Black Bear: This photo may look sharp, especially at a small size, but it's not "tack sharp". Follow through the series with me to learn the process of creating "tack sharp" images.
The term "tack
sharp" is used in photography to represent the absolute best clarity of detail
in an image. Sharpness is affected by two elements: focus and contrast. When
you have an image with crisp focus and well attained contrast, and no visible
blur when looking at it at pixel level, it is considered to be "tack sharp".
If you are
thinking you can correct the clarity of your images by using the Photoshop
‘sharpening and contrast’ tools to enhance your images, you may want to rethink
that approach. If you don't have a “tack sharp” image while photographing in
the field, no amount of post production work is going to produce quality
contrast, make a blurry image sharp or create fine detail where there is none.
Therefore, it is important to know how to capture "tack sharp" images straight
from the source—your camera.
experience teaching beginning photography classes, I have found that taking
blurry photos is the most common obstacle that students need to overcome.
Typically this is due to one of the following: camera shake while hand holding
the camera, shooting with a slow shutter speed, and/or not using a fast enough
shutter speed when the subject is moving. Understanding how to correct these
issues is vital to creating “tack sharp” images.
So let’s start
with shutter speed. What shutter speed should you use? That will depend on
what you are shooting--if your subject is moving or still and what type of
affect you are trying to achieve (show the motion or stop the motion).
Stop race cars
or pro-athletes 1/2000 - 1/4000 sec.
Stop a bird in
flight 1/1000 - 1/2000 sec.
Stop action at
gymnastic meet 1/800 - 1/1500 sec.
Still life or
portraits 1/125 - 1/250 sec.
Landscapes 1/20 - 1/100
Waterfall on a
cloudy day - velvet smooth water 1/2 - 1/30 sec.
City lights at
night 8 - 30 sec.
indoors with no flash & no movement 5 - 30 sec.
sec. @ f/4.5 ISO 100 Lens: EF 100-400mm f/4.5-5.6L IS USM - hand held
This is an
example of how you can have part of an image "tack sharp", while the rest of
image can be blurry. The important thing to remember is that you want the focal
point, in this case the eye, to be "tack sharp". The wings being blurry shows
movement, and the background being blurry is called bokeh, which is an aesthetic
the closer you are to a moving object, the faster that object will be relative
to you and the camera, which means you will have to use a faster shutter speed
in order to stop the action. So if you are sitting in the first row at a race
and are right next to the track, your shutter speed will have to be faster in
order to stop a race car, runner, or horse, than if you are sitting in the top
row, far away from the track.
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the most used “rule of thumb” in photography. It is used to determine the
slowest shutter speed you can safely use while hand holding your camera and
still prevent camera shake. It states that when hand holding your camera, the
shutter speed should not be slower than the reciprocal of the effective focal
length of the lens you are using. So, if you have a 55 mm lens, then the
reciprocal of that would be 1/55, which means that the slowest shutter speed you
should use would be 1/55 seconds.
200mm lens: Shutter Speed (SS) > = 1/200 sec.
100mm lens: SS > = 1/100 sec.
70mm lens: SS >
= 1/70 sec.
Golden Eagle: 1/400 Sec. @ f/7.1 ISO 100 Lens: EF 100-400 f/4.5-5.6L IS USM @ 400mm
Tulip: 1/200 sec. @ f/4.0 ISO 100 Lens: EF 70-200mm f/2.8L IS USM @ 120mm - hand held
This shot was taken outdoors after a late May snowfall when the sun was out. I used an extension tube on my 70-200mm IS lens and was still able to get the speed fast enough to hand hold it.
Much has been
written regarding the reciprocal rule, some positive, and some negative, but if
you use it as a guideline only, a starting point from which to base your shutter
speed decisions, then this rule should serve you well.
Be sure to
factor in the following questions when making your choices:
1. How steady
are your hands?
2. What method
do you use to hold the camera steady?
3. Do you have
vibration reduction or image stabilization on your camera or lens?
4. Are you
using a full frame sensor or a cropped sensor?
5. Is your
subject moving or holding still?
like to change the rule a bit to ensure really sharp images. I like to add 1/2
to 1 stop faster to the reciprocal rule for my hand held shots, since my hands
are not as steady as some. If there is not enough light and the aperture is
close to being wide open, then I have to choose between opening the aperture
wider or slowing the shutter speed. I will usually open the aperture all the
way before slowing the shutter speed.
length of a lens is based on the size of 35mm film. If the digital sensor in
your camera is full frame (the same size as 35mm frame) then the "effective
focal length" is the same as the markings on the lens. However, if you have an
entry-level DLSR you will have a smaller sensor. If this is the case, you will
have to do some math in order to calculate the “effective focal length".
Consumer grade Nikon cameras usually have a 1.5 crop factor, while Canon's have
a 1.6 crop factor. Check your camera's manual to see if your camera has a crop
factor. If you have a crop factor, you need to multiply the reciprocal of your
focal length by the crop factor in order to get your minimum shutter speed.
lens: (200 x 1.5) SS > = 1/300 sec.
lens: (200 x 1.6) SS > = 1/320 sec.
lens: (100 x 1.5) SS > = 1/150 sec.
lens: (100 x 1.6) SS > = 1/160 sec.
Another way to
increase your chances of getting “tack sharp” images while hand-holding your
camera is to use the continuous shooting mode on your camera to take several
shots in rapid succession. This will increase your chances of having a least
one shot that is “tack sharp”.
Stabilization allows you to use a slower shutter speed. Some lens manufactures,
and or lens review sites, say you can shoot at speeds 2-4 stops down from the
hand held rule of thumb, depending on the lens. That means that if you shoot
down 4 stops (16 times longer), you would get similar levels of sharpness with
IS on at 1/8 sec. as you would at 1/125 sec. with IS off. Personally I don't
like to stop down more than 3 stops or to go below 1/60 sec.
Full frame &
200mm lens: SS >= 1/200 sec. 1/100 - 1/60 sec.
lens: SS >= 1/300 sec. 1/150 - 1/75 sec.
lens: SS >= 1/320 sec. 1/160 - 1/80 sec.
Be careful when
purchasing a tripod. Not all tripods are created equal. You want to make sure
that the tripod you use can support your camera with your largest lens
attached. A gust of wind will easily knock over a camera on a tripod if it's
not sturdy enough to hold the weight and even a mild breeze can cause camera
shake if your camera is mounted on a flimsy tripod. The better your tripod is,
the less movement you camera will encounter, and the sharper your images will
A sturdy tripod can be made sturdier by attaching your camera bag or other heavy
articles at the base of the tripod.
Chimney Rock at Monument Valley, Utah
1/200 sec. @ f/5.6 ISO 400 Lens: EF 24-70 f/2.8L USM @ 50mm
will give you a weight limit which you can compare to the weight of your camera
with the largest lens you have or expect to have. You should also take into
consideration that the closer your camera, with its heaviest lens, comes to the
maximum weight limit, the more likely it is to shake, wind or no wind. A good
rule of thumb is to use a tripod which has a maximum weight rated 25% above the
weight of your camera and largest lens.
When using a
tripod with an image stabilized lens or camera, be sure that you read the manual
for your lens. Some IS (image stabilizer)/VR (vibration reduction) lenses
recommend that you turn off the IS when mounted on a tripod. When an IS/VR lens
is mounted on a tripod, and there is no movement, the system tries to find some
movement, which causes the IS/VR system to produce erratic effects and
movement. However, few tripods are able to keep a camera and lens absolutely
motionless, especially with larger lenses. And newer IS/VR lenses can detect if
they are on a tripod, so you can leave the IS/VR on, even while on a tripod. If
you are not sure about the IS/VR on your lens, check the lens manual.
1/20 sec @ f/18 ISO 100 Lens: ef 24-70mm f.2.8L USM using a tripod
0.8 sec. @ f/10 ISO 100 Lens: EF 24-70mm f/2.8L USM @28mm
This image was inside a dark slot canyon and required a long exposure. I used a cable release so I wouldn't shake the camera by pressing the shutter release button.
Remote Shutter Release or Self-Timer:
While a tripod
will drastically reduce camera shake and allow you to take long exposures, the
movement from pressing the shutter release will make the camera shake enough to
prevent you from getting “tack sharp” images when using slow shutter speeds. In
order to minimize camera shake and get the most out of using a tripod, use a
remote shutter release or self-timer so that you don't have to touch the camera.
There are two
types of remote shutter releases--a cable release and a wireless release. If
you don't have a remote shutter release, you can use the self-timer function to
release the shutter without touching it.
Now it’s time
to go out and practice what you’ve learned. Try taking shots with the various
shutter speeds and focal lengths—try the multiple bursts. Then take some shots
using your tripod—if you don’t have one, find something sturdy that can support
your camera and try shots with and without the remote shutter release or
self-timer. The more you practice, the better you’ll understand and the better
“tack sharp” images you’ll get.
Most of all
Go to Part II – Aperture and Lens Quality
Part III –ISO, Focus Lock, AF Focus Mode, Manual Focus
and Mirror Lock-up
Go to Part IV – Macro Photography, Macro Equipment,
Focus Stacking and Lens Flare
Go to Part V – Fast Lenses, Filters, Teleconverters/Extenders,
Environment, LCD Image Review, Monitors, Image Compression, Sharpening