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Rules of thumb?
As a new DSLR user, I am trying to find out if there are any rules of thumb when it comes to aperture and shutter speed..

I have read that you should use a shutter speed faster than the length of the lens. I have played around with this and I think I get the concept. I have tried faster and slower speeds and have seen the results..

What I am looking for help with is the aperture settings. I have been fooling around with different settings and wanted to know if someone could give some tips around these..

I am clicking a lot of pictures at different settings and examining them after the fact. This has been very helpful, I am just looking for some "rules of thumb". Stuff like for portraits stick to an aperture of Fx or don't go above Fx if you are shooting inside without a flash. Anything that will jump start me or provide me additional things to try..

Thanks a bunch, you folks have been most helpful already...

Comments (19)

If you are using a canon rebel series, as I think you are from a quick look at your previous posts, the rule is actually 1.6x your focal length... E.G. 50mm times 1.6 = 80, or 1/80th of a second. This is because the sensor is 1.6x smaller than a piece of 35mm film..

As for aperture, the smaller the f/ number, the wider your aperture. the wider your aperture, the more light gets in (and also your depth of in-focus area "depth of field" shrinks). each "stop" represents a doubling/halving of light. the stops are 1, 1.4, 2.0, 2.8, 4.0, 5.6, etc (multiply by 1.4 to get next value). so shutter speed of 100 at f/5.6 or shutter speed of 50 at f/4.0 lets the same amount of light hit the sensor.richalborn.smugmug.com..

Comment #1

Thanks for the quick response. You are right, I am using a Canon XTI..

I understand the math that you laid out for the shutter speed and it makes sense to me. The one thing I was confused on was if it was the focal length, which is what I thought or the max range of the lens..

I am gaining a better understanding of the apertures and your example of shutter speed of 100 at f/5.6 and a shutter speed of 50 at f/4.0, makes sense..

Based on your experience, do you have recommendations on the shutter speed or f/stop for a few situations. For example, indoor shooting during the day, indoor at night, sports or outdoor night shots and such? I know that there are many options based on the amount of light etc, but I am just looking for a guide..

Thanks again...

Comment #2

Well, it's not the MAXIMUM focal length, but the one you're using at the time. Most lenses have markings on them that will indicate what focal length you're using..

Just play around in P mode and watch the settings change. You can choose to adjust the exposure with exposure compensation. I think on your camera, you hold the aperture button while moving the shutter speed wheel. Watch the little carrot slide across the bottom of the viewfinder. when it is in the middle, it is properly exposed... at least the camera is guessing it is.



Some situations will require you ask the camera to shoot as much as a couple stops over or under what it thinks is correct exposure. The camera wants to make everything middle gray, so you'll have to "over expose" to capture white snow (as opposed to gray snow) or under expose for a close up of a black suitcase..

Duane0524 wrote:.

Thanks for the quick response. You are right, I am using a Canon XTI..

I understand the math that you laid out for the shutter speed and itmakes sense to me. The one thing I was confused on was if it was thefocal length, which is what I thought or the max range of the lens..

I am gaining a better understanding of the apertures and your exampleof shutter speed of 100 at f/5.6 and a shutter speed of 50 at f/4.0,makes sense..

Based on your experience, do you have recommendations on the shutterspeed or f/stop for a few situations. For example, indoor shootingduring the day, indoor at night, sports or outdoor night shots andsuch? I know that there are many options based on the amount oflight etc, but I am just looking for a guide..

Thanks again..

Richalborn.smugmug.com..

Comment #3

Rules of thumb. try the foillowing-.

For general photography, not special purpose or specific use(macro, motion stopping, astro, hyperfocusing, etc.), use a shutter speed of 1/125 or faster AND an fstop of f5.6 or smaller. do this and you will find that you can take near 90% of your shots with good quality..

The other 10% needs special consideration of either shutter speed or fstop or BOTH in order to make the shot work..

Shutter speed fomula. lens in mm = 1/shutter speed. if dslr use lens in mm X crop factor(multiplier) = 1/shutter speed..

Hand hold to 1/60, below use tripod. remember that SR/IS/VR only helps, it is not the answer to critical sharpness. critical sharpness is a image sharp enough that no consideration need be given at ANY level of enlargement because of sharpness. you can go to 20x30inches and not even think about how sharp the image needs to be. and at a 1/60 handheld you may not be able to make a 20x30inch print. the prints that m reichman has shot for luminous landscape 90% were on a tripod.

And he still puts the camera/lens on a tripod..

For myself if there is ANY POSSIBILITY that I will make big enlargements then it goes on a tripod..

A lens max IQ and sharpness occurrs about 2-3 fstops closed down from wide open. OR RPT OR f8.0 if you do not know the fstop max IQ. me, I just use f8.0 and worry about it..

Metering. any camera or light meter assumes that the scene in question is reflecting light at a normal rate, sometimes stated as 18% reflectance. if you have a scene that is NOT NORMAL then the metering system needs help from the user. this si in the form of exposure compensation or EC. such a scene could be mostly or all snow scene or a beach. a black cat sitting on a coal pile.

A white cat sitting on a coal pile. a black cat sitting on a snow field. these situations will cause your camera's meter to meter incorrectly. this is when the user uses EC in apositive or negative way. please note that the direction of the movement depends on what exactly is your subject.

Unless the scene is your subject. also note that the scene and subject suggested exposure could exceed the Dynamic Range of the sensor in the camera. this means that some part of the image will not be correctly exposed but the subject will be if the EC was done right...

Comment #4

The most important rule to remember is the BS (Bright Sun) rule. And that is simply the exposure in brigth sun is no matter where in the world you shoot is always f/16 for the f stop and the iso is the shutter speed. That is 1/ISO ...

Comment #5

Runrider wrote:.

So shutter speed of 100 atf/5.6 or shutter speed of 50 at f/4.0 lets the same amount of lighthit the sensor..

Unless you are are talking about 100 seconds and 50 seconds, you have it backwards..

F/5.6 at 1/50 = f/4.0 at 1/100.

Remember with fractions, 1/50 is longer than 1/100...

Comment #6

Some good ROTs here already. Many thanks, all..

How about portrait photography. The BS rule would imply that I'd use f16 for an outdoors picture, but what if I want a BS shot with narrow depth of field?Sean..

Comment #7

Msjhaffey wrote:.

Some good ROTs here already. Many thanks, all..

How about portrait photography. The BS rule would imply that I'd usef16 for an outdoors picture, but what if I want a BS shot with narrowdepth of field?Sean.

Going from this rule of thumb, you just want to keep same EV (Exposure Value),.

Now if the exposure is going to be, say, f16 + 1/100 sec @ISO 100,.

You want to narrow DOF, just go up on Aperture by two stops to f8, you decrease your time by two notches, in this case 1/400..

So you keep going in same direction, i.e. brighter apertiure and faster times, by same number of steps and you will keep reducing your DOF, be carefull, if you can easily reduce your DOF razor thin to a point where nose is in focus and eyes are not..

Shoot to capture, not kill !.

Minolta 7D 7000i 50/1.7 28/2.8 35-70 70-300 28-80 70-210 Tam 28-200Panny FZ5 FZ7Fuji F20 F40..

Comment #8

The BS rule only set a point of reference. You can change the either aperture or speed in a relative way. Speed goes up. open more aperture. If you really want to learn using camera manually you can do the BS thing as it is really easy to remember. For general sniping using the various modes can make life a lot easier..

For portraits, I would use the aperture priorty mode (I am a Pentax and Nikon user, so I don't know what is that called in C). For a shallow depth of view use the smallest F number (ie 2.8, 2 oer 1.4) and let the camera select the speed. Then see if that combination is usable (speed may be too low for handheld eg). If yes take picture then see result and experiment more. If not then either use tripod or up the ISO..

Don't be bound by conventional rules. Do use higher ISO, do play with aperture and shutter setting, and do place subject in various positions. Instead of having to pay for developing and printing, checking result is quick and free. So do play around. But you must know the various metering mode (spot, centre weight and full screen average) , understand and apply them in a sensible way. For portrait, I would use centre weight or spot as required..

For a beginner, I would start with getting close to the subject and get the so call head shot. It is simpler and you have less to worry about. Try to focus on the eye and play around with the speed, aperture and focus point. After you are comfortable with the technique then you can just move back when you want and try to make the background help to set the mood.This is not a guide but just how I learnt. See if that could help...

Comment #9

Thanks to everyone, this is the sort of stuff I was looking for. Just wanted a place to start knowing that everyone has the preference..

I appreciate the advice...

Comment #10

Ouch, you got me. Math was never my best subject... I wrote it backwards. Sorry to the orig poster!.

Dave_s93 wrote:.

Runrider wrote:.

So shutter speed of 100 atf/5.6 or shutter speed of 50 at f/4.0 lets the same amount of lighthit the sensor..

Unless you are are talking about 100 seconds and 50 seconds, you haveit backwards...

Comment #11

This is about the only thing you will ever need to memorize in your photographic career, but learn this and review it every 6 months for the next four or five years (by then it's in your brain permanently). I will give you a simple mnemonics method to learn it. I will explain afterwards:.

Learn this and be able to say it quickly backward and forward:.

1 ..... 2 ..... 4 ..... 8 ..... 16 ..... 32.

Now learn this, same deal backward and forward:.

1.4 ..... 2.8 ..... 5.6 ..... 11 ..... 22.

Now learn this, again backward and forward:.

1 ..... 1.4 ..... 2 ..... 2.8 ..... 4 ..... 5.6 .....

11 ..... 16 ..... 22 ..... 32.

Photographers think in terms of "stops;" a stop doubles or halves the last value. The f stops I have had you memorize in the last line are how you can work with apertures. Too open a lens up, means to let more light in so if you are shooting at f11 and I say to you, you need to open your lens up more, open it by two stops, you would then use..... (quick calculate, lower numbers means more light) ..... f5.6..

If I say to you, you need more depth of field and you are shooting at f4 and I recommend stopping your lens down (letting less light in) by one and a half stops (trick question) the answer will fall roughly in between f5.6 and f8. Grab your camera and turn it on, go into Av mode and look at all the f's available to you and you won't see and of the numbers stand out like I have them illustrated above, but you will see those numbers, so again go into your camera and adjust the f value from 5.6 to f8, you will see numbers in between, these values are 1/3rd apart so f5.6, then f6.3, then f7.1 then f8. Now you are starting to think like a photographer..

Next:.

Lesson 1: Generally the sweet spot of your lens (best image) is two stops in from the advertised speed of the lens. So the sweet spot on my Sigma 150 f2.8 lens would be (two stops down = 2.8 to 4, 4 to 5.6) at around f5.6 and f8. You can generally get your best images from a lens by using the f's available in the middle. So if you have a f4 lens that goes to f22, your middle apertures are f8 and f11. Shot at a lens "wide open" (in the example of an f4 lens, at f4 and you will get a softer image, generally. Shot with the lens closed down (again with the f4 to f22 lens, at f22) and your shot will be soft..

Lesson 2: Landscape: Best landscape f stops are with the lens "closed down" to the smallest "optimum" opening to get a quality image..

Lesson 3: Portraits: Depends on the subject and the flaws in the face, etc. You might want a "wider" f stop (more open) to reduce sharpness a bit and reduce depth of field to blur out the background. You might want a smaller f stop to get detail in, a character face for example..

Lesson 4: Macro: depth of field is always a problem in macro photography, the more the better, but even "more" is pretty shallow. So shooting at around f11, or f16 might work since macro lenses are very sharp, you might pull off an f16 or even f22, experiment..

Lesson 5: Sports, put your camera in sports setting and let the camera figure it all out - every thing is happening pretty quickly. Then when you understand more, shoot sports in Tv mode (shutter preferred) since you need to know what your shutter speed is doing to control action..

Lesson 6: Unless it is sports photography, shoot in Av only; you will learn fastest doing this.Rationally I have no hope, irrationally I believe in miracles.Joni Mitchell..

Comment #12

Rsn48 wrote:.

Lesson 5: Sports, put your camera in sports setting and let thecamera figure it all out - every thing is happening pretty quickly.Then when you understand more, shoot sports in Tv mode (shutterpreferred) since you need to know what your shutter speed is doing tocontrol action..

Actually, when you shoot most sports, you generally shoot in Av wide open. You use ISO to make sure that you have a fast enough shutterspeed. Say you want a min acceptable shutterspeed of 1/500, if you go to an area of the field with more light, it is OK to have 1/1000. If you use Tv, you will go from f2.8 to f4 and change the DoF (generally you want to isolate the person from a distracting background) and you are still at your min acceptable shutterspeed of 1/500...

Comment #13

To simplify some of the good hints already given, I suggest you first think about the result you want for the scene at hand..

If there's a main subject you want to emphasize, use a small f-number. The smaller the f-number, the fuzzier the foreground and background will be, thereby emphasizing the subject and minimizing motion problems..

For landscapes or shots where you want everything to be in focus use a higher f-number..

You can hand-hold your camera for exposure times of roughly 1/effective_focal_length; maybe 3/effective_focal_length for IS shots of slow subjects.*.

Once you've decided on the above, select the lowest ISO that will allow the shutter speed you need. This will vary with your camera and end purpose; viewing un-cropped images on an electronic display allows much higher ISO than making enlarged prints..

Dave.

*sometimes motion of the subject will dictate everything else - Use the smallest ISO you can consistent with the necessary shutter speed and f-number. Learn to pan the camera (track the subject with while shooting) to relax the shutter speed requirement & to add a sense of motion...

Comment #14

Based on Lesson 1, how often do you think you shoot in the "sweet" spot versus wide open? Is this a most of the time use the middle unless you want a shallower depth of field?..

Comment #15

Thanks again for the additonal responses. My wife is getting tired of me know as everytime I read these boards, I am off playing with the camera for a few hours. The amount of stuff that you folks post for the beginners is unbelievable..

Thanks a bunch for what you have shared and what you will be sharing in the future!!!!..

Comment #16

Folks,.

I have read this thread about 40 times and it has been very helpful. I get the information that was presented and have tested it all out many times..

The next rule of thumb that I am confused about is the lighting. As the sun goes down, which will require the shutter to stay open and the ISO to increase which then impacts that f/stop, any tips here?.

I had a large Wild Turkey running through my yard the last few nights and I took several pictures of him with all different settings. I have to say that I did not have much luck using the aperture setting, as the best shots came out when I controlled the aperture as well as the shutter speed..

I would love some tips on shooting when light is not at it's best. I don't have an external flash, so the flash did not help much either..

Thanks,..

Comment #17

Think about the outcome you desire..

If you must freeze motion then set the ISO as high as you can tolerate noisewise and the shutter speed as low as you think is ok. Let the camera decide the rest..

If you want large DOF then set the ISO as high as you can tolerate noisewise and the shutter speed as low as you think is ok. Let the camera decide the rest. Note: this is the same strategy..

If you want low DOF then open the lens as far as possible with the highest ISO you can tolerate noisewise consistent with how steady the camera can be held and/or how still the subject is..

I think most cameras are pretty good at auto adjusting after you set the ISO..

One thing to watch out for is the effect of Zoom on exposure. Most zoom lenses increase f-number as the lens extends. This results in longer exposures or higher ISOs than the same scene at wider angles. In low-light conditions it might be wise to shoot at wide angles and zoom digitally with your computer...

Comment #18

Dave Martin wrote:.

Think about the outcome you desire..

If you must freeze motion then set the ISO as high as you cantolerate noisewise and the shutter speed as low as you think is ok.Let the camera decide the rest..

My turn to catch mistakes now. You mean the shutter speed as FAST (or high) as you can. To stop motion, you want at least 500 (1/500 of a second)or faster (like 1000 which is 1/1000th of a second).

To tell you exactly what the problem is, it would help to see some of your images. It might be a focus problem if you shrink your DOF, or a shutter speed problem, or who knwos what else..

Get a photo posting site likehttp://www.flickr.com and post links to your photos here. Links to photos automatically put the photo in with the text..

Fueled.by.ambition..

Comment #19

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This question was taken from a support group/message board and re-posted here so others can learn from it.

 

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