ClioSport.net

Register a free account today to become a member!
Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members through your own private inbox!

Tutorial - Camera Filters



A while ago I wrote this basic tutorial on camera filters for another forum which Im not so active on now, I thought I'd post it up here as it may help someone! :cool:

This tutorial will cover two main types of filters: Circular Polarizers and Neutral Density (ND).

Before I begin, I will start by saying that these are luxury items, and are not necessary to take great photos. They are tools to help improve photos, or provide new ways to take photos (more on this later).

So first up: Circular Polarizers.

The main use for these, and forgive my unscientific answer, is to make photos prettier.
Circular polarizers:
- darken the sky
- improve the contrast between the sky and clouds (pics below)
- remove glare from water surfaces ie. sea and lakes etc.
- generally increase the saturation of all colours in the photo

Enough talk, lets see some pics:

filters.jpg

Photo 1: Photo taken under normal conditions with no filters.
Photo 2: Photo taken with circular polarizer (correctly set <-- more on this later)
Photo 3: Photo taken with circular polarizer and NDx8 filter <-- more on this later.

The visual differences between photos 1 and 2 are very obvious. The sky is a much darker and richer colour, and the contrast has been improved. Also, the very ligh clouds at the top of the frame are much more obvious in photo 2.
Photo 3 is slightly different from photo 2, the colour cast is different, and the sky has lost the rich blue colour. On the negative side, note how the clouds are slightly over exposed.

Unlike most filters, the circular polarizer can be adjusted by rotating it. So care must be taken to correctly set the polarizer before taking the photo. You will see as you rotate the polarizer as the sky becomes darker - that is when the polarizer is at maximum effect.

CorrectUncorrect.jpg

Left: Polarizer incorrectly set
Right: Polarizer correctly set.

Another BIG use for circular polarizers (CPLs) is in motorsport. If you want to seriously get into this type of photography, then a CPL is a MUST.......NO QUESTION!!

The biggest effect thats noticable is that it removes the glare from the windscreen, so you can see that driver, see these two pics:

DSC_3134.jpg

The glare is so bad that you can only just make out the driver's helmet.

EDC_1778copy.jpg

The CPL has completely removed the horrible glare, and now we can see the driver :)


Again, to create this effect, the CPL has to be correctly set. My tip is to find some other car/ambulance ;) to use, and then rotate the CPL until the glare has been removed.
NOTE: If you change position, remember to re-set the CPL.

TIP: To see if your CPL is working correctly, remove it from the camera, hold it up to a LCD/TFT monitor, look through it with your eyes and rotate it - see what happens :)


Well, that's CPLs covered. Now lets talk about Neutral density (ND)filters.

NDs are a lot more basic, they just attach onto the lens, and that's it, no adjustments to make. Basically, the job on an ND is to block light - that's it.

This may sound dull, but it can be VERY useful. Common applications of it are shooting waterfalls. Classic waterfall shots show a lot of movement:

DSC_6533.jpg

The classic style waterfall shot, the low shutter speed (3 seconds!) creates the smooth flowing effect.

To create this effect, you need a low(ish) shutter speed, and on a bright sunny day and at f/32 you may not be able to go low enough. So this is where an ND filter is essential. The ND blocks light, allowing you to use a much lower shutter speed.

Other very common applications are when using automotive rig shots. The cars are driving (usually pushed!) very slowly, so to create the sense of movement, a ND is needed to drop the shutter speed right down.

4019610609_24955a546a_o.jpg

Here, an ND helped me to use a shutter speed (4 secs) slow enough
to create the sense of movement needed. Without one, it would have been impossible.

NDs also have an effect on landscape photography:

NDs.jpg

The ND has darkened the sky, but the contrast is still
very similar. The clouds are a little darker, showing a little more detail.

NDs come in various ratings ie. x4, x8. The higher the number, the more light it blocks.


Well I hope that's helped some people, like I said before - these are luxury items, but they're worth every penny. They can be quite expensive depending on the size you require. I've found some bargains on eBay (reputable dealers!!!).
Any questions, feel free to ask. I'm sure ive forgot some things, but hopefully the pics say more than words ever could!
Dan
 

Ian

  Focus TDCi
Nice write-up Dan, very useful. I use a Hoya CPL and it does come in incredibly useful; yet to try it with automotive stuff though.

If anyone wants to try out ND filters, but can't really justify paying out for one, then have a look here. It's a welding shade, but acts exactly the same as a 10 stop (I think) ND filter. £2 posted - bargain. It gives a slight green cast, but this can be corrected with a custom white balance, or in post-processing. Obviously if you have the money I'd still go for a proper ND filter, but it's good to try things first. :)
 

Ian

  Focus TDCi
Love that ghetto solution Ian, going to acquire one from our Welders. Nice write up Dan.

They fit in one of the standard filter holders too, but I can't remember which. I've only tested mine once, but an elastic band either side around the camera works well:



Oh! And I accept no responsibility for any damage caused to your equipment lol. :)
 
  coiled 'berg
very informative, makes me wanna buy a camera and have a play! my old man has got a old (15yrs olds) pentax 35mm SLR with some lenses etc, would this be sufficient?? or do you need modern stuff
 

TheEvilGiraffe

South East - Essex
ClioSport Area Rep
Nice write up.. CPLs are fantastic and very worth while !!


I've been after some NDs for a while ..

[newbie mode]
does the camera detect a lack of light, i.e.: can i use aperture mode, and the camera sorts out the shutter, or do i have to do it all my self in manual mode ?
[/newbie]

Cheers :)
 

Ian

  Focus TDCi
Nice write up.. CPLs are fantastic and very worth while !!


I've been after some NDs for a while ..

[newbie mode]
does the camera detect a lack of light, i.e.: can i use aperture mode, and the camera sorts out the shutter, or do i have to do it all my self in manual mode ?
[/newbie]

Cheers :)

The ND filters do block light, the camera senses this and adjusts the shutter speed accordingly (in the case of AV priority). :) Depends what time of day it is, but there's a good chance you'll need to use bulb mode using an ND filter in the evenings.

Which shade did you get Ian, 10? It won't damage my equipment, I'm more likely to drop the welding shade & smash it!

Yeah I got the 10. That test shot was taken around 2pm and took 180 seconds.
 
but there's a good chance you'll need to use bulb mode using an ND filter in the evenings.

You probably wouldnt want to use a ND filter when it's dark though, as you could probably get the lower shutter speeds anyway. But every situation is different.

[newbie mode]
does the camera detect a lack of light, i.e.: can i use aperture mode, and the camera sorts out the shutter, or do i have to do it all my self in manual mode ?
[/newbie]

Cheers :)

As said above, the cameras meter will detect the change and automatically adjust settings for you :)
 

Ian

  Focus TDCi
You probably wouldnt want to use a ND filter when it's dark though, as you could probably get the lower shutter speeds anyway. But every situation is different.

Yeah definitely, combination of required shutter speed, time of day and ND strength I suppose. :)
 
  TTRS & V50
Interesting read.

I might sound a tit for this, but for the cheap skates out there, could adobe photoshop not be used to do exactly what ND's do ?
 

Ian

  Focus TDCi
No because the effect of ND filters is to allow for longer exposures, so you can get the waterfall effect and that kind of thing. I suppose you could use some sort of blur effect in PS, but it's a lot easier with an ND filter. However, if you're thinking of a graduated ND filter, then yeah to a certain extent you can imitate that in PS quite easily; I use it occasionally with my photos in Lightroom.

Edit:

In fact I applied a graduated filter in Lightroom to this photo. I'm personally one for trying to get as much right in camera as possible though. Alternatively I could have used a Circular Polariser to make the sky pop.
 
Last edited:
Interesting read.

I might sound a tit for this, but for the cheap skates out there, could adobe photoshop not be used to do exactly what ND's do ?

For ND filters, no. Because you are physically stopping light from entering the camera, that you can't replicate in PS.

You can get graduated ND filters in PS, which I use occasionally, and they do work pretty well.

There are filters which try to replicate polarising filters, but I havent seen a decent one which works like a proper filter.

Filters are all about controlling or manipulating the light as it enters the camera, so there's no real way of simulating it in PS unfortunately.

Thanks for the comments though, glad some people find it useful. I can't stress enough how important a polarising filter is for automotive photography though!
 
^ The grad ND filters work well for that sort of shot, as you can see in Ian's shot.

That's one example where you probably wouldnt need a physical filter.
 
I use a Nikon 12-24mm at the moment. That uses a 77mm filter, which ive just googled is the same as the Sigma.

I've got a NDx8 and a circ-pol.

I got them both from ebay japan, and I honestly cant remember what I paid, but I know it was significantly cheaper than the RRP in the UK!
Just make sure they have loads of good feedback and you'll be fine.

oh...and thanks for the sticky! :)
 
Nice guide, really useful stuff and unlike most books, actually readable! Most filters are a dark art to me, but if anyone wants to explore further, one book that is very good is this Lee Frost effort, very clear with lots of examples and more filters than I knew existed.

Another BIG use for circular polarizers (CPLs) is in motorsport. If you want to seriously get into this type of photography, then a CPL is a MUST.......NO QUESTION!!

At the very top end, then yep probably, but for 99.9% of us I would put this pretty far down the list when it comes to motorsport togging. For those that spend all day in the same spot shooting the same angle then fair enough, but if you're moving around it's a lot to think about as the results look pretty messy if it's not spot on. Thankfully, the nice circular airfield nature of most UK circuits means you can move around during the day to shoot on good terms with the sun if it's imperative to see the drivers, Combe in the afternoon, for example, is fine if you're over on the Old Paddock side of the circuit.

I've met a lot of fellow Sigma 120-300 shooters, but not yet one who has felt the need to supplement his £3k lens with a £200+ CPL :)

I'm guessing you have some ND/pol filters for your Sigma 10-20mm? How much were they? Links?

Worth noting that nature joins the fight when you start mixing CPLs and UWAs, as demonstrated by my lack of skills here...



At 10mm you will pretty much never get even coverage if you happen to be shooting sky, 15-20mm is fine as long as you get the correct angles.
 
^That should be fine, although it might be a bit dodgy regarding the quality. You'd expect to pay probably double that for just one Hoya filter.

But for experimenting and starting out it should be ok.
 
  Motorbikes
^That should be fine, although it might be a bit dodgy regarding the quality. You'd expect to pay probably double that for just one Hoya filter.

But for experimenting and starting out it should be ok.

Cool thanks, not much point having "all the gear but no idea".

Are graduated filters more suited to landscape then?
 
I actually feel so embarrassed... I've had a CPL for ages and always been skeptical about the results it provides, some days helping me reduce glare, some days not. I never knew you had to set it :eek: Thanks Dan :)
 

Ian

  Focus TDCi
steven.m said:
Cool thanks, not much point having "all the gear but no idea".

Are graduated filters more suited to landscape then?

Yeah they're for when part of what you're photographing is a lot brighter than another part (eg. sky and land). Worth noting you can stack any combination of filters to achieve longer exposures / different colours / reduce dynamic range.

I crudely used a colour graduated ND for my photos in the Anglesey seascapes thread. They came out alright for a first attempt, but I'd really like to try again. :)
 

Aaron..

ClioSport Club Member
I feel a bit of an idiot now though, i didn't realise you had to set the
P.L filter :eek:. I guess i must have just been lucky the few time's i used it as they came out ok.

As for the N.D filter, that is next on my list so i can start doing more long expo photography having just purchased a remote trigger and new (cheap but it'll do the job) tripod.

I forgot how expensive this hobby can be!
 
Very true. I just bought a new lens yesterday and have been digging around trying to find filters today for it. 77mm filters get pricey, and there is no point in scrimping on the filter when the lens is $$$$!
 
  Camel
Have just started to get into this and read the above so just bought a Sigma UV filter and a Hama Pol Circular filter to play around with so wish me luck :eek:) wasnt sure what to buy so just go these to to start with.
 
  "Navy" N17 TWO
Lots of great info there Dan :) very useful indeed

Anyone use the Cokin P series filters on here?
 
Anyone use the Cokin P series filters on here?

I bought a whole load last week and it arrived today, wide and normal holder, 62, 67 and 77mm adaptors, circular polarizer and ND2, 4 and 8 grads. Happy to note that the wide holder works fine with my Nikon 12-24, some people report vignetting but I'm not getting any at all thankfully.

Not had a proper play with it yet, but it all seems straightforward enough to use so I'm looking forward to giving it a hammering in the next few weeks.

A quick sample straight out of the camera (both shot manually with the same settings)...

No filter


ND8 Grad



Instant results without the need to mess around in Photoshop = me a happy boy.
 
^ Nice results. I take it you are using hard edge grad filters?

I've got these (the house shot above was taking with the ND8 Grad)...

P121L Gradual Grey G2 Light (NDx2)
P121M Gradual Grey G2 Medium (NDx4)
P121S Gradual Grey G2 Soft (NDx8)

I wasn't sure what to go with to be honest, but I figured soft would be better as I'm not near the coast so rarely shoot clearly defined horizon shots. Any suggestions for commonly used ones? I've got an ND8 on the way but that was the only other one I was going to get for now.
 
  2.2 bar shed.
Dan have you got a Lee/Cokin filter setup or are you rocking screw ins? Im looking at getting the Digital entry kit and a 10 stop hitech.
 
Samp,
I've actually got eh digital starter kit from Lee, and I've added a few filters myself. That kit and the hitech should be a good combo.
 
  "Navy" N17 TWO
Does the starter kit get you going, ie all you need is different size adapter rings for your lenses after that? :)
 


Top