Filters Question ?

[Carl in Louisiana]

With all the rain and overcast days (and work days, things that get in the way of a great hobby) I have been through lots of tutorials. Then I started on the filters and checking out different filters and reading comments about what can be done with software in the PP stage, oh my head hurts.... What filters are still needed that can not be duplicated in software? I have read that there are some like polarizers that can not be duplicated, but thought I would ask all the pros here(ease throbbing head). Not sure what I would need and not need, or do I need any at all right now. If so what brand is better? We have lots of water around this part of Louisiana and there could be times that I would be on said water with fishing season coming up real soon (another hobby). With the 17-55mm f/2.8 lens (should be here tomorrow) would I be best suited with a polarizer in these conditions and would I need to buy a 82mm polarizer w/a step up ring on a 60D? What other filters should I put on a wish list to pick up along the way? Sorry about so many questions. Most of the time I will be indoors and low light conditions, unless landscapes and fishing draw me out as I do like them also. For right now this new lens and the 50mm f/1.4 will have do, the wife has been throwing strange looks in my direction ever since I told her what I just bought. Any and all comments will be greatly appreciated. Thanks to all for your comments and suggestions that helped me out on picking the new lens. I can't wait to get it......

[The Blue Boy]

Hi Carl,

There are many different opinions on what filters should be used for what so I'll try and be brief before Colin gets here (he works for Singh Ray! )

A polarizing filter can be used to reduce reflections on water and reflective surfaces and can make a blue sky a richer blue with more contrast with clouds. Personally I don't like them. Some people never take 'em off a lens.

Some people will argue that a UV filter is an absolute must. I only use mine in extremely dusty conditions or near salt water for protecting the lens.

Now if you're shooting landscapes then a Graduated Neutral Density filter will be useful for when the sky is a bit too bright but having said that, this can be avoided/duplicated (although not as well) in photoshop.

Neutral Density filters are the only filters that I actually use on a regular basis. These can be used for a longer shutter speed (to blur water/people/movement in general) or for a wider aperture (a greater depth of field/bokeh)

Hope this helps as a start mate.

[rpcrowe]

Mark,

I generally agree with your assessments. I am a user of CPL filters for certain environments. All or any of my statements must be qualified in that the benefit of the CPL is contingent on the angle of the sun.

There are several other advantages of a CPL filter, other than those you mentioned:

The CPL will increase the color saturation of foliage and sometimes of flowers because it will reduce the reflections when these are wet or dew covered.

The CPL reduces the exposure by 2 stops and can assist in slowing shutter speed or allowing a wider aperture for a more narrow depth of field.

In darkening the sky, it not only makes the clouds seem more evident, it somewhat balances the exposure between the sky and the rest of your frame, often bringing the image to within the dynamic range of the camera.

Shooting in hazy conditions, the CPL can help penetrate the haze because it reduces the reflections off the particulates in the air.

It will enhance the saturation of the colors of rock formations by reducing the glare off the rocks. This is particularly beneficial when shooting in areas like the American Southwest Desert, such as the red rock formations in the State of Utah. Unfortunately, I didn't shoot a comparison shot of this image from Red Rock Canyon Utah but, the difference between the shot with the CPL and without was significant.



And, of course, it also provides the same amount of protection against physical damage as does a UV filter.

Speaking about UV or protection filters:

I will use a clear or UV filter to protect my lens. Although, ANY filter might impact image quality to a certain degree; I have not noticed any significant impact on the image quality of my 17-55mm f/2.8 IS or 70-200mm f/4L IS lenses due to the Schneider produced B+W UV filters that I use. On the other hand, except for physical protection (pretty important on a thousand U.S. Dollar plus lens) the UV filter performs no other benificial service for digital photography. Film was sensitive to UV wavelengths so a UV filter helped landscape shooting with film based cameras.

BTW: Round GND filters can be a PITA to use because the demarkation line is straight through the center of the circular filter. This means that when using a round GND filter, you either need to frame your horizon through the center of the image (boring!) or do some extensive cropping.

I absolutely hate the effect of a salmon colored GND filter which many photographers use to enhance twilight shots. However, my wife loves the effect. Different strokes for different folks!

I think there was a typo in your comment when you mentioned a greater depth of field for a wider aperture and when you mentioned bokeh as analagous to depth of field.

Finally, I would recommend using top-line filters or no filters at all. However, there is a point of diminishing returns when you mount an expensive filter on a cheap lens in order to protect the lens. IMO, it isn't really worth purchasing a fifty dollar filter to protect a lens which you can buy used for seventy-five dollars....

[William W]

What filters are still needed that can not be duplicated in software?

The most used filters for me are (no particular order or significance):

UV, Skylight1A, Clear – use: To seal particular lenses. For protection of front element from sand and salt spray, beer, spit and sometimes blood and sticky fingers and dog’s tongues and damage on corners of tables etc, esp. when carrying two or three cameras

PF (Polarizing Filter) – my use - for some copy work, documents mainly.

CPF (Circular Polarizing Filter) –my use - water sports, particular swimming in outdoors pool or open water events – cuts shine and shimmer.

ND2, ND8, ND400 (Neutral Density Filters) – my use - to allow slower Tv (Shutter Speed) / to allow a larger Av (Aperture) for any specific lighting scenario.

CU+1, CU+2, CU+3 and 500D (Close Up Filters) - sometimes listed as "Close Up Lenses" - my use - a quick adaption to a lens to make a close up shot.

Most Photographers would agree that these uses are difficult to reproduce in Post Production.

***

What filters are still needed that can not be duplicated in software?

Just because something can be duplicated (or very close to duplicated), farther down the production line, doesn’t necessarily always make it the better option.

There are few, but still some circumstances when it might be easier to use other filters on the camera one niche example is for those of us who revel in Available Light Shooting.

When shooting under low wattage incandescent lights for example a large ballroom with chandeliers, typically these lights at a CT < 2500°K, it is better to suck up a small lens speed loss and use a CC (Colour Correction) Filter such an 82A (has a loss of ⅓Stop and Mired shift -21) and set the Camera’s WB to 2500°K~2800°K, or even use an 82B (-⅔Stop and -32Mireds) if necessary, for example when shooting under Candlelight.

It is understood that conveying the “warmth” in the final, of the ambient lighting in such lighting settings is often important – and I am not suggesting that these images are CC to be pristinely perfect (cold.neutral) white balance.

What I am saying is when shooting under ambient light which is sub 2800°K - it is a whole different ball game making:
(a) uniform White Balance over a set of images and
(b) making uniform Colour Balance across Gowns which are Green or Purple, for example.

Getting it very close to "correct" in the camera is often much easier and saves a great deal of time later. Time spent playing is great if one is playing, but time is very costly if it is one’s job.

[yes I shoot raw + JPEG(L)]
[yes, most DSLRs only get to around K = 2500°K]
[yes, down at that end of the CT spectrum the exposure is out by about minus ½Stop]


There are other examples when shooting under none continuous spectrum lights to eliminate some Colour difficulties / anomalies which arise and are difficult and time consuming to fix in Post Production and when a big swathe of the Colour Correction can be done on site at the camera end – one other example was shooting a Cattle Exhibition in a large barn lit with (old) Hg Vapour Lamps: Flash is very big no-no shooting portraits of Stud Bulls and they do like the Colour Balance to be correct.

There are other examples when I have chosen to use B&W Contrast Filters and also Soft Filters, but these cases are rare, but still, it was quicker and also easier than to employ PP later.

These cases are where the single outcome is clear in my mind and time was usually the primary concern obviously: it would be silly to un-leveraged the advantage of multiple adjustments which I have available, in Post Production, for no gain (of time).


***

With the 17-55mm f/2.8 lens (should be here tomorrow) would I be best suited with a polarizer in these conditions and would I need to buy a 82mm polarizer w/a step up ring on a 60D?

I would not do that.

I would buy a Slim Profile CPF to suit the size of the lens (Assuming the EF-S 17 to 55F/2.8 IS USM), I believe that is 77mm.

Most probably you will wish to use the CPF at the wider Focal Lengths: using step up rings to an 82mm filter you will run the risk of Optical Vignette.

***

What other filters should I put on a wish list to pick up along the way?

What other photos do you want to make, in what lighting situations, that you cannot make, now?

WW


PS:
Also - I agree with RPCrowe on two points which are worth re-iterating

1. Bokeh is different to DoF and it is important that the two should not be confused or assumed to be the same.
2. If you want to use a filter - buy only quality filters.