Aperature setting w/ Depth of Field

[JanB56]

I am new & have been doing a lot of research on setting my aperature to the correct D of F , I understand about shooting with f 1/8, would be narrow dof, that points out the subject I'm shooting @ would be in focus , but objects behind would be blurry, here's my newbie ?, if I set the aperature to f1.8, to set the shutter properly, would I be better to use the ' shutter priority ' or set the shutter myself & if so, what would my shutter setting be, say i'm shooting @ something 6 feet away, & I want to have my focus on ONE object, but everything else behind be blurry, this is what I cannot figure out how to do. doing on line course for digital photography & i'm finally understanding the f stop settings, but I still get confused on setting the shutter w/ what I need. Is it as simple as practice, practice, practice....

 

[astroNikon]

Start testing your knowledge with a stationary subject and a measuring tape.

measure your distance to the subject and measure the respective DOF
More Clouds and Composition Effort | Photography Forum

by using a DOF calculator
A Flexible Depth of Field Calculator

Also you focus point is very important.
You have not mentioned your specific equipment
so I'm going to assume, say a nikon d7000

you want to set the Focus points on AFS-Single
Do not let the camera choose for you, so don't use AFC-d39

and practice focusing on the eye, or the specific subject you want as your DOF will take other things OOF. If someone is standing partially sideways you could easily get one eye in focus and the other eye out of focus unless you use the correct aperture setting, and correct DOF for both eyes.

So check each photo in the LCD screen for selected focus point and make sure it's what you wanted.
And practice, practice, practice. The measuring tape really hammers home the DOF calculations.

 

[Derrel]

Shooting at f/1.8 with say a 50mm f/1.8 lens, or a 35mm f/1.8 or 85mm f/1.8 lens is called shooting wide-open. Shooting wide-open means the depth of field band will be as narrow as is possible with that lens. If the lens is closed down one f/stop, there will be a little bit more depth of field. if the lens is closed down two full f/stop values from wide-open, there will be a bit more in-focus, a little bit deeper of a depth of field band. At three full f/stops below maximum aperture, there will be even more of a depth of field band, and enough to start giving you a bit of leeway on focusing, so that focusing is not utterly critical.

If you want to shoot at a SPECIFIC f/stop setting, like say f/1.8 or f/2.5, or f/3.2, I would suggest using A-mode on Nikons, Av mode on Canons; this is Aperture-priority auto on a Nikon, and Aperture value mode on a Canon--they are identical in function. This allows you to choose your priority value, which is the Aperture, and the camera adjusts the shutter faster or slower for the lighting levels.

I will give you a little tip: on people photos, at close shooting distances, like say 6 to 15 feet, shooting at f/1.8 often causes missed focus, or too shallow of a depth of field, and results in inferior photos. It's almost always better to close the lens down a bit, to say f/2.8 or so, or f/3.2, and shoot there; those aperture settings are still quite large, and let in a lot of light, but they also give a little bit better optical quality, and they give you a very slight bit of leeway on focusing errors, so that you can get a good picture even if you miss the focus by an inch or two. AT CLOSE RANGES, the f/stop used becomes very important as far as making an images either usable, or not usable. At distances of less than 10 feet, a very small focusing error can be disastrous, especially at f/1.8.

In all honesty, I think that for most people photography, using an aperture value of from f/4 to f/5.6, from 7 to 15 feet away is the best overall aperture setting range for getting a really good, usable image on the highest percentage of photos. Again--the CLOSE DISTANCE is what gives that nice, blurred background...the closeness is a little bit more of a factor in producing the out of focus background than the aperture used...being closer to the subject is what causes the depth of field to drop off rapidly in the area BEHIND the subject plane; the benefit to an f/stop like f/4 to f/5.6 is that you gain some sharpness right at the subject's plane, for a foot to two feet, but then the stuff well behind that distance drops off into out of focus-ness.

 

[jcdeboever]

Shooting at f/1.8 with say a 50mm f/1.8 lens, or a 35mm f/1.8 or 85mm f/1.8 lens is called shooting wide-open. Shooting wide-open means the depth of field band will be as narrow as is possible with that lens. If the lens is closed down one f/stop, there will be a little bit more depth of field. if the lens is closed down two full f/stop values from wide-open, there will be a bit more in-focus, a little bit deeper of a depth of field band. At three full f/stops below maximum aperture, there will be even more of a depth of field band, and enough to start giving you a bit of leeway on focusing, so that focusing is not utterly critical.

If you want to shoot at a SPECIFIC f/stop setting, like say f/1.8 or f/2.5, or f/3.2, I would suggest using A-mode on Nikons, Av mode on Canons; this is Aperture-priority auto on a Nikon, and Aperture value mode on a Canon--they are identical in function. This allows you to choose your priority value, which is the Aperture, and the camera adjusts the shutter faster or slower for the lighting levels.

I will give you a little tip: on people photos, at close shooting distances, like say 6 to 15 feet, shooting at f/1.8 often causes missed focus, or too shallow of a depth of field, and results in inferior photos. It's almost always better to close the lens down a bit, to say f/2.8 or so, or f/3.2, and shoot there; those aperture settings are still quite large, and let in a lot of light, but they also give a little bit better optical quality, and they give you a very slight bit of leeway on focusing errors, so that you can get a good picture even if you miss the focus by an inch or two. AT CLOSE RANGES, the f/stop used becomes very important as far as making an images either usable, or not usable. At distances of less than 10 feet, a very small focusing error can be disastrous, especially at f/1.8.

In all honesty, I think that for most people photography, using an aperture value of from f/4 to f/5.6, from 7 to 15 feet away is the best overall aperture setting range for getting a really good, usable image on the highest percentage of photos. Again--the CLOSE DISTANCE is what gives that nice, blurred background...the closeness is a little bit more of a factor in producing the out of focus background than the aperture used...being closer to the subject is what causes the depth of field to drop off rapidly in the area BEHIND the subject plane; the benefit to an f/stop like f/4 to f/5.6 is that you gain some sharpness right at the subject's plane, for a foot to two feet, but then the stuff well behind that distance drops off into out of focus-ness.

That's what I have been finding out, good explanation Derrel

Sent from my XT1254 using Tapatalk

 

[Designer]

I plugged your parameters into the DOF Master and came up with this:

Subject distance 6 ft

Depth of field
Near limit 5.85 ft
Far limit 6.16 ft
Total 0.3 ft

In front of subject 0.15 ft (49%)
Behind subject 0.16 ft (51%)

Hyperfocal distance 230.3 ft
Circle of confusion 0.02 mm

So your TOTAL DOF is only 0.3 ft, which is roughly 4 inches. A person's face is deeper than 4 inches, so if you happened to get their noses in focus, their ears would not be in focus.

So stop down, as Derrel has suggested, and get that shot!

BTW: if using f/5.6 means your shutter opening is too long for a hand-held shot (check the camera's meter to find out) then you've got two choices; set the ISO higher, or add light with a portable flash (preferably slightly to one side or the other).

 

[JanB56]

Start testing your knowledge with a stationary subject and a measuring tape.

measure your distance to the subject and measure the respective DOF
More Clouds and Composition Effort | Photography Forum

by using a DOF calculator
A Flexible Depth of Field Calculator

Also you focus point is very important.
You have not mentioned your specific equipment
so I'm going to assume, say a nikon d7000

you want to set the Focus points on AFS-Single
Do not let the camera choose for you, so don't use AFC-d39

and practice focusing on the eye, or the specific subject you want as your DOF will take other things OOF. If someone is standing partially sideways you could easily get one eye in focus and the other eye out of focus unless you use the correct aperture setting, and correct DOF for both eyes.

So check each photo in the LCD screen for selected focus point and make sure it's what you wanted.
And practice, practice, practice. The measuring tape really hammers home the DOF calculations.

Thank you for your help, this is one area that is kicking my butt. it's making me feel like I might not get the hang of it, but I won't stop trying. I do use a Nikon D3100 , I have purchased 4 diff lens, 50mm 1:8G - 18-55 5.6G - 35mm 1.8G & 55-200mm 5.6G , which would be better for shooting to get the best DoF & which do you consider the worst ?

 

[JanB56]

Shooting at f/1.8 with say a 50mm f/1.8 lens, or a 35mm f/1.8 or 85mm f/1.8 lens is called shooting wide-open. Shooting wide-open means the depth of field band will be as narrow as is possible with that lens. If the lens is closed down one f/stop, there will be a little bit more depth of field. if the lens is closed down two full f/stop values from wide-open, there will be a bit more in-focus, a little bit deeper of a depth of field band. At three full f/stops below maximum aperture, there will be even more of a depth of field band, and enough to start giving you a bit of leeway on focusing, so that focusing is not utterly critical.

If you want to shoot at a SPECIFIC f/stop setting, like say f/1.8 or f/2.5, or f/3.2, I would suggest using A-mode on Nikons, Av mode on Canons; this is Aperture-priority auto on a Nikon, and Aperture value mode on a Canon--they are identical in function. This allows you to choose your priority value, which is the Aperture, and the camera adjusts the shutter faster or slower for the lighting levels.

I will give you a little tip: on people photos, at close shooting distances, like say 6 to 15 feet, shooting at f/1.8 often causes missed focus, or too shallow of a depth of field, and results in inferior photos. It's almost always better to close the lens down a bit, to say f/2.8 or so, or f/3.2, and shoot there; those aperture settings are still quite large, and let in a lot of light, but they also give a little bit better optical quality, and they give you a very slight bit of leeway on focusing errors, so that you can get a good picture even if you miss the focus by an inch or two. AT CLOSE RANGES, the f/stop used becomes very important as far as making an images either usable, or not usable. At distances of less than 10 feet, a very small focusing error can be disastrous, especially at f/1.8.

In all honesty, I think that for most people photography, using an aperture value of from f/4 to f/5.6, from 7 to 15 feet away is the best overall aperture setting range for getting a really good, usable image on the highest percentage of photos. Again--the CLOSE DISTANCE is what gives that nice, blurred background...the closeness is a little bit more of a factor in producing the out of focus background than the aperture used...being closer to the subject is what causes the depth of field to drop off rapidly in the area BEHIND the subject plane; the benefit to an f/stop like f/4 to f/5.6 is that you gain some sharpness right at the subject's plane, for a foot to two feet, but then the stuff well behind that distance drops off into out of focus-ness.

Wow, good information Darrel, no doubt you know your stuff. what you mentioned about shooting @ close distance, is something I really want to achieve also. I guess it's time for me to start using this helpful information & start practicing more, I think I'm letting this intimidate me & I don't want it to. Thanks so much for you great help , I am Thankful for these forums.

 

[astroNikon]

Best DOF ?
Do you mean which ones provides the shallowest DOF ?
that would be your 50mm and 35mm f/1.8 lenses. The smaller the "f" number the shallower the DOF

f/1.8 is a wide opening in the aperture, which gives a shallow DOF

As Derrel mentions with people f/5.6 is good for DOF
Artistically though you may want to use f/2.8 or f/1.8
but use a ruler, you'll see your distance etc per Designer numbers from a calculator show what you have to work with.

Also, still be aware of your shutter speed. Try to keep it above, say, 1/125 if shooting people just to not let motion blur (by people or your hand) affect the photo.

 

[runnah]

Do what I do when working on car when I don't have a torque wrench. Tighten until you hear a crack then back off a quarter turn.

 

[Derrel]

Any of the lenses you have will be fine at f/5.6. The closer you stand to people, the more-critical absolutely dead-on accurate focusing becomes. I personally think that seven feet is the absolute closest you ought to ever be when doing people photography, unless you want distorted hands, arms, legs, noses, etc.. For pleasing, portrait-type photos of people, I think it's easier to be a little bit farther away from them, say 10-15 feet, and to use a zoom lens to get the right framing. If you shoot portraiture at f/5.6, you almost always can hit focus, even on two people, and as long as you are in the 12 to 20 foot distance range, focusing is not super-critical, the way it is at the closest distances.

If you want to do say a very tight head shot, you could use the 35mm lens from three feet away, OR move back, and use say the 55-200mm lens from 15 feet; moving back, and using the longer lens will result in a different picture, with the SAME head size in the frame. My vote is almost always for a longer lens, from a bit farther back, than it is shootjng from too close a distance.

 

[Designer]

I have purchased 4 diff lens, 50mm 1:8G - 18-55 5.6G - 35mm 1.8G & 55-200mm 5.6G , which would be better for shooting to get the best DoF & which do you consider the worst ?

Hey, don't stress it! Nobody is born with the ability to "just know" how to calculate the DOF, that's why somebody has put that thing online.

As for "best DOF", what exactly are you going for? Usually people want the subject(s) to be IN FOCUS, and the background and foreground OUT OF FOCUS, so I'll use that premise as the starting point for formulating my answer.

To get somewhat of a shallow DOF, while keeping your subject in focus, you're going to have to plug in the numbers yourself because we won't know how far away from the camera your subjects are. That being said, I would suggest the longer lens to minimize distortion of being way too close to your subjects. The 50 mm might work, but then so would the 55-200mm if the background was far behind the subjects.

 

[TCampbell]

The image above looks like you applied either a strong skin-softening brush or perhaps applied a strong amount of de-noising (which tends to soften the look of an image.)

If you are trying to create a sharp subject with blurred background, then using a longer focal length lens with a low focal ratio really helps... here's a candid shot I took at 200mm f/2.8. Sometimes I'll use f/4 at a long focal length -- even f/5.6 works. But as the focal ratio (f-stop value) increases, the blur in the background is going to decrease but the depth of field will increase. When using low focal ratios with more than one subject in the shot, you'll need to compose them so they are at very similar lens-to-subject distances or one may be sharp and the other soft.

Your 50mm f/1.8 will achieve more background blur than your 35mm f/1.8 (at the f/1.8 focal ratio) and remember to frame the subject close but keep lots of separation between subject and background (so the background is well beyond the focused area in the depth of field. Do not, for example, place a subject right up against a wall.... pull them away from the wall.)

You could also use your 55-200mm f/4-5.6 lens but use it at the long end (e.g. minimally 150mm or longer) at which point it won't let you use f/4... you won't be able to go below f/5.6, but even at f/5.6 you will be able to achieve some background blur as long as you make sure your subject is relatively close (as close as possible and still frame what you want) and your background is well behind the subject. The blur will not as strong as you see in the above image (that was f/2.8) but it will be stronger blur than your 35mm lens example above.

Something else that may be helpful is to learn to search pixel-peeper.com for sample images taken by various lenses and at various focal ratios. The long link below is a pixel-peeper.com search to find images taken with a Nikon crop-frame camera (same sensor size as your D3100) and with the Nikon 85mm f/1.8 lens (a very popular focal length for portraiture) but I've also limited it to only show sample images taken at low focal ratios (between f/1.8 and f/2).

Full-size sample photos from Nikon 85mm F/1.8

 

[Ido]

You set the f-number to get the desired depth of field. That can be selected manually in either Aperture Priority or Manual mode. Shutter Priority will give you direct control over the shutter speed, not the aperture.

The shutter speed you choose has no effect on depth of field. And unlike aperture, there is no rule of thumb or universal setting for the shutter speed for those situations. It simply depends on the amount of light. If you’re shooting in daylight, you’ll need a fast shutter speed to get decent exposure. If you’re shooting in low light, you’ll need a slow shutter speed for the same brightness of the image. People are always in motion—even if we think we’re completely still, we’re probably still moving a bit—so using a slow shutter speed isn’t an option, because they will be blurred. That’s where the ISO comes into play; if it’s too dark to use a shutter speed that’s fast enough to freeze motion and get a sharp image, with the aperture set how you want it for depth of field, raise the ISO to get a faster shutter speed.

Start out in Aperture Priority mode with Auto ISO. You choose any f-number you want within the lens’s range, and the camera calculates the necessary shutter speed and ISO for a “good” exposure, based on its built-in light meter. I think Nikon cameras have sophisticated Auto ISO, which makes sure the shutter speed doesn’t drop below 1/f, where f = focal length, to avoid camera shake, so that’s a good start. “Chimp” a lot—view the image in the rear LCD right after it’s been captured, and zoom in, to see if the subject is sharp. This isn’t best-practice for an experienced photographer, but it is a good way to learn and improve.

Many beginners get the impression that everything they do should be in Manual mode, and that all skilled and respected photographers shoot that way. That is simply not true. I, like many others, shoot at least 90% of the time in Aperture Priority mode. The rest I shoot in Manual, mostly when I have the camera mounted on a tripod and the light isn’t changing quickly.

Depth of field gets shallower the closer you are to the subject and the bigger the aperture is. The diameter of the aperture is the ratio between the focal length and the f-number, so your 50mm f/1.8 lens, when set to f/1.8, has an aperture diameter of 50 ÷ 1.8 ≈ 27.78mm. Your 55-200mm f/4-5.6 lens, when set to 200mm and f/5.6, has an aperture diameter of 200 ÷ 5.6 ≈ 35.71mm, so technically, you will get shallower depth of field with the 55-200, but realistically, you’ll be much closer to the subject with the 50mm lens, so in the end it will give you shallower depth of field. However, depth of field shouldn’t be your main concern with choosing which lens to use for a certain image—choose the focal length that gets the framing you want at the distance you want from the subject (when photographing people, try to have a fair distance to avoid distorting facial and body features), the aperture you need for the lighting conditions, etc.—but I understand you want ot practice some more, learn a bit and try to shoot with a shallow depth of field, so that’s what you need to keep in mind.

 

[Jade16]

Great explanation! So, does one not need to be as careful when standing farther away and then zooming in? does the same not apply? in terms of shooting wide open and getting crisp focus? For example, I have a Miii and am shooting with a canon 24-70 2.8. Am I more likely to get the crisp shot (when shooting wide open) if I stand farther away and zoom in than if I were to stand closer to the subject without zoom?

Any of the lenses you have will be fine at f/5.6. The closer you stand to people, the more-critical absolutely dead-on accurate focusing becomes. I personally think that seven feet is the absolute closest you ought to ever be when doing people photography, unless you want distorted hands, arms, legs, noses, etc.. For pleasing, portrait-type photos of people, I think it's easier to be a little bit farther away from them, say 10-15 feet, and to use a zoom lens to get the right framing. If you shoot portraiture at f/5.6, you almost always can hit focus, even on two people, and as long as you are in the 12 to 20 foot distance range, focusing is not super-critical, the way it is at the closest distances.

If you want to do say a very tight head shot, you could use the 35mm lens from three feet away, OR move back, and use say the 55-200mm lens from 15 feet; moving back, and using the longer lens will result in a different picture, with the SAME head size in the frame. My vote is almost always for a longer lens, from a bit farther back, than it is shootjng from too close a distance.

 

[JanB56]

I have purchased 4 diff lens, 50mm 1:8G - 18-55 5.6G - 35mm 1.8G & 55-200mm 5.6G , which would be better for shooting to get the best DoF & which do you consider the worst ?

Hey, don't stress it! Nobody is born with the ability to "just know" how to calculate the DOF, that's why somebody has put that thing online.

As for "best DOF", what exactly are you going for? Usually people want the subject(s) to be IN FOCUS, and the background and foreground OUT OF FOCUS, so I'll use that premise as the starting point for formulating my answer.

To get somewhat of a shallow DOF, while keeping your subject in focus, you're going to have to plug in the numbers yourself because we won't know how far away from the camera your subjects are. That being said, I would suggest the longer lens to minimize distortion of being way too close to your subjects. The 50 mm might work, but then so would the 55-200mm if the background was far behind the subjects.

Thank you for the help, it is very much appreciated, I'm going to take everyone's input & use it to help me, this is why I love this beginners forum, you guys are more than kind to us beginners & lending a helping hand, thank you.... so much