Jump to content

Cut Filter: Must See This


Guest guy_mancuso

Recommended Posts

  • Replies 307
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Posted Images

Guest guy_mancuso

I was in A mode and not sure they have a filter factor of 1 so in theory there is no exposure compensation but in reality you are cutting IF light which is still part of the visable light that a meter sees. So i would say slightly but that needs to be tested on manual and also when you WB sometimes exposures change slightly also. This is all very small stuff

Link to post
Share on other sites

Guest guy_mancuso
OK, time to take it indoors.

Many of the problem images I've seen posted and all the problems I've encountered with mine have been indoors with tungsten light.

 

Thanks for testing, though. :)

 

Robbe Gibson

 

 

Robbe go check the 1250 ISO stuff also to get some idea. It will take tungsten light and cut the IR which is heavier and converted to look like daylight. So indoors will have some effect for sure . I'm just out of time for that kind of test

Link to post
Share on other sites

OK, just did fast tests before I head out the door. Guy's absolutely right....these work!

 

I tested in incandescent light (which is heavy in IR) and the results came up aces. Blacks seem and read (RGB numbers) just where they should be. Will do full tests next week, compare to 5D, etc. but I am very happy with results and will use the M8s for tomorrow's wedding.

 

I think, for now, Leica is right....just use the filters. The improvement in incandescent light is dramatic.

 

BTW, have been speaking with Scheider USA Weds and Thurs and we've talked about the M8, etc. It's my hope that they will be bringing in many more of these filters in the sizes we need: 39, 46, etc.

 

Guy, I'm glad that the suggestion paid off for you so far.

 

Just spoke with Schneider again. The challenge is that these are very complex filters and it takes a long time to make them in Germany. My advice to anyone reading who is interested....snap em' up wherever you can find them. I suggested to Tony at Popflash that he order in a bunch of 39s, 46s, etc. and I believe he did but it may take awhile to get stock.

 

Also, at first blush it looks like the pictures with the IR cut actually seem to show *better* resolution than the naked lens (28 Summicron for example). Maybe I need to rethink my filter prejudices.

 

Lastly, for anyone who still had doubts, I'm absolutely convinced that IR is the source of the red cast. What a huge difference these filters make.

 

Cheers,

 

Sean

Link to post
Share on other sites

Guest guy_mancuso

Yes thanks for your help there also. i agree i think we will see even more effect on the inside with tungsten. it will corrct the magenta cast no doubt but will also change the color temp of the room to more daylight becuase tungsten is rich in IR . Man just think about how much IR light you are sitting in watching the boob tube, YUKS

Link to post
Share on other sites

Guy Looks good no green cast on my calibrated monitor, how much do they run?

 

I run two monitors side-by-side, one calibrated (for my Photoshop workspace) and one not (for tool palettes etc.) The whites look green on the uncalibrated one and fine on the calibrated one. It's kind of funny to drag the window so half of it's on one monitor and half is on the other -- really dramatizes the difference.

 

Moral of this story: calibrate your monitor before you get too sweaty about tweaking C1 settings!

 

Incidentally, for Mac users, you can calibrate just as well by eye as you can via a hardware calibrator if you check the "Advanced" box in the Display preference pane so you get all the extra options. Takes longer, but is quite accurate -- the eye has poor absolute color judgment but is a rather good comparator.

Link to post
Share on other sites

My monitor is calibrated too and they are green. I looked at the pictures in Photoshop and the one without has white at Lab=95, 0, 0. The one with the filter has white at Lab=95, -2, 1 which is indeed a green cast.

 

Yes, you can actually see this difference in the color checker shots. But it's still a good work around, if one can find the filters in the right sizes.

Link to post
Share on other sites

Guest guy_mancuso

Here is the key that we need to understand what in effect we have done is take out the offending light globally across the board so now your blacks are what they should be , now at this point you take that file and WB that in C1 and the extra cast goes away and in this case slightly green or you simply make a global adjustment in your C1 program. But the key is you are taking away the IR that is the Root cause here than simply make a fine WB or profile adjustment to your file. You can even in C1 chnage the tint and apply to a whole folder or change the color temp and do the same. What you are getting in the long run is a basic good file that now the small adjustments can be worked . Is it perfect well is magenta blacks perfect no but it is so close to it that it is the option that we need now as we wait for the permenant fix.Homestly droping 800 on filters was not my idea of fun but to get this into service to shoot a event or a wedding for some guys this is the only choice for now

Link to post
Share on other sites

Guy, I'm glad that the suggestion paid off for you so far.

 

Just spoke with Schneider again. The challenge is that these are very complex filters and it takes a long time to make them in Germany. My advice to anyone reading who is interested....snap em' up wherever you can find them. I suggested to Tony at Popflash that he order in a bunch of 39s, 46s, etc. and I believe he did but it may take awhile to get stock.

 

Also, at first blush it looks like the pictures with the IR cut actually seem to show *better* resolution than the naked lens (28 Summicron for example). Maybe I need to rethink my filter prejudices.

 

Sean

 

Guy,

Thanks for the work !

 

Sean,

Of course the filter augments rez, IR has a different focus point, so if you have IR it is splashing your image.

 

Edmund

Link to post
Share on other sites

Guest guy_mancuso

I think these filters are great for when you need them , but shooting oudoors in nice light and doing scenics and such , your not going to need them. These will be handy for indoors and when those blacks are present. i intend to leave them on , simply because i can make easy adjustments in C1. Remember i did not WB those images either because i was trying to show the effect they have so certain casts may not be there anyway.

Link to post
Share on other sites

Guy--You must have found the only supply of those filters in the USA. I've been calling all over and checking web sites trying to find a B+W 486 UV-IR Cut filter in E39 for my 35/2 asph, and nobody has it. Any hints?

Adorama lists it, although it's a special order item.

 

B + W 39mm Digital Pro UV/IR Blocking #486 Glass Filter for Blocking Ultra Violet and Infrared Radiation

Link to post
Share on other sites

This is very encouraging.

 

As far as the cyan corners go, i do see it when i'm looking for it. The explanation here is that the filters work basically like cheese cloth, they only let wavelengths of light through that can fit between the microscopic gaps in the coating. Light from steep angles is passing through and not getting completely blocked. I'm not smart enough to figure out why it would turn what used to be a magenta shift into cyan, but I'm sure there is a physics/sensor reason.

 

_mike

Link to post
Share on other sites

Andy i have not noticed any exposure effect at all it maybe in certain high IR lighting that may change a little. I honestly don't think our meter measures IR light and only the visable light, need a engineer to confirm that.

 

The pre-production M8 I had metered accurately with an 89b filter. A true joy to use for IR photography! 1/60 sec at f/8-11 in sunlight at 640.

 

With an 87 it didn't meter accurately.

 

Henning

Link to post
Share on other sites

Guy,

Thanks for the work !

 

Sean,

Of course the filter augments rez, IR has a different focus point, so if you have IR it is splashing your image.

 

Edmund

 

That's true in theory. I'll see in the comparison test what the actual difference is in practice. It certainly looks encouraging on that front.

 

Cheers,

 

Sean

Link to post
Share on other sites

Guest guy_mancuso

I went back and re process the filter shot with the Zeiss 21mm and did a WB from a color checker from the same light and added 100 kelvin to it and it looks pretty darn good now plus brought the value down a little. i am using a thick filter here and maybe getting something in the bottom right corner from it. They have thick and thin filters , maybe a thin one would have been better .

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...