question about shutter speed

[shingfan]

i like to clarify something about shutter speed...the rule about shutter speed being 1/focal length(*1.5 for digital)....this rule is mainly a general rule for hand shake prevention right?.....and to freeze motion.....i'll need to consider how fast the object is moving relative to its size in the frame...is this correct?..If so, what kind of shutter speed would you need to capture the following (the object being about 20%-30% size of the frame).....

1) person walking
2) person running

***i guess i can probably do the math as well with a calculator and pen......but i just like to make sure my understanding is correct first

say if i have a VR lense that allow me to do 200mm at 1/100 without blurness on still object....i can use that on a walking speed object and freeze motion (if 1/100 is fast enough to freeze motion...havent done the math yet....but shoudl be a relatively simple trig. problem)

 

[ksmattfish]

In general, with people walking and moving about in a general manner, 1/125th will work. If moving faster it will depend on how fast, and in what direction. Motion will be more apparent with subjects travelling in a direction perpendicular to your line of sight, than it would be with subjects travelling parallel to your line of sight (this is why people get hit by trains).

 

[cosmonaut]

i like to clarify something about shutter speed...the rule about shutter speed being 1/focal length(*1.5 for digital)....this rule is mainly a general rule for hand shake prevention right?.....and to freeze motion.....i'll need to consider how fast the object is moving relative to its size in the frame...is this correct?..If so, what kind of shutter speed would you need to capture the following (the object being about 20%-30% size of the frame).....

1) person walking
2) person running

***i guess i can probably do the math as well with a calculator and pen......but i just like to make sure my understanding is correct first

say if i have a VR lense that allow me to do 200mm at 1/100 without blurness on still object....i can use that on a walking speed object and freeze motion (if 1/100 is fast enough to freeze motion...havent done the math yet....but shoudl be a relatively simple trig. problem)

The rule of thumb for focal length is not to let your shutter speed drop below the focal length. If you are using a 200mm don't shot below 1/200 without support. 100mm would be 1/100 of a second. I think that your shutter speed would depend on how fast the object moves in 1/100 of a second. Most that shoot sports with big zooms use higher ISO's so they can use the higher shutter speed.
Cosmo

 

[shingfan]

In general, with people walking and moving about in a general manner, 1/125th will work. If moving faster it will depend on how fast, and in what direction. Motion will be more apparent with subjects travelling in a direction perpendicular to your line of sight, than it would be with subjects travelling parallel to your line of sight (this is why people get hit by trains).

ppl get hit by trains because they are stupid playing on the track......lol

those who got hit by trains....they could have seen the train miles away and have plenty of time to stop their feet from getting their body so close to the track so they were not in danger.......

thx for the 1/125 info....after all....it's good to hear from ppl with more experience...rather i me playing with my calculator and drawing numbers on paper which might be different from a practical pt of view...haha

The rule of thumb for focal length is not to let your shutter speed drop below the focal length. If you are using a 200mm don't shot below 1/200 without support. 100mm would be 1/100 of a second. I think that your shutter speed would depend on how fast the object moves in 1/100 of a second. Most that shoot sports with big zooms use higher ISO's so they can use the higher shutter speed.
Cosmo

that is why i'm trying to understand what is the main purpose of the rule...what is it trying to prevent the blurness from.....shaking or motion....if it is shaking.....i think the VR system on my lense does a pretty good job in providing at least 2-3 stops.......but i'm going to experiment tonight with handheld and tripod to see how far in can go with the shutter compare handheld and tripod

 

[Big Mike]

say if i have a VR lense that allow me to do 200mm at 1/100 without blurness on still object....i can use that on a walking speed object and freeze motion (if 1/100 is fast enough to freeze motion...havent done the math yet....but shoudl be a relatively simple trig. problem)

VR, IS...any of the anti-blurriness features...will not help you to freeze a moving subject. This seems to be widely misunderstood.

There are two reasons why a photo may show blurriness due to motion. One is camera shake and the other is subject movement. VR (and the others) only stabilize the movement of the camera (to a degree)....you are still left with subject movement. Even if the camera is perfectly still...on a tripod...a moving subject will appear blurry...depending on the shutter speed.

A faster shutter speed will combat blurriness from both types of movement....this is why faster lenses are better than slower VR or IS lenses.

 

[Big Mike]

that is why i'm trying to understand what is the main purpose of the rule...what is it trying to prevent the blurness from.....shaking or motion

The rule is for camera shake...because it's dependant on a constant (the focal length). Subject movement is much more variable...and depends on many factors.

Don't forget about panning. You can get a sharp shot of a moving subject if the camera is panning with the subject.

 

[cosmonaut]

ppl get hit by trains because they are stupid playing on the track......lol

those who got hit by trains....they could have seen the train miles away and have plenty of time to stop their feet from getting their body so close to the track so they were not in danger.......

thx for the 1/125 info....after all....it's good to hear from ppl with more experience...rather i me playing with my calculator and drawing numbers on paper which might be different from a practical pt of view...haha



that is why i'm trying to understand what is the main purpose of the rule...what is it trying to prevent the blurness from.....shaking or motion....if it is shaking.....i think the VR system on my lense does a pretty good job in providing at least 2-3 stops.......but i'm going to experiment tonight with handheld and tripod to see how far in can go with the shutter compare handheld and tripod

Just remember too, that the higher the ISO, the more grain you will produce. Even when I used film I never shot over 400 ISO, It just wasn't good enough quality for my taste...
Cosmo

 

[shingfan]

VR, IS...any of the anti-blurriness features...will not help you to freeze a moving subject. This seems to be widely misunderstood.

There are two reasons why a photo may show blurriness due to motion. One is camera shake and the other is subject movement. VR (and the others) only stabilize the movement of the camera (to a degree)....you are still left with subject movement. Even if the camera is perfectly still...on a tripod...a moving subject will appear blurry...depending on the shutter speed.

A faster shutter speed will combat blurriness from both types of movement....this is why faster lenses are better than slower VR or IS lenses.

yes..this part i understand...that is why i was trying to udnerstand the 1/focal lenght rule...is it only for shaking factor...and then on the motion blurness subject....i was asking separately what shutter speed would be required to freeze those motions

Just remember too, that the higher the ISO, the more grain you will produce. Even when I used film I never shot over 400 ISO, It just wasn't good enough quality for my taste...
Cosmo

yes....i treid not to use anything other than ISO 100 unless i have to.....i dont like noise either

The rule is for camera shake...because it's dependant on a constant (the focal length). Subject movement is much more variable...and depends on many factors.

Don't forget about panning. You can get a sharp shot of a moving subject if the camera is panning with the subject.

i dont think i'm skillful enough to do panning shot....maybe later on when i'm more expereinced..i'm still "green"

 

[cosmonaut]

Panning isn't as hard as you think. I went to an air show a did fine my first time out.
Cosmo