Special Effect Filters: Star, Fog, Centre-Spot & DFN

Today we continue our investigation into photography filters, following on from our previous look at a selection of special effect filters. We’ll be introducing you to the second batch of wacky and wonderful filters today – star, fog and center spot to name a few! Join us after the break to spice up your photography.


Star Filters

Star filters are simply designed to produce stars on your images. A series of thin lines are etched into the flat optical surface of a clear filter. These lines diffract the light coming into the lens into long thin lines. If the lines are positioned horizontally then you will get vertically oriented star lines. The line spacing also matters; the closer the gaps the brighter and more intense the stars will be.

In order to get a really sharp star, you have to use the lowest aperture you can – you might find a 50mm prime lens is the best to use. Only the strongest light can produce star shapes, for example the image below only has one star due to the sun being the strongest light source.

Now like most filters, star filters come in many different shapes and sizes. You can also purchase filters designed to produce 2, 4 and 8 stars.

The effect can be recreated inside of Photoshop but if you want a quick and easy way to create stars then simply purchase a filter!

Recommendations:

Tiffen appears to have the best range with many more filters producing different styles of stars.

Image courtesy of jonnyfixedgear


Fog Filters

When shooting real fog you will notice that the fog blurs the light source(s) in your image. The fog filter attempts to recreate that same effect. A fog filter will add a soft glow/flare to the image as well as lowering the contrast and the sharpness of the image. One good use of fog filter would be when you are attempting to show the user how humid any area is.

The disadvantages are that fog filters cannot recreate the effects of strong fog because the image becomes too fuzzy. Instead you would need to buy a double fog filter, which have a milder flare and softening characteristics that the standard fog filter doesn’t produce.

Recommendations:

Image courtesy of Lowell_Mariannika


Center Spot Filters

The idea of a center spot filter is that the center of the image will stay nice and sharp while the rest of the image is diffused and the detail in the background is blurred. This effect is created by the center of the filter containing either a hole or simply a piece of clear glass.

In my opinion, they are a really poor type of filter to use. You would be better off spending more money and purchasing a lens with a really high aperture such as a 50mm F1.4 in order to shoot images with a shallow DOF. Although don’t be put off by my opinion! Try one yourself at a local camera store and see for yourself!

If you own Photoshop, Alien Skin sell a nice plugin designed to create the same effect for about the same price as the filter. For more information have alook at their website.

Image courtesy of lone photowolf


Day For Night Filters (DFN)

Want to shoot at night but would rather shoot in the day? Then a day for night filter is for you. Hollywood blockbusters use to use them all the time before CGI improved to today’s standard. There are many tips to try and get a fake looking twilight effect using a SLR camera, mostly involving tricking the white balance into thinking white is orange, which will give you a tinted blue coloured image.

The filter is designed to underexpose the shot by about two stops but also at the same time create a slightly blue overcast. Post production is still often needed (adding lights for example) but it is a useful filter for those planning to fake lots of shots. Disadvantages of the filter include the fact light sources don’t appear as natural as in twilight as their colour is effected.

Currently the only brand I could find producing DFN filters was Tiffin. Other brands only offered ND filters which would reduce the stops but would not tint the image at the same time.


Enhancing Filters

Enhancing filters, also known as Intensifying and Didymium filters, are designed to increase the intensity and saturation of red objects. They are all designed to provide better colour saturation and contrast on the red, brown and orange colours without effecting the cooler range of colours. They are perfect for use when shooting landscapes containing natural objects such as trees and bushes, perfect for use in the autumn with dead trees etc.

Do you need one? If you live in an almost season-less location such as California, I wouldn’t bother. Personally I shoot RAW and edit the colours afterwards – its easier and cheaper. If you shoot JPEG then you will be glad to know that Photoshop contains a handy warming (and cooling) filter built into the program.

Recommendations:

Image courtesy of Szeke


Conclusion

If you have followed the series so far you will have seen us cover a huge range of filters including ND, UV, Polarizers and more. I hope you have enjoyed learning about them and I hope they help you improve your photography.

You also might want to think about purchasing a filter wrench! These help get those filters off your lenses which you have put on too tightly!

Thanks for reading, and let us know if you have any other suggestions in the comments!

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