ND Filters

I'm old.

Sigh.

I remember that when I was really into photography in the late 60's, UV, Sky, and the new polarizers were all the rage.

All my lenses now have the above compliment of add-on glass (some actually by Pentax!) I'm also collecting a small library of vintage literature about Asahi Pentax Spotmatics and the gear that was around at the time.

I've been seeing a lot of reference here on the forum to Neutral Density filters, and wonder if you folk could give me a quick synopsis of where these came from and what they do.

As always, thanks a bunch and have a great day.

Old grape juice is wine.
Old wine is cognac.
vinegar is soured wine.
as human beings, only our attitudes and outlook on life, diferentiate the cognacs from the vinegars.
Neutral density filters are like sunglasses for lens.
they allow you to use wider apertures with slower shutterspeeds in any given light.
graduated nd filters are no smarter than the highschool dropouts. they just let you control contrast in the scene where part of the image area is beyond the exposure lattitude of the film/sensor.

Don

I've said it before, and I'll say it again - love your attitude. And now I love your philosophy too.

So, a non graduated ND filter - I'd guess the screw-on type - simply slows down fast film so we can get less D.O.F. at bigger openings. I can see the benefits (been using opposing polarizers for the same thing).

I can also see why they came along later in the evolution of film where we actually wanted to slow it down. Back in the early days we begged for speed and even hated loosing a 1/2 stop to a Sky Filter.

I guess the graduated versions help balance bright sky against lush foliage or snow against dark sky - depending on how it is mounted. Would these be more the square Cokin types, or do they make a round rotating version like a PL?

Am I also correct in assuming (a deadly thing to do) that they have no impact at all on colour? (Neutral?)

Thank's again,

In some ways, they're more useful on film than digital.

EDIT: I MEANT: MORE USEFUL ON DIGITAL THAN FILM

I can't turn my studio flashes down far enough to give me the optimum aperture because the lowest ISO is 200. Cue ND.

Makes me yearn for the days of Kodachrome 25. Nobody could complain that was too fast.

G

You do get screw on ones but they're generally not much use as it forces you to put the horizon across the centre of your picture. The Cokin ones are a lot more useful as they're long enough that you can place the start of the graduation where you like.

The ND ones are (more or less) neutral, but there others such as sunset & tobacco grads, but those are less useful.

I hadn't really thought about using them in the studio but that does make sense. My studio lights aren't powerful (they're the Jessops Portaflash ones) but even with those I'm generally at F8 or F11 with the 200 ISO setting and sometimes I'd like to use a wider aperture. I must see about picking up some Cokin ND's and giving them a go.

I have been given 3 of these filters #2 #4 #8 I have no idea how or what to use them for, I know you can create some wonderful effect with them , but that where it stops for me any advice however small would be extremely helpful as I would love to use them.

Paul it's amazing how you can find these old threads.

These days we also have now variable ND filters, you can turn them and like that adjust the density of the filter.
Very handy.

there are several ways to show the density, here is a list with them all http://en.wikipedia.org/wiki/ND_filter

ND2 - cuts 1/2 (lets through 50% of the light) - 1 f/stop
ND4 - 1/4 (25%) - 2 f/stops
ND8 - 1/8 (12,5%) - 3 f/stops
ND16 - 1/16 (6.25%) - 4 f/stops

You can stack the effect.
so an ND8 x ND2 = ND16 or you can say 3 f/stops + 1 f/stop = 4 f/stops

That is useful - I was wondering how many stops a given ND filter takes off. I have an ND2 and ND4 but haven't used them much.

I may try adding an ND8 to the collection, stacking them, and doing some interesting things with lakes. I've been getting the milky water effect with infra-red film recently (where shutter speeds of several seconds are common) and it'd be interesting to get it in colour.

Infra red is certainly intersting, sadly with the K10D you need very long shutter speeds, I hope with the K5 I can use the higher ISO to shorten those times.

You should try duotone your IR images, it can give a great effect.


I hope to shoot more of these in the future.

I'm not sure whether the K-m can do infra-red? I did briefly try the filter but just got blackness even after adjusting the exposure settings.

I've been using Ilford SFX in my KX, along with a tripod and cable release. Takes about 9mins to develop then another 5mins or so in the fixer.

If you want to capture the tide flow over some rocks for say 30 seconds in sunlight, then you will need Neutral Density Filters to get the correct exposure at say f22 and ISO 100. The Neutral Density Filters should not change the colours, but just the exposure.

You can get a variable neutral desity effect by using 2 Polarising Filters and rotate them in oposite directions.

The K-M and the K10D sensors are the same.
It has a filter that cuts Infra-red light so you need to use very long exposures.
I used 1 second at ISO400 for that shot, as you can see the sun was even in the photo so with other shots you might need to push it even to 2 to 4 seconds.

This is all very interesting, thank you all I'll try them out tomorrow down at the lakes, and at the lock gates where it's like a waterfall.
Paul