- This topic is empty.
iso and exposure, complete beginner Q
-
Quick question guys, ive been taking pics trying to figure out iso and exposure, I set camera to iso 100 through to 1600, I cant find how to change the shutter speed that’s the exposure right? Is it automatic and im hunting for nothing? The difference from iso 100 and 1600 is very little so far, ive only took shots of a running tap, im trying to learn lol, ive been downloading pdf files and watching youtube tutorials but getting confused with manual and tv settings etc, I hope this makes sense, ill get there but any pointing in the right direction appreciated!
any know guides or tutorials about for my particular camera?
canon 350d and sigma 18 – 200 lense
I’m no expert but the way i understand it. Exposure is the amount of light captured.
Exposure is a juggle of three things. ISO , Aperture and Shutter speed.
lol thanks for the reply, im completely lost, ill have to join a club! pity none about during the day in Derry!
Hey Paddy,
The ISO comes into play when the light is not quite right for the shutter speed
you want, so if you are handholding your camera (having left your tripod at home)
and you need a shutter speed of say 1/125 the light is so bad, you have
opened the aperture as far as you can and still the only shutter speed
you can get is 1/50 then you would increase the ISO to bring the shutter speed up
a little, the trade off is “noise” while most of the newer cameras handle this quite
well.Shutter speed, aperture and ISO are all interlinked, it seems quite daunting in the
beginning but it will all drop into place with practise!When I started I let the camera do all the work, just put it into Auto and snapped
away all the while I was checking what settings the camera had chosen for pictures
that I liked the look of. Then I moved onto Aperture or Shutter priority which is
really easy to get the hang of and gives you a lot more control over how your pictures
will turn out. For instance if you know you want to throw out the background (make it
blurred) then you know you will need a wide aperture 2.8 or 3.5 or 4.0 so you set your
camera to Aperture priority and set your aperture to say 2.8 and the camera will set
the shutter speed for you, likewise if you know you will need a fast shutter speed then
use Shutter priority and set the shutter speed the camera will pick the aperture, thats
when ISO comes into play if you are still not getting the shutter speed you want then
increase the ISO.thanks m8, i think im getting it, not quite 100% but… i took a few snaps just now on a tripod of derrys walls from my home in the dark, i done this last week on auto and used manual focus as it wouldnt focus, they were all black and or blury, im messing with iso and Tv mode and saving in raw, i opened them in bridge and i can see the differences in the settings info in bridge. im now getting images i can work with, i know there nit great but better than black! i still dont know what im talking about lol the “noise” you mention must be the glow im getting?
im not sure what to ask as i still dont know for sure what im doing but thanks for the replys guys, great to know someones out there!
heres the difference for anyone interested, 1st pic is last week on auto and manual focus, 2nd is tv and messing with iso.
thanks
[attachment=0:3o3rhuc5]last week (Small).jpg[/attachment:3o3rhuc5]
[attachment=0:1feboj9t]1stnighshot (Small).jpg[/attachment:1feboj9t]
sorry cant add 2 pics in 1 post?
btw i coulnt see a thing in the eyepiece lol
You are going in the right direction Paddy, just keep playing with the
settings and you will soon get what you want.Noise is a kind of speckled effect especially in the brighter parts of
a night shot.Hi plasticpaddy,
I think confusion would be a normal state when first trying to get to grips with the relationship between ISO, shutter speed and f stops.
The ISO number is a measure of the sensitivity of a sensor or piece of film to light.
The higher the number the more sensitive the sensor/film is to light.Film has a fixed ISO so different films have to be loaded in order to change the ISO. (Film can be “pushed” to a higher ISO in processing but that’s another story :D )
So if you were shooting in a low light situation you might load a high speed film (Maybe ISO 800) in order
to increase your chances of getting a useable image.With digital we can change the ISO setting for the sensor.
With higher ISO settings the signal from the sensor is amplified more.
Of course any noise present is also amplified.
The technology in this area is improving all the time.Jenny has explained why you might need to bump up the ISO.
Here is a practical example.
You are in a lowlight situation with your camera set at Aperture Priority. (You set the aperture (f stop) & camera sets shutter speed)ISO Aperture (f stop) Shutter speed
Setting 1 100 f5.6 1/4 second
Setting 2 3200 f5.6 1/125 secondIn Setting 1 it would be difficult to keep the camera steady during the exposure and if anything is moving in the frame it will probably
be blurred.
In Setting 2 the high ISO has allowed a faster shutter speed which gives a better chance of producing a useable image.Practice and experiment as much as you can and I’m sure you’ll get to grips with all the setting and the relationships between them.
Cheers,
John.
Hi John,
Re 2 photos in 1 post, you need to host the photos on flickr/photobucket etc and embed them here, instead
of adding them to the post in the way that you are. That’ll sort that for you.cheers
thanks for all the help, encouragement and info guys/gals but i can only find the iso numbers 100 to 1600. the f stop, shutter speed and f5.6 1/4 second stuff etc is beyond me at the moment and i dont know what aperture priority is either, i dont think my camera has all these things or ive still not discovered them, although the f numbers do show up in bridge in the info!
thanks
steve
Aperture is the amount of light that you are allowing to hit the sensor.
The higher you go in stops, F11, F13 etc the greater amount of time is needed for
the sensor to absorb the light as the ‘eye’ is smaller than it was say at 5.6 so the camera needs to be still.
I’ve put in an example with the info’ Hope it helps!
F18Just turn the dial to AV mode & select a high aperture assuming of course that
you’re shooting at night & see what happens. Mount the camera on a tripod.
Good luck!thanks, i think ive finally “clicked” pun intended. i set it to Av and shot in the dark at 5.6 and way other end 30s just to see the difference, lol its quite different!! so low number is more light/time, i just hadnt worked out av was aperture priority and changing the f stops? was the numbers meaning aperture “eye” size and changing it with with the wee wheel lol.
sorry for sounding daft but its a bit more complicated than i imagined!
again, many thanks!
edit. the higher fstop is more time and light.
Hi Steve,
It’s difficult to grasp everything in one go but when you get to grips with ISO, f stops and aperture and
how the interact you will be able to get on with the really important stuff like making photographs.Your camera has all the settings mentioned above.
The ISO range of the 350D is 100 – 1600.Here is a link to a page which you might find helpful.
You can input the ISO and the type of conditions and the calculator gives a range of shutter speeds
and ISOs for the given settings and conditions.
Notice how higher ISO settings give you a faster shutter speed for any given f stop.You will see that in Aperture Priority (AV mode where you set the f stop and ISO and the camera sets the shutter speed) you
may have to bump up the ISO to get a fast enough shutter speed to allow you to get a decent image in certain light conditions.http://www.calculator.org/calculate-online/photography/exposure.aspx” onclick=”window.open(this.href);return false;
All the best,
John.
as all above said.
If you think of a correctly exposed photograph as a full glass of water. Imagine the water is the light to fill/expose the shot. You have a number of ways of filling the pint from a tap. tap barely open (small apperture) for a long time. Or tap fully open (large apperture) for a short (shutter time) time. either way you get a photo correctly exposed . (this is ignoring settings to freeze action etc. just a starting way of thinking about the relationship between shutter and apperture. ) now if you had a big tap (high iso) the time (shutter) and opening of the tap (apperture) will be much shorter to fill the glass. Dont know if this helps but its how I got it into my head.aye thanks, ive nearly got it i just need to practice with different settings to fully understand it. its a bit like maths etc at school or any new ifo that a bit technical.
i had a good day today at Grianan fort in Burt Donegal, taking landscapes etc mainly on full auto and landscape and experimenting with manual focus but still on full auto, im thinking it will be harder using the manual setting etc in daylight too but make as much difference to the outcome as dark does! so its something ill have to understand to continue.
i made a flikr in my signature if anyone wants to give me pointers!
thanks, its a great help being here!
You must be logged in to reply to this topic.
