Hand shake detection

samya · July 15, 2005

Hi Folks,
My first opportunity to play significantly with the manual settings of my rebelXT came on my visit to Yosemite last week. I was shooting manual, and using high f-value in Av mode to have larger DOF for quite a few landscape shots. I was also keeping and eye on the shutter speed to make sure I have enough leeaway with hand shake.

However, on returning home and downloading the photos, I was disappointed :cry due to significant number of shots with hand shake. Guess I was more tired than I tought from all those hikes.

Now comes the crux of the question. How do I look at the LCD of my dSLR and say if the photo has hand shake. For huge shakes, it's pretty obvious, but not for some small shakes. Is there any technical information that can tell me there was a potential shake? Is it possible?

Also, is there any photoshop/other tool to fix photos with shaken hands.
TIA.
-Samya

gus · July 15, 2005

What was the shutter speed & corresponding lens length for the shots you were disappointed in ?

Nothing fixes out of focus or blurry....you can patch it but if the information of the photo isnt there for a prog to interperate then it cant be done.

You can do artsy fartsy stuff with it though.

jwear · July 15, 2005

landscapes =tripod =minskake --landscapes with handheld=blur, rule of thumb or thats what Ed told me one of the 2

colourbox · July 15, 2005

samya wrote:

Also, is there any photoshop/other tool to fix photos with shaken hands.

Photoshop CS2's Smart Sharpen filter has a Motion Blur option that can reduce blur introduced by movement. It looks like it tries to reverse-engineer the motion effect after you give it an angle and a distance. Only problem is that it only works if the blur was in an exact straight line, but it has helped in a few situations.

My Canon point-and-shoot has two features to warn of camera shake. There is an icon indicating possible shake conditions, and a feature that will force the camera to use a usable shutter speed when possible. Those consumer features aren't on the XT, as far as I can tell, probably because they assume we know what we're doing. For the XT, you can head off camera shake by watching your shutter speed at all times. I think the old 35mm film rule is that to avoid camera shake you should aim for a shutter speed that sounds like the focal length of your lens. For example, for a 35mm to normal lens, 1/30 of a second is about as low as you can go. If you are using a 200mm lens, then your shutter speed should be around 1/200 sec. This assumes you're holding the camera as steady as possible and I don't know how the numbers change for these digital focal lengths. I just got the XT and am still getting to know it. However, I do know that if your shutter speed isn't where it should be, rotate the dial by the shutter button to change the shutter speed and aperture together so the overall exposure stays the same. I'm talking about the creative zone modes - don't know how the auto modes work because I'm never in them.

JamesJWeg · July 15, 2005

Does the XT have a way to zoom in on the shot? If not I don't know how you can check in camera for hand shake. On my D2H I can zoom in and then you can see shake that you can't see before zooming in. my D70 has a limited level of zoom, and while it helps it is only so helpful.

James.

Safari · July 17, 2005

samya wrote:

I was shooting manual, and using high f-value in Av mode to have larger DOF for quite a few landscape shots.
-Samya

- DOF is rarely a problem with landscapes. Why not set a faster shutter?
- Handshake blur increases with distance, focal length and zoom - all typical of landscapes. When you don't have a tripod, use the best available substitute - tree, fence, rock, sit and brace the camera on your knee, etc.
- Are you sure it was handshake?
- Maybe motion blur due to wind? A faster shutter will help.
- Fog, mist, smog, haze, humidity?

erich6 · July 17, 2005

What I usually do is zoom in as much as I can on the viewfinder to see how the edges look. The LCD resolution is not that great so you won't be able to pick up subtle blurring but it is better than nothing. Usually, if in doubt, I'll take another shot or more and then compare how they look on the LCD. Usually, one will look sharper than the other and then I know what shutter speed to stick to.

In the end, the best thing to do is follow the rule-of-thumb that the shutter speed is proportional to the focal length you have set your lens to (i.e., for 50 mm focal length use 1/50 sec exposure or faster). With digital cameras with the 1.5 or 1.6 X factor multiply that to make your speed faster by that amount. If you are not sure you can hold the camera steady then try doubling the speed. That should get you there.

In the end, even if you follow this rule-of-thumb, you have to keep in mind the speed at which what you are taking a picture of is moving. If this moves faster than the shutter speed it will also come out blurred. This is usually not an issue when shooting landscape except when it is windy out and leaves or flowers can come out blurry if you have a low light situation.

Erich

wxwax · July 18, 2005

I haven't yet seen a camera with a display that can truly tell you if your shot is in focus. You can get a general idea by zooming in on the image, but that's about it.

You do know the rule of thumb, right? Your shutter speed should be the same as or greater than your focal length. e.g. 50mm = 1/50th, etc.

As for trying to fix a blurry image, if all else fails, try this technique.

muddyknees · July 18, 2005

Seems to me all that advice I read about using aperture-priority assumes tha camera is on a tripod. If you're using it hand-held, makes more sense to me to use shutter-priority. Set the speed using the rule of thumb - 1/lens focal length. That'll give you the optimal aperture given your speed constraints, without having to keep watching your speed and having to adjust by fiddling with the aperture.

You might also check to see whether you are habitually "twitching" the camera just as you are pressing the shutter. You could maybe test or practice your shutter-pressing technique at home with a very slow shutter speed and a long lens and a sharp-edged distant object. Take a few shots & load them onto your computer to check, then repeat to try to improve. Then see for yourself what speed you need to get an acceptable image. (I suppose you could also see how much blurr you can detect with the camera LCD - my opinion is it's useless for that and a waste of time except maybe to review composition - I just leave it off and save my battery.)

Also, get yourself plenty of memory so you can take "backup" shots and "bracket" your speed/aperture/ISO and focus distance. (That'll also get you into the habit of just tossing out the bad and moving on.) BTW, if you do want to really extend your depth of field look into a software program like CombinZ.
(see http://www.outbackphoto.com/workflow/wf_72/essay.html for a review.)

Finally, here's a bit of a radical suggestion to consider: You've got a "professional-looking" camera that's somewhat conspicuous and bulky to carry compared to all the tiny digitals everyone else pulls out of their pockets - might as well go all the way and sport a tripod as well! In fact, leave your tripod attached to the camera even when you're taking "hand-held" shots! You can cut your shutter speed in half this way. And, if you need even more DOF, you've already got your tripod half-way set up to do the long exposure.

Here's how I carry the tripod attached to the camera: it's folded up, upside down so camera is at the bottom, strap around my neck. When I'm just hiking not actively looking for pictures to take or I need both hands free, one leg of the tripod is tucked under the strap of my backpack. When I'm getting ready to shoot, I'm holding the camera and the legs are still pointing up cradled in my arm. When I'm ready to shoot, I bring the camera to my eye and the tripod legs rest on my shoulder, or, for a low-angle shot, under my arm. Note that the head of the tripod is angled 90 degrees so that the axis of the lens is parallel with the tripod legs.

samya wrote:

Hi Folks,
My first opportunity to play significantly with the manual settings of my rebelXT came on my visit to Yosemite last week. I was shooting manual, and using high f-value in Av mode to have larger DOF for quite a few landscape shots. I was also keeping and eye on the shutter speed to make sure I have enough leeaway with hand shake.

However, on returning home and downloading the photos, I was disappointed :cry due to significant number of shots with hand shake. Guess I was more tired than I tought from all those hikes.

Now comes the crux of the question. How do I look at the LCD of my dSLR and say if the photo has hand shake. For huge shakes, it's pretty obvious, but not for some small shakes. Is there any technical information that can tell me there was a potential shake? Is it possible?

Also, is there any photoshop/other tool to fix photos with shaken hands.
TIA.
-Samya

JamesJWeg · July 18, 2005

wxwax wrote:

I haven't yet seen a camera with a display that can truly tell you if your shot is in focus. You can get a general idea by zooming in on the image, but that's about it.

You do know the rule of thumb, right? Your shutter speed should be the same as or greater than your focal length. e.g. 50mm = 1/50th, etc.

As for trying to fix a blurry image, if all else fails, try this technique.

Have you played with a D2H? the zoom level with the screen size makes it easy to spot blur.

James.

BigAl · July 18, 2005

erich6 wrote:

What I usually do is zoom in as much as I can on the viewfinder to see how the edges look. The LCD resolution is not that great so you won't be able to pick up subtle blurring but it is better than nothing. Usually, if in doubt, I'll take another shot or more and then compare how they look on the LCD. Usually, one will look sharper than the other and then I know what shutter speed to stick to.

I agree with Erich. On max zoom on the LCD if it looks even slightly fuzzy, take another shot.

regards
alan

wxwax · July 18, 2005

JamesJWeg wrote:

Have you played with a D2H? the zoom level with the screen size makes it easy to spot blur.

James.

No, I haven't. But I know someone who has one.

I'll look.

Hand shake detection

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