Site Sponsors
Results 1 to 20 of 20

Thread: LCC plates

  1. #1
    Sr. Administrator Jack's Avatar
    Join Date
    Oct 2007
    Location
    Los Altos, CA
    Posts
    10,486
    Post Thanks / Like
    Images
    1031

    LCC plates

    So I decided to try a few different materials in the search for an "ideal LCC plate. I won't bore you with all of the details, but will share a few things I discovered.

    First off, the Capture Integration "2-stop" plate works extremely well, and I used it as my gold standard benchmark. I experimented with denser and less dense, or more accurately less transmissive and more transmissive materials.

    What I learned is it didn't really matter much as long as you have a reasonably centered histogram on the capture file, the material has enough diffusion to give a smooth gradient to work with, and of course that it is neutral in color. Some specifics:

    1) A denser material called "sign white" in 1/8th" thickness was a very clean white but required a 3-stop correction. While it worked very well, it did raise the noise floor on long exposures. I never noted that the noise corrupted an LCC, but it's a PITA to add 3-stops for the LCC when you're already shooting say a 1 second early morning landscape exposure. (In fact, I realized it's a PITA to have to change the exposure at all.) This material is also available in 1/16th inch, but it still required a near 3-stop correction factor, so not really any help.

    2) I tried a 60% transmissive 1/8th" mild diffusion plexi that did NOT generate a good LCC. It did not require any exposure correction, histo was centered at base exposure, but it generated an LCC that over-correctied for lighting falloff by about 1/3rd stop. Not exactly sure why, but it did, and so the LCC was not accurate. The zero exposure offset was certainly welcome in the workflow, but since it didn't work perfectly it got tossed.

    3) The material I settled on is called 40% transmissive "standard diffusion" plexi, again I used the 1/8th" thickness. This material has a nominal 1-stop offset, but the reality is the histo is so close to centered that you don't need to actually add the offset -- very convenient when shooting! This generated an identical LCC to the CI plate.

    4) The other thing I experimented with was buffing to knock the gloss off so the surface was not reflective. Good news is it does kill reflections and generates an identical LCC to either my or CI's glossy plate. I have had a few issues when my CI plate was not firmly against the lens and the LCC had a weird reflection in it that ruined the LCC, so I decided this might help. My hope is this mitigates that problem and initial tests seem to confirm it will. I used a "green" Scotch-Bright synthetic steel wool pad to buff down the surface of the plate. (Note you can buy the 3-stop sign white material in matte surface, but I had already ruled out 3-stop material as unfriendly to my workflow.)

    The only reason I started this search is the CI plate was not quite large enough to fit over my compendium hood and I was looking for a possibly easier workflow when using my tech cam with the hood than having to spin the hood out of the way. My larger plates worked great with the hood, but then I got another idea -- I modified the edges of one plate to slide into the filter slot of my compendium hood. For me this is an attractive convenience, and so far in use I like the hands-free bit

    I obtained all of my material from a local TAP plastics store, but you can of course order online from them or probably find it in any well stocked home supply store.
    Jack
    home: www.getdpi.com

    "Perfection is not attainable. But if we chase perfection, we can catch excellence."

  2. #2
    Senior Member
    Join Date
    May 2009
    Location
    Marseille, FRANCE
    Posts
    972
    Post Thanks / Like

    Re: LCC plates

    hi,
    i'm not shure if it's a good idea to use it in front of the compendium... closer it is to the lens better it will be...

    i've tried different solutions as well... i used to have the big one sold by phase, but i've lost during a trip !
    it was good, big too big for my use !

    i've tried the plate sold by capture integration... quite good as well !

    But, i've found that the best LCC i have ever produced was using an expodisc neutral filter... but it's 3 stops... i've bought one with the diameter of my larger lens (67mm), and put step up rings on the others... on the 35xl the step up ring act as a sun shade as well !

    If you are using a CF, then you will need a bigger one !

  3. #3
    Member
    Join Date
    Nov 2008
    Posts
    68
    Post Thanks / Like

    Re: LCC plates

    Dear Jack,

    have you try this one?
    http://www.bhphotovideo.com/c/produc...al_Format.html

    best

    M

  4. #4
    Sr. Administrator Jack's Avatar
    Join Date
    Oct 2007
    Location
    Los Altos, CA
    Posts
    10,486
    Post Thanks / Like
    Images
    1031

    Re: LCC plates

    Just to be clear, I avoided the Expo-disk once I determined that a 3-stop correction was more than I wanted to deal with, and frankly even making the 2-stop correction was kind of a PITA. So my goal was then to find a plate that did not require any compensation and still rendered a perfect LCC. I did find that, and why I shared it here
    Jack
    home: www.getdpi.com

    "Perfection is not attainable. But if we chase perfection, we can catch excellence."

  5. #5
    Subscriber Member jotloob's Avatar
    Join Date
    May 2008
    Location
    KEMPTEN / GERMANY
    Posts
    1,513
    Post Thanks / Like
    Images
    116

    Re: LCC plates

    Quote Originally Posted by m21apsh View Post
    Dear Jack,

    have you try this one?
    http://www.bhphotovideo.com/c/produc...al_Format.html

    best

    M
    I have this EXPO filter and find it quite useful , especially the handle . Unfortunately the short side is too small and does not cover the front diameter of all my lenses .
    That filter should be a square with its current long side as side a/b of the square .

    I now use a rather dense milky acryl glas square , 2mm thick and 20x20cm
    in size . Both surfaces are matte . An exposure time of + 2 stops results in a histogram , exactly as it should be and the LCC is perfect .
    Regards . Jürgen .
    -----------------------------------------------------------------------------------

  6. #6
    Subscriber Member jotloob's Avatar
    Join Date
    May 2008
    Location
    KEMPTEN / GERMANY
    Posts
    1,513
    Post Thanks / Like
    Images
    116

    Re: LCC plates

    Quote Originally Posted by m21apsh View Post
    Dear Jack,

    have you try this one?
    http://www.bhphotovideo.com/c/produc...al_Format.html

    best

    M
    I have this EXPO filter and find it quite useful , especially the handle . Unfortunately the short side is too small and does not cover the front diameter of all my lenses .
    That filter should be a square with its current long side as side a/b of the square .

    I now use a rather dense milky acryl glas square , 2mm thick and 20x20cm
    in size . Both surfaces are matte . An exposure time of + 2 stops results in a histogram , exactly as it should be and the LCC is perfect .
    Regards . Jürgen .
    -----------------------------------------------------------------------------------

  7. #7
    Member
    Join Date
    May 2008
    Posts
    242
    Post Thanks / Like

    Re: LCC plates

    Thanks for the tip Jack- I'm off to the plastic store!!

  8. #8
    Member
    Join Date
    Feb 2011
    Posts
    159
    Post Thanks / Like

    Re: LCC plates

    Quote Originally Posted by Jack View Post
    Just to be clear, I avoided the Expo-disk once I determined that a 3-stop correction was more than I wanted to deal with, and frankly even making the 2-stop correction was kind of a PITA. So my goal was then to find a plate that did not require any compensation and still rendered a perfect LCC. I did find that, and why I shared it here
    I've found stacked sheets of vellum paper to be pretty effective for the creation of LCCs for over-sized lenses. I don't recall, exactly, how many sheets I used, but the benefit is that it's cheap, easy to experiment with, and easy to replace if it's damaged/lost. Depending on how many sheets used, naturally, it also does not impart too much neutral density.
    --
    Gabe

  9. #9
    Member
    Join Date
    Aug 2010
    Location
    Gainesville, Georgia
    Posts
    177
    Post Thanks / Like
    Images
    21

    Re: LCC plates

    I recently noted some odd scratches on my LCC card (the one requiring 3 stop exposure); I am not sure how those scratches took place since I have been reasonably protective of the card. When exposing enough to get the desired placement in the histogram some of the scratches and spots on the card actually appeared in the LCC image. I checked my sensor to be sure what I was seeing was not on the sensor and the sensor was quite clean. When I examined the LCC card I found the same patterns that appeared on my LCC image on the card itself. It would seem to me that a three stop exposure might have greater likelihood of revealing defects on the card. More importantly, I have started keeping my LCC card in a protected filter container. It may seem a bit over the top, but the plastic container that the CI LCC card comes in creates some problems trying to get the card out and does not adequately protect the Card. In the future I plan to protect the LCC card as if it were an expensive filter! Charles

  10. #10
    Sr. Administrator Jack's Avatar
    Join Date
    Oct 2007
    Location
    Los Altos, CA
    Posts
    10,486
    Post Thanks / Like
    Images
    1031

    Re: LCC plates

    Charles,

    Scratches are another reason I buffed the surface -- it seems to work and may be worth a try. However, I have abandoned my 3-stop plate after New Hampshire and moved to this newer material. FWIW I store mine in a slot I made in my bag between two adjacent padded dividers.
    Jack
    home: www.getdpi.com

    "Perfection is not attainable. But if we chase perfection, we can catch excellence."

  11. #11
    Administrator, Instructor Guy Mancuso's Avatar
    Join Date
    Oct 2007
    Location
    Arizona
    Posts
    23,623
    Post Thanks / Like
    Images
    2555

    Re: LCC plates

    I wonder if scratches would have a effect here since it is so out of focus. I could see maybe a deep gouge in the surface might have some. It's a great question mark it seems. I do like the idea of buffing the surface though which may disperse the light better and cut reflections. I think I may try that and see how it goes.

    Maybe a 600 grit sand paper might work nice. Jack what did you use.
    Photography is all about experimentation and without it you will never learn art.

    www.guymancusophotography.com

  12. #12
    Sr. Administrator Jack's Avatar
    Join Date
    Oct 2007
    Location
    Los Altos, CA
    Posts
    10,486
    Post Thanks / Like
    Images
    1031

    Re: LCC plates

    Quote Originally Posted by Guy Mancuso View Post
    Maybe a 600 grit sand paper might work nice. Jack what did you use.
    I used a medium or "Green" Scotch synthetic steel wool pad. Worked great. I buy them at my local hardware store.
    Jack
    home: www.getdpi.com

    "Perfection is not attainable. But if we chase perfection, we can catch excellence."

  13. #13
    Administrator, Instructor Guy Mancuso's Avatar
    Join Date
    Oct 2007
    Location
    Arizona
    Posts
    23,623
    Post Thanks / Like
    Images
    2555

    Re: LCC plates

    Great idea I will get some and try tomorrow . Getting ready for a model shoot today.
    Photography is all about experimentation and without it you will never learn art.

    www.guymancusophotography.com

  14. #14
    Member
    Join Date
    May 2011
    Location
    San Francisco
    Posts
    104
    Post Thanks / Like

    Re: LCC plates

    Just curious, I don't really understand the objectionable difference from a workflow perspective between a 3, 2, or 1 stop LCC. Almost 50% of my exposures are LCCs. I use the ExpoDisc thing and have never thought twice about it.

    Quote Originally Posted by Jack View Post
    Just to be clear, I avoided the Expo-disk once I determined that a 3-stop correction was more than I wanted to deal with, and frankly even making the 2-stop correction was kind of a PITA. So my goal was then to find a plate that did not require any compensation and still rendered a perfect LCC. I did find that, and why I shared it here
    Last edited by alan_w_george; 15th October 2011 at 10:16.

  15. #15
    Senior Member
    Join Date
    Jun 2008
    Location
    SoCal
    Posts
    291
    Post Thanks / Like
    Images
    15

    Re: LCC plates

    Quote Originally Posted by Jack View Post
    .....
    3) The material I settled on is called 40% transmissive "standard diffusion" plexi, again I used the 1/8th" thickness. This material has a nominal 1-stop offset, but the reality is the histo is so close to centered that you don't need to actually add the offset -- very convenient when shooting! This generated an identical LCC to the CI plate.
    Jack, I went to the TAP plastics website (http://www.tapplastics.com), but I can't seem to find the material you're talking about. It's probably me being dense . Maybe you could provide a link? Many thanks.

    Cheers, -Peter

  16. #16
    Sr. Administrator Jack's Avatar
    Join Date
    Oct 2007
    Location
    Los Altos, CA
    Posts
    10,486
    Post Thanks / Like
    Images
    1031

    Re: LCC plates

    Quote Originally Posted by alan_w_george View Post
    Just curious, I don't really understand the objectionable difference from a workflow perspective between a 3, 2, or 1 stop LCC. Almost 50% of my exposures are LCCs. I use the ExpoDisc thing and have never thought twice about it.
    Alan, it's simple -- I am lazy and don't want to have to change the exposure for the LCC! . In my capture workflow, I compose, tweak, wait for the light and make my capture, then shoot my LCC's after my main capture but before moving on to my next image. In a studio environment with flash, it can be tricky to try and add exposure without changing aperture, so having a plate that requires no exposure adjustment is a benefit as it simplifies my workflow.
    Jack
    home: www.getdpi.com

    "Perfection is not attainable. But if we chase perfection, we can catch excellence."

  17. #17
    Sr. Administrator Jack's Avatar
    Join Date
    Oct 2007
    Location
    Los Altos, CA
    Posts
    10,486
    Post Thanks / Like
    Images
    1031

    Re: LCC plates

    Quote Originally Posted by PeterL View Post
    Jack, I went to the TAP plastics website (http://www.tapplastics.com), but I can't seem to find the material you're talking about. It's probably me being dense . Maybe you could provide a link? Many thanks.

    Cheers, -Peter
    Peter,

    You might have to call them and specify the 40% transmittance "translucent" 1/8th Acrylite. It might be what they're calling "Lighting Sign White" on the site, but I'm not sure -- my local store specifically referred to it as 40% transmittance white acrylic. If you click on the physical properties link on this page and scroll down, you'll find its specs: http://www.tapplastics.com/shop/product.php?pid=340&
    Jack
    home: www.getdpi.com

    "Perfection is not attainable. But if we chase perfection, we can catch excellence."

  18. #18
    Senior Member
    Join Date
    Jun 2008
    Location
    SoCal
    Posts
    291
    Post Thanks / Like
    Images
    15

    Re: LCC plates

    Thanks Jack, I'll try that.

    Cheers, -Peter

  19. #19
    Senior Member
    Join Date
    May 2009
    Location
    Marseille, FRANCE
    Posts
    972
    Post Thanks / Like

    Re: LCC plates

    shipping 60$ + taxes for france... anyone knows a source in france or CEE ?

  20. #20
    Senior Member
    Join Date
    May 2009
    Location
    Marseille, FRANCE
    Posts
    972
    Post Thanks / Like

    Re: LCC plates

    and what about using a ground glass ?

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •