Image quality different settings same light

Flukester

Flukester

Flukester

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Hi photo nerds... could anyone give some insight into the below question. What's prompted me to ask is returning from a recent holiday and noticing huge differences in image quality. (noise / colour reproduction / detail)

Given camera on minimum ISO and image properly exposed with no motion blur which setting gives best image quality.

Opened aperture with fast shutter

or

Closed up aperture with slow shutter


In my head I'm thinking they could be the same, but are they ?.

You let the same amount of light in with both (with the correct settings), but is one better than the other ? (maybe lower noise etc). Is one better suited to a bright sunny day for example ? ...even though you have adjusted to expose the sensor to same qty of light.

Maybe the only difference is going to be depth of field... ? (though that's a none issue on long distance landscapes ?

My reasoning could be flawed here, but I'm sure this will spark some debate :D

:eek::(:confused:
 
Flukester said:
Hi photo nerds... could anyone give some insight into the below question. What's prompted me to ask is returning from a recent holiday and noticing huge differences in image quality. (noise / colour reproduction / detail)

Given camera on minimum ISO and image properly exposed with no motion blur which setting gives best image quality.

Opened aperture with fast shutter

or

Closed up aperture with slow shutter


In my head I'm thinking they could be the same, but are they ?.

You let the same amount of light in with both (with the correct settings), but is one better than the other ? (maybe lower noise etc). Is one better suited to a bright sunny day for example ? ...even though you have adjusted to expose the sensor to same qty of light.

Maybe the only difference is going to be depth of field... ? (though that's a none issue on long distance landscapes ?

My reasoning could be flawed here, but I'm sure this will spark some debate :D

:eek::(:confused:
Click to expand...
 
Andy90 said:
Most lenses do actually benefit from being stopped down (i.e smaller aperture) rather than being wide open. That said there comes a point where if you stop down too much your image sharpness will decrease. It is called Diffraction.

Take a look at the following article

http://www.cambridgeincolour.com/tutorials/diffraction-photography.htm/
Click to expand...

Thanks :)

Dam yeah forgot about that... remember reading how often lenses are not so sharp wide open

I'm guessing then the advice is shoot wide open only for depth of field effects or if lights calls for it and you want natural light ?
 
Only the ISO setting affects your image noise
Aperture changes depth of field and therefore sharpness of near/far objects
Shutter speed freezes action. If you have no fast moving subjects then set it as the same as your focal length to avoid camera shake image blur.
 
You will get some increased noise with a longer shutter speed,but it will only be of concern over very long exposures of several minutes, mainly due to the sensor heating.
 
It's also worth noting that "minimum ISO" isn't always the best ISO. Minimum ISOs are often extended down below native ISO by underexposing and then bringing the exposure backup - losing dynamic range.

Check out the native ISO for your camera, and that's the "best" one to use in terms of both noise and dynamic range.
 
uv said:
It's also worth noting that "minimum ISO" isn't always the best ISO. Minimum ISOs are often extended down below native ISO by underexposing and then bringing the exposure backup - losing dynamic range.

Check out the native ISO for your camera, and that's the "best" one to use in terms of both noise and dynamic range.
Click to expand...
ISO values below the native will be labeled Low1, low2 etc do it should be obvious.

When the sensor underexposes and increases gain is what happens at high ISO values. The oposite happens the lower than native settings, images are overexposed and the brightness brought down, so your loose the highlight headroom.
 
D.P. said:
ISO values below the native will be labeled Low1, low2 etc do it should be obvious.
Click to expand...

Depends entirely on the camera, and the OP doesn't say what camera they have. My RX100mk2 certainly doesn't do that - base ISO is 160 and it also displays 100 and 125.
 
uv said:
Depends entirely on the camera, and the OP doesn't say what camera they have. My RX100mk2 certainly doesn't do that - base ISO is 160 and it also displays 100 and 125.
Click to expand...

Sorry Oly OM-D EM-5 II ...ISO 200, no settings to go lower AFAIK

Thanks for all your replys. Has cleared things up in my head.... also confirms the mistake I used to make a year back of running around taking everything at F1.8 :-)

For most of holiday I was in Aperture priority around F4, and F4 is the sweet spot on my two primes I think where the lens performs well

This is all like rocket science to me :)
 
uv said:
Depends entirely on the camera, and the OP doesn't say what camera they have. My RX100mk2 certainly doesn't do that - base ISO is 160 and it also displays 100 and 125.
Click to expand...

It should give some kind of extra warning too, terrible design if it doesnt't.
 
Flukester said:
Sorry Oly OM-D EM-5 II ...ISO 200, no settings to go lower AFAIK

Thanks for all your replys. Has cleared things up in my head.... also confirms the mistake I used to make a year back of running around taking everything at F1.8 :-)

For most of holiday I was in Aperture priority around F4, and F4 is the sweet spot on my two primes I think where the lens performs well

This is all like rocket science to me :)
Click to expand...


Choose an aperture based on the depth of focus you require and ignore any differences in lens sharpness or sensor behaviour.
 
D.P. said:
Choose an aperture based on the depth of focus you require and ignore any differences in lens sharpness or sensor behaviour.
Click to expand...

Thanks :), I'm guessing in low light indoors for example, if you want natural lighting you have to work with shallow depth of field and have lens wide open ? (assuming you don't want ISO to creep up, I kind of treat ISO as my enemy, not sure I should but I don't like the way high ISO shots look, at least not on my camera)

I guess stepping back a little might solve any focus issues though between subjects to a degree

One day I will understand this... my current tactic is to take lots of photos and hope they are ok

On the cruise we were on all the pro photographers working on the ship had full frame Nikons set to manual... this surprised me, either they know what they are doing all the time, or they know settings which work in the ships lighting.
 
Don't worry about ISO, switch auto-ISO on and ignore it, choose the aperture to give the desired DoF. Wrong focus ruins a photo and there is nothing you can do about it, extra noise doesn't badly effect a photo and can be treated with noise reduction software. And seriously. You print out a photo at iso 6400 and it will look great, print a photo with wrong focus/DoF and it will look terrible.

To avoid raising the ISO use a tripod.in fact if you are really worried about getting the best image quality use a tripod, mirror-up, remote shutter and use hyper focal focusing to get an aperture as close to f/8 as possible
 
Quite simply - what's the sweet spot of your lens' aperture? There's a way to find out ya know.. and it depends on what body and lens you're using as well - as the sweet spot on a FF lens on an FF body is going to be different to the one with the same lens on a crop body etc.
 
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