Where does the ¹/shutter speed = focal length rule for hand shake come from?

Question

The generally accepted rule of thumb is that the shutter speed must be the same or larger than the inverse of the focal length.

As is, it seems that it makes no sense as is:

1. On a 24 Mpixels full-frame camera, at 100%, the blur from camera movement will be more visible than on a 10 Mpixels full-frame camera.

2. A photo intended to be printed small can have slight blur at 100%: nobody will see it when scaled down for printing. When doing a high-quality large print, even a small blur will be noticeable.

3. Image stabilization (vibration reduction) affects the blur when shooting handheld.

4. The blur will not be the same on a cropped vs. full-frame sensor.

I imagine that the rule of thumb appeared first when there was no DSLRs yet, and photographers were talking about SLRs with 35mm film. Is this that fact that makes the three of four points irrelevant? If yes, what about the second point? If not, what is the origin of this rule?

Answer

I did some quick Google Books searches, and while I can't pinpoint the origin, there are a number of references to it as a rule of thumb or general guideline in the early 1970s, and none that I can find before that. There are plenty of earlier references to the idea that a longer focal length requires a faster shutter but they're all general advice.

The first reference I find is from Popular Photography in 1972:

A rule that will help you determine the slowest hand-held shutter speed to use is: place the number one over the focal length of the lens (in millimeters). For example, with a 100-mm lens, one over 100 is ¹⁄₁₀₀ (¹⁄₁₂₅ would be the closest speed to set); with a 250-mm lens, the rule gives ¹⁄₂₅₀ sec. Use this rule as a guide. You may be able to hold for somewhat slower speeds if you're steady and your camera holding technique is good. If you're shaky, you may have to shoot at a faster speed than the rule indicates. Experience will tell this. If in doubt, use a tripod or other firm support and a cable release, when possible.

A year or so later, I found this

You can minimize or completely eliminate camera movement if you remember this rule: For hand-held shooting, don't use a shutter speed any slower than the focal length of the lens. The normal lens on a 35mm camera is is 50 to 55mm. When using this lens, set the shutter at ¹⁄₆₀th second. ... — Walter Chandoha, How to Photograph Cats, Dogs, and Other Animals, Crown Publishers, 1973

I doubt that either of these is the first occurance, though. There's a whole bunch of examples from around the same time, like this:

A rule of thumb is to use a shutter speed at least as high as the focal length of the lens: a 60th for the 50mm, 125th for the 105mm, 250th for the 200mm, and so on. But experience may show you are steadier or shakier than this rule assumes. — Robert Foothorap and Vickie Golden, Independent Photography: a biased guide to 35mm technique and equipment for the beginner, the student, and the artist, Simon and Schuster, 1975

So, I don't know exactly where it came from, but it's definitely an idea for 35mm film, and it's clear that in its early form, it was seen as a general guide, not a law.

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Should I keep Image Stabilization (IS) off when I do not actually need it?

Question

I own a Canon 7D and a EF-S 15-85 IS lens and I keep the image stabilization turned on all the time.

Recently, an experienced photographer told me that this is a huge mistake because it reduces image quality overall.

Except the battery draining, is there any evidence that using IS the image quality will be reduced?

Thank you :)

Answer

I don't know how it works with this lens, but I've seen charts for Pentax's in-body stabilization system where the data shows that contrary to conventional wisdom I.S. gives a (decreasing but still there) benefit up until rather high shutter speeds, at which point it doesn't matter (and doesn't make things worse).

If you have the camera on a very steady tripod, though, off is probably better. On a lightweight, wobbly tripod, it may be different.

It's also important to keep in mind that the stabilization takes time to engage and "settle" — typically half a second or so after you half-press the shutter button. If you have it on, make sure to allow that time.

Update: I don't think these are the charts I remember, but they show the same thing and are quite well done: How can I determine the minimum shutter speed to avoid blur from camera shake?.

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How can I maintain camera stability without a tripod?

Question

I was shooting some photos last night and I was having trouble not blurring the images. The issue I know comes from me shaking while the shutter is open. A tripod would have been the perfect fix but I did not have a tripod on me at the time.

Are there any techniques, tips, or tricks that I can try to help maintain stability when shooting in low-light conditions without a tripod?

(This question applies to both point-and-shoot and DSLR cameras.)

Answer

Some "tricks"

• Ninja breathing, as above. Learn to hold breath at critical moment.

• Body braced in as stable a position as you can get it. "Think like a rock" :-) ie elbows in against body, head pulled down against body, "hunched" posture feet placed consciously firmly and maybe slightly spread.

• Brace against something !!! - Lamp post railing, corner of building, nearest person (introduce yourself first). Maybe crouch with knee on ground.

  • Place camera on or against something and attempt to lock it rigidly - pull down against surface so it doesn't move. You may need to place arock, pen, stick under part of base to allow you to lock it in right orientation. This is more for the "10 second Hong Kong skyline at night with no tripod shots" than slow shutter.

• Use the 2 second timer if present. When bracing etc the action of moving your hand to press the shutter button can either result in post shot tremor with shutter open or painfully locked with finger in mid air. and less stability than you would have had. A 2 second shutter delay lets you push the button and then concentrate on turning you and the camera into a rock for 2 seconds.

• String/cord/rope under boot and pull up to get taut cord.
  Cord from 2 points even better.
  Cord from 3 points and pulled to tension approaches a tripod in stability.

• Monopod.

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What software could I use for aligning time lapse stills to remove camera shake?

Question

I've been playing around with some time lapse sequences shot from the roof of our building in New York. It's terribly windy and the resulting sequence exhibits some slight camera shake.

I'm seeking a software solution to align the images to compensate. Note: I don't have PhotoShop.

Answer

Aligning can be done for example with stitching-programs like Hugin.

• add all you pictures to the hugin-project
• let the pictures be analyzed/matched by "align image stack" (Images - Tab: Feature-Matching)
• add some points if needed (Control Points - Tab)
• set optimization to Position and Translation at the most (Optimiser-Tab)
• Optimize (Optimiser-Tab)
• check with "Preview panorama" (button above)
• go to Stitcher-Tab, set Projection to "Rectilinear"
• choose Output as "Remapped images"
• stitch! :D

You will get your pictures remapped into several exactly overlapping ones in the choosen format/size (Stitcher-Tab: Autocrop can remove nonoverlapping borders). It's a nice side-effect and prerequisite of stitching, I used it to create ghost-images (people swinging down a slope: put them five times into one picture), just stitching them together later (using enfuse/enblend on command line).

Hugin can do much more (like every decent stitcher, I guess), for example remove your barrel distortion and also vignetting. Look into optimizations for that.

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How can slightly blurred photos be improved in post processing?

Question

I have heard quotes which say "If its not good, delete it."

I go by that advice, but sometimes you capture some precious moment but you see that photo is slightly blurred because of camera shake. I don't have an IS lens, and it's too late to somehow do it over.

What best one can do in post processing to improve the quality of the picture?

Ideally, I'd like to use Gimp or Picassa for this.

Edit: I came across a video regarding this -
http://www.youtube.com/watch?v=xxjiQoTp864&feature=player_embedded

Answer

I used to think that blurring was one of those things that was impossible to recover from in post. Amazingly enough it's possible to take an image that is blurred beyond recognition:

and recover all the original detail if you know the exact blurring function:

So why isn't this done all the time? Well firstly you never know the exact blurring function so you can't create a perfect inverse filter, secondly if you have noise in the blurred image:

this will totally bias the outcome, as the inverse filter is unable to replicate it:

pseudo inverse filters such as the Wiener filter can cope much better with noise but you still get ringing artifacts like the following:

image (c) MathWorks, see http://www.mathworks.de/products/image/demos.html?file=/products/demos/shipping/images/ipexwiener.html for more detail

This is a bit of a digression, but it shows that deblurring is at least possible in principal. There are some very clever algorithms that outperform the Wiener filter by guessing what parts of the original image looked like, in order to estimate and reverse the blurrig function, based on the statistical likelihoods of various light patterns existing. There are some Photoshop plugins that offer image deblurring using such advanced methods, you might want to take a look at the following (which offer free trial versions)

• http://www.focusmagic.com/
• http://www.oceansystems.com/forensic/forensic-Photoshop-Plugins/toolset.htm
• http://www.humansoftware.com/pages1200/ApertureEdit/HSapertureedit111.html

The results are never perfect but for shots that are irreplacable it's better than nothing!

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How to take good photos while using maximum optical zoom?

Question

I have a point and shoot camera with 6X optical zoom.

However when I shoot with high zoom (above 3X), the sharpness of the picture seems to come down. Is it a feature of all cameras or is it due to higher sensitivity to camera shakes during captures in higher optical zoom regions?

Some of the photos in the higher zoom range are pretty good, usually the ones of scenery — so I I feel it can not be a camera problem.

Are there any other things to be taken care of when we shoot with higher optical zooms?

Answer

There's two things at issue here.

The first is zoom range, which is the longest focal length a zoom lens has divided by the shortest. That is, a lens which goes between 25mm equivalent focal length and 150mm is a "6x" zoom lens. This terminology is usually reserved for point and shoot cameras; for SLR lenses, one usually gives the actual focal lengths instead. High-zoom-range lenses require more design compromise, and it's likely that that compromise results in relatively weak performance at the extreme ends of the range. So that could be part of it.

Second is the issue of camera movement. Higher focal lengths — "more telephoto", or as you say, in the higher part of the zoom range — show a smaller portion of the scene magnified to the same size, and that means that small movements in the camera translate into larger movements in your photo. This means the effect of camera shake is much more pronounced the more you zoom in.

You can easily demonstrate this to yourself by simply looking at the live-view screen (or viewfinder) as you turn the camera slightly — at short focal lengths you can see a small change, and zoomed-in you can see that the whole scene changes with just a little turn. This same effect magnifies very small movements as well, increasing blur.

There's a particular compromise that most point and shoot cameras and superzoom lenses have which makes camera shake more of an issue when zoomed in. Specifically (as @Itai points out), these lenses usually provide a more-limited aperture at higher zoom. This means less light, which means either boosting the signal (higher ISO), resulting in more noise, or else longer shutter speeds — making it more important to reduce camera movement.

There's not much to be done about the first except to be aware of the strengths and weaknesses of your equipment, and to avoid using the higher focal lengths in situations where the weaknesses are most obvious — like in low-light.

For the second, simply keeping your camera more still will help significantly. You can get better results with improved technique and awareness of your motion as you press the shutter, but a tripod or other support will be even better. You'll also want to make sure that image stabilization is enabled in your camera if available — and make sure it has a chance to activate by half-pressing the shutter and waiting a second before firing.

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