need help getting my head round the numbers

[eeyore]

Originally Posted by glsammy

Got to agree with you on this. It was the poor ISO performance that made me change to a DSLR. Anything much above ISO 100 was pretty hopeless.
I'm sure Pete knows this very well, I think he just missed the point the user was using a bridge camera and not a DSLR.

it wasnt that i missed that point rather that i didnt realise that the noise was so bad on bridge cameras, when i went digital i went straight to the dslr , and tho i have a fz7 in the car i donr=t use it enought to be conversant with all its pecadilloes , bizarely the noise control on my little F10 walking arround camera is pretty good up to iso 400 - still and all its better to have a noisy pic than no pic at all so i still wouldnt hesitate to turn the iso up on a bridge camera if the light is too bad to shoot otherwise. -

Originally Posted by theblackrabbit

This will obviously increase your shutter speed to probably more than 1/250th second, unless you've got bright light on your side.
Thats too bad I'm afraid.

one point doug reducing the iso will decrease your shutter speed probably to less than 1/250 unless you have bright light etc - every step down in iso costs you one fstop so if you have iso 400 1/250 you will get 1/125 with iso200, 1/60 with iso 100, and 1/30 with iso 50

I'm sure you are aware of this really but its very easy for folk new to photography to get their increase/decrease muddled up.

[The Black Rabbit]

Originally Posted by eeyore

it wasnt that i missed that point rather that i didnt realise that the noise was so bad on bridge cameras - still and all its better to have a noisy pic than no pic at all so i still wouldnt hesitate to turn the iso up if the light is too bad to shoot otherwise.



one point doug reducing the iso will decrease your shutter speed probably to less than 1/250 unless you have bright light etc - every step down in iso costs you one fstop so if you have iso 400 1/250 you will get 1/125 with iso200, 1/60 with iso 100, and 1/30 with iso 50

I'm sure you are aware of this really but its very easy for folk new to photography to get their increase/decrease muddled up.

Yeah. Sorry Pete. I was aware!
1/250th second to 1/60th second will always mean INCREASING the length of the shutter opening time (decreasing its speed I suppose) to me! I'm an old fogey!
Doug

ps - as for your point about increasing the ISO on bridges Pete - I do so when ABSOLUTELY UNAVOIDABLY SO, and thats it.
Was out at dawn today, snapping a wintering BArn Owl at dawn at ISO 400 - bleedin' awful noise - but no option at all I'm afraid!
Aw well.... the sight made up for it!

[eeyore]

Originally Posted by The Black Rabbit

Yeah. Sorry Pete. I was aware!
1/250th second to 1/60th second will always mean INCREASING the length of the shutter opening time (decreasing its speed I suppose) to me! I'm an old fogey!
Doug

I know what you mean - and thats a valid way of looking at it , but most books and magazines use "increase" to mean a higher bottom number and i try to stick to that so as not to confuse the newbies

its hard enough for beginers to get there heads round the fact that opening the apperture wider means a decrease in the f no without getting confuzzled on the speed as well.

[The Black Rabbit]

Originally Posted by eeyore

I know what you mean - and thats a valid way of looking at it , but most books and magazines use "increase" to mean a higher bottom number and i try to stick to that so as not to confuse the newbies

its hard enough for beginers to get there heads round the fact that opening the apperture wider means a decrease in the f no without getting confuzzled on the speed as well.

Gottae admit - I didn't know that - ie "most magazines etc... have an "increase" as a larger bottom number".

Thats SHOCKING! I really am an old so and so.

Since when does a quarter (1/4) to an eighth (1/8) mean an increase?!
Heh heh!
No wonder we're all illiterate and terrible at maths in this country!

Doug

[eeyore]

Originally Posted by The Black Rabbit

Since when does a quarter (1/4) to an eighth (1/8) mean an increase?!
Heh heh!
No wonder we're all illiterate and terrible at maths in this country!

Doug

when its a fraction of a second for an action to take place - if it takes less time then it is going faster and like you said the speed has increased

and it is generally reffered to as shutter speed (at least when considering wildlife photography) rather than length of exposure though either is valid.

its another thing for new folk to get their heads round - increasing the speed with which the shutter moves decreases the length of the exposure (ie the length of time the shutter is open) and vice versa - so long as they get their heads round that it doesnt matter which we use , so long as we make it clear which we are reffering to.

[The Black Rabbit]

Originally Posted by eeyore

when its a fraction of a second for an action to take place - if it takes less time then it is going faster and like you said the speed has increased

and it is generally reffered to as shutter speed (at least when considering wildlife photography) rather than length of exposure though either is valid.

its another thing for new folk to get their heads round - increasing the speed with which the shutter moves decreases the length of the exposure (ie the length of time the shutter is open) and vice versa - so long as they get their heads round that it doesnt matter which we use , so long as we make it clear which we are reffering to.

I understand Pete! Honest!
Its just that the SPEED is not 1/250th of a second is it? Thats purely the length of time, not the distance covered in that time, ie "speed".

Its like calling mass, weight etc...
but if you answer in NEWTONS a question from someone who asks you how much you weigh - even though you are quite correct, all it gets you is a bloody nose!

Pedantic? Me?!
I think you mean PICKY...

Doug

[eeyore]

Originally Posted by The Black Rabbit

I understand Pete! Honest!
Its just that the SPEED is not 1/250th of a second is it? Thats purely the length of time, not the distance covered in that time, ie "speed".

Doug

I know you do , i was just making it clear for any one else reading this thread.

technically you are correct about "speed" but i think i will leave it up to some one else to calculate the actual true speeds , especially as it will vary depending on the size of the shutter curtain, and that is a circular movement on most cameras not a purely linear one - my head hurts already.

[thes3raph1m]

while the time elapsed is not a measurement of speed, it can be used to reference speed when a fixed motion is occuring within a certain time frame... in this instance, the speed of the shutter is dependant on how long you provide for it to complete its open-expose-close cycle