Lens Talks

[erizai]

Hi there,

Having notice the lens with attributes like f3.5-5.6, or f4-XX and etc...

The price could be so much different if f2.8 and smaller...

Anyone can enlighten me on this?:dunno:

 

[TMC]

coz smaller f number need larger lens elements and they cost more. If you are talking about fixed aperture lens like the 70-200/2.8, they can maintain that aperture throughout the range instead of going from f3.5 to f5.6 as you zoom out.

 

[erizai]

But the price different can be 4 to 5 times that the normal lens!

But anyway thanks for answering...:sweatsm:

 

[ortega]

harder to make mah
and also usually the constant f-stop F2.8 is professional grade lens

 

[Witness]

act its coz at 2.8, the relative size of the aperture is alot larger than say at 3.5 or above.... thus it lets in more light, and allows u to use the lens at a higher shutter speed (but wider aperture) in dim light conditions....

that's y 2.8 lenses (especially the constant ones) are in such high demand...esp for telezooms... with a longer focal lenght..if u stick by the 1/focal lenght rule for shutter speed, a wider aperture will help u achieve the faster shutter speed....

cheers...

 

[Canew]

the 1/focal lenght rule for shutter speed, a wider aperture will help u achieve the faster shutter speed....

cheers...

For the 1/focal lenght rule for shutter speed of telezooms, do we need to take the FOV multiplier into consideration? For example on a 1.6X FOV camera, will we need to set the shutter speed to 1/320 sec. or the usual 1/200 sec. when we are shooting using a 200 mm lens?

Thanks.

 

[user111]

For the 1/focal lenght rule for shutter speed of telezooms, do we need to take the FOV multiplier into consideration? For example on a 1.6X FOV camera, will we need to set the shutter speed to 1/320 sec. or the usual 1/200 sec. when we are shooting using a 200 mm lens?

Thanks.

that rule is just a rough guide

use whatever shutter speed u can manage

 

[vkashi]

But the price different can be 4 to 5 times that the normal lens!

But anyway thanks for answering...:sweatsm:

at the telephoto end of that lens a f2.8 aperture instead of a f5.6 implies 2 f stops which translates into 4 times the amount of light ~ 4 times the cost

 

[Canew]

that rule is just a rough guide

use whatever shutter speed u can manage

Thanks, user111.

 

[tunster]

act its coz at 2.8, the relative size of the aperture is alot larger than say at 3.5 or above.... thus it lets in more light, and allows u to use the lens at a higher shutter speed (but wider aperture) in dim light conditions....

that's y 2.8 lenses (especially the constant ones) are in such high demand...esp for telezooms... with a longer focal lenght..if u stick by the 1/focal lenght rule for shutter speed, a wider aperture will help u achieve the faster shutter speed....

cheers...

Add on to this, for a bigger aperture (smaller F stop). The lens can focus faster. Because lens are focus wide open and stop down during shutter release.

 

[Witness]

For the 1/focal lenght rule for shutter speed of telezooms, do we need to take the FOV multiplier into consideration? For example on a 1.6X FOV camera, will we need to set the shutter speed to 1/320 sec. or the usual 1/200 sec. when we are shooting using a 200 mm lens?

Thanks.

honestly this is debatable.... but if we take the censor size as a guide to the "real focal length" then i guess yes.... but i erhm dun follow this rule and still get great results hahaha

cheers..

 

[tincup]

For the 1/focal lenght rule for shutter speed of telezooms, do we need to take the FOV multiplier into consideration? For example on a 1.6X FOV camera, will we need to set the shutter speed to 1/320 sec. or the usual 1/200 sec. when we are shooting using a 200 mm lens?

Thanks.

I think no need to take 1.6X multiplier into account. Just shoot at 1/200 sec will do...cos you're still shooting at 200mm...

It's just that the sensor is smaller, cropping the image to a smaller field of view.

 

[roti_prata]

I think no need to take 1.6X multiplier into account. Just shoot at 1/200 sec will do...cos you're still shooting at 200mm...

It's just that the sensor is smaller, cropping the image to a smaller field of view.

as the image is cropped, so is the blur due to camera shake. steady hands with tripod and/or VR/IS/OS will give blur-free images most of the time. with my 70-200vr@200mm, i can handhold @1/20sec. of course VR/IS/OS lenses are considerably more expensive

 

[Canew]

Thanks everyone, for all the comments.