What filters should I purchase

[Kenny A]

I have just purchased a new Sigma 10-20mm (77mm) & Sigma 18-200mm (72mm) len.

Due to the size of these lens over the standard Nikor kit lens, I'm up for some new filters. So what should I buy and how much do I need to spend.

My main use is out doors..landscape, People, buildings, action sports. I live on the Sunshine Coast in Qld so their is a bit of beach work.

Your thoughts please.

[ricktas]

Landscapes:

Polariser
Neutral Density (ND) filter set 2/4/8 stops
Neutral Density Graduated (ND Grad) filter set 2/4/8 stops

[milesy]

on this - can you explain what the difference is between a ND and ND grad (im guessing it sounds self explanitory but please do anyway) and are there any decent cheaper kits with 2/4/8 stops (my largest lens is 77mm) ..........and (lol on a roll here) what are the variable ND's - these are bloody expensive? - sorry to Kenny to hijack your thread but this topic interests me also

[Kenny A]

milesy..no problem..I was surprised to see reference to the ND filters also. I did see a utube video where the photographer was shooting in a stream and he used a graduated ND filter to change the effect between the stream on the landscape and the light on the up half of the shot. It kinda makes sense. What's wrong with the good old fashion UV that the camera shops alway seem to recommend..?

Thanks Ricktas for the reply, but a bit more tech info on why you recommend ND would be great.

Cheers

[ricktas]

OK.

Polarisers have many uses, the most obvious one is that when you turn then (they have to be rotated to get the effect) they increase saturation, most notably the blues, thus making skies look a nice rich deep blue colour. They also increase contrast, and make the clouds etc stand out more. Polarisers can be annoying to master, there are a few things to watch out for. One you need too turn the polariser to increase decrease the effect (visible through the viewfinder), and if you do not get it right, it can mean one side of your photo has a different blue to the other side. Also polariser are a solar filter, in that they work in relation to the sun. So the effect is different if the Sun is behind you, over your left shoulder, or in front of you. The best angle to the sun for a polarising effect to be seen is about 90 degrees, so when taking shots if the sun is off either of your shoulders, you can be assured you will get the best polarising effect. Polarisers also have another effect. Just like polarised sunglasses reduce glare on water, reflections etc, so does a camera polarising filter, great for getting rid of reflections on shiny cars, or taking photos of fish in a pond, where the sun is reflecting the surrounds on the waters surface.

ND filters are a Neutral Grey, they are just a dark piece of plastic, the 2/4/8 is the basically how dark they are. The purpose of an ND filter is to darken the scene. For example, you want to shoot a waterfall and get the milky water effect, but the day is bright and every time you take a shot with a slower shutter speed, the photo is over-exposes. Placing an ND filter over you lens, effectively cuts out a heap of light, making the scene through the viewfinder darker. So then it allows you to shoot at a slower shutter speed, without over-exposing the scene. There is also a thing called a 10 stopper, its basically a 'blackout' filter, it can hardly be seen through with the naked eye (it is like welding glass), this lets you take long exposure shots even on the brightest day.

ND Grad filters are like ND Filters except the grey part is only partial. One end of the filter is grey and it slowly turns to clear at the other end. These have a fairly specific purpose (though experimenting can be fun). You go out to take a sunrise or sunset shot, but the sky is much brighter than the foreground, so you are left with a lovely vibrant sky with great clouds, colour and interest, but the foreground is dark. So you change your settings to capture more detail in the foreground, but this over-exposes the sky and you colours and clouds are no more. Use an NDGrad filter. Place the darkened part at the top so that it decreases the light coming into the lens at the top of the scene, and the clear bottom part stays over the foreground. This balances out the light levels in your scene and voila you get the great sunset, and the foreground all visible and exposed well.

The reason they come in different strengths is because sometimes you only need a slight darkening (2) or othertimes the difference in light levels is dramatic and an (8) is needed. You can also stack them by putting both a 2 and 4 stop ND filter on, you get 6 stops.

As to which brand, there are several. Cokin make a few different systems, all with different price points. My Suggestion is that you save up and buy decent now, to save money in the long term. I use the Cokin Z-Pro system, its a 100mm filter system, and Lee (probably the best filter maker) also uses 100mm filters, so you get to pick and choose your filter selection. The Lee holder is expensive, the Cokin less so.

Cokin make a starter kit, which is the holder and a set of filters, I got the ND Grad starter kit, and then added to my collection with other filters. But research this first, a polariser for a 100mm system is several hundred $.

The Cokin P system is good, is a smaller sized filter system, BUT, if you are a landscaper and like to use wide angle lenses, the filter system can often impinge on your photos. I use a 10-20mm on my Nikon D200, but with a P system filter holder on, I could not go lower than 14 mm's otherwise the edges of my shot were black, as the filter holder became visible in the shot. Also if you use it on larger diameter lenses, you may notice this as well.

Lee filters are brilliant, and are often more expensive than the Cokin ones.

There is also an issue with some Cokin filters, which is much reported on the net of a Magenta colour cast when stacking filters (putting more than one on). A couple of years ago it was being reported on AP with several threads. One thing was noted, Canon users experienced the issue more than Nikon, and it did not happen all the time, even using the same filters on the same camera, did not result in a magenta cast every time. A bit of research by AP members came to the conclusion that the Cokin Magenta Colour Cast issue is a white balance issue in the camera, that under certain lighting conditions, became apparent. Under certain conditions, using Auto White Balance, the camera reported a false white balance result and tinged the resultant photo(s) with a magenta cast. If you shoot RAW, it was correctable in your editing software. We never had our conclusion verified, but it became the consensus amongst those with the issue, that it was an issue with how cameras determined white balance that caused the magenta cast at times with stacked Cokin filters. I have had it happen only once, in my entire time of shooting digital, others had it happen a lot. Which made us believe the quality of light and direction of the sun at certain locations increased the likelihood of the camera reporting a false white balance and giving the resultant photo a Magenta cast, when Cokin filters were stacked.

I would not use the Magenta cast as a reason to not use Cokin filters, a google search will find a heap of naive comments about how bad Cokin are cause of it etc, when it has not been investigated to what the base cause is, which we believed we did a couple of years ago, here on AP. Cokin filters are great, and value for money, compared to the Lee filters (which are also brilliant filters).

You can buy screw on filters, Polarisers are fine as screw on's, The is a Vari-ND screw on available, which also works well, but do not buy screw on Grad filters. These have the change from the dark grey to the clear in the very centre of the filter, so if you wanted to compose a shot with 2/3rd foreground and 1/3 sky, you are left with the screw on ND Grad darkening part of your foreground cause it cannot be adjusted as to where the grey finishes and the clear starts. The square slide in Grad filters, and filter holder systems, allow you to slide the filter up and down till you get the graduation from grey to clear, where you want it.

Hope this all helps (rather than further confuses you) about the role of filters. Investing in a good set of filters and looking after them, they can last a lifetime, and if you are into photography, particularly landscapes, then they will help your photography get to the next level.

Most filters can be emulated in editing software these days, but the Polariser is the one that no-one has produced a really successful digital version of. If you want to try to see how ND and NDGrad filters work and have photoshop, download a trial copy of Nik Software's Color Efex filter set, install it and give the ND and ND grad digital filters a go, if nothing else it will show you how the effect of ND and ND grad filters works.

[milesy]

great explanation there thanks Rick

so is this the type of Cokin adapter your talking about

http://www.ebay.com.au/itm/77mm-ring...item2a15801085

it surprises me that these seem particularly cheap, not quite what i expected after having been looking at Polorizors which vary in price siginificantly but seem to go up to around $300 when looking at the B&W ones

[ricktas]

great explanation there thanks Rick

so is this the type of Cokin adapter your talking about

http://www.ebay.com.au/itm/77mm-ring...item2a15801085

it surprises me that these seem particularly cheap, not quite what i expected after having been looking at Polorizors which vary in price siginificantly but seem to go up to around $300 when looking at the B&W ones

Yep, that link is to to what looks like a generic version of the P system. Note that it doesn't say it is Cokin as such

Brand New 77mm ring adapter + holder +filter case +ND2/ND4/ND8/+Graduated Color Filter (Orange, Blue, Gray)for Cokin P series

So it could be fine, but it could also be a cheap ripoff and fall apart after a few uses. It is often (not always) the case that these cheap generic filters are not 'neutral' and will leave your photos with a distinct colour cast.

[nhoj]

Great explanation Rictas.

Milesy. I have 10 - 20 lens and use Cokin P series. Even with the wide angle adaptor I still cannot get full frame at 10mm. Also with the wide angle adaptor you can only use one filter at a time. If you are starting out with filters I would suggest the Z-Pro system if you can afford.

[milesy]

thanks nhoj

i note that the P system is recommended for focal lengths of 28mm and above where as the Z system is for 20mm and above (both based on 35mm format) so for really wide angle the X system is recommended....

the Z kit (with holder + ND2/4/8 is about $150 USD where as the P system for the same thing seem to be around the $50 USD mark - i cant even find the X kit but the individual filters seem to be around $110 USD so the kit i would imagine would be $300+

Z-pro seems a reasonable choice i think

[ricktas]

I use the z-pro on my D3 - FF sensor, and at 17mm (equiv to about 12mm on a cropped sensor camera) I cannot see the edge of the filter holder etc.

[Kenny A]

Gee....what a reply.
thanks Rick..very helpful info.
I do like the filter kits so i'll do a bit investigation on pricing.

Cheers