Tech Tuesday – Sharpness and Mega pixels……….

You can’t trust me, I’m just as likely to do this on Tuesday as Friday….. A little explanation, I have an early call for the show in San Antonio tomorrow and then it’s straight to the airport to fly back to Knoxville and then the drive home. I wanted to get this filed before all the mad dashing starts.
Imaging USA is the show I’m working for Nikon and a large number of people have been asking about resolution and sharpness at the booth and I thought maybe this might be something everyone wonders about. The image above is, I think, a good example of a crisp, sharp image. So how do we get sharpness? Let’s examine some factors that contribute to sharpness.

Camera movement: Sharpness is impossible if the camera moves enough to smear the image, simple as that. The answer is to keep the camera completely still during the exposure. The only way to absolutely guarantee that, is affixing the camera to something solid. 99% of the time that would be a tripod. If a tripod is solid (prone not to transfer vibrations, { wood and carbon fiber are the best material for tripod construction }, and is set up in a very stable way and is not influenced by any vibrations from within the environment in which it is placed. Further at the very moment of exposure a cable release (preferably) an electronic one must be fires so as not introduce any shake during the firing of the camera. Environmental circumstances like wind can also introduce unwanted movement. To make things even more complicated the longer the focal length of the lens, the narrower the angle of view and the more movement affects the final image.
For instance if you are shooting with a 24mm lens and there is the slightest of movement during exposure is will only be 1/12 as damaging as the same movement with a 300mm lens! 300 divided by 24 equals 12.5. Vibration Reduction or Image Stabilization may help a great deal, but will not replace the value and effectiveness of a tripod.

Speed of the Shutter: If the shutter takes 1/2 second to open and close, softness due to camera movement is 10 times more likely than a shutter speed of 1/2000th of a second. So it seems apparent that all things being equal, the faster the shutter speed the better your chances of avoiding unsharpness due to movement.

Quality of the lens: The sharper the lens, the higher the detail, the more detail the more apparent sharpness. That’s why extremely high quality lenses matter. I’ve always advised “serious” photographers that it is better to own three exceptional lenses than ten that are so-so. Fact that hurts, quality costs, if it’s too cheap to believe, don’t believe it. Pro lenses are designed for Pros, they are made better, designed more carefully, and are tack sharp out of the box, and more importantly, are much more likely to stay that way after years of hard use. ED elements, and Aspheric elements are not cheap, but they are often necessary to make lenses perform the way you expect them too. Coatings matter too, and usually only the best Pro grade lenses will get such high tech coatings such as Nikon’s Nano coatings.

Direction of the light: Light that strikes the subject from the side will create shadows that reveal texture and enhance the appearance of sharpness.

The resolution of the camera: If everything else is equal, a 24 mega pixel 35mm size sensor camera will make images that look sharper than a 12 mega pixel 35mm size sensor camera. However 16 mega pixels on a DX size sensor (smaller sensor) may have more apparent sharpness than even the 24 mega pixels camera, this is called “pixel resolution”, how tightly the pixels are packed on the sensor.

Technique: Good technique is all the things we have discussed above. If you have a high resolution camera, outfitted with a superb, clean, lens, mounted on a solid tripod, properly set up, and fired by a vibrationless electronic release in calm air on ground that is rock solid. Further if the lens is properly focused on the exact part of the subject you desire to be sharp in the final image,
the image should be sharp, unless the subject moves at the moment of exposure fast enough to cause blur.

Have said all of that, it seems a miracle if we ever get a sharp image! However, the more we pay attention to those things above the better the chances that we can consistently make sharp images.
The image at the top? Sit down. Shot hand held, with a Nikon D70 (6 mega pixel) camera. Hey even a blind hog finds an acorn every once in a while. Below I’ve offered some evidence that the above suggestions work.

Enjoy and God bless,

the pilgrim

Good technique, sharp lenses, a solid tripod = sharpness. It’s worth it………..

God bless,

the pilgrim