POLL: 1/focal length rule

Which one is correct?


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tokrot said:
Anyway, I always uses 1/focal length becoz the multipler is just like a crop factor. If you shoot exactly at 1/focal length and crop at multiplication of factor using PS, I am sure you dun see blur motion either. ;) Unless the general /focal length rule is wrong in the first place.. :confused:

Do you see more motion blur of an image from far or do you see more of it magnified? That's what crop factor do, magnify the original image.

Increased resolution also magnifies motion blur on screen. But they will look the same on similar sized prints.

Cheers!
 

tokrot said:
Anyway, I always uses 1/focal length becoz the multipler is just like a crop factor. If you shoot exactly at 1/focal length and crop at multiplication of factor using PS, I am sure you dun see blur motion either. ;) Unless the general /focal length rule is wrong in the first place.. :confused:

theoretically, your reasoning means that I can shoot at 1/60 sec at full zoom on my Oly 750 (eq. 380mm) and still get sharp pics?
 

BurgaFlippinMan said:
theoretically, your reasoning means that I can shoot at 1/60 sec at full zoom on my Oly 750 (eq. 380mm) and still get sharp pics?

No... You need 1/focal length which is 1/380 sec in this case..
 

UY79 said:
Do you see more motion blur of an image from far or do you see more of it magnified? That's what crop factor do, magnify the original image.

Increased resolution also magnifies motion blur on screen. But they will look the same on similar sized prints.

Cheers!

Yes, the rule 1/(focal length x multipler) will have sharper pics since its shutter speed is faster BUT dun forget that most zoom lens are NOT bright lens. In this case, you are making your shots very difficult to shot at telephoto length with large aperture value under low light situation. Correct me if I am wrong.. :)
 

tokrot said:
No... You need 1/focal length which is 1/380 sec in this case..

If this is the case, then this post contradicts your previous post. Unless it's the resultant focal length that you are using. So which is it?

tokrot said:
Yes, the rule 1/(focal length x multipler) will have sharper pics since its shutter speed is faster BUT dun forget that most zoom lens are NOT bright lens. In this case, you are making your shots very difficult to shot at telephoto length with large aperture value under low light situation. Correct me if I am wrong.. :)

That's why they make stabiliser for telephoto ranges to tackle this issue. Of course using supports is the best way of avoiding camera shakes.

Cheers!
 

UY79 said:
If this is the case, then this post contradicts your previous post. Unless it's the resultant focal length that you are using. So which is it?

???? I thought I made myself clear that I always used "1/focal length"?
Paiseh, maybe I need some english lessons? :confused: :embrass:


That's why they make stabiliser for telephoto ranges to tackle this issue. Of course using supports is the best way of avoiding camera shakes.

Cheers!

Well, not everyone can afford Stabiliser lens.. hehehe ;)
 

1/focal lengths...

croppin factor is only field of view....

food for though:
if u use film and take a photo..print it out..then u manually crop it at 1.5 times....does it mean tt the centre cropped out would be a softer image.......???

cheers....
 

tokrot said:
???? I thought I made myself clear that I always used "1/focal length"?
Paiseh, maybe I need some english lessons? :confused: :embrass:

Olympus 750's lenses has a maximum physical focal length of 63mm, crop factor of about 6 which ends up with a resultant focal length of 380mm.

As your answer is 1/380s, then you are actually following the 1/(focal length x crop factor) rule.

Cheers!
 

UY79 said:
Olympus 750's lenses has a maximum physical focal length of 63mm, crop factor of about 6 which ends up with a resultant focal length of 380mm.

As your answer is 1/380s, then you are actually following the 1/(focal length x crop factor) rule.

Cheers!

sorry, I think I am confused with the resultant focal length and the physical focal length ....How's abt the DSLR physical focal length? when we talk abt 18-125mm... are we talking abt physical focal length? sorry about my limited theory.. :embrass:
 

Witness said:
1/focal lengths...

croppin factor is only field of view....

food for though:
if u use film and take a photo..print it out..then u manually crop it at 1.5 times....does it mean tt the centre cropped out would be a softer image.......???

cheers....

For your case, there will be no difference as you are not magnifying the crop.

If you actually go and blow up the crop to the size of the original print, you should see it being softer.

Cheers!
 

tokrot said:
sorry, I think I am confused with the resultant focal length and the physical focal length ....How's abt the DSLR physical focal length? when we talk abt 18-125mm... are we talking abt physical focal length? sorry about my limited theory.. :embrass:

DSLR lenses always are stated as physical focal lengths. For resultant focal lengths, you'll have to calculate yourself.

Cheers!
 

UY79 said:
DSLR lenses always are stated as physical focal lengths. For resultant focal lengths, you'll have to calculate yourself.

Cheers!

In that case, if I would to say abt physical focal length about 300mm zoom, am I right to say 1/300sec is 1/focal length rule? Correct me If I am wrong. :embrass:
 

tokrot said:
In that case, if I would to say abt physical focal length about 300mm zoom, am I right to say 1/300sec is 1/focal length rule? Correct me If I am wrong. :embrass:

Yes. Then would you shoot at 1/60s with a Olympus 750 at max zoom?

Cheers!
 

UY79 said:
Yes. Then would you shoot at 1/60s with a Olympus 750 at max zoom?

Cheers!


heheh that's a bit tricky to answer, But I will use the physical focal length rule on DSLR instead since the crop factor in DSLR is not so big in magnification isn't it... ;).
 

tokrot said:
heheh that's a bit tricky to answer, But I will use the physical focal length rule on DSLR instead since the crop factor in DSLR is not so big in magnification isn't it... ;).

For DSLR, the half to one stop difference might not matter much. But the rule should still hold.

Cheers!
 

Alamak...the (1/focal length) shutter speed rule is only a rule of thumb...and it works well for the computers inside the cameras to warn people of possible camera shake. With practice and experience camera shake should not be foremost on your mind during shoots.

I've done as slow as 1/8 @ 24mm and still get a sharp image. However I can't say I will always get a sharp image with 1/250 @ 135mm on my SLR. It depends I ate breakfast or not. :D

To add to the issue in discussion though, I take the stance of (1/focal length). Crop factor is NOT image enlargement, but a view crop. To understand better, check: http://www.dpreview.com/learn/?/Glossary/Optical/Focal_Length_Multiplier_01.htm
 

UY79 said:
If you print both the original and the cropped image at say 8R, which of these has more enlargement done to it?

Cheers!

Ah Pao has already said it's a rule of thumb. It's just a guideline. Simply saying it can't be done is not the way to go about things? There can be various factors which would determine the resulting shutter speed to use (whether you ate enough, whether you're tired, whether the wind is strong). I'm not saying 1/focal length works all the time, but it has worked before and similarly for times where 1/<focal length for when conditions are great.

As for the issue with digicams... well the flange distance--or ratio???--is changed from dSLR and SLRs, so that issue is abit more clouded. But as before, it's a guideline and it'll be better for individuals to find out their limits--or capabilities. No? :dunno:
 

RiStaR said:
Ah Pao has already said it's a rule of thumb. It's just a guideline. Simply saying it can't be done is not the way to go about things? There can be various factors which would determine the resulting shutter speed to use (whether you ate enough, whether you're tired, whether the wind is strong). I'm not saying 1/focal length works all the time, but it has worked before and similarly for times where 1/<focal length for when conditions are great.

As for the issue with digicams... well the flange distance--or ratio???--is changed from dSLR and SLRs, so that issue is abit more clouded. But as before, it's a guideline and it'll be better for individuals to find out their limits--or capabilities. No? :dunno:

I'm not going into whether anyone follow this rule or not debate. It's impossible.

But saying crop factor just crops the view of the image and yet having the same quality as the original is something else.

Edit: Made a mistake in this post which is now highlighted.
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Cheers!
 

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