Cheap filters

Discussion in 'Medium Format Cameras and Accessories' started by Gary Holliday, May 9, 2007.

  1. Gary Holliday

    Gary Holliday Member

    Messages:
    826
    Joined:
    Apr 12, 2006
    Location:
    Belfast, UK
    Shooter:
    Medium Format
    I'm currently looking for a new IR filter (100mm 89B) and I'm very limited in my choices to suit my lenses.

    I have an opportunity to buy an unbranded ebay special and wondered how bad can this resin filter be?

    Is it worth the £30?
     
  2. Nick Zentena

    Nick Zentena Member

    Messages:
    4,679
    Joined:
    Nov 21, 2004
    Location:
    Italia
    Shooter:
    Multi Format
    Unbranded resin filters? Sure it's not a lighting filter?
     
  3. Christopher Walrath

    Christopher Walrath Member

    Messages:
    7,114
    Joined:
    Dec 30, 2005
    Location:
    In a darkroo
    Shooter:
    Multi Format
    With the costs involved in IR, I would want my stuff to be right. I don't think the words 'cheap' and 'IR photography' fit in the same sentence.
     
  4. Gary Holliday

    Gary Holliday Member

    Messages:
    826
    Joined:
    Apr 12, 2006
    Location:
    Belfast, UK
    Shooter:
    Medium Format
  5. Bob F.

    Bob F. Member

    Messages:
    3,984
    Joined:
    Oct 4, 2004
    Location:
    London
    Shooter:
    Multi Format
    If you can live with Cokin P size then they are about 25 quid, but I've not noticed any 4" at a sensible price - the Cokin Pro series ones are more than twice the P-size cost.

    Good luck, Bob.
     
  6. Steve Smith

    Steve Smith Subscriber

    Messages:
    8,970
    Joined:
    May 3, 2006
    Location:
    Ryde, Isle o
    Shooter:
    Medium Format
  7. Steve Smith

    Steve Smith Subscriber

    Messages:
    8,970
    Joined:
    May 3, 2006
    Location:
    Ryde, Isle o
    Shooter:
    Medium Format
    Update

    As my Rollei film has not arrived yet, I decided to try out my cheap filter with one of those non-film cameras (sorry!).

    It appears to work very well. Interestingly, the exposure on the digi thing was six stops more than the metered daylight reading which is about the same as is to be expected from the film from what I have read so far.

    The picture I took was with the camera hand supported but resting on a garden bench with the filter held in front of it. The exposure was one second at f8 on a bright day with about 50% cloud cover. Once converted to grayscale, it showed the classic IR characteristic of white foliage. Although I quite liked the pinkish image before it was converted.

    Anyway, enough of this digi-nonesense. Where's my film?!!


    Steve.
     
  8. coriana6jp

    coriana6jp Member

    Messages:
    810
    Joined:
    Apr 13, 2005
    Location:
    Japan
    Shooter:
    Large Format
    I recieved a notice that my film had shipped in late March and it finally showed up yesterday! So I wouldnt worry too much, it will show up. I think the German postal system is very slow, or everytime I mail something to Germany it is.

    Gary
     
  9. Steve Smith

    Steve Smith Subscriber

    Messages:
    8,970
    Joined:
    May 3, 2006
    Location:
    Ryde, Isle o
    Shooter:
    Medium Format
    Update:

    After wasting two rolls of Ilford SFX (Silverprint sent me this instead of the Rollei film at my request) I would say don't waste your money on these cheap resin filters.

    I tried mine on a roll of SFX yesterday and got a completely blank roll of film other than some nicely exposed edge markings.

    Today I tried another roll with a couple of 'control exposures' at the start without the filter then a sequence of exposures from -3 to +4 stops from Ilford's recommended exposure (1/30 f5.6 in bright sun).

    The two test exposures came out perfectly but the rest of the roll was blank except for the last frame which seems to be just slightly darker than the edge of the film. i.e. you can just about make out the shape of the frame but no detail.

    I think I will now buy a proper filter from a reputable manufacturer. And some more film!


    Steve.
     
  10. glbeas

    glbeas Member

    Messages:
    3,307
    Joined:
    Sep 25, 2002
    Location:
    Roswell, Ga.
    Shooter:
    Multi Format
    I think this has more to do with the lack of true IR sensitivity of the SFX film rather than anything to do with the filter. If you are still bent on trying the SFX then use that last frame as a start point and do maybe five more stops over from that in one stop steps. You can used several layers of unexposed and processed slide film as an IR filter with acceptable results.
     
  11. Steve Smith

    Steve Smith Subscriber

    Messages:
    8,970
    Joined:
    May 3, 2006
    Location:
    Ryde, Isle o
    Shooter:
    Medium Format
    I think I will get a proper filter then try it again. Looking at the film, I think what I can see is light reflected off of the rear of the filter (in a Cokin holder) rather than IR through the filter.
    The frame just shows a slight darkening around the edges with the majority of the frame being as clear as the edge of the film.

    Steve.
     
  12. Gary Holliday

    Gary Holliday Member

    Messages:
    826
    Joined:
    Apr 12, 2006
    Location:
    Belfast, UK
    Shooter:
    Medium Format
    Thanks for the pm Steve, I was nearly going to go and get the filter tonight. The B+W equivalent is 3 times the price, plus an adaptor.
     
  13. Steve Smith

    Steve Smith Subscriber

    Messages:
    8,970
    Joined:
    May 3, 2006
    Location:
    Ryde, Isle o
    Shooter:
    Medium Format
  14. Sponsored Ad
  15. Roger Hicks

    Roger Hicks Member

    Messages:
    4,913
    Joined:
    May 17, 2006
    Location:
    Northern Aqu
    Shooter:
    35mm RF
    No-one I know who has methodically tested filters (instead of relying on what 'everyone knows') has seen any quality loss with resin. You need to go to window glass for detectable losses. Transmission and lens correction/focus correction are far more important than filter material.

    A filter with a T50 of 715nm should work fine with both SFX and Efke IR -- I have had success with both. Try 'sunny 11' at EI 6 as a starting point.

    Cheers,

    Roger
     
  16. AgX

    AgX Member

    Messages:
    11,204
    Joined:
    Apr 5, 2007
    Location:
    Germany
    Shooter:
    Multi Format
    Roger,

    was the original question about the filter being made of resin or being unbranded?
    I don't know. But as you know Lee Filters produce camera filters made of resin. This interest in limited extension IR-films should them make think about offering 100mm² 89B type filters.
     
  17. Bob F.

    Bob F. Member

    Messages:
    3,984
    Joined:
    Oct 4, 2004
    Location:
    London
    Shooter:
    Multi Format
    I don't know if you are aware, but the filter that comes in the kit (and sold separately) is a gel filter in a Cokin gel holder (I have one). I'd be tempted to go for the Cokin P007 filter which I *THINK* is a resin one (but check that before buying).

    As a general point, any filter that cuts off much deeper in to the infrared than a Wratten 89b or equivalent will be too deep to register anything on SFX film as the film is only sensitive to around 740nm.

    Cheers, Bob.
     
  18. Steve Smith

    Steve Smith Subscriber

    Messages:
    8,970
    Joined:
    May 3, 2006
    Location:
    Ryde, Isle o
    Shooter:
    Medium Format

    I think that is the problem with the filter I have i.e. it is too far into the IR region (rather than it being a resin filter). Although I have no way of testing it other than with film. The fact that it worked with my D100 is no indication that it will work with film.

    Steve.
     
  19. Steve Smith

    Steve Smith Subscriber

    Messages:
    8,970
    Joined:
    May 3, 2006
    Location:
    Ryde, Isle o
    Shooter:
    Medium Format
    I'm sure you're correct. I don't think the fact that it's a resin filter is the problem, I just think that this cheap filter is too infra red to register on the film.


    Steve.
     
  20. Roger Hicks

    Roger Hicks Member

    Messages:
    4,913
    Joined:
    May 17, 2006
    Location:
    Northern Aqu
    Shooter:
    35mm RF
    Dear Steve,

    Entirely possible. Do they give a T50 (50 per cent transmission figure)?. And of course you are dead right that resin wouldn't blank things out completely. My post yesterday was after a 3000 mile drive in 3 weeks in a 1972 Land Rover, visiting Leica, Zeiss and Gitzo/Manfrotto, as well as going to Hungary for the spas and taking some pics in Capodistria on the way...

    Cheers,

    Roger
     
  21. Steve Smith

    Steve Smith Subscriber

    Messages:
    8,970
    Joined:
    May 3, 2006
    Location:
    Ryde, Isle o
    Shooter:
    Medium Format
    No, they don't say much other than to claim a similarity to an 89B filter. To be fair to the seller, he only mentions its use on digital cameras and he does give a list of models which have been tested with it.
    I suppose I was asking too much of it really.
    At four stops above Ilford's recommended exposure, I would expect at least a very feint image (actually, I would expect an overexposed image!) so I can only think that it cuts off too much of the near visible IR to be effective on SFX film.
    I will have to spend even more money now on a good filter!

    Steve.
     
  22. Gary Holliday

    Gary Holliday Member

    Messages:
    826
    Joined:
    Apr 12, 2006
    Location:
    Belfast, UK
    Shooter:
    Medium Format
    An 89B should be fine with SFX, but having a closer look at the eBay descriptions for your filter and mine, he states two different wavelengths for the supposedly same filter. Mine says transmission starting at 720nm and yours at 700nm. Both are comparable with an 89B and R72 according to him. An R72 is a bit strong for SFX.

    You can use this chart for an indication where all the IR filters start transmission.
    http://www.eazypix.de/ir/filter/filter.html

    But this was the point of my original post is that an unbranded filter may not be as accurate as it claims.
     
  23. Gary Holliday

    Gary Holliday Member

    Messages:
    826
    Joined:
    Apr 12, 2006
    Location:
    Belfast, UK
    Shooter:
    Medium Format
    Last edited by a moderator: May 28, 2007
  24. Bob F.

    Bob F. Member

    Messages:
    3,984
    Joined:
    Oct 4, 2004
    Location:
    London
    Shooter:
    Multi Format
    With an 89b, Ilford suggest rating at x16 filter factor (4 stops). I've used 6 - 12ASA in the past - not had a chance to shoot the new stuff yet - so you should certainly have got somewhere close to correctly exposed negs. Is it possible you accidentally went the other way and closed down 4 stops (done that myself more than once on the spur of the moment when adjusting for reciprocity or bellows factor etc...).

    Cheers, Bob.
     
  25. Roger Hicks

    Roger Hicks Member

    Messages:
    4,913
    Joined:
    May 17, 2006
    Location:
    Northern Aqu
    Shooter:
    35mm RF
    Dear Bob,

    I'll second your EI 6-12 recommendations (and 6 rather than 12) but thought you might like Frances's phrase for stopping down instead of opening up (as we've all done) -- 'photo dyslexia'.

    Cheers,

    R.
     
  26. Steve Smith

    Steve Smith Subscriber

    Messages:
    8,970
    Joined:
    May 3, 2006
    Location:
    Ryde, Isle o
    Shooter:
    Medium Format
    I suffer from 'photo dyslexia' as much as anyone else but when I did this test, I actually wrote down the exposure details which is rare for me!
    My longest exposure was two seconds at f11 which is four stops above Ilford's 1/30 f5.6 recommendation for bright sun so something should definitely have registered on the film.
    Looking again at the only frame with any density, the very slight darkening is at the corners i.e. where the Cokin filter holder plastic does not extend to the edge of the filter. This reassures my belief that what I got was light reflecting off the rear of the filter.

    Steve.