Filters

If you intend doing any Landscape Photography then a polariser is essential, mine is pretty much permanently fixed to my lens.

ND grads are also very useful in "contrasty" lighting to balance foreground/subject.

I think these 2 are the only filters that can't fully be replicated in PP.

As for lens protection I often use a UV when my polariser is not attached, this is mainly because I do lots of coastal photography & sea salt isn't the best thing to be having on the lens coating !!

Simon

The two common filters that can't be replaced by software are the polariser and the UV/skylight filters. (I'm talking about colour, not monochrome.)

These provide the sensor with more information, whilst other filters tend simply to change the colour balance or add those "special effects" so beloved by wedding photographers and others of like mind.

One other filter that does have a use is a non-graduated ND that can be used to allow the use of a slow shutter speed in strong light.

G

Yes I intend to use it for landscape.


Which lens are you using and could you post a link for the Polariser you are using .

I read on Cokin's homepage that the normal filter holder only allow down to 20mm focal length. I have seen they have a slimmer holder (1 filter only) for wide angle. Is this the one you are using - or is it a screw-in type?

Btw - which ND grad do you recommend?

I use the standard Cokin P-holder & haven't had any problems on my Sigma 17-70. I believe the thinner holder may well be required if using something wider (10-20 , 12-24 etc)

I have a Cokin ND4 & ND8

Simon

One thing to remember is that the Pentax sensors are significantly smaller than the 35mm frame. When Cokin says that 20mm is the widest lens you can use, they are (probably) talking about film. You should be able to use a wider lens on digital without vignetting.

I use a 49mm step-down ring on my 100mm macro lens which takes a 58mm filter, and there is no problem.

G

An ND grad effect can be easily replicated, not by using HDR software, but simply by using 2 exposures, one for the sky and one for the land (assuming a landscape photo), or even just one raw file as long as the highlights aren't blown, just process one for a darker sky and one for the correct foreground.

Open one file in photoshop, paste the other on as another layer (let's say this is the darker sky on this layer), then crop off the bottom section of the top layer, using a feathered edge selection. You don't have to do any fancy selection work, an ND grad has a straight edge, so this selection can be straight too. The example below is just one raw file, top image exposed for the foreground, second one shows the same with the top layer visible, after cropping down.







Granted, if there's plenty of movement in the scene, and you have to take two exposures to get the full range of tones, then you can run into problems, but for many shots this is as good as, or better (more control) than an ND grad.

Dan

Utilising software to replicate an ND grad filter is useful but has limitations.

If the scene you're shooting is high contrast then there is a good chance part of the detail will be beyond the Dynamic Range of the camera & that detail is lost. Using an ND grad in these situations ensures that ALL the detail in the scene is captured.

Also even when shooting Raw, recovering shadow detail in high contast scenes can generate unsightly shadow noise which, whilst removable using Noise reduction software again destroys some of the original detail.

My own personal preference is to make the most of the scene "in-camera" and then use PP to enhance this where required. Also I'm much happier taking photographs than I am spending time on Photoshop

Simon

Good point.

G

Which is why I said you may well need to take two photos at different exposures. This can often be quicker than getting the correct filter on the lens, getting the position of the filter just right etc. Might be the difference bewteen a shot got and a shot missed.

This is true!

The thing I dislike about ND grads is if you have a tree that projects above the skyline, and you end up with the top of the tree being much darker than the bottom. Similar things happen with mountain tops. The Old Man of Storr springs to mind too. Filters are best (IMHO) when you can't tell that they've been used.

Oh, and never, ever, ever have a sky darker than it's reflection!

Dan

Apologies, missed the bit about 2 exposures - thought you meant from the 1 RAW file.

I know what you mean about light/dark transition with the ND Grad, not always easy to disguise.

To be honest I do try to avoid using the ND Grads if possible & try to catch the light "just right". Obviously I'm not always so lucky & the filter can make the difference between getting a decent shot or not - they take a little getting used to though

Simon

I guess that means you could use the "normal" holder from 13 mm then...13*1.5 = almost 20mm.

And slight vignetting from 10-13mm.


Thanks Daniel for the tip!

Much appreciate the guidance Simon.

Actually reading my one back it looks like I mean 2 jpegs or one raw file. Sometimes you can get away with just the one raw file, but as I always shoot raw, I did mean 2 raw files.

I use a grad so rarely that it suits me more just to do the 2 exposure thing, but it's obviously better for you and your workflow to use the filters.

Dan

I got a lot of information from photographic magazines such as AP and Digital Camera and some of the associated sites also have information on filters.

There is only one filter that cannot be replicated on the computer and that is the polariser (you need a circular polar). I also have a graduated ND filter as using High Dynamic range photography, though great, takes time.

As long as you shoot in RAW, you only need a polariser (I use Cokin P-Series) and a dedicated filter (I use a UV filter) on each separate lense.

David

trick is to use all both methods.....where they work best.
2 (or more) shot method for stationary subjects....
Multiple exposures for motion blur effects....
Nd grads for moving subjects that need to be sharp...(is people shots, wildlife shots (on a trail or in a blind for example where you set up and wait for your subject to come into your frame) etc...)

See the comment on page 1 from ChrisA - for C&N you might, but it looks like you don't for Pentax

Again, C&N front elements may be fragile, but you'll find there are those who have no dedicated filter on their Pentax SMC lenses
(Hint: the only lens that I have ever needed repairing was because the Hoya Pro-1 filter - read expensive - on it crunched the front of the lens and the shards nearly gouged out the front element :roll

Just my thoughts
Matt