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07-29-2009, 07:57 PM   #1
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Minimum shutter speed with shake reduction

I was using my 135mm prime today, longest and least used prime, and was reviewing the pictures were almost all ruined b/c of camera shake .almost all the ruined pictures were 1/100s. a few at 1/160s were fine.

we've all heard the rule of having a minimum shutter speed of 1/focal length. pentax claims 2.5 - 4 stops faster shutter speed with its shake reduction.

with shake reduction, does the minimum handheld shutter speed get longer with longer focal lengths?

the camera asks for focal length input for shake reduction purposes, so how does this affect the way it works?

07-29-2009, 08:46 PM   #2
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For manual focus lenses, you definitely need to input correctly the focal length in order for the camera to work out the correct amount of SR compensation.
Something is quite wrong if you are getting camera shake at 1/100s.

I regularly have blur-free shots (static objects)with SR on my DA 55-300mm @300 mm at 1/30s . That's equivalent to 3 stops slower shutter speed than the 1/focal length rule.
You do need to pay attention to body posture at such slow shutter speeds. The old technique of tucking your elbows in close to your body certainly helps.
07-29-2009, 08:52 PM   #3
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I know that this is a stupid question, but are you sure that it's not motion blur as opposed to camera shake? Would you mind posting a sample?
07-29-2009, 10:00 PM   #4
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A 135 on a APS-C hand held no SR, you need to shoot at 1/200 min. Remember the inverse rule is with the focal length adjusted for crop factor.

Two stops under is 1/50 min. That is about the slowest I would go.

You still need to use good technique, and wait for the SR to start up.

How does SR work for you on shorter lenses?

07-29-2009, 11:02 PM   #5
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Yes, the 1 / focal length rule is really about FOV, so applying the crop factor is definitely appropriate. Also, it was really only designed to work in a world where we mostly made 4x6" prints, not a world where we pixel peep at 100% [ EDIT: meaning it's not conservative enough - you really need faster shutter speeds to stand up to 100% pixel peeping than you do for 4x6" prints ]

But most importantly, keep in mind that the 1 / focal length rule isn't a physical law that comes with an ironclad guarantee, like the rule that tells you how long it takes to reach the ground if you jump from particular height. It's just a rough guess at a shutter speed that might result in an acceptable nbumber of keepers from a photographer of "average" steadiness. Good technique will always increase the keeper rate (or let you shoot at a slower shutter speed), bad technique has the opposite effect.

Last edited by Marc Sabatella; 07-30-2009 at 09:14 AM.
07-29-2009, 11:06 PM   #6
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Also, make sure you're getting the "SR Active" hand in the viewfinder. If you fire before that, you can get blur even at high shutter speeds.
07-29-2009, 11:52 PM   #7
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QuoteOriginally posted by Marc Sabatella Quote
Yes the 1 / focal length rule is really about FOV, so applying the crop factor is definitely appopriate. Also, it was really only designed to work in a world where we mostly made 4x6 prints, not a world where we pixel peed at 100%.

But most importantly, keep in mind that the 1 / focal length rule isn't a physical law that comes with an ironclad guarantee, like the rule that tells you how long it takes to reach the ground if you jump from particular height. It's just a rough guess at a shutter speed that might result in an acceptable nbumber of keepers from a photographer of "average" steadiness. Good technique will always increase the keeper rate (or let you shoot at a slower shutter speed), bad technique has the opposite effect.
Marc Sabatella says -
"Also, it was really only designed to work in a world where we mostly made 4x6 prints, not a world where we pixel peed at 100%."

This is a very good point in considering the old rule. I have thought of this myself pixel peeping, or even just looking at pics on large monitors we demand much higher resolution than in the past; as we all know, but did we think of old rules in film days and how they may or may not apply today? However I have found the rule does work fairly well even pixel peeping, with steady hands. But that's me, and I for sure don't represent the whole world, so for others it may not work; especially given marks updated thoughts of the 'old' rule. It may need testing at 100% viewing size and revising?

I can tell you this. Given identical cameras shoot a pic at 100mm and 1/150sec, and without SR, shoot the same pic with SR. The SR pic at 100% does show more detail (amount dependent on each individual). I have seen this myself.

Its another advantage built in SR has over non SR dSLRS. Even if the shooter of a non SR dSLR stays at X1.5 (shutter speed) for the focal length, without a VR lens they will have less detail more than likely compared to the SR camera, this can go much higher even say 3X shutter speed for a given focal length or higher!

And those dSLRs can't use VR in fast primes, what a waste. Really and truly IMO in this day and age any dSLR without built in SR is just plain backwards period. No good reason for not having it compared to its benefits. Oh well...

Sorry this does not help the OP too much.

07-29-2009, 11:59 PM   #8
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Personally, I wouldn't consider any future dSLR purchase without built-in SR.
Its become a deal-breaker feature for me.

07-30-2009, 07:11 AM   #9
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i was reviewing the pictures and selected shutter speeds again last nite. i was wrong about the shutter speed. it seems most of the images affected by camera shake were 1/60 or less. it was about 50/50 with the camera shake, and the other bad images were just poor focus.

when shooting more normal focal lengths (~50mm), i would hesitate, or at least shoot a few extra pictures at 1/10s. sure I might get an in-focus picture, but the keep rate would be low. for 50mm, i woudl say 1/30s would give a pretty solid amount of unaffected images with SR. it seems that like Kungpow said, the minimum shutter speed would be higher for a longer focal length.

what would be the slowest speed you guys would use for longer focal lengths? (please state which focal length). i know theres no magic formula, but just from your experiences.

i love SR, im just trying to find the limitations.
07-30-2009, 09:14 AM   #10
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For my DA55-300mm, at 300mm I like to be at 1/180. Although in testing I can less than half that speed, the keep rate in real world shooting just goes down too much however.

The Pentax will show you want speed it thinks you need for SR for example it does pick 1/180 for my DA55-300mm (at 300mm). Put it into Av mode with an iso range of 100-3200 or less. Play with the aperture out doors with your 135mm, there will be a minimum speed the Pentax does not go under as you stop down, it will increase the ISO to maintain this minimum speed. That's your golden speed for great IQ with SR on, already figured out by Pentax through testing. Play around with it and you will see what I am talking about.
07-30-2009, 09:23 AM   #11
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Actually, there is a magic formula I use.

(1/(FL*1.5))*2 where FL is focal length.

I know I can get 1 stop out of the SR easily. If I feel I can do better, then I try another stop or two. Depending on how well you handhold, you will be able to get more stops out of the SR.

So, 135mm lens:

(1/(135*1.5))*2=1/100
07-30-2009, 09:28 AM   #12
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QuoteOriginally posted by eyou Quote
what would be the slowest speed you guys would use for longer focal lengths? (please state which focal length). i know theres no magic formula, but just from your experiences.
That depends entirely on the situation. Sure, I'd love to get 1/180" or better when shooting at 135mm. But I use that lens a lot in low light (concert photography), and those kinds of shutter speeds are just not going to happen. So I'll shoot at whatever shutter speed I can get (perhaps underexposing a bit, knowing I can fix that and the resulting noise in PP that much more easily and effectively than I can fix blur). When dealing with slower shutter speeds, I'm also much more careful in how I brace myself for the shot - elbows in, controlled breathing, ideally supporting myself against a wall, table, counter, etc. And I'll take several shots in hopes of one being good enough. But there's no point in getting out the tripod to get even slower shutter speeds when shooting people who aren't holding *perfectly* still - normal movement is such that there are limits to how slow a shutter speed you can get and stop subject motion, even for subjects who aren't being particularly active but are just engaged in conversation or whatever. There, good timing is everything - trying to catch people during moments of direction change when the actual speed of their motion is less. And Again, just shooting a bunch hoping one comes out good enough is the secret, not some magic number that tells you how fast is fast enough.

Also, the standards of sharpness differ for high ISO low light photography than for outdoor photography. Getting something even "kind of" sharp is accomplishment, so a picture that might have been a tosser outdoors might be a keeper indoors.

Anyhow, if you're looking a basic ballpark figure, for me, I'd say I don't like to shoot below 1/30" with a medium telephoto lens like a 135mm, and even then, I expect a fair number of blurry pictures, depending on how well braced I am and whether there is any subject motion at all. I'd generally rather underexpose at 1/30" than take my chances 1/15", although I do settle for 1/20" on occasion.

My personal best - in a setting where I had my elbows braced on a countertop, which helped tremendously, I'm sure, as did having an amazingly still subject - was this, shot at 100mm and 1/6":

07-30-2009, 09:41 AM   #13
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in quickly reading all the responses, there are a couple of things to note here.

first of all the 1/focal length rule was developed for 35mm film, printing to a basic 8 x 10 print.

If you consider the "crop factor" of the ASP-C sensor, the impact is that you are making an enlargement 50% bigger, therefore, you need to multiply by the sensor crop factor.

This means for the same size print, you need for a pentax DSLR to consider without shake reduction, shutter speed = 1 / (Focal Length x Crop Factor)

If you intend to make enlargements greater than 8 x 10, or if you crop your image, you would need to increase the shutter speed accordingly by the enlargement or crop factor ratio relitive to your full image on 8 x 10 print.

Also remember that this is somewhat variable, individual users and their techniques can impact this.

With shake reduction ON, and again depending on technique, you can usually get 2-3 stops improvement, therefore instead of a shutter speed of 1/(FL x 1.5) or 1/200 for your 135mm lens, you should be able to shoot at 1/200, and might get away with 1/50 or 1/25 again depending on your camera holding technique

Note however shake reduction, while good has 3 things it cannot account for,
- first is panning, if your subject is moving, shake reduction cannot easily determine the difference between panning motion and shake, in these instances it is usually recommended to turn it off
- second, shake reduction cannot account for subject motion, if your subject is not perfectly still, even if you have shake reduction off it may not give you a sharp image due to subject motion
- third, and many people for get this point, shake reduction only applies for motion in the focal plane, i.e. up and down, left and right, and on pentax cameras rotationally, but it cannot account for chang in subject to image distance and the impact on focusing errors induced by motion of the photographer. This becomes extremely important the closer you get to the subject, or the wider open the lens is (shallow DOF) and the length of the lens (since long lenses have shallow DOF)

I havve found shake reduction is good, as far as it goes but it can;t correct everything.

For the OP

IN reading the follow on comment, about shooting 1/30 with a 50mm, this is equal to 1/90 with a 135mm and 1/10 with the 50mm is equal to 1/30 with the 135mm.

Also 1/10 with a 50mm lens is 3 stops and about the limit of SR, 1/10 is also almost too slow unless you are shooting ab building to insure subject motion itself does not give you a problem

for Marc
I keep telling you you should get the 135 F2.5

Last edited by Lowell Goudge; 07-30-2009 at 09:46 AM.
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