Should I use a CP filter as my main filter instead of a UV one?

Discussion in 'Beginner Questions' started by allan_martin, Oct 20, 2013.

  1. Hi!
    Ill be soon buying a 50mm for street photography and candid shots.
    I wanna get used to it and make it my "standard" focal length for when I have to take just one fast prime lens.
    Well, my question is this: Should I get a regular UV filter or a CP filter? I dont want to change filters, I want only one, leave it there and forget about it.
    So, do you think CP filter would bring me any advantages for the kind of work I want to do?
  2. do you think CP filter would bring me any advantages for the kind of work I want to do?​
    No. Almost none at all, and plenty of disadvantages (loss of light, internal reflections, etc.) Why do you need any filter?
  3. To answer your question directly, a UV filter is typically a lens protector and that's about it, if your intention is never to change out filters then this is the one you want as Curt said a CP will reduce the light available to the camera's sensor.
    Now the added bit, I don't see how one could go about capturing images in all shooting conditions and not expect to carry a couple of filters to match the conditions, can you get results without filters sure you can, will you get better results utilizing the correct filters for the conditions or setup absolutely.
  4. I would be curious to know why you think you need this on a regular basis. Is it to cut atmospheric or window reflections
    and the like? Otherwise, no, I don't think you need such an arrangement, but maybe for some things.
  5. david_henderson


    No, oo not. A polariser produces effects on your photographs that you want to choose frame by frame whether you want
    them and to what degree. A filter to leave on all the time? My choice would be -and is- none. But if you want to protect
    your lens then a uv or skylight will have little to no effect on your photographs.
  6. The UV filter is commonly sold as insurance against damaging our valued camera lenses. Personally I never damaged a lens but I have seen scratched lens. Personally I would not mount one but I can understand the basic concept. The down side is, every filter has two surfaces that act to reflect some light away. The light loss is about 2 percent if the filter is coated and about 4% if un-coated. The back surface faces film or sensor and it ketches light reflected off the polished surfaces of lenses that follow. These will be reflected into the image forming rays by the filter. These are misdirected rays that reduce contrast. I am taking about flare and filters induce more flare. Flare is devastating so a good rule of thumb is, never add a filter unless the benefit outweighs the harm.
    Now the UV is indispensable for film camera work if the subject is distant landscape, mountain views, scenes over water and aerial photography. What happens is, atmospheric haze is blue scatter light with a high UV content. Films are supper sensitive to these short wavelengths. A UV will mitigate haze allowing some detail to be seen in the distant mist. Unless your subject is quite distant the UV filter is worthless except to protect the underlying lens. The modern digital sensor is highly sensitive to UV thus the sensor sports a cover glass that protects the sensor from harm and stops UV before it gets to the sensor.
    Now the polarizer is quite valuable. Fist it offers the same UV filtration as the UV alone. Next it mitigates reflections from some shinny surfaces. It is particularly valuable when shooting subjects behind glass and objects submerged in shallow water. Additionally the polarizer darkens blue sky enhancing white clouds. It can add saturation to a vista without changing the color balance. The polarizing screen is the most valuable of all the filters.
    The standard polarizer is linear and these work just fine. Now some digital cameras use a polarizing screen in the focusing and exposure mechanism. If true the linear polarizing screen can interfere. Enter the circular polarizing filter. This design is two filters sandwiched together the side that faces the subject is a standard linear. The leading filter does the deed. The side the faces the camera is called a retarder. The retarder scrambles the polarized light so it won’t cause any impairment. The effects of the polarizing screen are not impaired by the retarder. The downside is you are adding two filters with 4 surfaces. Again, benefit outweighs the harm?
  7. Alright guys, thanks! I had a wrong idea about polarizing filters. Think they wont add much to my photos needs in this case. Ill stick with the UV for protection.
  8. You don't really need a protective filter unless you're shooting boxing and martial arts ringside, at a beach or on a boat with sea spray, under trees leaking sticky sap or in a nightclub with beer flying. For those situations, sure, a clear, UV or similar protective filter can be helpful. I usually carry 'em in my bag. For me it's mostly when trees are leaking sap - the stuff dries hard as resin and creates a tiny translucent pimple surface that can contribute to flare. It's easier to wipe off the filter and replace it every few years.
    But for most street and candid photography, it's better to leave 'em off. With a low angle sun peeking between buildings or streetlights at night, filters just add another surface for flare.
  9. Your "main filter" should in most cases be no filter at all.
    But if you do want to keep a filter on your lens at all times, a circular polarizer would be a bad choice for several reasons. Stick with a high quality, multi-coated UV filter if you feel that you must have something mounted onto your lens.
  10. Think I'm just not ready to leave my lens unprotected! I tried it once and I realized I was constantly checking the glass minute after minute to see if something had touched it or whatever. I'm a little OCD about my photography stuff...Hopefully that will go away if I ever start to make money out of it!
  11. Allan, your lens is not unprotected without a filter. Lenses are not all that vulnerable, and a lot of filters are less scratch-resistant than modern lenses, I think. A lens front element does not just scratch all that easy, plus you should use a lens hood where possible anyway (which does also protect your lens a lot better than a filter will). As Lex described, I have UV filters only for lenses that I use in adverse condition to make cleaning easier - and then I am talking about sand, salt water, dusty and dirty enviroments - not fingerprints and bits of normal grease, which are no issue at all to clean. Realistically, get over the fear of damaging the lens, because good lenses are made to be used, and hence can stand a little knock here and there.
    Nobody is suggesting to treat your gear badly, but you have to be realistic about the level of protection you expect from a filter, and how likely it is your gear will actually really get damaged by walking around with it.
    A piece of non-requested food for thought: sure about a 50mm? If you have a APS-C camera, 50mm is quite long. Before committing to a single focal length, try with a zoom-lens which length you actually prefer. The bog-standard advice to get a 50mm prime (because they are cheap and because they were used a lot back in the days of film) is not that fantastic advice. Get a length you "feel" right with.
  12. If you are going to use UV filters to protect your lens, don't be tempted to buy cheap ones. I do occasionally leave UV filters on to protect lenses - i often leave my camera on the seat of a dusty work truck for days and days, or have it out in the snow, or stick it in silly places, and UV filters are a bit of an assurance. But there is no sense putting an inferior piece of glass, that all light in an image transfers through, in front of your nice lens. The last UV filter I bought cost me $160.
    I second Wouter's unsolicited advice - 50mm is a bit long on an APS-C camera. If you like that, go for it, but make sure you think about it first.
  13. Well $160 is definitely very expensive for me to pay for a filter. I'll probably pick one from hoya, super HMC.
    But thanks guys, I'll sure think about this and hopefully get rid of everyday-filters.
    Now, regarding the 50mm, I already have a 35mm and I find it great, except for bokehs, which I love. With the 35mm, in order to make a good bokeh I usually have to come too close to the subject, and especially for people, it looks bad. Also, I think a little bit more range would be beneficial for street photography, although I still could crop stuff with the 35mm.
  14. To answer your question about circular polarizing filters, my personal opinion is that they are utterly worthless for street photography.
    Worse than worthless, in fact, because they'll cost you two stops of much needed shutter speed.

    I won't try to talk you out of "protecting your lens" with filters. That's a personal decision. I feel that a lens hood is a better choice in most
    instances except for environments where dirt, blowing sand, splashing liquids, or dog snouts are likely to come in contact with the front
    lens element. I want the ability to mount my Lee filter holder quickly when required. I don't want to have to unscrew and then yptempoarily
    store a glads filter first.
  15. William Michael

    William Michael Moderator Staff Member

    I am curious what camera you'll be putting the 50mm lens on for "street photography and candid shots."

    For example I want to alert you to asking yourself . . . if you have a Nikon DX Camera: are you aware that the 50mm lens will act as a short telephoto lens on than camera?

    Have you thought through the probable shooting scenarios for "street photography and candid shots" and then chosen 50mm as the most suitable Focal Length Prime, to accommodate your specific outcomes?
  16. Willian, yes, it is. D7000 more specifically.
    I'm aware of that. A time ago I remember reading somewhere the a 85mm 1.8 would be great lens for street/candids, used by lots of pros. 85mm would sure be too long for me with a D7000, so 50mm should be alright.
    Also, take a look at this:
    He's just starting out with this kind of photography and most of the pics are taken with a DX + 50mm. I find his hots interesting for a beginner. Thought I could do the same.
  17. William Michael

    William Michael Moderator Staff Member

    Thanks for answering.
    I disagree that an 85mm lens would be the "best" lens for that type of work: but that is an artistic / subjective choice and opinions will vary and you should follow what you want to do.
    But I think that you should base your choices on accurate research - I had a look at the link: the pictures are interesting, thanks.
    However viewing the pictures in the link - there was a concern that was raised in me when I thought of your comment: "most of the pics are taken with a DX + 50mm."
    The reason why I was concerned is that I believe that I have a reasonable eye - and when viewing the Flickr page at a scan, I couldn't see many that seemed to be of a perspective that would be created by a short telephoto lens - so I investigated.
    I think that there are 63 photos on display.
    According to the EXIF they were shot with either a Nikon D5200 or a Samsung NX1000 - both are APS-C cameras.
    But, only 20 were shot with a 50mm lens.
    37 of the images were made with a 35mm lens
    6 used a lens between 20mm and 22mm.
    It might be that you like the images where he was using a 50mm lens: but it seems that they are definitely not in the majority of those that you have displayed as samples in that Photostream set.
  18. Allan, before buying a lens, take a look at the EXIF data for your existing photos. Some photo editing software and metadata editors can help identify our tendencies. I discovered only after buying a 50/1.8 for my DX sensor dSLR that I rarely used that focal length. I was accustomed to the "normal" lens for my 35mm and medium format film cameras, but the 50 was too long for my preferences on the DX sensor camera. So it was a waste of money. I'd have gotten more use from a fast 28mm or 35mm lens, or a faster midrange zoom in place of my variable aperture zoom.
    In fact, I bought that 50/1.8D AF Nikkor around 2006 for my D2H, and ended up using it very rarely until I got a CX sensor Nikon V1. On the V1 the 50mm makes a nifty and useful equivalent to a 135mm f/1.8 on a full frame or 35mm film camera. So I've been using the 50 on the V1 for low light performance photography.
    By analyzing your EXIF data for tendencies you might find that you'll get more use from an even longer lens. I know of some photographers who prefer longer lenses, up to 200-300mm for street photography. Not my style, but it suits them. Just depends on how comfortable you are getting close to people, and whether you enjoy chattering with folks you meet out in public while snapping pix.
  19. Hmm alright, good point guys. I really thought they were all taken with a 50mm, sorry about that.
    But well, you do agree that 35mm is way too short for a nice bokeh without major distortions right? And that a 85mm would be TOO long for street, meaning Id be able to get mainly headshots, otherwise Id have to stay too far from the subject?
    As far as I know there are only these 3 primes I could be taking into consideration.
  20. The term "bokeh" is generally used to describe the *quality* of the out-of-focus parts of the photo, not merely the existence of out-of-focus areas. Bokeh is affected by many factors: optical design; whether the aperture is stopped down at all; the shape of the iris (although this is less important than is often described); distances between camera and subject, and between subject and background/foreground; shapes of the out of focus elements.
    I typically shoot candids and street photos stopped down and often with wide angle lenses, so bokeh is irrelevant to most of my photos. Everything is more or less in focus. But I usually prefer a busier looking photo and the milieu is essential to the photo, not a distraction to be blurred out.
    I've seen results from the 35/1.4 Zeiss Distagon used wide open that show both excellent sharpness and appealing bokeh. So it's possible to get both with a moderately wide angle lens, at least on a full frame format dSLR or 35mm film. And 35mm primes are usually well corrected to minimize distortion. Most I've seen have minimal barrel distortion, reasonably flat field and are usually well corrected to minimize chromatic aberration (although Nikon's 35mm f/1.8 DX is noted for purplish fringing in high contrast areas, such as around foliage against a bright sky).
    If you prefer to shoot wide open for shallow DOF, and if the budget allows, go for an f/1.4 prime. The 50mm f/1.4 primes are usually fairly affordable, a little more than double the price of the f/1.8 versions. The 50/1.8 lenses are great values but not necessarily great lenses. Biggest mistake I made in settling on the 50/1.8D AF Nikkor several years ago was not ponying up a bit more money for the f/1.4 version. I already had the 50/2 AI Nikkor and the 50/1.8 offered no real advantages, other than the clunky screwdriver autofocus.
  21. William Michael

    William Michael Moderator Staff Member

    "But well, you do agree that 35mm is way too short for a nice bokeh without major distortions right? And that a 85mm would be TOO long for street, meaning Id be able to get mainly headshots, otherwise Id have to stay too far from the subject?"​
    There are several questions you ask.
    Firstly using a 35mm lens on an APS-C camera and concerning Bokeh:
    Bokeh is Subjective – so what you like will not necessarily be what the guy or girl next to you likes.
    Bokeh also has many constituent parts and it is NOT just about the physics of lens, for example the Texture of the Background and the Lighting on the Background plays some part in the visual effect of Bokeh.
    Lex has also mentioned other factors
    The Bokeh in this photograph is pleasing to my eye: but you might not like it.
    Secondly, the “Distortion” question:
    The ‘distortion’ that you refer to is actually all about: Perspective.
    Perspective has two elements – they are DISTANCE and VIEWPOINT – that is to say, the distance of the Camera to the Subject and the position of the Camera relative to the Subject, respectively.
    The closer we get to the Subject with any lens the more likely we will see these “distortions” to which you refer.
    Depending upon the DISTANCE and VIEWPOINT, Wide Angle lenses can have the effect of broadening or lengthening facial features, such as the nose and also making people appear broader in then hips or bigger in bottom, thus appearing “fatter” . . . or in this case, where 24mm lens was used on a ‘full frame’ camera, the Perspective created by the lens being very close to the Subject can be used to emphasise an element of the photograph, such as the Sunglasses.
    Or here where the Viewpoint of the Camera with a Wide Angle Lens was ELEVATED above the Subject to emphasise the elements of the Artist belonging in his studio and the ownership of his work.
    Again you might not like the visual effects of the Perspective of these Portraits made with wide angle lenses – but again, that analysis is subjective and for you to choose what you want.
    Now the question, about getting (nice) Bokeh, WITHOUT ‘distortions’:
    Probably the most pertinent issue for you to consider about what Prime Lens you choose to use on your FX Nikon . . . is what will be the DISTANCE from the Subject that you will be, to get the type of images that you desire.
    Also consider if you are comfortable working at that distance, when making Portraits.
    I don’t have a lot of 35mm lenses on APS-C shots at the ready to show you – but I do have a few 50mm lens on 135 format Camera shots – and that combination is about the same FoV as a 35 on an APS-C and I am not fussed at all about any ‘distortion’ and I don't mind the bokeh - but I am not really all that interested in Bokeh as the main element of candid portraiture
    Note that we will always get MORE Depth of Field at any one particular aperture when you use a DX camera compared to making the SAME FRAMING and using an FX camera. I mention this because although DoF and Bokeh are NOT the same they are related – so as a general rule when using an APS-C camera, you will tend to frame your portrait shots TIGHTER rather than LOOSER if you want nice ‘bokeh’.

    On the question of an 85mm lens on a DX camera requiring you to be “too far away” for street work:
    That is about the same Shooting Distance as using a 135mm lens on an FX Format camera.
    I don’t find much of a problem with working at that distance – I find that it does create a certain ‘aloofness’ – especially at night.
    And it certainly doesn’t mean that you will only get headshots.

    As a general comment about choosing a fast prime lens to use in available light:
    Personally, the lens I like the most and also the lens I use the most, is a fast 35mm lens on an FX body: because I like the personal and up close flavour that combination of lens and camera provides me – so that would mean I would be using a fast 24 if I used a Nikon DX Camera.
    I understand that you stated a fast 24mm lens is not part of your equation – and neither, frankly, should what I like to use be the best option for you: but this commentary is an insight into what I use and some of the reasons, why I use, what I use.
    My closing comment / advice is:
    Do what Lex recommended – have a look at what Focal Lengths you tend to use now – and then also have a good think about how far you actually like working from people, when you are in the street.
    Also consider that if you use a wider lens, you can always crop a bit in Post Production to make the framing tighter, but, if your back is against the wall and you cannot move back any further because you have chosen longer lens, then you cannot frame the shot looser to get more in the frame. This is important to consider, especially if you plan to shoot available light / low light, indoors.

  22. 85mm would be TOO long for street, meaning Id be able to get mainly headshots​
    I wouldn't call this a head shot, and I wasn't very far away.

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