when to adjust aperture vs speed or iso?

[Semidevil]

so I have a basic understanding of aperture, shutter speed, and iso. I'm watching a youtube video and I have a question on this situation:

The person basically was talking about an outdoor picture that is overexposed. He mentioned that it is overexposed, so he has to options to make it better if he retakes the picture. He can either adjust the f/stop, or adjust the shutter speed. He then mentions that at times, he wants to adjust the speed vs the f/stop.

Why would he choose to adjuste the shutter speed vs the aperture? What's the difference on the result of the picture?

 

[iGas]

Try reading your camera manual and get a book on basic photography.

Most cameras have exposure compensation (EV +/-), white balance adjustment with exposure compensation, and film cameras ISO can be set independently of its rating so you can over expose for colour saturation, or under expose it and push process to stretch the ISO speed.

Why would he choose to adjuste the shutter speed vs the aperture? What's the difference on the result of the picture?

It doesn't affect any thing unless he is in manual mode and using it to compensate for under/over exposure of the image. Camera sensor tend over expose dark scene (night photography), or under expose bright scene such as out door bright sky/water/snow/etc... Perhaps, he is trying zonal shooting for the subject/specific area in the scene that he want the camera to expose for.

One can use manual mode with exposure compensation to bracket the shot and pick the best result.

 

[The Stigenator]

This is a good thread... there was an cheat sheet somewhere that showed what the effect of aperture / vs shutter speed at a given ISO..

I will admit the EV thing really screws up things for me at times.. I am fine with Aperture/shutter/iso changes.

 

[iGas]

This is a good thread... there was an cheat sheet somewhere that showed what the effect of aperture / vs shutter speed at a given ISO..

I will admit the EV thing really screws up things for me at times.. I am fine with Aperture/shutter/iso changes.

I use ISO shift as EV compensation on some of my old 35mm cameras, medium format, and large format cameras.

Change ISO is old school, back when film cameras doesn't have EV compensation feature. It is a cumbersome way to do things while most modern cameras come with EV compensation.

Zone System in a nutshell.

What you want to do is gauge your scene and zone into the area that you want to set as mid tone can be a highlighted area or shadow area (average spot metering for that area, or incident metering), then set the EV +/-compensation according to your calculation, then set your camera for bracketing at 3 or 5 shots with EV +/- increment pending your camera allowance (can be up to +/-5 EV, at 1/2 or 1/3 stop increment).

That said, you can just bracket the hell out of it and pick your favorite image out of the bunch and forgo the zone shift calculation (no need for spot metering, or add highlighted meter readings to shadow readings and divide the number of readings, or incident metering).

Most Zone System shift isn't greater than 2 stops, and only few Zone System shift that I have seen are greater than 2 stops. So bracket the hell out of the scene at 1/2 stop increment up to +/-5 EV will get the result that you want, then post process the contrast to range that you like.

PS. Ansel Adam spend most of his time in the darkroom to manipulate/remaster his negative (dogging/burning/push & processing/shifting contrast) for printing even those he is the father "Zone System". It is a simple concept that has been over complicated/convoluted by photographers/authors that aren't well verse with basic shifting of the mid tone (or 18% gray) "Zone System".

 

[shortylickens]

First and foremost, I always leave it at the lowest film speed to get the best image quality. This has not changed with digital photography and the sensor gain, except for the fact that I can try multiple combinations without changing the film.

But I think its better to only play with two settings vs. three. So I set the ISO to my lowest (D40 only does 200) and then just go back and forth between aperture and shutter. I recommend doing plenty of shots while adjusting each and seeing what result you like best. Try and get some photo software that lets you look at your camera settings while viewing the image. ACDSee does that.

 

[angry hampster]

First and foremost, I always leave it at the lowest film speed to get the best image quality. This has not changed with digital photography and the sensor gain, except for the fact that I can try multiple combinations without changing the film.

But I think its better to only play with two settings vs. three. So I set the ISO to my lowest (D40 only does 200) and then just go back and forth between aperture and shutter. I recommend doing plenty of shots while adjusting each and seeing what result you like best. Try and get some photo software that lets you look at your camera settings while viewing the image. ACDSee does that.

With modern cameras, ISOs below 1600 are basically noiseless and will not differ in IQ.



It's already been mentioned in the thread, but read your camera's manual.

 

[sswingle]

They all do the same thing, but at the same time they dont.

Changing aperature will also change your depth of field
Changing ISO will give you more or less noise
Changing shutter speed will give you blur depending on what your subject is.

 

[yhelothar]

My algorithm to maximize image quality via shutter speed vs aperture vs ISO depends on two main factors: depth of focus desired and light amount.

Large apertures(low F/stop) will create small depth of fields. This is creates special effects. However, image quality usually suffers wide open. You generally want to stop down the lens 1-3 stops to really maximize sharpness with the lens.

If there is lots of light around, I'd choose the sharpest aperture, or less if I want to create the short depth of focus effect.

If the lighting is dim, I'd usually open up the aperture one to two stops more than ideal. Then I would use whatever shutter speed required from there. A good guideline of shutter speed to prevent motion blur is that you don't want to go below the shutter speed for every mm in focal length. So for a 15mm lens, 1/15s is the lowest shutter you'd wanna use, or 50mm would be 1/50s.

If you can't get a bright shot after lowering the aperture/shutter, then you would resort to upping the ISO.

 

[virtuamike]

Change aperture if you want to change composition (relation between foreground vs background vs subject, weight & feel of an image, etc).

Change shutter if you want to change what you're capturing (time & motion).

 

[finbarqs]

Zone system, in a nutshell, is to get the "perfect" exposure and to post the hell out of it to get what YOU want.

I use ISO shift as EV compensation on some of my old 35mm cameras, medium format, and large format cameras.

Change ISO is old school, back when film cameras doesn't have EV compensation feature. It is a cumbersome way to do things while most modern cameras come with EV compensation.

Zone System in a nutshell.

What you want to do is gauge your scene and zone into the area that you want to set as mid tone can be a highlighted area or shadow area (average spot metering for that area, or incident metering), then set the EV +/-compensation according to your calculation, then set your camera for bracketing at 3 or 5 shots with EV +/- increment pending your camera allowance (can be up to +/-5 EV, at 1/2 or 1/3 stop increment).

That said, you can just bracket the hell out of it and pick your favorite image out of the bunch and forgo the zone shift calculation (no need for spot metering, or add highlighted meter readings to shadow readings and divide the number of readings, or incident metering).

Most Zone System shift isn't greater than 2 stops, and only few Zone System shift that I have seen are greater than 2 stops. So bracket the hell out of the scene at 1/2 stop increment up to +/-5 EV will get the result that you want, then post process the contrast to range that you like.

PS. Ansel Adam spend most of his time in the darkroom to manipulate/remaster his negative (dogging/burning/push & processing/shifting contrast) for printing even those he is the father "Zone System". It is a simple concept that has been over complicated/convoluted by photographers/authors that aren't well verse with basic shifting of the mid tone (or 18% gray) "Zone System".

 

[finbarqs]

In all honesty, See what you Want, and use the tools to get there! More DOF? Less DOF? Action? Feel? You want noise/grain?

 

[corkyg]

Why would he choose to adjuste the shutter speed vs the aperture? What's the difference on the result of the picture?

A good example of that can be found in magazines such as Arizona Highways, where pro photogs like to have moving water blurred with the rest of the scene sharp. That is done by putting the camera on a tripod and using a slow shutter speed with a tight aperture. This causes the water's image to blur while all the stationary landscape is sharp.

 

[Fardringle]

With modern cameras, ISOs below 1600 are basically noiseless and will not differ in IQ.

Not necessarily. My Fuji s6000 is excellent at ISO 100, acceptable at 200, ugly at 400, and awful (usually completely unusable at 800+). Nikon D40 is acceptable up to 800 (although visibly worse than 200) but anything beyond that is only for situations where there is no other choice. Now, if you said modern PRO cameras, I'd agree with you, but most consumer and even intermediate/pro-consumer cameras lose image quality quickly at higher ISO settings.

 

[Suspicious-Teach8788]

Not necessarily. My Fuji s6000 is excellent at ISO 100, acceptable at 200, ugly at 400, and awful (usually completely unusable at 800+). Nikon D40 is acceptable up to 800 (although visibly worse than 200) but anything beyond that is only for situations where there is no other choice. Now, if you said modern PRO cameras, I'd agree with you, but most consumer and even intermediate/pro-consumer cameras lose image quality quickly at higher ISO settings.

i think he means most modern SLRs. I'd say 800 is still a little grainy on my 7D, but it's not noticeable at viewing resolutions. The same goes with 1600. I have no problem using 100-400 without even blinking.

Adobe Lightroom can do some good touchup for noise reduction making 1600 a breeze for me. 1600 is all my clubbing photos.

I try to stay low as people have said for ISO. I shoot f/2.8 a lot now. You just gotta be sure you know how to position yourself so your subject(s) don't become partly OOF.

 

[iGas]

I think the OP was talking about over/under expose using aperture/shutter/ISO setting instead of talking about aperture priority & shutter priority for DOF & motion.

 

[iGas]

Zone system, in a nutshell, is to get the "perfect" exposure and to post the hell out of it to get what YOU want.

Perhaps you over simplified it. The "perfect" exposure may not be the general mid tone that your camera often expose for. It mean that you expose just for a particular subject/area in the entire picture, and may purposefully blow out highlight or purposefully drop the shadow area.

 

[novasatori]

when trying to teach a friend this link helped quite a bit to show him the relationship between the different settings:
http://beej.us/guide/bgp/sfi.html

 

[corkyg]

when trying to teach a friend this link helped quite a bit to show him the relationship between the different settings:
http://beej.us/guide/bgp/sfi.html

That is good - photography is all about light.

 

[tdawg]

Here's a good, simple simulator: http://camerasim.com/camera-simulator.html

 

[novasatori]

Here's a good, simple simulator: http://camerasim.com/camera-simulator.html

much better than my link, thanks

will be very useful in the future

 

[actuarial]

i think he means most modern SLRs. I'd say 800 is still a little grainy on my 7D, but it's not noticeable at viewing resolutions. The same goes with 1600. I have no problem using 100-400 without even blinking.

Adobe Lightroom can do some good touchup for noise reduction making 1600 a breeze for me. 1600 is all my clubbing photos.

I try to stay low as people have said for ISO. I shoot f/2.8 a lot now. You just gotta be sure you know how to position yourself so your subject(s) don't become partly OOF.

It depends on where you are. I almost always use ISO 800 indoors, even with a lightsphere on my camera, to limit the effect of the flash. I can notice a difference when zoomed right in on the picture, but not in prints at all.

My biggest regret is getting the 50mm 1.4. It's a little tight sometimes indoors (on a D5000), and the depth of field is often too shallow to use it below the ISO I can get on the kit lens. I should have gotten the 35mm 1.8 (and may still trade the 50mm in for the 35mm).

Outdoors I'm always 200/400 and I don't notice much difference between them.

 

[slashbinslashbash]

Basically you want to keep things in a "reasonable" range depending on what you're photographing.

ISO should be as low as possible while keeping everything else reasonable. I really don't hesitate to bump to 400 if needed; 800 if it's dim, 1600 in dark. I usually keep my cameras on 200 or 400 when I put them away -- these are pretty all-purpose ISO's if I have to pull the camera out quickly and start shooting.

Shutter speed really depends on what you're shooting, but for most subjects at normal focal lengths (say, 24mm to 100mm equivalent, with an Image Stabilizing lens) you will be fine keeping it in the 1/100 to 1/200 range. Maybe even as slow as 1/50, as long as your subject isn't really moving. If it is bright enough that I am getting up to the 1/400-1/500 range for normal shots, I will drop the ISO a stop and come back down to 1/200. So 1/200 is effectively my everyday upper limit on shutter speed. If shooting sports, kids running around, or something else when I want to freeze motion then 1/500 or 1/1000 is warranted. If I am shooting something where I want some motion blur then down to 1/10 or so. If I have a tripod then even slower. If you are shooting an absolutely static subject (landscape, still life, etc.) then there is no reason not to use as long a shutter speed as you want, as long as you've got a sturdy tripod, use mirror lock-up and a remote shutter release or auto-timer. (At intermediate shutter speeds (say from 1/5 to 1 second), the motion of pressing the shutter button can be enough to induce blur, as well as the shake from the mirror moving in the camera. Mirror lock-up and remote shutter releases compensate for these problems.)

Aperture just depends. It is a good thing to test out your lenses and see if you're comfortable using them at their maximum apertures. I am with all of my lenses except the 17-40 f/4L -- I really try not to use it at f/4. All lenses will look better (sharper, contrastier) when stepped down from their maximum. Most lenses look their best in the f/5.6 to f/8 range. (If you have a full frame like a 5D then there is usually some benefit up to f/11 and I often shoot at f/11 -- f/11 on many crop bodies can lose resolution due to diffraction, however.) Fortunately, this is a fine range for everyday shooting, and it generally gives a nice depth of field. However, when it gets dark (or you want shallow DOF) then you have to open that thing up. Most zooms don't get very open (f/4 or f/2.8 max aperture) so you are a bit limited and have to start bumping the ISO and slowing the shutter speed pretty quickly in darker environments. With nice primes of f/1.4 or f/1.8, keep the aperture at f/2.0 or under and you can keep your ISO a little lower and shutter speed a little higher. I would rather change from aperture f/2 to f/1.4 than bump ISO from 400 to 800, in most circumstances.

So basically my rule of thumb for basic, non-artistic, non-sports snapshots is "keep shutter speed as high as possible up to a max of 1/200; keep ISO as low as possible, although below 400 it doesn't really matter; and keep aperture in f/5.6-f/11 range unless going for DOF effects". This is easily doable in well-lit scenarios, but once things get darker you have to start making choices.

I will give an example using my 5D and 24-105 f/4L IS lens. Say we start out bright and sunny, I'm at ISO 100, f/11, 1/200 -- meeting my goals in every regard. Now evening starts to come and things start getting darker, but I keep a static subject.
One stop darker: ISO 200, f/11, 1/200
Two stops: ISO 200, f/8, 1/200
Three stops: ISO 400, f/8, 1/200
Four stops: ISO 400, f/8, 1/100
Five stops: ISO 400, f/5.6, 1/100
Six stops: ISO 400, f/4.0, 1/100
Seven stops: ISO 800, f/4.0, 1/100
Eight stops: ISO 800, f/4.0, 1/50

Now let's say I switch to my 50mm f/1.4 lens. Almost everything above would stay the same with this lens, except I would change things up a bit, starting at
Seven stops: ISO 400, f/2.8, 1/100
Eight stops: ISO 400, f/2.0, 1/100
Nine stops: ISO 400, f/1.4, 1/100
Ten stops: ISO 800, f/1.4, 1/100
Eleven stops: ISO 800, f/1.4, 1/50
Twelve stops: ISO 1600, f/1.4, 1/50

At this point I am making a lot of sacrifices: noisy high ISO, wide-open aperture that gives very shallow DOF, and a slow enough shutter speed that camera shake might start to come into play. But if it's that dark then a well-exposed photo is worth the trade-offs.

So you can see from the above that I will usually increase ISO and decrease aperture before I drop the shutter speed. Nothing more frustrating than a blurry photo due to camera shake or motion blur. 1/100 is still pretty "safe" in this regard, but 1/200 is pretty much bulletproof unless you're shooting sports, moving cars, etc. (Note again, this is at "normal" focal lengths -- if you're using a 300mm telephoto lens then you will want a higher shutter speed. Rule of thumb there is to have shutter speed equal to 1/focal length, i.e. 200mm = 1/200, 400mm = 1/400, etc. Image Stabilization can make this not as necessary, but still it's a good rule to reach for.)

 

[bobdole369]

A good read is "Understanding Exposure" where Bryan Patterson breaks down the search for the "correct exposure" and how you can achieve that based on your creative intent.

He really gets into how shutter speed can freeze action, vs blurring details and when you might want to do that. Same goes for aperture (which typically is adjusted in order to vary the depth of field, but also has an impact on sharpness). ISO under 1600 on any consumer dslr made within the past 5 years is usable, but less is almost always "better" in terms of IQ. There are exceptions to that, such as when you WANT to use a further stopped down aperture (which you would make up for with ISO) or you WANT to freeze action in lower light (which you would make up for with ISO) in the case that your aperture is unchangeable (when you want full frame focus that is).

 

[CuriousMike]

keeping everything else reasonable. I really don't hesitate to bump to 400 if needed; 800 if it's dim, 1600 in dark. I usually keep my cameras on 200 or 400 when I put them away -- these are pretty all-purpose ISO's if I have to pull the camera out quickly and start shooting.

I'll give you two direct examples of when *I've* adjusted the ISO.

Since I run with kit lenses, they're not particularly fast.

1.
My kid is in a play, and they don't allow flash photography and I'm sitting 10 rows back in a dim-auditorium with varying degrees of lights.
If I left the ISO at 200, my camera would want 2 seconds to make a correct exposure.
Bump my ISO up to 1600, and suddenly I can manage 1/30th or 1/60th -- almost enough for handheld.
(I realize my example exposure times are garbage... just making a point.)


2.
My other kid is in Fall Ball -- and his game starts at 4pm and runs until about 6:30pm.
Normally, I want a fast shutter speed ( I find 1/200 or 1/400 works well ) to freeze the action and get a sharp image.
But as the light starts to fall, and the shadows come into play ... I can't maintain a fast shutter. Fading light and shadows, the light meter will tell me I'm shooting at 1/30 or less -- far to slow for hand-held *and* dimming light.
Boost my ISO up to 800 or so, and suddenly I'm shooting at 1/100 or 1/200.

For a novice photographer, I'm always very happy with the photo quality even at these higher ISO's.
In the past with my P&S cameras, I'd get nothing but blur.

 

[slashbinslashbash]

Perfect examples, Mike. In a dim auditorium, ISO 1600 is definitely called for, especially with a kit lens. I would look into a cheap 50mm f/1.8 (around $100) to give you more flexibility in those situations. Then you could keep your ISO at 800 or bump up your shutter speed to 1/100 or faster under the same lighting conditions. The shallow DOF will also work wonders with portraits, etc.

BTW I always shoot in full Manual mode, and I recommend that anybody comfortable with their understanding of aperture, shutter speed, and ISO to determine exposure (as it seems most in this thread are) learn to do the same.