What does stopping down the lens do?

“Stopping down a lens” refers to increasing the numerical f-stop value. This decreases the size or diameter of the aperture of a lens, which usually has the effect of sharpening detail resolution and increased depth of field (more on this later!).

Do lenses lose sharpness over time?

No, a lens will not lose sharpness with age. The optics, glass will not age, however the seals, coatings and glue may.

Why are lenses less sharp wide open?

Even though camera lenses use several elements chosen so that their aberrations cancel out as much as possible there is always a residue. As the aberrations get worse further from the centre line they make the lens softest at its widest aperture.

What aperture are lenses sharpest at?

The sharpest aperture of your lens, known as the sweet spot, is located two to three f/stops from the widest aperture. Therefore, the sharpest aperture on my 16-35mm f/4 is between f/8 and f/11. A faster lens, such as the 14-24mm f/2.8, has a sweet spot between f/5.6 and f/8.

What does stop down the aperture?

In photography, stopping down refers to increasing the numerical f-stop number (for example, going from f/2 to f/4), which decreases the size (diameter) of the aperture of a lens, resulting in reducing the amount of light entering the iris of a lens. Reducing the aperture size increases the depth of field of the image.

What is a fast shutter speed?

A fast shutter speed is typically whatever it takes to freeze action. If you are photographing birds, that may be 1/1000th second or faster. However, for general photography of slower-moving subjects, you might be able to take pictures at 1/200th second, 1/100th second, or even longer without introducing motion blur.

Do lenses degrade over time?

Yes. Other than rather obvious damage, the glass elements will remain the same forever. However: coatings can fade, particularly on the front element.

Do camera lenses get old?

Old film SLR lenses change a little when you put them on most digital SLRs. They actually zoom in a bit further, as digital SLRs only see the centre half of the picture. This is rarely a problem for long zoom lenses, as they will zoom even further on a digital SLR.

Is f4 good for portrait?

f4 would be OK depending on your subject to background distance (you might want to frame your subject relatively tight and make sure you have a good distance between your subject and background). 2.8 would be a bit better though for portrait work.

Do I need a wide aperture lens?

Typically, a wide maximum aperture lens: Enables faster shutter speeds able to stop subject and camera motion in lower light levels potentially at lower ISO settings for less blur and less noise. Enables shallower depth of field for stronger a background blur.

Why are my images not sharp?

If the subject in your image is blurry, but something closer to the camera or farther away is perfectly in focus and sharp, it is most likely a focus issue. If the whole image is blurry and nothing is sharp, it is generally due to using too long of a shutter speed handheld.