Neutral Density (ND) Filters

Neutral density filters reduce the light entering your camera without introducing color biases. When the effect is meant to be uniform across the camera's field of view, round NDs are perfectly adequate.

In bright ambient light, an ND will allow any camera to reach

• a slower shutter speed to enhance motion blurring, or
• a larger aperture to enhance subject-background separation or image detail.

On the digital side, you may be able to accomplish the same thing by selecting a lower ISO setting, with the added bonus of reduced image noise. But when you can't lower ISO enough, an ND (or stack of NDs) can get you where you need to go.

NDs address two practical limitations stemming directly from the small physical CCD sizes typical of consumer-grade cameras—excessive depth of field and diffraction-limited resolving power at smaller apertures. Thanks to the latter, digital cameras seldom offer apertures smaller than f/8. Under bright conditions, that aperture floor can be a real hindrance, but ND filters can fill the gap.

Slowing Down
Forcing a slower shutter speed at a given aperture and ISO enhances motion blurring when that's the goal—say, when photographing flowing water in bright sunlight. Suppose your smallest available aperture is f/8 and your slowest ISO is 100, as is commonly the case on the digital side. At ISO 100, the bright scene will probably require an exposure of ~1/400 sec @ f/8 by the sunny f/16 rule, but you'll need to slow down to 1/25 sec to get the desired blurring. Stacking a 3-stop (0.9) and a 1-stop (0.3) ND filter will nicely bridge that 4-stop gap in shutter speed.

Opening Up
Selective focus enhances subject-background separation by blurring the background to draw the eye to your well-focused subject. By forcing a wider aperture (smaller f-number) than would otherwise obtain at a given shutter speed and ISO setting, an ND filter promotes background blurring by reducing depth of field, which can sometimes get too deep on the digital side, especially in portrait work.

ND filters also allow you to stay near your camera's resolving power sweet spot (often f/5.6 or wider) in bright ambient light.

UV Filter

UV, skylight and haze filters all block ultraviolet (UV) light to varying degrees. UV filter nomenclature is a bit confusing. The term "UV filter" by itself usually refers to a neutral (untinted) filter blocking the shorter wavelength UV-B (320-280 nm) and UV-C (10-280 nm) bands while letting a good bit of the UV-A (320-400 nm) through. Haze and skylight filters are UV variants that often carry a tint. Haze filters block more UV-A than regular UV filters but also take a bite out of visible blue. Skylight filters also cut some blue but are no more effective in the pesky UV-A band than regular UV filters.

The optical role for UV filters in digital photography relates to an artifact known as "purple fringing". Purple fringing is most commonly seen in digital images but also occurs in film images. It typically appears as a multipixel band of bright purple surrounding the peripheral edges of dark objects cast against a bright background. Central edges are spared. Backlit leaves set against a bright sky are a common purple fringing scenario.

Besides, you can use this filter full time in order to protect the front element of your lens from scratches and dust.

Optical Filter Benefits

With sophisticated image editing tools like PhotoShop readily available, why bother with optical filters? Given enough time, talent and patience, you probably could emulate most filter effects in post-processing. Post-processing is no substitute for the filter types listed below — at least when they're properly applied.

Polarizers	Among other things, polarizers can easily save you from fatal white-outs due to bright reflections — not just off water, glass and car paint, but also off foliage. (Foliage reflections are a serious but commonly overlooked problem in landscape work.) The hard fact is, there's not good post-processing cure for white-outs, especially those complicated by CCD blooming. Polarizers can help you control excess contrast in other ways as well. They also improve color saturation in ways hard to reproduce at post-processing.
Neutral density (ND) filters	ND filters allow you to achieve slower shutter speeds or wider apertures than would otherwise be possible in a given scene. (Note that polarizers make decent 1-2 stop ND filters in the absence of polarized light.)
Graduated ND (GND) filters	GNDs allow you to reduce excess contrast in scenes that would otherwise be impossible to capture in a single shot. Yes, there are effective post-processing techniques for excess contrast control, but they're not without their challenges, and most require multiple perfectly registered exposures — which means a tripod and remote triggering.
IR pass and UV pass filters	Even if you could simulate the surreal luminance relationships found in the near IR (NIR) in post-processing — you'd never be able to fake the phenomenal atmospheric clarity found at NIR wavelengths. Nor would many be able to fake the odd world waiting to be discovered at UV-A wavelengths.
UV cut filters	In theory, UV filters add clarity by cutting UV scatter in high UV environments — e.g., at extremely high altitude (well over 10,000') or in long shots over water, but most digital cameras are too UV-insensitive to benefit here. Post-processing can suppress or sharpen a hazy blue channel to good effect, particularly in B&W work, but an effective UV filter (most likely a haze filter) might allow you to improve clarity while preserving blue channel data in your color images.

Digital Camera - MegaPixels vs Printable Size

"I'm buying a digital camera - how many megapixels do I need?"
The number of pixels you need depends on the use you are making of your pictures. The chart below shows the recommended size an image should be printed according to the resolution of the camera.

Megapixels	Pixels Resolution	Print Size @ 300 ppi	Print Size @ 400 ppi
3.0	2000 x 1500	6.67" x 5.00"	5.00" x 3.75"
4.0	2309 x 1732	7.70" x 5.77"	5.77" x 4.33"
5.0	2582 x 1936	8.61" x 6.45"	6.45" x 4.84"
6.0	2828 x 2121	9.43" x 7.07"	7.07" x 5.30"
7.0	3055 x 2291	10.18" x 7.64"	7.64" x 5.73"
8.0	3266 x 2449	10.89" x 8.16"	8.16" x 6.12"
9.0	3464 x 2598	11.55" x 8.66"	8.66" x 6.50"
10.0	3651 x 2739	12.17" x 9.13"	9.13" x 6.85"

Note: 300 ppi (pixels per inch) becomes roughly 150 dpi (dots per inch). 300 ppi is the accepted standard for printing photographic quality images, but 400 ppi is highly recommended.

Edinburgh Fireworks Concert 2007

The Bank of Scotland Fireworks Concert was at 9pm on Sunday 2nd September 2007. It is recognised as one of the world's greatest fireworks concerts, performed by the Scottish Chamber Orchestra against the stunning backdrop of Edinburgh Castle and forms the climactic finale of the Edinburgh International Festival. There are 5 parts altogether. Enjoy!!!