some questions
Discussion
Ok, so i am now reading the manual and trying to digest
1/Stops, stopping down, stopping down the lense etc
This is a phrase which i hear a lot, even in the manual but i still have no idea what it means. For i giggle i will let you know that i always presumed it was half depressing the the shutter releas button/shoot button. But i have also read it in context with iso on this forum.
What does it mean and how/when do i use it?
2/ In creative mode on the Canon 300D there are 7 focal points which can be selected individually.
Is it a a world war 2 type target for the boys to make sure they get their shot dead centre?
Don't worry, i'm not THAT lame
i realise that whilst using auto focus the camera will decide which focal points to use and indeed you may not have wanted your picture focused on the cameras chosen point. But.....Given the choice as we have been, why would you want to select a far right or left focal point for your picture? Or any other one apart from the center one which you would place over your target.
The manual explains that this has to do with speed but i don't realy understand that.
3/Iv'e brushed through white balance and think i understand the basics but what is colour temperature?
Do you use auto bracketing and is it worth it with?, more to the point would be - does the /a cmera get auto WB so wrong sometimes that there is a need to auto bracket? Bearing photoshop in mind and the fact that it uses 3 times the memory space.
3/ISO
Ok, i think i get the fact that the darker it is the higher the iso and the faster an object moves the higher you want your iso setting.
However, the camera will only use 100-400 by in auto although i am able to dial up 800 and 1600 also but i understand that more noise will be picked up in the image.
When would i use 800-1600 and wouldn't the fact that we use a flash lower that speed, or indeed the need to use such a high speed?
How do i know or calculate what speed to use without a light sensor?
Will the iso speed have any impact on the shutter speedand or aperature value? ( infact i can experiment with that later)
sorry for the lenght of this post i think i will leave it there for now. I was quite surprised by how brief the instruction booklet is with more information on direct printing and auto shooting than getting creative. I suppose the camera is aimed for people with a basic knowledge of photoghraphic techniques though.
Ian
Thanks to anyone with the time and patience to answer any of my questions
1/Stops, stopping down, stopping down the lense etc
This is a phrase which i hear a lot, even in the manual but i still have no idea what it means. For i giggle i will let you know that i always presumed it was half depressing the the shutter releas button/shoot button. But i have also read it in context with iso on this forum.
What does it mean and how/when do i use it?
2/ In creative mode on the Canon 300D there are 7 focal points which can be selected individually.
Is it a a world war 2 type target for the boys to make sure they get their shot dead centre?
Don't worry, i'm not THAT lame
i realise that whilst using auto focus the camera will decide which focal points to use and indeed you may not have wanted your picture focused on the cameras chosen point. But.....Given the choice as we have been, why would you want to select a far right or left focal point for your picture? Or any other one apart from the center one which you would place over your target.
The manual explains that this has to do with speed but i don't realy understand that.
3/Iv'e brushed through white balance and think i understand the basics but what is colour temperature?
Do you use auto bracketing and is it worth it with?, more to the point would be - does the /a cmera get auto WB so wrong sometimes that there is a need to auto bracket? Bearing photoshop in mind and the fact that it uses 3 times the memory space.
3/ISO
Ok, i think i get the fact that the darker it is the higher the iso and the faster an object moves the higher you want your iso setting.
However, the camera will only use 100-400 by in auto although i am able to dial up 800 and 1600 also but i understand that more noise will be picked up in the image.
When would i use 800-1600 and wouldn't the fact that we use a flash lower that speed, or indeed the need to use such a high speed?
How do i know or calculate what speed to use without a light sensor?
Will the iso speed have any impact on the shutter speedand or aperature value? ( infact i can experiment with that later)
sorry for the lenght of this post i think i will leave it there for now. I was quite surprised by how brief the instruction booklet is with more information on direct printing and auto shooting than getting creative. I suppose the camera is aimed for people with a basic knowledge of photoghraphic techniques though.
Ian
Thanks to anyone with the time and patience to answer any of my questions
bilko said:
2/ In creative mode on the Canon 300D there are 7 focal points which can be selected individually.
Is it a a world war 2 type target for the boys to make sure they get their shot dead centre?
Don't worry, i'm not THAT lame
i realise that whilst using auto focus the camera will decide which focal points to use and indeed you may not have wanted your picture focused on the cameras chosen point. But.....Given the choice as we have been, why would you want to select a far right or left focal point for your picture? Or any other one apart from the center one which you would place over your target.
The manual explains that this has to do with speed but i don't realy understand that.
In this crazy arty farty world we live in, the focal point of a 'good' picture doesn't always have to be in the centre of the shot. Image a scene with some greenery up close in the bottom left of the frame, a road in the background and the car coming in from the top right. You wish to focus on the car with the blurred shrubbery in the fram still. Using all focal points or just the centre will not achieve what you want!
It is rare but the need does arise. Personally I mainly use the center point only. Otherwise if tracking a fast moving object the focus can get confused and you lose the shot completely.
>> Edited by Phil S on Saturday 4th December 20:42
Lots of questions you ask!
I'll do my best to answer them, but I'm sure others will be along soon to add to what I say.
1) A stop is basically a standard difference in exposure settings.
A particular exposure is obtained when a certain amount of light hits the film/digital sensor. If you think of this in terms of water filling a cup, the aperture is the size of the tap and the shutter speed is the length of time the tap is open for. A big aperture (small f number, e.g., f2.8) lets in more light than a smaller aperture (e.g., f11). To get the same exposure, you would need a quicker shutter speed with the bigger aperture, and vice versa.
In photography, aperture sizes and shutter speeds have certain values, and the differences between them are measured in "stops", for example, an aperture of f8 is one stop smaller than f5.6, and a shutter speed of 1/250s is one stop faster than 1/125. Most cameras give you the option to change exposures by 1/2 or even 1/3 of a stop too.
2) You don't always want the object that you're focusing on to be in the middle of the picture, so it's useful to be able to frame the picture with the focal point off to one side, and then select the focus point that is most suitable.
3) Very basic explanation, but the temperature of light is a way that the colour properties of it are measured. Lower temperatures have a warmer light (more red/yellow), and higher temperatures have a cooler look (more blue), which is why photos taken at dawn look warmed and redder than ones taken at midday. The WB setting determines the colour of the light, and adjusts the image so that white actually looks white, which the human eye does automatically.
4) ISO numbers
This relates to the sensitivity of digital sensors and film.
Generally speaking, the lower the ISO number the better the picture quality is, however this is at the expense of shutter speeds (and this comes back to stops mentioned earlier). For example, a picture taken at ISO 100 may require an aperture of f8 and shutter speed of 1/125. At ISO 200, the same exposure would be f8 and 1/250 as ISO 100 is one stop slower than ISO 200. The same applies going from ISO 200 - 400, and 400 - 800.
In film world, higher ISO films use larger crystals, so you get more grain. The digital equilavent of grain is noise.
One reason you would want to use higher ISO settings is if light levels are such that you can't get high enough shutter speeds with the current ISO setting (good rule of thumb is to use a shutter speed with a number greater than the focal length of your lens, e.g., if you've got a 100mm lens, use 1/125 or faster). If you've got ISO 200 set, and you find that the fastest shutter speed you can get is 1/60s, then changing to ISO 400 will give you the 1/125 shutter speed that you need to keep your pictures sharp.
You don't need a light meter as your camera will work out the correct shutter and aperture settings (unless you set it to Manual mode), although you may want to over-ride it by using Aperture priority mode (where you tell it the aperture setting you want, and the camera works out the shutter speed), or Shutter priority mode (where you tell it the shutter speed you want, and it works out the aperture) if you want more control.
Hope this helps!
I'll do my best to answer them, but I'm sure others will be along soon to add to what I say.
1) A stop is basically a standard difference in exposure settings.
A particular exposure is obtained when a certain amount of light hits the film/digital sensor. If you think of this in terms of water filling a cup, the aperture is the size of the tap and the shutter speed is the length of time the tap is open for. A big aperture (small f number, e.g., f2.8) lets in more light than a smaller aperture (e.g., f11). To get the same exposure, you would need a quicker shutter speed with the bigger aperture, and vice versa.
In photography, aperture sizes and shutter speeds have certain values, and the differences between them are measured in "stops", for example, an aperture of f8 is one stop smaller than f5.6, and a shutter speed of 1/250s is one stop faster than 1/125. Most cameras give you the option to change exposures by 1/2 or even 1/3 of a stop too.
2) You don't always want the object that you're focusing on to be in the middle of the picture, so it's useful to be able to frame the picture with the focal point off to one side, and then select the focus point that is most suitable.
3) Very basic explanation, but the temperature of light is a way that the colour properties of it are measured. Lower temperatures have a warmer light (more red/yellow), and higher temperatures have a cooler look (more blue), which is why photos taken at dawn look warmed and redder than ones taken at midday. The WB setting determines the colour of the light, and adjusts the image so that white actually looks white, which the human eye does automatically.
4) ISO numbers
This relates to the sensitivity of digital sensors and film.
Generally speaking, the lower the ISO number the better the picture quality is, however this is at the expense of shutter speeds (and this comes back to stops mentioned earlier). For example, a picture taken at ISO 100 may require an aperture of f8 and shutter speed of 1/125. At ISO 200, the same exposure would be f8 and 1/250 as ISO 100 is one stop slower than ISO 200. The same applies going from ISO 200 - 400, and 400 - 800.
In film world, higher ISO films use larger crystals, so you get more grain. The digital equilavent of grain is noise.
One reason you would want to use higher ISO settings is if light levels are such that you can't get high enough shutter speeds with the current ISO setting (good rule of thumb is to use a shutter speed with a number greater than the focal length of your lens, e.g., if you've got a 100mm lens, use 1/125 or faster). If you've got ISO 200 set, and you find that the fastest shutter speed you can get is 1/60s, then changing to ISO 400 will give you the 1/125 shutter speed that you need to keep your pictures sharp.
You don't need a light meter as your camera will work out the correct shutter and aperture settings (unless you set it to Manual mode), although you may want to over-ride it by using Aperture priority mode (where you tell it the aperture setting you want, and the camera works out the shutter speed), or Shutter priority mode (where you tell it the shutter speed you want, and it works out the aperture) if you want more control.
Hope this helps!
bilko said:
3/Iv'e brushed through white balance and think i understand the basics but what is colour temperature?
Do you use auto bracketing and is it worth it with?, more to the point would be - does the /a cmera get auto WB so wrong sometimes that there is a need to auto bracket? Bearing photoshop in mind and the fact that it uses 3 times the memory space.
OK, I'll take this one!
White balance is to do with 'colour temperature'. Basic physics: if you take a chunk of metal and apply heat, it will start to glow. First it glows red, then as the temp rises it glows orange, then white, then blue/white. The colour is exactly dependent on the temperature, so colour is expressed in degrees Kelvin. For example, 5400 deg is red, and 7000 is white (approx).
Daylight, being 'white', has a high colour temperature. By contrast tungsten lighting is red/low. To get accurate rendition of colour, the colour tempertaure (or white balance) must be right. I use Auto WB and it works for me, but you can play if you like! I think people do tend to get carried way with it, as PhotoShop Autolevels is very good at correcting any WB problems.
As for bracketing, this just means a series of shots (3 or 5) with one parameter varied. It can be exposure, white balance or anything else.
simpo two said:
OK, I'll take this one!
White balance is to do with 'colour temperature'. Basic physics: if you take a chunk of metal and apply heat, it will start to glow. First it glows red, then as the temp rises it glows orange, then white, then blue/white. The colour is exactly dependent on the temperature, so colour is expressed in degrees Kelvin. For example, 5400 deg is red, and 7000 is white (approx).
Daylight, being 'white', has a high colour temperature. By contrast tungsten lighting is red/low. To get accurate rendition of colour, the colour tempertaure (or white balance) must be right. I use Auto WB and it works for me, but you can play if you like! I think people do tend to get carried way with it, as PhotoShop Autolevels is very good at correcting any WB problems.
As for bracketing, this just means a series of shots (3 or 5) with one parameter varied. It can be exposure, white balance or anything else.
Brilliant!
The hottest part of the flame is blue!
I think i was trying to relate hot to red, as you do.
Cleared that one up as well.
Thanks simpo!
Boy will i be scared to post more pictures now that i understand a bit more. Still; there is always the line "sometimes a bit of luck DOES help " to fall back on
simpo two said:
For example, 5400 deg is red, and 7000 is white (approx).
Not sure if you're talking about heated metal there but, photographically speaking, 'daylight white balance' is around (depending which manual you're reading) 5500° Kelvin. This is derived from a measurement called 'mean noon sunlight' which is the average colour of light on a summers day with some blue sky and puffy white clouds. If the sky had no clouds and was a brilliant blue the colour temperature would be around 11000° Kelvin.
Tungsten white balance is 3200°. In the good old days there were two types of tungsten film, A & B. B was rated at 3400°. A domestic light bulb is around 2800° and a candle, 1800°. Outside white balance varies hugely depending on many factors. Time of day, angle of sun, clouds, time of year etc. Photographing a sun-tanned girl in a sunset on a tropical beach in summer will have a much lower colour temperature than a scene at midday, in snow, with a blue sky in the Arctic. In the old days it was a matter of picking the right film for the job and then fine tuning with filters. Much easier in the digital age
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Well OK, I was nearly right! Actually I was thinking about the degrees K on video cameras - and I've seen them on some Canon DSLRs too I think? Gassing Station | Photography & Video | Top of Page | What's New | My Stuff