Filters In Simple English ..

[mdq8]

Hi guys ..
Im trying to use Cokin filters,for the first time,but some explanation is needed here,can someone explain this paragraph in simple english for a beginner !!

" To decide which filter density to use, you need to measure - spot measuring with your camera or wit a separate spot-meter - the clear zone where you wish to keep the detail and the zone that will be used for the final exposure. Then count the number of stops difference - at constant speed. For a 2 stops difference you will need a density of 0.6 (ND4).

Take care to modulate your effect depending on the subject; for example, a reflection must be less bright than its source. Finally, depending on the way that the zone separating light and shadow presents itself, you will choose either a short or long transition zone filter.

You must then adjust the filter - close the diaphragm as much as possible by pressing the depth of field preview button to better see the transition zone in the viewfinder while adjusting the filter vertically until its transition zone corresponds perfectly with the light intensity line of your framing. The effect of the filter depends both on the lens and on the disphram setting. The more the aperture is reduced, the more the effect of the graduated shading will be noticeable. Note that the capture settings has an impact on what the filter can do.

Exposure for the foreground. With experience, you will determine at a glance the filter you need to use and it will only take you a few seconds to adjust it efficiently with precision. The best practice would be to always carry the three densities to fit almost any lighting condition. "


Thanks ....
Paragraph taken from Cokin website ..

 

[astroNikon]

I hope this is simple enough without over simplifying it and making it wrong.

I'm going to guess that you do not understand the "stops" aspect of it.

If you look here ==> Neutral-density filter - Wikipedia, the free encyclopedia
you'll see a column called "f stop reduction" and "% transmittance"
essentially a filter will "stop down (related to the aperture - f/stops)"
which essentially is how much light does it block.

info about f/stops which is probably more than you want to know ==> Understanding the Camera Numbers of photographic Aperture f/stop, Shutter Speed, ISO

Thus an ND2 (and the other names) limits the light that the camera sees without the filter to 50% of the light being transmitted through the filter.

So technically you either want to adjust your Aperture to a larger hole to let more of the "reduced" light in. OR adjust your shutter speed Slower to the equivalent "f-stop" and provide the proper exposure.

The copy you have talks about either a Soft or Hard Gradient Filter.
- A regular ND filter has a consistent blockage of light across the entire filter.
- A soft ND filter has it lighter on one end and darker on the other with a minimal transition throughout the filter.
- A Hard ND you can easily see the lines.

The part of the article talks about "transition zone" This is where you adjust the Soft or Hard ND filter in relation to say, a picture where the sky is bright and the horizon and below are darker. So the filter will let in less bright sky, and more darker ground area.

Example, say you are using Aperture f/5.6, Shutter 1/500, ISO100
you put on a ND2 filter to adjust for that you decrease your shutter speed to 1/250 which gives the sensor more light and a longer exposure with all else being equal (keeping it simple).

With that basic understanding, now read this ==> Neutral Density Filters

and this about GND - graduated nd filters (the ones with the transitions) ==> Using Graduated Neutral Density Filters

 

[Dave442]

I would say it simply as: point camera at the light area and take a reading then point the camera at the dark area and take a reading, then you have the maximum difference you would use. Example: the light area that you want to darken gives you an 1/500 reading, the area you do not plan to darken gives a reading of 1/125; so 1/500 - 1/125 = 2 stops.

The exposure to use for the final image with the filter installed is that taken from the lower area so it would be the 1/125 shutter speed and whatever f-stop and ISO. You can then make the normal adjustments to the shutter speed/f-stop/ISO to meet your desired results.

 

[mdq8]

I hope this is simple enough without over simplifying it and making it wrong.

I'm going to guess that you do not understand the "stops" aspect of it.

If you look here ==> Neutral-density filter - Wikipedia, the free encyclopedia
you'll see a column called "f stop reduction" and "% transmittance"
essentially a filter will "stop down (related to the aperture - f/stops)"
which essentially is how much light does it block.

info about f/stops which is probably more than you want to know ==> Understanding the Camera Numbers of photographic Aperture f/stop, Shutter Speed, ISO

Thus an ND2 (and the other names) limits the light that the camera sees without the filter to 50% of the light being transmitted through the filter.

So technically you either want to adjust your Aperture to a larger hole to let more of the "reduced" light in. OR adjust your shutter speed Slower to the equivalent "f-stop" and provide the proper exposure.

The copy you have talks about either a Soft or Hard Gradient Filter.
- A regular ND filter has a consistent blockage of light across the entire filter.
- A soft ND filter has it lighter on one end and darker on the other with a minimal transition throughout the filter.
- A Hard ND you can easily see the lines.

The part of the article talks about "transition zone" This is where you adjust the Soft or Hard ND filter in relation to say, a picture where the sky is bright and the horizon and below are darker. So the filter will let in less bright sky, and more darker ground area.

Example, say you are using Aperture f/5.6, Shutter 1/500, ISO100
you put on a ND2 filter to adjust for that you decrease your shutter speed to 1/250 which gives the sensor more light and a longer exposure with all else being equal (keeping it simple).

With that basic understanding, now read this ==> Neutral Density Filters

and this about GND - graduated nd filters (the ones with the transitions) ==> Using Graduated Neutral Density Filters

Thank you so much ....

 

[mdq8]

I would say it simply as: point camera at the light area and take a reading then point the camera at the dark area and take a reading, then you have the maximum difference you would use. Example: the light area that you want to darken gives you an 1/500 reading, the area you do not plan to darken gives a reading of 1/125; so 1/500 - 1/125 = 2 stops.

The exposure to use for the final image with the filter installed is that taken from the lower area so it would be the 1/125 shutter speed and whatever f-stop and ISO. You can then make the normal adjustments to the shutter speed/f-stop/ISO to meet your desired results.

Thank you, i know it sounds simple to you but it would be great if there is a video out there showing how to use filters and adjust f stops, step by step.
Thank you again.

 

[astroNikon]

Beginners Overview


Detailed Overview

 

[astroNikon]

filters over view

 

[TCampbell]

This is one of the more helpful videos I've found. It's made by Lee Filters (basically a high-end version of what the Cokin system does), but all the concepts translate since both systems work exactly the same.

Watch the whole thing because the first example describes the metering techniques (and should clear up all those questions you had) while also describing why they chose to use a "hard edge" grad (both grads have soft transitions... it's just that one transitions over a very small space and the other transitions over a greater space so the transition is less noticeable in situations where you don't have a nice flat line separating the bright vs. dark area of the exposure (usually the sky vs. foreground).

In the second scene (about 8 minutes into the video) they take you into the woods and do the same thing, but explain that they want to use a soft edge grad because otherwise you'd notice the very obvious transition point. The soft-edge hides the transition when the subject crosses the line between foreground and sky (such as the tall trees.)

Lastly, they do a an example that stacks in three filters and uses both hard edge and soft edge and the same time (and when you see the results, you'll probably understand why.)



Incidentally, they do use some color filters and they talk about use of white balance. But shooting landscape is typically always done using "RAW" and then using image processing software on the computer to adjust. The computer software can VERY easily compensate for color cast / white-balance correction so the need for a filter which adjusts for color globally (across the entire frame of the image) is something we don't really need much in photography anymore. Lightroom can even apply gradient filters (just like a physical grad filter) except the physical grad filter improves the dynamic range and doing it in software doesn't improve the dynamic range (if something was close to being blown such as an over-exposed highlight then it's too late to save it when it's on the computer... the pixels needed to be protected from over-exposure before the image was captured. So physical grad filters (such as your Cokin filters) are technically better then doing it in software (e.g. Lightroom's gradient filters).

 

[mdq8]

This is one of the more helpful videos I've found. It's made by Lee Filters (basically a high-end version of what the Cokin system does), but all the concepts translate since both systems work exactly the same.

Watch the whole thing because the first example describes the metering techniques (and should clear up all those questions you had) while also describing why they chose to use a "hard edge" grad (both grads have soft transitions... it's just that one transitions over a very small space and the other transitions over a greater space so the transition is less noticeable in situations where you don't have a nice flat line separating the bright vs. dark area of the exposure (usually the sky vs. foreground).

In the second scene (about 8 minutes into the video) they take you into the woods and do the same thing, but explain that they want to use a soft edge grad because otherwise you'd notice the very obvious transition point. The soft-edge hides the transition when the subject crosses the line between foreground and sky (such as the tall trees.)

Lastly, they do a an example that stacks in three filters and uses both hard edge and soft edge and the same time (and when you see the results, you'll probably understand why.)



Incidentally, they do use some color filters and they talk about use of white balance. But shooting landscape is typically always done using "RAW" and then using image processing software on the computer to adjust. The computer software can VERY easily compensate for color cast / white-balance correction so the need for a filter which adjusts for color globally (across the entire frame of the image) is something we don't really need much in photography anymore. Lightroom can even apply gradient filters (just like a physical grad filter) except the physical grad filter improves the dynamic range and doing it in software doesn't improve the dynamic range (if something was close to being blown such as an over-exposed highlight then it's too late to save it when it's on the computer... the pixels needed to be protected from over-exposure before the image was captured. So physical grad filters (such as your Cokin filters) are technically better then doing it in software (e.g. Lightroom's gradient filters).

Thanks, the video was really helpful, i only need now to know how to calculate the f stops after adding the filters and taking the meter reading.