Few Question about polarizer

Willis · 23 Jul 2008 at 08:42

I have a Nikon D200 and just need a it of help. I was at the beach on Sunday round the rock pools and the tide was coming in and wanted to get a shot of the water coming in, now I left my shutter open for a few seconds and it came out over exposed. I dropped the exposure right down to -5 but still too bright. A girl there mentioned getting a polarizer :confused:

What am I doing wrong? and will a polarizer help.

Scott W · 23 Jul 2008 at 09:17

Your best bet would be to get a ND filter as this will come in different levels of (ND8, ND110, etc..) and this will allow you to keep the shutter open for longer and not over expose the shot.

A polarizer will basically allow you to get brighter blues, etc... from the shot.

rpstewart · 23 Jul 2008 at 09:18

You can't just increase the shutter speed and expect the exposure to remain correct.

The correct exposure is a balance of shutter speed, aperture and ISO sensitivity. If you want to change one then you need to balance that change with changes in one or both of the other two.

So to get a long shutter speed you need to stop the aperture right down and reduce the ISO. If that still doesn't give you a long enough shutter opening then you need to physically reduce the amount of light entering the lens. A polariser will do that but that's not the main purpose of one, what you really need are neutral density filters - basically sunglasses.

JBuk · 23 Jul 2008 at 09:53

Scott W said:
Your best bet would be to get a ND filter as this will come in different levels of (ND8, ND110, etc..) and this will allow you to keep the shutter open for longer and not over expose the shot.

A polarizer will basically allow you to get brighter blues, etc... from the shot.

it sounds like he doesnt have the correct combination of iso,shutter and aperture and an ND could help to compensate for an error but he should really get those settings correct first and go from there

a circular polariser can make your blues / greens deeper and also reduce reflections and glare which in turn can help balance the brightness of a scene and help the overall exposure

i doubt a CP would help as your cameras metering would compensate for the it and if you havent got the correct settings to start with the shot will end up the same

Willis · 23 Jul 2008 at 10:23

I spoke to someone about this and the guy told me if your shooting in the middle of the day with bright sunshine then its very very hard to get the shot you want.

a1ex2001 · 23 Jul 2008 at 11:13

Willis said:
I spoke to someone about this and the guy told me if your shooting in the middle of the day with bright sunshine then its very very hard to get the shot you want.

Very true most people will say the hours just before and just afer sunset/sunrise are the best times to take photo's as the light is more intersting and generally not as strong.

In the situation you were in an ND filter would have allowed you to have the shutter open long enough to get a blur on the water which I think is *** you were after. Have a look at a p system holder and some filters from the likes of Kood or Hitech. Something like this would be a good starter kit.

http://cgi.ebay.co.uk/Kood-COKIN-P-...hash=item200238314484&_trksid=p3286.m14.l1318

JBuk · 23 Jul 2008 at 11:44

Willis said:
I spoke to someone about this and the guy told me if your shooting in the middle of the day with bright sunshine then its very very hard to get the shot you want.

only if you pointed your camera directly at the sun or the sky and clouds were very very bright in that case an ND Grad would be helpful for a landscape, if it was for a portrait of a person or something in the foreground then fill flash is your friend

its hard to judge where your going wrong without seeing a shot , can you provide one of the shots your unhappy with?

Willis · 23 Jul 2008 at 11:47

JBuk said:
only if you pointed your camera directly at the sun or the sky and clouds were very very bright in that case an ND Grad would be helpful for a landscape, if it was for a portrait of a person or something in the foreground then fill flash is your friend

its hard to judge where your going wrong without seeing a shot , can you provide one of the shots your unhappy with?

Its for shooting water.

JBuk · 23 Jul 2008 at 12:57

a polariser will help a little with water by removing some of the glinting and reflections, i would recommend buying one - i use mine in about 90% of outdoor shots

unless you can provide us with one of your dodgy shots complete with exif its hard to tell where things are going wrong, there are so many variables to consider such as brightness of sky ,clouds , sun, water reflection ,lighting of the ground

a1ex2001 · 23 Jul 2008 at 13:06

JBuk said:
unless you can provide us with one of your dodgy shots complete with exif its hard to tell where things are going wrong, there are so many variables to consider such as brightness of sky ,clouds , sun, water reflection ,lighting of the ground

I'd agree with that, while it's easy for us to give generic advice about what filters will do it would be much easier to be specific if you could upload one of you photos and explain what it was you were trying to achive (possibly with a link to a photo that inspired you).

Willis · 23 Jul 2008 at 13:35

I want to make the water fuzzy and this can be done by leaving the shutter open for a few seconds. You see the effect on flowing river and waterfalls.

King4aDay · 23 Jul 2008 at 13:43

Willis said:
I want to make the water fuzzy and this can be done by leaving the shutter open for a few seconds. You see the effect on flowing river and waterfalls.

You'll need to get a neutral density filter of around 6-10 stops to get an exposure of several seconds or more on a sunny day. I'd recommend the B+W branded screw-on filters.

Also, and don't take this the wrong way, but it sounds like you could do to spend some time reading up on exposure and how to meter properly.

King4aDay · 23 Jul 2008 at 13:54

For example, this was shot on a very sunny day at mid-afternoon using a 6-stop ND filter (1 second at f/22).

Whereas shooting on overcast days (or when the sun is low in the sky) will let you use much longer shutter speeds (this was also using the 6-stop ND, 60 seconds at f/27).

a1ex2001 · 24 Jul 2008 at 10:42

King4aDay said:
Also, and don't take this the wrong way, but it sounds like you could do to spend some time reading up on exposure and how to meter properly.

Time to recomend 'Understanding Exposure' by Bryan Peterson an essential read for the new photographer!

Great examples King4aDay I don't really do long exposure stuff and I was too lazy to search for a thread to link too!