Avoid blurry photos Pt.2

In How To Avoid Blurry Photos Pt.1 we looked at the problems of photos appearing sharp on the camera’s screen, only to be disappointed in the image when we get home and view it on a computer. We talked about properly adjusting your diopter setting to ensure the image you see in the viewfinder is tack-sharp.  We now move onto what is probably the most common reason for photos looking blurry.

When I run my workshops for new photographers, I often put a blurred image on the screen and ask them to tell me what’s wrong with the photo.  In most cases, the majority reply in one voice…

“It’s blurred”

Then I’ll show them another image, very similar, and ask them the same question

“That’s blurred too”

“OK..”

I’ll reply,

“So what’s the difference between them ?” (putting them up on the screen side by side)

And then there’s quite often silence.

What they’re looking at is one image that is genuinely out of focus but the other one has nothing to do with focus at all. 

It looks blurred because it’s suffering from camera-shake.  The camera wasn’t held steady-enough when the photograph was taken and even a small amount of movement has made the image look soft.

This is incredibly common.

The person or object being photographed may well be perfectly in focus, but because the shutter speed was too slow for the photographer to hand-hold, camera-shake manifests itself as a blurred image.  In fact, a couple of things could be going on here.  Either the person taking the photo has not held the camera steady enough, or the shutter speed had been to slow to capture movement from the subject.

The photo at the top of this page was deliberately shot at a slow

Motion blur

Photograph someone running and you need a fast enough shutter speed to freeze the action.  And of course the closer they are to the camera, the faster that shutter speed has to be. 

This makes sense doesn’t it?  If someone is a hundred metres away and runs left to right across the picture, they will seem quite slow.  But if they were running just one metre away from the camera, they pass by at lightning speed.

So as a photographer, you have to ensure your shutter speed is appropriate for the situation you’re photographing.  Every moving subject can be captured mid-action by an appropriate shutter speed.  Any speed that isn’t man enough for the job, one that is too slow… and there will be motion blur.  Faster speeds, of course, are fine, but there will always be a minimum speed, below which we lose that sharpness.

What’s that speed? 

What’s the secret sauce needed to capture someone running in front of the camera? 

If I had a pound for every time someone asked me that (sigh).

Yup, it’s a question I get asked a lot.  Sadly the answer always disappoints.  There is no universal magic minimum shutter speed to capture someone running.  Neither is there a universal shutter speed to capture a cyclist, a child playing football or a bird in flight. 

There are too many variables… How fast they’re going, how far away they are, what lens you’re using, whether your lens has some kind of image stabilisation built to assist with panning, and whether the runner is running perpendicular to the lens or at an angle.

“So how do I know what shutter speed to use?” I hear you say.

Practice

I’ve been doing it for so long now, I can usually make a good guess.  But it has only come to me through ‘practice’, regular practice.  Going out and shooting lots of photos.

The good news is, that digital has made it easier for us.  Back in the days of film, we had to be far more calculated.  With today’s camera’s we can take a shot and if it doesn’t look right, we take another one (and maybe several until we get the shot we like).  However, some shots may be unrepeatable and you only have one chance to grab it.  You daren’t make a mistake and so you have to cover your bases by cranking up the shutter speed as high as you reasonably can.

 

Camera Shake

“What about blur caused by camera movement?” I hear you say.   

“Can’t I just use a tripod?”

Obviously, a tripod will be the answer for some situations, but in most cases, you won’t have one to hand and it’s these situations I want to look at now.

When I’m teaching, occasionally I come across a student who has been taught (sometimes on other photography workshops) that to avoid camera shake, they should ensure that their minimum shutter speed is not less than 1/50 sec.  They have slavishly followed this guideline, but it hasn’t always worked.

[Sharp intake of breath]

Here’s the thing, there is a very simple formula (very simple) to help anyone determine what their minimum hand-held shutter speed  (MHHSS) should be in almost any given situation (there are some exceptions, i.e. macro photography, where the massive magnifications create their own problems).

Knowing how to calculate the MHHSS for any shot should be written into every photographer’s DNA.  You should know it so well that you don’t have to think about it.  It must become second-nature and until it does, you’ll continue to get blurred photographs

So where did the instructors running those other photography workshops get this magic 1/50 second MHHSS from?

And why are they wrong?

They have kinda picked up a half-truth and not taken the trouble to really check it out.

We have to go back to the days of 35mm film to understand its origins. 

I certainly remember being taught back in the 1960’s a very simple guideline.  The guideline was a full-proof (in theory) formula to help photographers ensure they avoided camera shake by always shooting at shutter speeds above a certain minimum.

When you bought a 35mm film camera all those years ago, it would come fitted with a standard 50mm lens.  The zoom lenses we see fitted as standard these days were not readily available back then, they were expensive and not that optically good.  The 50mm was a great choice of lens as its field of view (what it sees) roughly matched that of our eyesight (excluding peripheral vision).  Someone had determined that provided we kept our shutter speeds faster than 1/50 sec, most people could hold their camera steady enough for good stability.

So this rule came into place:

With a 50mm lens, the slowest shutter speed you should use is 1/50th sec

If we changed to a different lens (longer or shorter) the ratio between focal length and that slowest speed remained and was expressed like this:

You shouldn’t hand-hold a camera and any shutter speed less than the focal length of the lens you’re using

This was so easy.  If we changed lens, we mentally took note of the focal length and adjusted our shutter speed accordingly.   The focal length in millimetres instantly told us what our slowest shutter speed should be.

The longer the lens, the faster the speed, the shorter the lens, the slower the speed.  I remember having a 400mm lens in my first SLR back in the 70’s.  My minimum hand-held shutter speed would have been 1/400 sec

Here’s a simple table showing a range of popular focal lengths and their MHHSS

If your camera doesn’t have a shutter speed that exactly matches the focal length of your lens, you simply round it up to the nearest speed.

Focal length	Minimum hand-held shutter speed
35mm	1/35th sec
50mm	1/50th sec
100mm	1/100th sec
200mm	1/200th sec

 

If you stick to this guide of shooting at speeds equal to (or greater than) the equivalent focal length of the lens, you will massively reduce camera shake in your photos.

“But I have a zoom lens, my focal length changes”

The easiest way to deal with zooms is to ensure your MHHSS is set to the longest focal length the lens zooms to.  So if you were using an 18-55mm kit lens (kit lenses are lenses that come with most cameras), set your MHHSS to cover the longest focal length of 55. 

Personally, I would round it up to 1/80^th sec or even 1/100^th sec.  That would give you a good margin for error.

Problem with this formula

There’s a problem with this formula, however.

Matching the MHHSS to the focal length, as I said, originated with the 35mm film camera.  It works perfectly well with photographers who own full-frame DSLRs (where the sensor size is the same size and 35mm negatives), but most photographers don’t have full-frame cameras.  Most of us use cameras with smaller sensors, cropped in size to make cameras smaller and cheaper to produce.

Cropped sensors produce an image which looks like it’s been magnified.  The magnification effect depends on how much the sensor has been cropped.  For most, the magnification effect (or to use its correct term, the crop factor) is around 1.5 times the image’s original size*

I can hear some of you screaming already.

If you want to know more about crop factors, here’s an old video I produced which very simply explains the principles

All you have to do is multiply your focal length and times it by 1.5.  Surely that’s not too difficult?

So 50mm now becomes 75mm and 100mm becomes 150mm.  Simples!

See the updated table below.

Focal length	MHHSS	With 1.5 Crop Factor
35mm	1/35th sec	1/50th sec
50mm	1/50th sec	1/75th sec
100mm	1/100th sec	1/150th sec
200mm	1/200th sec	1/300th sec

 

Putting it in the simplest way I can…

If you have a 50mm lens on your cropped sensor camera.  The minimum hand-held shutter speed in 50 x 1.5.

Answer 75.

1/75th of a second is the slowest shutter speed you should be shooting at if you’re hand-holding the camera.  Your camera may not have a 1/75th sec option, so just round it up to the next highest speed. it might be 1/80 sec or 1/00th sec.

Phew!

So the purpose of this post is to explain about the importance of having fast enough shutter speeds to either freeze moving subjects or to ensure you can comfortably hand-hold the camera without getting camera shake.

As always, if you have any questions please post them below and I will do my best to answer them.

I’m going for a beer.

Learn Photography

If you’re looking for photography workshops, photography courses or photography lessons, check out our website at Hampshire School of Photography or call Tuesday – Friday 01252 643143

 

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* Most DSLR cameras have a crop fact around 1.5 (ish).  Owners of four-thirds mirrorless systems (Panasonic & Olympus) have smaller sensors and their crop factors are 2

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