Lens filters, what is it for and why should i buy it?

[Solarflare]

UV filter - Useful as protection if you get into areas with a lot of dirt etc.

Polarizer - Useful if you know how to use them. Mostly for landscape shots, but for example also useful for cars - you can block their reflections because thats polarized light.

~2-4 Stop ND Filter - Useful to use your lens wide open in bright sunlight

10 Stop ND Filter - Useful to remove moving subjects from the picture. Needs a tripod.

2 Stop Gradient ND Filter - Useful for landscape photography, to compensate for the very often occuring bright sky, dark land situation.

Variable ND Filter - Useful for full control over aperture and shutter speed. Especially useful, in fact basically required, for good video.

Color Filter - Used by some for special effects.

Light Filter - For IR photography. Unless your camera is converted, it has a strong IR filter all by itself, which makes IR photography require tripods and very slow shutter speeds.

 

[astroNikon]

Are there any issues with picture quality of the filter distance from the glass. For instance using a step up ring for multiple lenses

 

[Gavjenks]

Are there any issues with picture quality of the filter distance from the glass. For instance using a step up ring for multiple lenses

No not really. The only times I can think of that mattering would be:

1) Gradients: you might only see the middle of your gradient, thus getting less of a gradient effect and not getting as much of the extreme edges.
2) If you have a really wide lens with abnormally small filter threads, then the stepup rings might make vignetting really bad. I.e., if the angle of the cone of stepup rings is less wide than the lens is, then they will all be adding vignettes.




Oh also, another filter type i forgot: center filters. They are darker in the middle and get clearer at the edges. These are a way to optically correct for vignetting without stopping down. They make the middle darker while leaving the existing vignettes alone, thus evening out the image, and then you compensate for all the darkness by increasing exposure some amount. Thus making vignettes disappear in exchange for slow shutter. Used for film much more so than digital.

 

[astroNikon]

Thanks. I wanted to get a circular polarizer for my 24-85/2.8-4 AFD which is 72mm filter thread and my 18-105 AFS which is 67mm filter thread and use a step up ring on the 67 to use the 72.

Plus a CS for my 50mm and 24mm which are both 52mm

The CS filters, good ones are expensive so one less to buy saves a ton and more money to put towards a FF.

 

[Stevepwns]

The 4 filters per lens I keep with my kit include, 1 - CPL Filter (Circular Polarize) and a 3 set of ND filters (Neutral Density) .6, .9 and a 1.2. Other than that, I dont have a purpose for anything else but a graduated ND filter but I am too cheap to buy another filter for each lens I have...... I do have some step up rings for my 50mm lens, and 28mm lens, they take a 49mm filter so I just use the step up ring and use a 62mm filter if the need arises. After buying ND sets for 62mm, 72 and 77mm on top of CPL filters for all 3 lenses I carry, I decided I had spent enough damn money on filters..... at around $100 bucks a pop that **** adds up...lol.

 

[Bulb]

I just bought this one for my Nikon 18-55 lens:

Amazon.com: Hoya 52mm HD Hardened Glass 8-layer Multi-Coated Digital Circular Polarizer Filter: Camera & Photo


What about ND filters? Do i need to worry about circular or anything like that? Or is any Hoya ND filter ok to use for my dslr?

ND filters are used to stop light from entering the lens. It may sound counter-intuitive, but it's quite useful for things like creating smeary waterfall streaks or a blur of people walking by when you've reached the limit of how slow you can set your shutter before overexposing. E.g. I want a slow shutter speed of 5 seconds, but it's pretty bright out and I can't close my aperture any more. Pop an ND filter on the lens and the shot won't overexpose.

They're rated in stops, although other numbers are used to rate them. Make sure you see it mention stops. Each stop will halve the amount of light entering the lens. It's up to you, but I would get a 3-stop or 4-stop ND. Not that there's any right or wrong answer. If you really want slow shutter speed in bright light then you could need as much as an 8-stop. There are also variable ND filters which can be rotated to block different amounts of light, but higher quality filters are expensive. It really depends on what you're doing and you may not even need one if you don't ever find yourself running into these sort of situations.

Don't worry. There's no such thing as a "circular" ND filter. It only applies to polarizers. A linear polarizer will polarize the light going through it. This means the light reaching the camera will be polarized. This has a tendency to mess up autofocus. Circular polarizers polarize the light and then scramble it again so it won't affect it.

 

[astroNikon]

Thanks for the advice. I bought B+W a 52mm slim Circular Polarizer filter for my 24mm and 50mm lenses
and a B+W 67mm Circular Polarizer F Pro filter for my 18-105mm lens.

I held off buying some because I never knew which were junk (like the Sunpak $9.99 specials) and didn't know where to find good ones. I have a B+W, Tiffen and Hoya filter from buying lens and I really liked the way the B+W was made (not that I'm a filter material expert or anything).

 

[hamlet]

I've got a question about the lens moving automatically. Will the lens push the filter off of it if that happens?

 

[Murray Bloom]

Huh?

 

[hamlet]

When the lens auto-focuses, doesn't it move on its own?

 

[Murray Bloom]

Yes, but filters attach to the front of the lens, so all is well.

 

[minicoop1985]

Just make sure you've got it screwed in tight. Don't ask how I know this...

 

[480sparky]

When the lens auto-focuses, doesn't it move on its own?

Some lenses move the front element, others (referred to as IF, Internal Focus) don't. Those that do merely move the filter threads as they do, so any filter attached just goes along for the ride. There's two flavors involved here.... threads that don't rotate during focus, and thread that do. If the threads don't rotate, you can focus to your heart's content and leave any filter you've attached alone. If the threads DO rotate during focus, you'll need to readjust any filters such as a grad ND or polarizer once you've established your focus.

 

[hamlet]

Few... means i can put this here away. :cheer:

 

[Gavjenks]

Don't worry. There's no such thing as a "circular" ND filter. It only applies to polarizers.

Yes, there is.

A variable ND filter is just two POLARIZING filters. When you spin them so that they are filtering polarized light at 90 degree angles, it stops almost all light. When you spin them so they are parallel, it only blocks as much as a normal polarizer.

I believe that usually, they are constructed of one circular + one linear polarizer. I don't actually know if this screws up autofocus the same way a single linear does. It might or might not. I can't find much on it, because people don't tend to use variable NDs along with intensive autofocusing, or refocusing after spinning things around. More often it's on a tripod and you manually focus or focus with the LCD with the heavy density on already.

There's also the very real possibility that cheaper variable ND filters are just two linears, not a linear + a circular. And it's possible that even if the c+L doesn't mess up autofocus, that a hypothetical cheapo substitute like this might.

I'm no expert, but it's worth researching at least if for some reason you plan to do a lot of focusing and then changing your density and shooting again without changing.



I would check it for you empirically, but I broke my only variable ND recently =/