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Hi again guys,

thanks for previous advise.

Been using the camera for a few weeks, working on white balance as a first step.

Now that I have that conquored (not mastered !) I am looking at ISO as this seems less complex than shutter speeds and exposure !!!

The camera has an auto ISO setting which i currently use - it seems that this is advised against ?

I dive in pretty clear waters and was going to work on ISO100 for macro and ISO 200 for others, whilst still sticking with manual white balance (not even looked at the strobe yet).

Does this sound about right, as usual all advise warmly received

Danny
 

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Hi Danny
ISO goes back to the days when films were made in different sensitivities to allow images to be taken in low light situations, the trade off was usually image quality. The same thing goes for digital sensors where higher iso's can lead to higher levels of digital noise in the image, not sure what type of camera you are using but the newer digital cameras are much improved in this area. ISO 100 is going to give you best image quality, but will have an impact on shuter speeds, if your camera controls the digital noise well I would go for at leat ISO 400 which would give you a good shutter speed (if you are anything like me you need as much help as you can in this area!!) My thinking is that a sharp image with a litle noise is beter than a higher quality image with blur.

As far as the auto ISO goes I think a lot of people prefer to make this decision for themselves rather than the camera, but it is a useful feature when you need to do things quickly.
hope this is of some help.
Best wishes
John
 

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Mark Milburn
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Personally, in your location, I would be using a low ISO number, like you say 100. Maybe even as low as ISO 80.

If you look back at the images you've taken in auto, you'll know what sort of setting is required normally for your location/conditions. When I'm in clear waters it is always ISO 80 or 100 on auto. Bracketing your photos by changing the ISO will show you how your camera reacts to the change.
 

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Dive tart, just can't say no :-)
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Danny depending on the light conditions you can use all 3 settings, shutter, aperture and ISO. pushing or increasing the iso is a trade off against image quality, whereas shutter speed and aperture is a trade off with depth of field. the slower the shutter speed the greater the depth of field and vice versa, so if you need a slow shutter speed to get a good depth of field you can increase the iso and thus the sensitivity of the "film" and so reduce the aperture. every gain in one direction is a loss in another so you need to experiment and work out what you want from a particular shot or set of shots.

If you want the subject to be pin sharp and everything else an out of focus blur as an example then a low ISO, wide open aperture, and lightening fast shutter.

Hope that makes sense.
 

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Danny depending on the light conditions you can use all 3 settings, shutter, aperture and ISO. pushing or increasing the iso is a trade off against image quality, whereas shutter speed and aperture is a trade off with depth of field. the slower the shutter speed the greater the depth of field and vice versa, so if you need a slow shutter speed to get a good depth of field you can increase the iso and thus the sensitivity of the "film" and so reduce the aperture. every gain in one direction is a loss in another so you need to experiment and work out what you want from a particular shot or set of shots.
The depth of field is controlled entirely by the apperture and has nothing to do with the shutter speed.

Using shutter priority, there may appear to be a relationship as forcing a slow shutter speed will make the camera choose a smaller apperture and hence give a greater depth of field, but it is only because of the change in apperture that one gets a greater depth of field.

Cheers, Chris
 

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uwila hate to say this but your wrong about the shutter having nothing to do with depth of field.
just look at it this way?
By governing the shutter speed you control the amount of light, which has an effect on the amount of image the camera can focus onto.

Set your aperature to say 8.0 ,increase your shutter speed. Set it as fast as possible, with a low ISO of say 100 for sharpness(low noise levels). And use your strobe,strobes as close as possible to the subject for the best color saturation of image.
The background is then controlled with shutter speeds.by increasing the camera shutter speeds you control the image detail.

Too-fast a shutter speed and you get black images.
By reducing the shutter spead down, the light levels come up .
and as the light levels come up, gives you more detail.

so as such ,apperature controls depth of field so to does shutter speed.
simon.
 

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aka Chimp 1 or Mavis...
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I agree with Uwila/Chris here, depth of field is a factor of aperture and has nothing to do with shutter speed.

For a fixed aperture and variable ISO/shutter speed (to deal with varying light levels) you will always have the same depth of field. DoF is to do with the diffraction around the iris which is only a factor of aperture.

What you refer to with regard to shutter speed and depth of light coverage is not depth of field but more the inverse square law of EM energy fall-off (light, radio waves).
 

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look at this way

yes your right about the DoF is to do with the diffraction around the iris which is only a factor of aperture.

but if you use the shutter to reduce the camera focus back from the depth of field point, shutter then has impact on the depth of field. as camera cannot fully use the depth of field as shutter is controlling the light.
simon.
 

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DOF is controlled by the aperture (f number) and NOT shutter speed as already said.
The shutter speed only controls the time the aperture is open and therefore how much light is made available to the film/sensor (dependant on aperture size).
Aperture controls the size of the opening.
By altering the aperture to a low f number (eg f/1.4) = large opening = shallow DOF, large f number (eg f/8)= small opening = deep DOF.






Effect of aperture on blur and DOF. The points in focus (2) project points onto the image plane (5), but points at different distances (1 and 3) project blurred images, or circles of confusion. Decreasing the aperture size (4) reduces the size of the blur circles for points not in the focused plane, so that the blurring is imperceptible, and all points are within the DOF.

Altering the shutter speed controls the exposure and determines how sharp the image will be if the subject or the camera is moving. The DOF will remain the same.

The images and text under the second image are from Wikipedia, who explain it further and in greater detail.

Aperture

Shutter speed

:)
 

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think if we are going to add pictures we can at least read, click on the aperature link .
Aperture - Wikipedia, the free encyclopedia
Now go down to photography, please read the top three lines.

does it or does it not say?
In combination with variation of shutter speed, the aperture size will regulate the film's degree of exposure to light. Typically, a fast shutter speed will require a larger aperture to ensure sufficient light exposure, and a slow shutter speed will require a smaller aperture to avoid excessive exposure.

The point i am trying to make is the shutter and aperature go hand in hand. shutter does not directly control the the point of field it has an impact on it !!.

you can go round and round but the fact remains that iso,shutter and aperature all have an effect on light ,which then has an effect on exposure . It doesnt matter what depth of field you have if the pictures p!!nts .

please play with your cameras and try swapping things around ,think about taking images of fast moving items, use the aperature and shutter and play.
and comment on your finds not the web.

photography is a hobbie and that is all i will claim.

dont you just love wooden spoons!!.
simon.
 

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uwila hate to say this but your wrong about the shutter having nothing to do with depth of field.
Uwila is absolutelty correct. Depth of field is entirely controlled by the aperture. Simon what you are saying about controlling the DOF with the shutter speed is a side affect of the camera altering the aperture as you alter the shutter speed.

Get a fully manual camera. Take a series of pictures by only moving the aperture - the DOF will change (and the pictures will be incorrectly exposed). Take a series of pictures by only moving shutter speed - the DOF will not change (and the pictures will be incorrectly exposed).
 

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Shutter speed does NOT effect DOF.
It has an effect on light/exposure as I posted previously, but not DOF which is what you posted earlier when you stated

simonmort said:
uwila hate to say this but your wrong about the shutter having nothing to do with depth of field.
Whether the resultant photograph is indeed pants, the DOF will remain the same for a given aperture.
 

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'Side effect' as in you can set camera to shutter priorty (S) then by increasing/decreasing the shutter speed, the camera will alter the aperture to achieve the correct exposure, thus giving the (wrongly) perceived idea that DOF can be controlled by shutter speed.

The combination thing that 'we' read is only reiterating what I have said above.

Now say after me, shutter speed does not effect Depth of Field.
 

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to achieve the best possible depth of field?
use the smallest aperture to achieve the best possible depth of field?
then the fact that this may require prohibitively long shutter speeds for correct exposure or higher iso yes .

long shutter speed can effect focus? ,which has impact on depth of field ?

bloody hell that wooden spoons getting hot:teeth: .
 

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The best possible depth of field is dependant on the photographer and what he wants to achieve. Landcapes are generally a greater DOF, macro generally means a shallow(er) DOF.

Out of focus and DOF are 2 different kettles of cod.

DOF is still set by and only the Aperture.

Spoon is yours :teeth:
 

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aka Chimp 1 or Mavis...
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aka Chimp 1 or Mavis...
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can i pass the wooden spoon,

dof is to do with focus is it not
Not necessarily. DoF is what is in focus if there is no camera shake or subject movement. This shot was taken of my cousin in a darkened room with an ISO of 200, focal length of 50mm and f1.8, shutter speed around 1/15-1/30th. There is quite a small depth of field (intentional) and the shutter speed was low.



Out of interest, how much experience have you had with a fully manual (film) camera where you can't change the ISO easily (other than pushing/pulling film). The variable of ISO adjustment is something that has really only been a player since the advent of digital cameras as you couldn't really adjust the ISO for a single frame unless you wanted to trash the rest of the film.
 
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