effect of (inexpensive) filter on image quality

Discussion in 'General Technical Discussion' started by fishbio, May 11, 2009.

  1. Hi All

    I bought a 2nd hand 300mm f4 AFS last summer to use with a PN-11 for dragonflies and the like. I used it and wondered what all the fuss was about. In fact I thought the image quality was terrible and blamed bad technique. I noticed some weird bokeh in a shot I took of some branches while checking it out and eventually took off the filter (Optex UV) and tried again - what a difference.

    I finally got around to doing a controlled test today. Below are comparison shots of some distant branches and a closeup of a soon-to-be-emerging Bracken fern. Branches were taken at f4, fern at f5.

    I've noticed similar Bokeh in 300 f4 AFS shots posted here by others. I wonder if this lens in particular doesn't like filters. At some point I'll try this particular filter on another lens to see what happens.

    Live and learn

    Cheers,

    Larry

    [​IMG]

    [​IMG]
     
    Last edited by a moderator: May 11, 2009
  2. mudfoot

    mudfoot

    863
    Dec 29, 2008
    Bronx,NY
    its probably just the filter. more than likely you'll get the same result on another lens.. report back and let us know..
     
  3. That's dramatic, thanks for sharing this example. Since entering digital I have been moving away from protective filters in general. It seems the effect of poor quality filters is even more pronounced on digital to my non-pixel peeping eyes and so now I try to rely on the lens cap and hood for protecting the lens. But fwiw, I have the older 300 F4 that I use on a decent quality skylight filter from time to time and I certainly don't get this issue.
     
  4. rvink

    rvink

    Mar 21, 2006
    New Zealand
    I had a cheap hoya polarizer which caused visible softening and smearing of detail when used on a 400/5.6 ED lens. If poor quality glass is used or the filter is not ground perfectly flat and parallel on both sides, the slightest defect will be magnified by long telephoto lenses. Extremely wide lenses which look through the filter at a steep angle are also very demanding of filter performance.

    If you are using high quality lenses it makes no sense to "protect" it with a cheap, poor quality filter. Good quality filters are made by Nikon, H&W and Heliopan, the Hoya HD range is also good. You can get away with cheaper filters when moderate focal lengths are used (most kit zooms). I tend not to use filters anyway, unless the conditions demand it (driving rain, sea spray, dust etc) or they actually enhance the image (polarizer etc)
     
  5. daniyarm

    daniyarm

    500
    Jan 2, 2009
    Tucson, AZ
    I just tested my 300/4 AF-S a couple of weeks ago with and without Nikon NC filter and there was ZERO difference between the images. It's gotta be the cheap filter.
     
  6. Mr Pogle

    Mr Pogle

    300
    Oct 28, 2008
    Herts, UK
  7. LynnTX

    LynnTX

    631
    Jun 23, 2008
    Texas
    No UV for me!

    I basically stopped using UV filters due to the variables involved.
    I don't see as many being used as I used to in the film camera days.
     
  8. I share the same opinion of the majority here. I have never cared for UV filters, regardless of manufacturers. If protection is the name of the game, keep your lens cap on when the lens is not in use and always use the lens shade.
    Always keep in mind that when a filter is used, regardless of manufacturer, another glass surface is added. Filters in general are prone to flare and when dirty, well you know what I am trying to say.
    A good polarizer would be one of the few filters I would use in my digital photography. A polarizer takes away reflections from non-metallic surfaces, eliminates UV transmission and saturates colors. We all know that it darkens a blue sky.
    My advise when cleaning filters with multicoating surfaces: be very careful. These filters are not easy to clean. I use a formula made for Ophthalmologists, that clean these filters in a breeze and leaves no residue. It is made by Amcon Laboratories, Saint Louis, Mo. and is called AR Kleen.
    By the way, I also read the interesting report on filters, as recommended by Conrad, and although I know Hoya makes good quality filters I did not expect them to surpass those German filters.
    William Rodriguez
    Miami, Florida.
     
  9. Damned be those marketing teams! I even know people that use protective filters! God forgive them because they believe in marketers' lies!
    At a serious level I am surprised how many UV filters are sold around, although their number is disproportionate to the number of pictures in the conditions that they are made for.
     
  10. adaml

    adaml

    976
    Feb 21, 2006
    chicago
    I'm going to espouse the contrarian view and tell you that in my experience, you always get what you pay for. A cheap filter will degrade your images, and a quality filter, like the B+W UV's that are on all my lenses will not only have no negative effect on your images (BTW, flare will adversely affect your images whether or not a filter is on the lens) and it will protect your lens, to which I can personally attest.


    BTW when my 70-200mm fell off my tripod (my fault) the lenscap was off because I was photographing at the time.
     
  11. adaml, do you believe that the filter saved your lens? I mean it took the hit (scratch) instead of the lens and without it your 70-200 would have needed a new front lens? How about the hood; was it in its place?

    PS: I'm asking all these questions because, until proven otherwise, I believe that this "buy protective filters for your lens" is only about marketing. Why aren't protective filters included with the lens? (some sort of removable front element)
     
  12. must be a HMC filter the regular ones make it bad i have test pics
     
  13. Chris101

    Chris101

    Feb 2, 2005
    Arizona
    Loft, take your naked lens to the beach and then scrape off the deposits from it's finely coated surface before you smash all the protective filters! They have a purpose.
     
  14. Chrïs, I wasn't talking about special situations. As far as I know beaches are full of UV light anyway.
    If you live most of your life at altitudes between 100 and 6-700 meters and most of your pictures are taken at these altitudes, do you really need an extra UV filter or the UV filtering provided by the bare lens is enough?
    But if you keep an UV filter for those "in case of" situations (in case of a swarm of mosquitoes would hit your lens, or a cat would lick your front element, or that a friend of a friend dropped his lens once) without even knowing what an UV filter really does...
     
  15. Chris101

    Chris101

    Feb 2, 2005
    Arizona
    In most cases digital cameras do not require any UV filtration. In fact UV photographers must go to great lengths (expensive lenses and filters, and long exposures) to capture that part of the spectrum. To protect my lens from the elements, when that is a necessity, I prefer the Nikon NC filter.

    That said, there may be some circumstances where UV filtration is needed. I have found that the filters called "Haze" filters are the most effective, followed by 1A (skylight) filters and finally by UV filters. Here are some spectra I made from a few of my clear filters:
    [imgn]http://homepage.mac.com/cheilman1/images/cameras/clearfilterspectra.jpg[/imgn]​
     
  16. I am pretty inexperienced in this photogarphy racket, but have decided to use filters for protective reasons, albeit good filters, Hoya HMCs. Contray to others, about the only the time I have a lens cap on a lens is when the lens is not on the camera. My little old D40 does not live in a case, but is out nearly all the time except if on a plane. Lens caps are a pain, plus I lose them. I have had to buy a few spares off fleabay.

    cheers
    Simon
     
  17. f5fstop

    f5fstop

    43
    Feb 6, 2009
    Utah
    And then there are those of us who have had a protective filter save a 1600 lens from damage.
    Not all of use walk around in perfect environments. Some of us get more dust on a lens in five minutes than some will get in three days. We drive and walk in desert conditions such as sudden dust storms in canyons, in and around large boulders. We want the protective filter to hold the dust, not the front lens element. We want the protective filter to take the blunt of a sudden impact with a rock; not the front lens element. We do not have time to put on or remove lens covers; however, we do use the lens hood for some protection.

    Hopefully, we use good filters (I do), but find they are a necessity for the conditions we shoot in.

    This use of protective filters is not from marketing hype, it is from a knowledge gained from working, playing under these types of conditions. And I do not need for God to forgive me for filters used on a camera lens.

    I guess if I was shooting in a city, or in a nice green field (no moisture), I would reconsider my need for protective filters for my lenses. When I have time to actually set up a camera on a tripod, and take a photo, I have then been known to unscrew the protective filter and put it in my pocket.
     
  18. garyosborne

    garyosborne Guest

    It's horses for courses. I have moved away from filters mainly because i have 2 lenses (14-24mm and 10.5 fish) that can't use them. Once i got used to it the stress eased. I have a filter on my macro though as i tend to stick it close to the subject. I have actually had a lens damaged by a protective filter. My camera fell off a car roof, serves me right for driving off with F801s with 180mm attached up there (DOH!) the protective filter shattered and the fragments marked the front element. It was in a bag but at 20mph what do you expect? to be honest we get so anal about such things but in truth it has next to no impact on IQ. I have seen shots taken with a lens that was completely shattered front element...you could tell the IQ wasn't the best but the results were very surprising......a loss of sharpness and contrast is all
     
  19. Bandwidth Conservation Suggestion: just do what works

    Lo those many years ago, with spanking new D100 in hand, I decided to look into the endless filter debate for myself. So I bought a heliopan UV, screwed it on a 28-70 f2.8 Nikkor got out the tripod, and shot a whole lot of images, with and without the filter. I studied them on screen, printed a bunch of 8x10s and looked at them with a magnifying glass. Couldn't see any difference. Been using filters (heliopan, Nikon, B+W) ever since. If you get different results, don't use filters. :biggrin:
     
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