest of the world and changed to "ISO". The numbers are the same and mean exactly the same thing.

With film, the ISO/ASA rating is the speed, or in other words, how sensitive the film is to light. The higher the number, the more sensitive and so the lower light conditions you can shoot in, or indeed the faster shutter speed or smaller aperture you can use for any given situation. The trade off for film was that the pictures from the faster films were grainy.

With the advent of digital, the manufacturers of the cameras kept the same ISO standards, but now this refers to how much amplification is added to the electronic signals generated by each of the little light receptors in the sensor. If you increase the ISO rating, what you are actually doing in increasing how much the cameras sensor boosts the elctronic signal, not actually making the sensor any more sensitive. The result is that higher ISO's will allow you to shoot in darker situations exactly the same as faster films. However instead of "grain" in the film, the trade-off this time is "noise" in the captured image resulting from electrical interference. The net result though, with either film or digital, is basically the same.

[mbird]

I would not recommend P ongoing as this limits creativity but it will allow you to see what the camera is choosing against your manual settings.

Interesting this one, as now I've read the manual that came with my camera, I've discovered something.

I normally shoot in Av mode, allowing me to adjust the depth of fields by way of the aperture size, and letting the camera sort ot the shutter speed. However, on my 50D, it seems the P mode has a similar function. P mode still allows you to adjust all the finicky bits, such as ISO, setting the AF sensor required ,adjusting white balance etc, where as full auto does not. When half depressing the shutter button to set the exposure, the camera then chooses an aperture and shutter speed - no surprises so far. However, what I did not know, is that by rotating the selection wheel, you can then cycle through the different aperature and shutter speed combinations, effectively allowing you to choose what aperture or shutter speed you want to use.

I may be a bit dim, but being able to do this, surely means that the P mode does the same as both the Tv and Av modes combined doesn't it?

[Guest]

I may be a bit dim, but being able to do this, surely means that the P mode does the same as both the Tv and Av modes combined doesn't it?

Sort of, but the big difference is that with P the aperture will keep shifting according to the light. If, say, you want f11 for a series of shots, it's far more efficent to use aperture priority and know that f11 will stay put. Even for a single shot in P mode you would have to keep the shutter button held down once you had shifted to f11, othewise the camera would take another reading - in other words, shifting the aperture (or shutter speed) to the desired one in P mode has to be the last thing you do in the set up sequence.

Personally I never change from aperture priority unless I'm shooting action that depends on choosing shutter speed, or using full manual mode.

Bruce

[mbird]

Good point, Bruce. I had been wracking my brain to think of a reason the P was different to Av and Tv, and I hadn't thought of that one.

[jillR]

thanks mark

in the days when I was using my first 35mm SLR camera, film speeds were quoted as ASA ratings in this country. However, at some point over the last however many years, the UK version "ASA" was brought into line with the rest of the world and changed to "ISO". The numbers are the same and mean exactly the same thing.

that i understand now.

e.g.

less light = higher ISO needed.

low F/stop number = larger aperture.

high F/stop number = tripod needed due to camera shake.

higher F/stop number = greater depth of field.

to put it crudely.

as a beginer, these one liners will help me in the field as quick referance notes

that i can take out with me.

i undersand what grain means in a pictue but can some one give me an example of

a picture badly affected by noise, please.

jill

[Guest]

Jill the appearance of noise in an image is actually quite similar to film grain - kind of like speckles or tiny splodges of colour spread throughout the image though they are much more noticeable over really dark backgrounds. If you ramp up your ISO and then go out and shoot in bright sunshine chances are the noise won't be too evident, though there are also other trade offs like loss of dynamic range and colour depth. You'll also find if you're shooting JPEG that the camera's JPEG processing engine will become progressively more aggressive at trying to hide the noise and that can lead to a slightly smeared look with some loss of actual detail as well as the image noise.

Mark, I'm willing to bet your 350D also allowed you to rotate the job wheel whilst in P mode and therefore change the aperture and shutter combinations. Not only do both my digital bodies allow me to do that but my old 35mm body did too. I can't speak to for Canon, but in the case of Minolta the LCD showed P mode until the moment you changed the combination then it showed PA or PS depending on which you were changing. Of course what I can' t now remember is how you tell it which one to change, though of course cycling through the combinations you should end up at the same place either way.

[pks1702]

Thanks Bruce beat me to it.

[mbird]

Jill the appearance of noise in an image is actually quite similar to film grain - kind of like speckles or tiny splodges of colour spread throughout the image though they are much more noticeable over really dark backgrounds. If you ramp up your ISO and then go out and shoot in bright sunshine chances are the noise won't be too evident, though there are also other trade offs like loss of dynamic range and colour depth. You'll also find if you're shooting JPEG that the camera's JPEG processing engine will become progressively more aggressive at trying to hide the noise and that can lead to a slightly smeared look with some loss of actual detail as well as the image noise.

Mark, I'm willing to bet your 350D also allowed you to rotate the job wheel whilst in P mode and therefore change the aperture and shutter combinations. Not only do both my digital bodies allow me to do that but my old 35mm body did too. I can't speak to for Canon, but in the case of Minolta the LCD showed P mode until the moment you changed the combination then it showed PA or PS depending on which you were changing. Of course what I can' t now remember is how you tell it which one to change, though of course cycling through the combinations you should end up at the same place either way.

I think you are probably right Simon, and I would guess the 350 had the same function. As I never use P mode though, I didn't realise it was adjustable until I RTFM

[Guest chriscraft]

hi Jill here,s iso 100,then iso h10,whch is 6400 plus,all other settings the same,sorry about the subjet!! click for big.

[jillR]

thanks trevor

ill have a twiddle with my camera soon

jill