Minimum hand held shutter speed for DSLRs


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Bee Hedge

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#1
I know the general rule of thumb for minimum hand held shutter speed is the reciprocal of the lens focal length.

How does it apply to DSLRs which has "magnication factor" of say 1.5 or 1.6?

Let's say I mount a 50mm lens on a DSLR that has a "magnifcation factor" of 1.5. What should the minimum hand held shutter speed be?

Should it be 1/50 sec?

Or should it be 1/(50 x 1.5) = 1/75 sec?

Would like to hear your views and opinions please.
 

Kit

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#2
Those numbers are just a guide. You should determine your own minimum handholding speed by experimenting with your limits.
 

nickmak

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#3
I agree.. with practice u can handhold ur camera at shutter speeds slower than what is said. With Image Stabilization on lenses it will aid you too...
 

sequitur

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#4
actually i don't know.

but i think it should be 1/80 for 50mm.


i think the law of this 1/whatever came because... maybe like say a 50mm shot.. you can take it at 1/50 and there is no -visible- hand shake.. but zoom in on an area till the perspective of a 200mm, and you can see handshake.. so if you shoot that particular area at 200mm with 1/50, it will be a shaken image.. but with 1/200.. it will not.. ?

i think only.
 

2100

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#7
If you are on a ferry (not cruise liner), multiply at least 3X. (eg 1/300s for 100mm effective) :bsmilie: Practical experience.
 

digit

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#8
There should be no difference to the rule of 1/(focal length) for film or DSLR cameras. The DSLR cropping factor is a 'cropping' factor meaning it only records a certain percentage area compared to the 35mm film. If you focus on a point on a subject and if this point image moves 1mm on a film plane on a film camera, this same point will also move 1mm on a digital sensor regardless if it's 1.6X, 1.5X or 1.3X ...

Put it another way, if a 1mm length subject is recorded on a film, the same 1mm length is also recorded on the digital sensor. However because we take 35mm film size as reference, hence when you stretch the digital sensor to be the same as the 35mm film size, you thus have the image enlarged. This is your so-called 'focal length multiplier' that you achieved but the image wasn't enlarged when it hit the digital sensor.

It's no different when you crop using photoshop. Assuming you have a 600x400 image and you crop it to be 300x200. If you resize the cropped image back to 600x400, your image doubled in size. Same thing with film and digital cameras and as such the 1/(focal length) rule applies the same for film and digital.

I hope my explanation isn't confusing (not very good at explaining things). Worse I hope I'm right ... else all the typing gone to waste ;p
 

Bee Hedge

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#9
Thanks for your inpur, digit.

Your explaination was a little confusing, but very informative. :)

So, am I right to say that for a DSLR with a "mag. factor" of 1.6, a 50mm lens would in a way "behave" like a 75mm. And by using the rule of thumb, therefore your theoritical minimum shutter speed should be at least 1/75 sec?

Because of the crop, the image is effectively "enlarged" (so to speak). The "enlarging" process would have the same effect as if u have taken the pic with a more telephoto lens. I dunno if this make sense to all of you but from the pictures I've taken so far, this has been esp. true. For e.g., I'm using a Canon 300D (1.6x), for a 55mm pic to be clear, I had to use shutter speed of at least 1/100 sec. Could be my hand isn't that steady as compared to the rest :(
 

coke21

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#11
Since you have a DSLR, why don't you just shoot and use the review to see if you've got the shot right? And learn from there? Different people can hold it steady at different speeds.
 

di0nysus

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#12
i concur with digit.

I having problems handholding, esp 200-300mm range. have to use very high shutter speeds. not sure exactly how to hold properly, i never hold rifle before.... only know steady breathing, squeeze index slowly when breathing out.... but thru the view finder.....everything is not steady at 300mm......tripod is one choice lah, but my current tripod super light one,...sian...
 

espn

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#13
Bee Hedge said:
Thanks for your inpur, digit.

Your explaination was a little confusing, but very informative. :)

So, am I right to say that for a DSLR with a "mag. factor" of 1.6, a 50mm lens would in a way "behave" like a 75mm. And by using the rule of thumb, therefore your theoritical minimum shutter speed should be at least 1/75 sec?

Because of the crop, the image is effectively "enlarged" (so to speak). The "enlarging" process would have the same effect as if u have taken the pic with a more telephoto lens. I dunno if this make sense to all of you but from the pictures I've taken so far, this has been esp. true. For e.g., I'm using a Canon 300D (1.6x), for a 55mm pic to be clear, I had to use shutter speed of at least 1/100 sec. Could be my hand isn't that steady as compared to the rest :(
Actually a 50mm is still a 50mm, the FLM you speak of is the viewing area. Let's look at a 24 f/2.8 instead.

A 24mm produces a view of 24mm wide, however with the FLM in play, it becomes only 36mm view, in short, it's still 24mm focal length, but the view has been cropped to show 36mm. A 24mm focal length can never become a 36mm focal length.

Thus if you're asking about the 1/[Focal length] rule, on a DSLR or SLR, it's still the same.
 

mpenza

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#14
the 1/focal length is for reasonable sharpness.

Generally, it should be 1/[focal length*cropping factor] . Just like a consumer/procumer digicam, the actual focal length (which has the same meaning as the focal length of SLRlenses) is small but it's difficult to handhold at 1/[actual focal length] and get sharp pics.
 

Amfibius

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#15
I agree with digit. If you can handhold at a certain speed with a film camera, you should be able to do the same on a DSLR. It is not a "magnification" factor, it is a CROPPING factor.

I suggest you do your own testing to see what your own limits are. Set your lens to 100mm, and then decrease the shutter speed and take an exposure every half stop. Examine your photos and you will see.
 

waileong

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#16
A 50 mm lens is still a 50 mm lens with a DSLR. However, because of the cropping factor, you are effectively using only the centre portion of the lens, and blowing up to the resolution you want when printing.

Eg to print at at S8R, a 35 mm negative would be enlarged 8x, whereas a DSLR image might be enlarged 10-12x (depending on your cropping factor of course), assuming both are printed to the same dpi.

Thus, the higher enlargement needed by the DSLR means that any camera shake becomes more visible relative to the SLR. Hence, the min handholding speed must be more than the SLR.

How much more depends on whether you can do linear interpolation, ie take 1/50 divided by 1.5, which I don't know. Maybe it's not linear, maybe it's an exponential increase (eg 1/50 divided by 1.5^2), or logarithmic, etc...




Amfibius said:
I agree with digit. If you can handhold at a certain speed with a film camera, you should be able to do the same on a DSLR. It is not a "magnification" factor, it is a CROPPING factor.

I suggest you do your own testing to see what your own limits are. Set your lens to 100mm, and then decrease the shutter speed and take an exposure every half stop. Examine your photos and you will see.
 

glchua

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#17
When you are trying out, take a few shots to compare. When we talk about hand-holdable shutter speeds, we should be looking at it statistically. Maybe the rule says no 1/30 for 50mm, it means that most of the time it is okay. For me, I can hand-hold a rangefinder with a 35mm or 40mm lens down to 1/15 and 1/8 and it is acceptably sharp most of the time. But for 1/4, I can only get it right half the time. These were tested in a sequence of single shots and same condition.

Also, different lenses have different hand-holding characteristics depending on weight etc, even with the same focal length. Testing all your equipment combinations may be a good idea instead of "rule-of-thumbs".

If your camera has continuous shot function, you can check this interesting article out:

http://www.photo.net/learn/poormansis/
 

ST1100

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#18
Let's assume, for simplicity of argument, that the average photographer has a certain amount of handshake (up/down/left/right), and that it is constant. i think this is where this rule of thumb originated.

This (fixed) amount of handshake moves the camera such that the image shake increases when the angle of view gets narrower. So for a 100mm VIEWPOINT with 35mm fullframe, he needs a 1/100s handholding speed.

The ROT (rule of thumb) is based on the angle of view, and thus (assuming similar camera weight and ergonomics => similar degree of camera shake), the required shutter speeds simply scales with the ANGLE OF VIEW (not focal length) - independent of format, ie for the dSLR, digicam, medium format, larger format, the ROT still applies, and for a dSLR, when you slap on a 50mm lens, the angle of view is that of a 80mm lens, you need a 1/80s for safe handholding. Further assumptions: the final print size is going to be the same.

To further expand on this principle, a doubling of the focal length gives you about a 25% (area) crop of the picture, ie going from 100mm to 200mm will be equivalent to cropping to 25% of the picture. So if i'm stuck with a 100mm prime, and i know i'm going to crop my next shot to 25% of it's original, i mentally 'up' my handhold speed to 1/200 for this shot, bumping the ISO or aperture as necc.

Of course, different camera ergonomics actually do affect how steady you can handhold the camera, and many many other factors come into play, like how big your intending print, how sharp you need the picture to be (eg landscape vs portrait), as well as image quality issues (ie looking beyond sharpness). That's why it's called a "rule of thumb" - just a very rough guide.
 

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