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11-08-2011, 08:33 PM   #1
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When NOT to use SR?

Do you all use SR in good light? Does it ever fight against you? I was shooting a lot of pictures at the NYC Marathon on Sunday with the 15mm f4 Limited. My exposures were all F11 at 125-180th of a second. But MANY of my pictures show significant motion blur. Now I was not being as careful as one could be, but with a 15mm lens and those speeds, motion blur should not have been that big of a problem. Does SR ever cause blur? Or am I a little off in thinking what a motion freezing shutter speed is...

Thanks!

11-08-2011, 08:41 PM   #2
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To freeze motion you would need something closer to 1/250s or 1/500s. SR can backfire if you don't allow it to "arm", but that happens rarely and it would only affect a few of your photos...

Adam
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11-08-2011, 09:16 PM   #3
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Okay, definitely a time I should have engaged either TAV or Sv modes, instead of Av I think. I should have just let the camera figure it out and have me pick 500th of a second. I just don't like the 15mm wide open, or even at 5.6. However I guess sharp at one of those apertures would have been better than blurred at f11. Oh well!
11-08-2011, 09:45 PM   #4
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When not to use SR: When the camera is immobilized / tripodded; and when shooting close, like at macro (1:2 or greater magnification) ranges, say within twice the focal length.

When to use SR: The rest of the time, as long as you've dialed-in the correct focal length. That can get tricky or tedious for MF zooms; otherwise it's no problem.

Falk Lumo posted some tests awhile back on the effect of SR at various focal lengths and shutter speeds. IIRC he found that SR gives a 2 to 3 f-stop advantage in best cases (with teles), and no disadvantage in worst cases. So except with camera immobilization, and MF zooms, and macro shots, there's no reason to switch SR off.

As Adam said, your problem was too-slow shutter. I've read that humans can physically react at speeds up to 75mph. If a car drives by doing 75 and we shoot at 1/125 second, we can expect some motion blur, eh? A runner might not be moving forward that fast, but their arms and legs are whipping along at a good clip. And if a baseball pitch is measured at 150-200 mph, that's how fast the pitcher's arm is moving.

If you want to stop human movement photographically, you need a shutter speed of 1/500-1/1000 second, depending on subject distance. With your 15mm you were probably up-close-and-friendly with the runners; their motions are emphasized so you needed a faster shutter. My suggestion: TAv mode, 1/800 second, f/5.6, and let the ISO float as needed. High-ISO noise can be cleaned up in PP but motion blur is forever.

11-08-2011, 10:40 PM   #5
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QuoteOriginally posted by Sperdynamite Quote
Now I was not being as careful as one could be, but with a 15mm lens and those speeds, motion blur should not have been that big of a problem.
That is 100% incorrect. You are getting confused with shutter speeds necessary to avoid camera shake. Motion blur is almost guaranteed at those speeds when photographing people running. As others have said, you needed 1/500 to 1/1000.

IT's a good learning exercise though, we've all done it, I bet you wont make the same mistake again
11-08-2011, 11:28 PM   #6
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IMO it depends on how you shoot. For normal shooting (family, landscape etc) I always have SR on but I've noticed that for quick street shooting it's best to switch SR off. I usually walk around with my K-r in my hand and only raise the camera to quickly compose and take the shot when I see something interesting. I usually use M mode and try to keep shutter speed high enough but if I have SR on I get a lot more blurry shots. 24mm at 1/250 shouldn't show camera shake but if the SR mechanism is still adjusting while you press the shutter you can get blur.
11-08-2011, 11:36 PM   #7
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Of course, you can play with the shutter speed more to convey what is really going on. If you want to absolutely freeze the runners, go 1/500 or faster. But artistically, I would find a panned shot at 1/60 or 1/125 more pleasing, as the runner's head and torso are frozen, but her arms and legs blurred (and even the background too), to convey the notion that they are running. This is where SR would actually work against you in reducing the background blur with camera panning.

It's the same for taking pictures of race cars. Freeze them completely, and it looks like these 170 mph cars are just parked on the race track. Not very interesting.
11-09-2011, 12:48 AM   #8
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It seems that the obvious was missed. You must switch off the SR when you use the tripod.

Otherwise, many Pentaxians simply leave the SR on all the time.....

11-09-2011, 01:23 AM   #9
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QuoteOriginally posted by ovim Quote
IMO it depends on how you shoot. For normal shooting (family, landscape etc) I always have SR on but I've noticed that for quick street shooting it's best to switch SR off. I usually walk around with my K-r in my hand and only raise the camera to quickly compose and take the shot when I see something interesting. I usually use M mode and try to keep shutter speed high enough but if I have SR on I get a lot more blurry shots. 24mm at 1/250 shouldn't show camera shake but if the SR mechanism is still adjusting while you press the shutter you can get blur.
I have noticed the same thing. When walking around and taking quick snapshots the SR often doesn't have time to stabilize and will cause blur. I nowadays keep SR off until I need it. Then I don't have to worry about waiting for that SR light to illuminate while the thing I'm taking a photo of is moving out of the frame.

My question is did everything in the pictures have motion blur? Or was it only the people running? If everything has the same blur then congratulations you have picked up on the same problem as us two. If only the runners, then you used an insufficient shutter time. And as stated before, don't try to use SR when panning.
11-09-2011, 02:29 AM   #10
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I don't understand why not use SR with macro shots. Can someone explain this ?
11-09-2011, 05:34 AM   #11
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When I said motion blur, I meant camera shake. The runners did show a little true motion blur but I'm okay with that, the shake, no. I'm going to try turning SR off until I need it...
11-09-2011, 07:21 AM   #12
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QuoteOriginally posted by Jimfear Quote
I nowadays keep SR off until I need it.
My approach, as well.

On the K-5, I use TAV with iso set to 'auto' 80-25600 and the shutter at a minimum of 1/500s, depending on the anticipated action of the subject. This frees me to concentrate most of my fiddling on the aperture to get the best DOF. I use the same approach with my K-7, but find its iso limitations (6400 max) calls for more creative post processing to produce a workable image.

Plenty of examples are posted on the web link in my sig, below. If you click on an image, It will open in Flickr and you can explore its exif data. My kit d'jour consists of a K-7 paired to the DFA 100/2.8 WR with F1.7x TC (FL=170mm) for use as a light weight medium telephoto for waterfowl. Unfortunately, the weather and my timing has not been good, so the current subject is fading Fall color. Normally, my K-5 would get the nod, but it's at CRIS for a cleaning and minor adjustment.

Anyway, it takes some practice to get tuned into the procedure, but you'll quickly get the hang of it.

Cheers and enjoy the season...
11-09-2011, 07:39 AM   #13
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QuoteOriginally posted by Jimfear Quote
When walking around and taking quick snapshots the SR often doesn't have time to stabilize and will cause blur. I nowadays keep SR off until I need it.
My understanding from reading the manual is that SR is a menu item. It also looks like it can be switched on and off in the Control Panel. Is that correct?

How long does it take SR to stabilize after a half press?

Jeff
11-09-2011, 08:25 AM   #14
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QuoteOriginally posted by Jeff Charles Quote
How long does it take SR to stabilize after a half press?

Jeff
Somewhere around 0.6 -0.7 seconds. If you shoot before that there is no problem because SR will not be used. If however the hand comes up and you make a slight adjustment and fires, then there might be a problem as the camera has no way of knowing if that slight adjustment was intentional or a shake that should be counteracted.
11-09-2011, 08:54 AM   #15
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QuoteOriginally posted by fs999 Quote
I don't understand why not use SR with macro shots. Can someone explain this ?
SR compensates for back-and-forth (X-Y axes) motions at normal focus distances. Close-up, your shaking fore-and-back (Z axis) becomes significant and SR can't compensate for that.
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