Digital photography: aperture
glandu Posted messages 25508 Registration date Status Contributor Last intervention -
Hello, I would like to know for a camera or even a smartphone, ... how should I set the f/* aperture?
To take a landscape photo? Is a large number better?
And does the aperture relate to distance, foreground?
Thank you for your help
3 answers
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Hello,
The other parameters are ISO sensitivity and shutter speed, not to mention those specific to the focal length of the lens (or zoom); they are nonetheless much more limited on a smartphone.
We cannot, and depending on the ISO we cannot play with the aperture to infinity without risking under- or overexposure.
The tricky part is that the lower the number, the larger the aperture, and the deeper the depth of field: for a landscape with no moving objects, we will therefore choose in order of preference 11 to 8 depending on the ISO and the external light.
Conversely, if we want to photograph a close-up subject with a blurred background, we will choose the smallest possible number, for example 2.8.
The sharpness of the subject itself when it is relatively close is not related to the aperture, but the focus, although at high ISOs not the subject itself but the whole photo risks being more or less noisy.
But there is no advantage to opting for high ISOs except in extremely dark or night photos.
Historically in film photography, the brand of film was a factor; schematically Kodak produced warmer colors whereas, for example, Agfa or Fuji were better in blue-green (forests...); I assume that in the digital era there are also such differences depending on the devices.-
Good evening,
Where it gets tricky is that the lower the number, the larger the aperture, and the shallower the depth of field becomes: for a landscape with no moving object, we would therefore choose in order of preference from 11 to 8 depending on ISO and exterior light.You must have written a bit quickly! It’s the opposite: the depth of field is greater when the diaphragm is closed (higher number: f/22 for example) and it decreases when you open the lens (f/4 for example).
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With a smartphone, I don’t ask questions. It’s for quick photos and I let the smartphone do the work: so automatic mode and no pro mode. The only correction that often remains is the color temperature.
With a DSLR, we generally arrange not to have too large an aperture (low f-number), which will reduce depth of field, unless that is precisely what you want (Bokeh effect).
In addition to the loss of depth of field, the lens doesn’t perform at its best (loss of sharpness). It’s therefore better to stick to mid-range apertures.
What is clearly conceived is expressed clearly,
And the words to say it arrive easily.
(Boileau) -
So if I understand correctly, the ISO should be set to the lowest when it's daytime
I can't adjust the aperture, I think, on my phone
And what speed is better to be at if what we're taking is static and about 30 meters away, with our smartphone?
I noticed that for photos I have 1/3000, ...
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Hello,
The ISO value defines the sensor's sensitivity. The definition has obviously evolved since film photography. See the details on Wikipedia:
However, there is one common point: a high ISO value is accompanied by a loss of detail: heavy grain in film photos, pixelation in digital photos.
So we usually choose a fairly low ISO value, provided it is compatible with the shooting conditions.
On smartphones where there is no aperture adjustment, one manipulates the speed/ISO pair to obtain the best possible exposure.
You may have noticed that by default the sensitivity is as low as possible and therefore the shutter speed adapts to the shooting conditions.The shutter speed value is not important for static subjects. It can be high since there are no mechanical constraints.
On my smartphone, the highest speed is 1/6000 s, while the lowest ISO is 50. It is quite rare to have overexposure.
ok thanks
about the exposure triangle: ISO, aperture, shutter speed
I knew it quickly. someone who used to take a lot of photos taught me this triangle. but it's mainly the aperture that I didn't understand very well.
In order to take photos at about 30m I would say (landscapes, on vacation, ...)
I didn't know if we could do something.
then for the speed yes I knew that if there is movement or even just a little, the number will be largerI also noticed that for photos I often have 1/4000, 1/6000 at 100m high in a drone. I quickly asked myself the question but is it related to vibration, wind ... apparently. ( I had written on google: 1/5000 drone 120m. and it said that ) (( I just specify that it displays IA systematically first ))
but apparently a very high speed for example 1/5000 reduces the amount of light entering. but I don't quite see what that means exactlyhello I can’t make it simpler
Rappel des règles en photo
the depth of field is the sharp area of a photograph
it is 1/3 in front of the subject and 2/3 behind the subject
the aperture and its opening the bigger the number (like 22) the smaller the hole that lets photons through and vice versa
the bigger the number the greater the depth of field
the focal length of a lens is a dimension in mm that goes from wide angle 14 18 35 50 to telephoto 85 105 200 and more
the bigger the number the shallower the depth of field and by deduction vice versa
the closer you are to the subject the more you reduce the sharpness in the background (artistic blur)
to have a photo with artistic blur you must have a foreground subject
you need a large aperture (open the diaphragm like 22) and long focal length 50 85 and more
if the telephoto is set to magnify more you must move away from the subject (e.g.: for a 200mm/1 8m)
with a 24 mm lens on a compact camera it will be impossible to create blur; the image will be sharp across the entire depth of field (infinity)
for a sharp photo with a subject and no blur, use wide angle up to 40 50
in drones you only have one plane, therefore all sharp to infinity
the longer the focal length you use on a telephoto, the more you need to increase the shutter speed or shoot on a tripod to avoid shake
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