# Shutter speed and f/stop ratio..



## SmokyMtnHiker (Feb 12, 2014)

I've been watching YouTube vids on photography; mainly Mike Browne's page. 

I've heard him say something about a relationship between the shutter and the aperture f/stop. Kinda like a ratio of one to the other to reduce the chance of camera shake. 

Can you elaborate on this? Or did I just misunderstand..?


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## Designer (Feb 12, 2014)

I think it was focal length rather than aperture.  

In short, yes, there is a relationship, but it has to do with exposure, not camera shake.

So to clarify; generally, you would not want to take a hand-held shot with any shutter speed slower than the inverse of the focal length.  (ex.) hand-held shot, 50mm lens: 1/50 second, maximum.


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## astroNikon (Feb 12, 2014)

you are asking about the basics of the Exposure Triangle.
Camera Exposure: Aperture, ISO & Shutter Speed

there's plenty of things to read online and here if you search


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## lennon33x (Feb 12, 2014)

There is an inverse relationship between the two (numerically) for proper exposure. The faster the shutter speed (1/500 to 1/800 to 1/1000) the wider the aperture (the lower the number). An additional player in here is ISO, hence the exposure triangle. Check out Understanding Exposure by Peterson. 

Think of it this way. Your sensor is a bottle and light is represented by water you pour into it. You place a funnel on it (the aperture) and you pour water into the bottle for a specific time period (shutter speed). Let's say you aren't getting to the right level with that particular funnel or speed you're pouring in water. In order to get to a specific level on the bucket (proper exposure), you need to either pour in water for a longer period of time or get a bigger funnel (i.e. wider aperture). This is an example of the relationship between the three.


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## JustJazzie (Feb 12, 2014)

Designer said:


> I think it was focal length rather than aperture.  In short, yes, there is a relationship, but it has to do with exposure, not camera shake.  So to clarify; generally, you would not want to take a hand-held shot with any shutter speed slower than the inverse of the focal length.  (ex.) hand-held shot, 50mm lens: 1/60 second, maximum.



It sounds like this is what you are talking about. So if I were using a 200mm lens, I wouldn't want to use a shutter speed slower than 1/200 because the focal length magnifies shake. Have you ever looked through a telescope and noticed the slightest movement turns everything into a blurry mess? Same thing here.

Although from what I understand if you have IS, or anti shake, you can stretch the rule and go a bit slower than standard rule.


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## Derrel (Feb 12, 2014)

I think you mean the 1/ over shutter speed idea, meaning if the lens focal length is 50mm, the shutter speed needs to be at least 1/50 second; with a 200mm telephoto, the shutter speed needs to be at least 1/200 second or faster. In today's digital age, many people feel that when using a high-resolution camera, like say a 24- to 36-megapixel camera, that the speed needs to be DOUBLED, so with a 50mm lens 1/100 second, with a 200mm lens 1/400 second. I myself feel that the double the length rule is a solid practice to follow.


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## Overread (Feb 12, 2014)

I think you've mixed two different things together. 

Shutter speed and Aperture are related as mentioned above by the others. They contribute toward the final photographic exposure along with the ISO setting. 


The shutter speed is also related to the camera shake aspect. When you hand-hold a camera a rough rule of thumb is 1/focal length of the lens = minimum shutter speed to avoid camera shake. So if you're using a 50mm lens 1/50sec should not have any camera shake. 

Now this assumes a few things:
1) Good standing posture - good posture is important as it helps maximise your stability; if you're holding the camera badly you're more likely to increase shake. 

2) Fatigue/health - if you're tired or worn out your body is going to be less stable; as a result you'll find it harder to get a clear sharp shot if you're at the lower limit toward the rule of thumb shutter speed

3) 35mm sensor/film. The rule of thumb is devised around the 35m camera; significantly heavier cameras and those with a larger sensor will change the rule of thumb to a degree. 

4) Static subject. Clearly this rule only applies to the camera shake; if you're shooting a moving target then the shutter speed requirements will be defined more by the subject than the camera holding. 1/500sec for a moving subject and any faster is ideal.


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## KmH (Feb 12, 2014)

Shutter speed should be no longer (time wise) than 1/the focal length of the lens. 1/the focal length of the lens is a ratio.

So with a lens focal length of 50 mm you want the shutter speed to be no slower than 1/50 when shooting hand-held
with a 200 mm focal length  you want the shutter speed to be no slower than 1/200.

However, if you can add some support - short of a good stable tripod - to the camera in addition to hand holding it, you can usually use a longer shutter speed.

Plus there is good hand holding the camera technique, and bad hand holding the camera technique. 
Da Grip « Joe McNally's Blog


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## KmH (Feb 12, 2014)




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## Gavjenks (Feb 12, 2014)

Agree with Derrel.

It seems obvious that what you are talking about is the 1/focal length rule.  This rule was from a long time ago, though, when:
1) People were much less pampered by autofocus and image stabilization, and knew how to brace their cameras better. And
2) People didn't pixel-peep as much. Or I guess "grain-peep." Still happened, but not as rampantly I don't think.

Thus yes, you are better off doing 1/(focal length * 1.5 or 2)
If shooting a STILL subject with image stabilization on, it's more like 1/(focal length DIVIDED by 2 or 3)


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## JacaRanda (Feb 12, 2014)

Should one factor in crop factor when using a rule of thumb like mentioned?


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## Braineack (Feb 12, 2014)

JacaRanda said:


> Should one factor in crop factor when using a rule of thumb like mentioned?


no, why would you?


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## Gavjenks (Feb 12, 2014)

That is a good point Jaca.  I would have to say yes.  The cropped portion of the image will be shaking more in a "pixels traveled per shake movement" sense, with the same lens, since you have more pixels per portion of the image on a crop sensor (really it's a function of pixel pitch, but for a beginner's forum, crop factor is a good enough estimator of that)

Similarly, if you know ahead of time in the field that you will be cropping and blowing up the crop in software/printing, then use a proportionately faster shutter speed.


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## lennon33x (Feb 12, 2014)

Braineack said:


> no, why would you?


  Because some theories suggest 1/(crop factor x focal length). Therefore Derrel's suggestion trumps.

50mm lens = 1/80 shutter speed


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## JustJazzie (Feb 12, 2014)

reavesce said:


> Because some theories suggest 1/(crop factor x focal length). Therefore Derrel's suggestion trumps.



Doesn't it always?


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## lennon33x (Feb 12, 2014)

JustJazzie said:


> Doesn't it always?



Blam!


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## Braineack (Feb 12, 2014)

reavesce said:


> Braineack said:
> 
> 
> > no, why would you?
> ...



But then on an FX, you're at 1/50 when you'd probably wanna be at 1/100.


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## Gavjenks (Feb 12, 2014)

> But then on an FX, you're at 1/50.



1 / ([amount the final image will be cropped versus a full frame] x [focal length] x 2)


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## Braineack (Feb 12, 2014)

Gavjenks said:


> > But then on an FX, you're at 1/50.
> 
> 
> 
> 1 / ([amount the final image will be cropped versus a full frame] x [focal length] x 2)



how in the world are you supposed to know that?  Seems to me that if you capture something as sharp as it's going to be captured, that decreasing the shutter speed further is not going to matter, no matter how much you crop.

if anything it should be: 1 / ( [focal length] x [2 + ([MP - 16] / 10) ] )*

Where a 36MP camera would be 1 / FL x 4
and a 24MP camera would be 1 / FL x 2.8

The formula is for trying to pick the shutter speed that will result in a tact sharp capture, beyond that crop at will, right?


*I realize my formula is completely flawed.


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## Overread (Feb 12, 2014)

As said the rule of thumb was devised on 35mm sensor/film cameras so any change to that factor will affect things. It's not a straight conversion though. A larger sensor/film would suggest a slower minimum shutter speed; however many of those cameras also have a much increased weight which fast increased fatigue which then flips in an increase. 

For crop sensor cameras a multiplication of 1.6 or 1.5 would generally suit as a rough value increase (Canon uses 1.6 crop cameras whilst Nikon uses 1.5 - although the difference there for usable shutter speeds will be negligible for most people). 

Remember its only a guideline its not a hard-fast rule so do some tests and see how you go. Some people can shoot fat slower, whilst others need to have a faster shutter speed.


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## lennon33x (Feb 12, 2014)

Braineack said:


> Gavjenks said:
> 
> 
> > > But then on an FX, you're at 1/50.
> ...



It's just a rule of thumb. 

1/1.6-2x focal length.


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## astroNikon (Feb 12, 2014)

1 * tweak the settings to get the exposure you want


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## Braineack (Feb 12, 2014)

astroNikon said:


> 1 * tweak the settings to get the exposure you want




I'm more of  1 / (FL x 4) and AUTO-FP on.


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## SmokyMtnHiker (Feb 12, 2014)

Designer said:


> I think it was focal length rather than aperture.
> 
> In short, yes, there is a relationship, but it has to do with exposure, not camera shake.
> 
> So to clarify; generally, you would not want to take a hand-held shot with any shutter speed slower than the inverse of the focal length.  (ex.) hand-held shot, 50mm lens: 1/50 second, maximum.



Yeah! Thats what is was! Thanks.


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## robbins.photo (Feb 12, 2014)

reavesce said:


> Braineack said:
> 
> 
> > Gavjenks said:
> ...



So since I'm all thumbs I should be using 1/2000 whenever I'm shooting my 70-200 mm?  Cool.. thanks.. lol.


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## lennon33x (Feb 12, 2014)

robbins.photo said:


> So since I'm all thumbs I should be using 1/2000 whenever I'm shooting my 70-200 mm?  Cool.. thanks.. lol.



No, you need something faster. Like the EOS 1D Mk I - 1/16000


And who the eff needs a shutter speed THAT fast?


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## Braineack (Feb 12, 2014)

reavesce said:


> robbins.photo said:
> 
> 
> > So since I'm all thumbs I should be using 1/2000 whenever I'm shooting my 70-200 mm?  Cool.. thanks.. lol.
> ...



When you want to get a portrait of the sun, but you want the rest the of universe in the bg out of focus.


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## Gavjenks (Feb 12, 2014)

> When you want to get a portrait of the sun, but you want the rest the of universe in the bg out of focus.


Sadly, even at f/1.0 and a 1200mm lens, everything from 75 kilometers out will still be in focus if you focus on the sun (which is at 146,000,000 kilometers).


I considered actually calculating the required f/stop for a sun taking up half the sensor, for giggles, but it got too complicated too quickly.  Probably something like f/0.0001 or whatever, and some sort of lens the size of Jupiter.


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## astroNikon (Feb 12, 2014)

Gavjenks said:


> > When you want to get a portrait of the sun, but you want the rest the of universe in the bg out of focus.
> 
> 
> Sadly, even at f/1.0 and a 1200mm lens, everything from 75 kilometers out will still be in focus if you focus on the sun (which is at 146,000,000 kilometers).
> ...



would that be a Gimbel mount that you would need for that lens the size of Jupiter ?
:thumbup:


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## runnah (Feb 12, 2014)

astroNikon said:


> Gavjenks said:
> 
> 
> > > When you want to get a portrait of the sun, but you want the rest the of universe in the bg out of focus.
> ...




Free hand like a boss.


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## Gavjenks (Feb 12, 2014)

No you don't need any mount, because it isn't standing ON anything. It just floats in heliosynchronous orbit. 
And you would probably simply construct it in the first place already pointing at its subject, so you don't need to turn it.


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## cynicaster (Feb 12, 2014)

I think it's rather silly to quibble over the correct statement of the 1/whatever formula, because its use--in ANY form--guarantees nothing, good or bad. 

For sharp photos just determine what is the fastest shutter you can get away with.  Then, if in doubt about whether you may need to bump your ISO to get more speed, mentally check it against the 1/whatever rule of your choice and make a call.  Apply good/steady hand holding technique and fire away.


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## Gavjenks (Feb 12, 2014)

Well yeah if you have time to check and a reason to, then check. The point of a rule of thumb is if you have a brief opportunity and need to choose NOW, not choose after taking 10 test shots and hemming and hawing over the relative % keepers in different shutter speeds using your tiny LCD screen, etc. So it does sort of matter. You'll either miss the brief opportunity or nail it, depending on if your rule is accurate or not.


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## vintagesnaps (Feb 12, 2014)

Overread said it, just a guideline. Go out and try different shutter speeds and figure out what works for you. I don't like shooting slower than 1/125 or 1/100, will go to 1/60 or so if it's low light and I need to use a slower speed. And I make sure I take time to get braced and balanced if I'm going to use a slower speed. 

But I prefer a faster rather than slower speed to make sure I'm getting sharp enough images. And I can use a slower speed with a shorter lens much easier than trying it with a longer lens that I'd have to give more support.


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## JacaRanda (Feb 12, 2014)

I should probably factor in how fast my finger can actually trigger the shutter button.  You know, like having your trigger finger on the ps3 or xbox controller in ready position as opposed to floating in the air.

Can we get a page or two more out of that scenario?


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## Overread (Feb 12, 2014)

JacaRanda said:


> I should probably factor in how fast my finger can actually trigger the shutter button.  You know, like having your trigger finger on the ps3 or xbox controller in ready position as opposed to floating in the air.
> 
> Can we get a page or two more out of that scenario?



Actually you'd be surprised how many wobbly photos are caused by the shutter button. You don't tend to notice it as much when shooing normally ,but when one shoots macro (esp high magnification macro) you fast find that you have to learn to squeeze without moving your hand as you do so. You still have to be quick, but its a gentle push not a hard one. 

Interestingly that was one big difference between my Rebel camera and my 7D. The rebel had a smooth and soft half press, and then you felt a small bump before a full press. This makes its easier to half-press for focusing/metering and not accidentally activating the shutter; but it means that when you press it you get a firm click that cause more shake asa result of your hand motions. The 7D on the other hand is a very gentle and soft squeeze all the way which whilst feeling odd at first (and a touch easy to press all the way too soon) does mean that you can squeeze gently


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## JacaRanda (Feb 12, 2014)

No doubt.  It would be nice (at least on my 60d) if I could slide the shutter button just a tad to the left whereas my finger could lie flat across the area up to the  button instead of curved.

Adjustable shutter button location hmmmmmm???????  Just 1/2 centimeter in either direction.


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## Overread (Feb 12, 2014)

Camera design is very much inhibited by convention and accessories. Film cameras had some physical requirements that defined a good portion of their resulting shape. Digital cameras are fast approaching a point where many of the conventions aren't or won't be needed. However the whole market surrounding and supporting them (eg tripods - tripod heads - etc.) is geared to one generalist overall design. This inhibits and discourages camera designers from trying for more ergonomic designs because chances are they'd each try something different - suddenly if you're out of the common market design its a problem (esp if they all went differnt random directions). 

You can see this with Sony and their own hotshoe design locking them out of a fair few 3rd party accessories.


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## JacaRanda (Feb 12, 2014)

Maybe Gav will work on it after that other thing he is making.


Sent from my iPad using Tapatalk


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## bratkinson (Feb 13, 2014)

Well, now that the newbies have been totally confused by the mental gymnastics put forth in this thread (me too, and I'm a geezer!), I try to keep the KISS rule (Keep It Simple, Stupid). So 1/focal length for minimum shutter speed to stop camera shake is a good starting point. 

But, as mentioned above, with the ability to blow up our images 100x and pixel peep rather than be satisfied with a 3x5 print from film, the 1/2 x focal length is probably safer. Thank you, Derrel, for that heads up. I've also noticed that the more grey hair I get, my hands are a bit less steady, and, I can even see it happening when I click the shutter the camera moves a bit as well. The slightly blurred images I've been getting prove it. IS (VR to the Nikon folks) helps keep it closer to 1/FL, but I'm down to only 1 of 4 lenses with IS, so I'll start using the 1/2 x FL instead.


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## pondball (Feb 13, 2014)

Derrel said:


> I think you mean the 1/ over shutter speed idea, meaning if the lens focal length is 50mm, the shutter speed needs to be at least 1/50 second; with a 200mm telephoto, the shutter speed needs to be at least 1/200 second or faster. In today's digital age, many people feel that when using a high-resolution camera, like say a 24- to 36-megapixel camera, that the speed needs to be DOUBLED, so with a 50mm lens 1/100 second, with a 200mm lens 1/400 second. I myself feel that the double the length rule is a solid practice to follow.


This one made sense to me! Very plain and simple explanation. Thanks Derrel!


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