relation between aperture and photo sharpness

[AmNikonboy]

hai friends
whts relation between aperture and sharpness of photo?

i heard that high F number give u much sharper photo
is it true?

[Bjorn van Sinttruije]

To describe it shortly: aperture influences both sharpness (image quality) and depth of field (which some people mistake for sharpness). The first is typically best below f/16, although some lenses do better or worse at smaller apertures. The second increases as you close the aperture: at f/1.4, depth of field is thin, so you'll get a blurry background, and at f/22 depth of field is much deeper, so the background won't be as blurry.

- Bjorn

[usernametaken]

+1 to what Bjorn said.
In addition - some lenses are softer when used wide open (at their largest aperture), especially towards the edges/corners.

In addition as you close the aperture to get greater depth of field you start to encounter a phenomena called diffraction which results in reduced image quality http://www.luminous-landscape.com/tutor ... tion.shtml. At f/11 onwards this can become quite pronounced.

[AmNikonboy]

thanks for your reply

i have nikon d5100 and kit lens(18-55mm)

so i wanna know how to take best and sharp pics using this camera and lens especially during low light and in night?

am new to photography so kindly help

[Maestro]

I suspect the lens aperture isn't the issue. It would be helpful if you could post some pics with EXIF data, but without that, I would recommend you use a faster shutter speed and higher ISO.

Mark

[Bjorn van Sinttruije]

You have three basic options for low light photography:

- Open up the aperture, raise the ISO, and hold still.
- Use flash (I would never recommend that, but I have to be complete).
- Purchase a fast lens, such as a 35mm f/1.8 or 50mm f/1.4. These will allow you to use slightly lower ISO values compared to your kit lens. Additionally, they tend to perform much better in terms of image quality than kit lenses.

Option three would be my advice, but I don't know if you are ready to invest in a prime lens at this moment. They aren't expensive, and they'll be well worth their price if you take a lot of pictures in low light.

- Bjorn