Hi all,
Hoping for some guidance on the use of lens filters. A lot of people recommend keeping a skylight filter on the lens to protect it etc, but what exactly does a skylight filter do?
A filter I have used in the past was a circular polarising filter. However I was not that happy with it on occasions as it took the blue sky way over the top, or perhaps I should of made an allowance for the P/L lens. Don’t know…. I am sure someone will point me in the right direction.
There may even be filters out there I would have never considered using for aviation or indeed general picture taking.
Any information and guidance on filters would be much apreciated.
Chemical Dave :confused:
By: Chemical_Dave - 23rd July 2008 at 17:33
Thanks very much for the information, very informative.
By: old shape - 23rd July 2008 at 02:13
The popular filters are a Skylight or a UV. They both improve the colour tone of skies and the UV absorbs the UV without any loss of “Exposure light”. Skylights also remove UV but some say it loses about a 1/4 stop of light.
Both claim to remove haze in landscape/seascape shots.
As you say, a lot of people use these just as a protector for the lens.
Polarisers do what they say on the tin, overuse will result in unfeasibly blue sky and sea, and outrageous greens. They take away two stops. Neutral Density filters just block out light in various stops. These are used to slow the shutter speed down on bright days, to capture a blurred waterfall for example. I used to stack a few ND plus a Polariser in my Cokin system, to remove 5 or 6 stops. At F22 I was exposing something like 30 seconds in daylight, which during the build up to a Thunderstorm gave me swirled trees, lightning in the background but solid buildings. Timing my 30 seconds to coincide with a lightning was the key. Mostly failed. I also used a black card which I held against the lens front and removed it for a few seconds at a time – hoping to get the lightning. This still kept my 30 secs exposure but the elapsed time of the “shot” was maybe 5 mins.
All other filters are gimmicks, grads, starbursts, blurry, blurry with colour, foggy etc. etc. All of this can be done in Photoshop. Polarising can be done in photoshop for the dark sky and sea, but on the telly you can’t remove the reflections from water / leaves like a polariser does. (Well you can but it would take hours n hours in PS).
In the days of film, it was always argued that putting a piece of cheap glass in front of a very expensive lens is an insult to the lens and reduces the quality of the image. If you want to protect the lens, then fit a large rubber hood on the end. So, expensive filters (And I’m talking £70 for a UV or skylight to fit a 52mm thread!) removed the quality issue.
Now in digital, that quality issue is still around but there is another problem. The CCD is reflective and there is potential for a Ghost image to appear. This would happen on a £7 or £70 filter.
And, the more expensive your lens, the likelihood is that the front element will be massive because the lens will be “Faster”. This means very large filters, which means very empty pockets!
Personally, I use the rubber hoods and tend to take more care with the lens. I am however often taking pictures in the rain or sea spray, and need to keep that lot off the front element coating and indeed the camera. I’ve experimented with cling film, but it takes perhaps 10 attempts to get a wrinkle free one! And, you can’t wipe it or it distorts. It’s a replace in-situ jobbie, not practical.
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July 19, 2008 at 6:12 pm