How Steady Are Your Hands?


The ‘best lens’ in the world (if there was any such thing) would no longer be the best if your shooting techniques are poor.
There can be several reasons for your pictures not being sharp – poor focussing, poor lens contrast, poor lens resolution, subject movement, and camera movement.

The biggest culprit is often the camera movement during ex-posure. Camera movements increase with slow shutter speeds. Please, once and for all, get it out of your head that you can shoot at low shutter speeds and get sharp images all the time. That is why professionals and advanced amateurs use a steady tripod whenever possible. But for the purpose of this article, we shall assume that using a tripod is not possible or is not al-lowed. We shall also refrain from using the advantages offered by image stabilisation systems. In such a scenario, you need to know how low can you go on your shutter speeds before the hand-shake-dragon gobbles you up.

First decide the genre of your interest; is it macro photography, function photography, street photography, or nature and wildlife photography? Each genre requires different focal length lenses, (with lens weight varying from a few hundred grams to a few kilograms), and as such, the lowest shutter speed for hand-held photography will differ.

Here is a simple rule of the thumb which will suggest you the lowest shutter speed for hand-held photography with whatever lens you may use:

1. Check the focal length. Let us assume it to be 200mm.
2. Next, consider the crop factor for the sensor size. We shall consider three crop factors – 1.6x (as with some Canon D-SLRs), 1.5x (as with some Nikon D-SLRs, and 2x (as with Micro Four Thirds ILCCs). With the Canon, the effective focal length would be 320mm, with the Nikon, 300mm; and with the Micro Four Thirds bodies, it would be 400mm. With full-frame camera bodies, there is no crop factor and hence the effective focal length does not change.
3. Now use the shutter speed which is the reciprocal of the effective focal length. Hence, the lowest shutter speed for the Canon would be 1/320 sec; for the Nikon, 1/300 sec, and for the MFT bodies, it would be 1/400 sec.
Now let’s add a 2x teleconverter to our 200mm lens. The Canon will now have an effective focal length of 640mm; the Nikon will be equivalent of 600mm. Currently, there are no teleconverters for MFT bodies. The lowest shutter speeds for hand-held photography will change accordingly.


The Practical Test
* Paste a newspaper on a wall, taking care that there is no unevenness in the pasting.
* Select the lens. We’ll do the test using a 200mm lens. The camera to subject distance will be 15 feet (your distance may vary with the lens). The camera will be in Shutter Priority mode. Firing mode will be ‘S’ (single frame). The ‘effective focal length’ in our example is 300mm.
* Mount the lens and take 10 shots at various shutter speeds. For example, shoot 10 frames at 1/350 sec (according to our thumb-rule), followed by 10 frames at 1/250 sec, then by 10 frames at 1/125 sec, followed by 10 frames at 1/60sec and so on till you reach 1 second. Take a break in-between shots so that you are not over-tired.
* Check the images very carefully at 100-percent screen size. Make a note of the number of sharp images at the various shutter speeds. You may rate the results as follows: Excellent, Good, and, Bad.

Here are the results of our test (done using a Nikon D200):

Out of
Shutter Speed
Rating
10 frames 1/350 sec 10 Excellent (Good show!)
10 frames 1/250 sec 7 Excellent; 3 Good
10 frames 1/125 sec 2 Excellent; 8 Good
10 frames

1/60 sec

2 Excellent; 8 Good
(similar to above but may
not always happen!)
10 frames
1/30 sec
1 Excellent; 2 Good; 7 Bad
10 frames 1/15 sec
0 Excellent; 3 Good; 7 Bad
10 frames
1/8 sec
0 Excellent; 0 Good; 10 Bad
10 frames
1/4 sec
0 Excellent; 0 Good; 10 Bad
10 frames
1/2 sec
0 Excellent; 0 Good; 10 Bad
10 frames
1 sec
0 Excellent; 0 Good; 10 Bad

Using fast shutter speed

Using slow shutter speed

You may repeat the test with lenses of other focal lengths. This will give you a general idea as to how low a shutter speed you can use for hand-held photography with various lenses. Remember, if you are tired, or not in good health, select the next higher shutter speed as your minimum.

It would be a good idea to conduct this test without using image stabilisation (even if your lens has it). I don’t mean to say that you should never use image stabilisation, but consider the stabiliser’s help as an added advantage instead of merely relying on it to save your skin.

Verdict
Since the Nikon D200 uses a APS-C size sensor, the effective focal length was 300mm. Going by the test, I would rule out shutter speeds lower than 1/250 sec. Remember, we gave our tester a lot of rest in between shots, but that may or may not be possible in real-life situations. If the image stabiliser was ‘on’, the number of acceptable shots may have increased. But I like to consider image stabilisation as an additional help rather than banking on it.

About Image Stabilisers
The lens manufacturer tells you how many stops of advantage you can get using the stabiliser. With zoom lenses, be aware that the quoted f-stop advantage is only true at the shorter end of the zoom. For example, if your 70-200mm zoom lens offers a 3-stop advantage, the 3-stop advantage is only at the 70mm end; at the 200mm end, where you require the most stabilisation, the advantage would be much less!

If you use a tripod and your lens has image stabilisation, please switch it off. If you are using a Monopod, the stabiliser may be kept ‘on’. Literature on some very recent image stabiliser lenses seem to say that the stabilisation could be kept ‘on’ (for example the VR II), but I am not absolutely sure that this is what the manufacturer meant, or if it is a misinterpretation from Japanese language to English. Till the time Canon or Nikon confirms or denies this, I would play safe and switch ‘off’ image stabilisation with all lenses whilst using a tripod.

Rohinton Mehta