when to adjust aperture vs speed or iso?

[BlahBlahYouToo]

so you're shooting in M in these examples, i take it?

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.)

 

[slashbinslashbash]

so you're shooting in M in these examples, i take it?

Yes. I shoot in M 99% of the time. I'd rather have the control, and it's not hard to judge by the light meter in the viewfinder. I also use Spot Metering which lets me pick exactly where I want to meter from; in a scene with a lot of contrast, this can make a big difference.

 

[CptObvious]

I would recommend learning by shooting in aperture-priority mode. You can learn a lot from seeing what shutter speed and ISO your camera selects in various situations to keep the scene properly exposed.

My summary of how I see aperture, shutter speed and ISO:

Aperture: The most important to learn first IMO, and one that should always be manually selected. Wide apertures allow for creative out-of-focus blurring (portraits) and more light in low-light situations; smaller apertures keep most of the shot in focus (landscapes). For best sharpness, contrast, and lowest color fringing, lenses usually perform best about 2 stops below their maximum aperture. A fast zoom or prime is usually sharpest at an aperture of f/4 or f/5.6; a slower zoom is usually sharpest around f/8.

Shutter speed: I often leave shutter speed on auto, but will switch to manual in 3 situations:
1. When there isn't enough available light - when handholding a camera, you need a certain minimum shutter speed to avoid camera shake. When I've already opened up the aperture and there still isn't enough light, I will set shutter speed to a high enough setting (depending on the length of the lens) and bump up the ISO, even though it increases graininess. The reasoning being, it's better to have a grainy photo than a blurry one.
2. When I want to freeze action (high shutter speed), or alternatively, show motion blur (low shutter speed). However, motion blur shots really need a tripod to do them correctly.
3. When using flash, or mounted on a tripod - for more predictable results.

ISO: simply, keep it as low as possible, but don't hesitate to bump it up shooting low-light handheld. For the current generation of consumer DSLRs, I think a max ISO of 3200 is acceptable. For bright daylight, night shots on a tripod (long exposure times), or using flash, ISO should be set as low as possible for cleaner images.

In short, I usually shoot in aperture-priority mode except in situations where shutter speed becomes a factor.

 

[BlahBlahYouToo]

Yes. I shoot in M 99% of the time. I'd rather have the control, and it's not hard to judge by the light meter in the viewfinder. I also use Spot Metering which lets me pick exactly where I want to meter from; in a scene with a lot of contrast, this can make a big difference.

question...
in general, do use spot metering and single point focus?
and if so, are those 2 generally around the same focal/metering point or area?

e.g. subject is off center in the frame, focal point is around the face/eye, metering is around the face area as well, or perhaps the clothing.

 

[BlahBlahYouToo]

I would recommend learning by shooting in aperture-priority mode. You can learn a lot from seeing what shutter speed and ISO your camera selects in various situations to keep the scene properly exposed.

My summary of how I see aperture, shutter speed and ISO:

Aperture: The most important to learn first IMO, and one that should always be manually selected. Wide apertures allow for creative out-of-focus blurring (portraits) and more light in low-light situations; smaller apertures keep most of the shot in focus (landscapes). For best sharpness, contrast, and lowest color fringing, lenses usually perform best about 2 stops below their maximum aperture. A fast zoom or prime is usually sharpest at an aperture of f/4 or f/5.6; a slower zoom is usually sharpest around f/8.

Shutter speed: I often leave shutter speed on auto, but will switch to manual in 3 situations:
1. When there isn't enough available light - when handholding a camera, you need a certain minimum shutter speed to avoid camera shake. When I've already opened up the aperture and there still isn't enough light, I will set shutter speed to a high enough setting (depending on the length of the lens) and bump up the ISO, even though it increases graininess. The reasoning being, it's better to have a grainy photo than a blurry one.
2. When I want to freeze action (high shutter speed), or alternatively, show motion blur (low shutter speed). However, motion blur shots really need a tripod to do them correctly.
3. When using flash, or mounted on a tripod - for more predictable results.

ISO: simply, keep it as low as possible, but don't hesitate to bump it up shooting low-light handheld. For the current generation of consumer DSLRs, I think a max ISO of 3200 is acceptable. For bright daylight, night shots on a tripod (long exposure times), or using flash, ISO should be set as low as possible for cleaner images.

In short, I usually shoot in aperture-priority mode except in situations where shutter speed becomes a factor.

do you mostly do auto or manual focus?

 

[CptObvious]

do you mostly do auto or manual focus?

Autofocus, except when 1) doing macro shots - my Tamron 60mm gets easily confused trying to AF in macro, and 2) photographing still objects on a tripod (or self portrait if I'm feeling vain, hehe). I did own a couple of excellent manual focus lenses (Samyang 14mm and 85mm) and would've kept them if I had a full-frame sensor camera, but I'm still on crop sensor (Canon 60D).

 

[Throckmorton]

What's the difference between exposure compensation and ISO?

Edit: Oh, it's exactly what I thought it was... Getting the camera to automatically change settings to make the image brighter/darker. The backwards picture in the 2nd post made me think it was some additional setting.

 

[Munky]

Leave it to AT forums to give the most complicated answer. Are you shooting in manual mode? If not, you'll be adjusting exposure compensation (+/- EV), and the camera is smart enough to adjust the shutter speed, aperture and ISO based on the conditions. If a high ISO is required, and you dial in negative exposure comp, the camera will lower the ISO instead of stupidly messing with the shutter or aperture. If the camera detects that you're shooting a daytime landscape, and you add positive exposure comp, it will lower the shutter speed instead of stupidly opening up the lens.

 

[slashbinslashbash]

question...
in general, do use spot metering and single point focus?
and if so, are those 2 generally around the same focal/metering point or area?

e.g. subject is off center in the frame, focal point is around the face/eye, metering is around the face area as well, or perhaps the clothing.

Yes, I use spot metering (which bases the metering off a small circle in the middle of the frame, generally taking up the center focus point plus a little more). You can't choose where the spot metering goes like you can choose a focus point; it's always in the center. I also use single point focus 100% of the time, 95% of which is the center point, the other 5% is another focus point. So basically I always put the center of the frame on what I want to capture.

Of course there are ways around this if you don't want to frame it that way. First off, meter off what you want to meter off of, by putting the center focus point on the subject and adjusting your exposure until it works (holding down the shutter button halfway so it shows you the meter in the viewfinder). Then, once you have your exposure established, you can leave it set while you take different shots with different framing; your subject will always be properly exposed even if you are getting a bunch of bright sky in the shot, for instance. For focus, you can use the center focus point, hold down the shutter halfway, and recompose (which I do sometime when I just want quick and dirty, and I'm not worried about DOF); or switch the focus point and then use that focus point. (Keeping in mind however that the center focus point is much more sensitive than the other focus points, so in low light or other difficult focusing situations, it's best to use the center anyway -- unless you've got a camera with really advanced focusing like a 1D series. All of this advice assumes the typical 9-point Rebel/XXD/5D type focus system that Canon has used for years with only minor upgrades).

Of course, in reality I hardly ever really spend the time to meter properly. I usually get "in the neighborhood" and chimp, then adjust from there. The meter in the viewfinder can help to remind me that I need to change exposure if, for example, I am now facing into the sun instead of away from it; but in general I am a bit loosey-goosey. All depends on what you're shooting though. For more critical work (which I haven't done much of lately), I obviously take more time to get things right. But in general, "estimation+chimping is my meter". The histogram display on the chimp screen can also do wonders in difficult situations. On Canon bodies, hit "Info" twice to display the histogram.

And to answer the question you asked of CptObvious, I also autofocus almost all the time. Exceptions: macro (when you set the focus all the way at 1:1 and then move the camera forward and back to get your focus right) and any trouble situation where AF doesn't work (happens when trying to focus on a clear blue sky, or anything else similarly featureless and without contrast). Usually I give AF a chance, and if it doesn't work twice then I will pop into MF. This seems to happen most often with my 17-40mm wide angle focused at infinity. In those circumstances, I probably could fix it by using a different focus point or switching multi-point AF instead of single-point, but I usually just switch to Manual because it usually doesn't cross my mind to switch my AF mode. Sometimes I switch the focus point.

 

[twistedlogic]

Yes, I use spot metering (which bases the metering off a small circle in the middle of the frame, generally taking up the center focus point plus a little more). You can't choose where the spot metering goes like you can choose a focus point; it's always in the center.

Just wanted to state that this is only Canon. Nikon will spot meter from the focus point selected.

 

[BlahBlahYouToo]

I also use single point focus 100% of the time, 95% of which is the center point, the other 5% is another focus point. So basically I always put the center of the frame on what I want to capture.

-snip-

Keeping in mind however that the center focus point is much more sensitive than the other focus points, so in low light or other difficult focusing situations, it's best to use the center anyway -- unless you've got a camera with really advanced focusing like a 1D series. All of this advice assumes the typical 9-point Rebel/XXD/5D type focus system that Canon has used for years with only minor upgrades).

hmmm... the reason i ask is because i'm reading/watching blogs and vids on the web and came across a guy advocating the "rule of thirds".
if i'm going to frame my subject in the center most of the time, then it makes things a lot simpler.

 

[ChairShot]

Great post with lots of good information. Showed to a bunch of people.

and I never have a problem with low lighting shoots anymore ISO 12800 with low noise = magic!

 

[slashbinslashbash]

Just wanted to state that this is only Canon. Nikon will spot meter from the focus point selected.

Ooh, that's neat, I didn't know that! Is that for all Nikon bodies, even the cheapies?

hmmm... the reason i ask is because i'm reading/watching blogs and vids on the web and came across a guy advocating the "rule of thirds".
if i'm going to frame my subject in the center most of the time, then it makes things a lot simpler.

Yeah yeah yeah rule of thirds blah blah. It is impossible to use this all the time (although I do use it on occasion); and it is *always* possible to crop a photo later to give a more interesting composition. It is better to have a sharp, in-focus, properly exposed photo to start with. Composition is something that you have to work on, but many times you don't really have the time, and you just have to get the best shot you can. Of course, a lot depends on the subject, but most of the time you are going to want your subject in the center of the frame. That doesn't have to mean *centered* in the frame, but it means that at least part of the subject will be in the center of the frame.

 

[twistedlogic]

Ooh, that's neat, I didn't know that! Is that for all Nikon bodies, even the cheapies?

I believe all bodies. Works on my ole' D40.

 

[BlahBlahYouToo]

do you guys use auto WB, built in presets, or custom?

 

[slashbinslashbash]

do you guys use auto WB, built in presets, or custom?

I use auto, it's usually good enough. I always shoot RAW, so it's easy enough to fix in post if necessary. (RAW doesn't "bake in" the WB like a JPEG does -- WB is essentially just another piece of EXIF information with RAW -- your viewer/converter applies WB, not the camera.) Usually I only do it for critical work (clients/friends) and don't bother for my own stuff. Also, it's easy to apply correction in batches so that you don't have to spend too much time with it if you were shooting a lot of shots under the same conditions. (Use iPhoto, Picasa, Aperture, or Lightroom)

I actually like the warm yellow/orangey color that you get when shooting under incandescent lights. That's how the lights actually look in real life; why not capture that with your camera?

 

[finbarqs]

What's the difference between exposure compensation and ISO?

Edit: Oh, it's exactly what I thought it was... Getting the camera to automatically change settings to make the image brighter/darker. The backwards picture in the 2nd post made me think it was some additional setting.

it's mainly for auto exposure modes... i.e. AV/TV/Professional Mode

not for M... you'll just manually adjust your exposure compensation