Jump to content

another v basic one from me!


shootinglulu

Recommended Posts

Advertisement (gone after registration)

I recieved my planar 50 today, I am very pleased with it (the lens cap is cr*p though).

The filter i have for it is B+W uv haze filter and i am wondering if i should have got uv ir instead? I don't understand the filters really! The colours aren't quite right, esp greens.

Thanks

Lucy

Link to post
Share on other sites

Also I may add that once you have a UV-IR filter on your lens you will need to set the information in your M8 menu.

 

And when you have:

  1. Coded lenses with IR filter
  2. Coded lenses without IR filter because you havent received it yet
  3. Uncoded lenses

You will have to reset the information in you M8 meny every time you change lens. And will of course forget it from time to time, resulting funny colors in your pictures :)

 

(18mm lens without IR filter but camera set to IR filter results in some really psychedelic effects in the corners)

Link to post
Share on other sites

If all of your lenses are coded, and you keep a filter on each lens, then you will only have to set the menu once though. :)

 

Which is the only way that old bats :) (apologies Nicole - it is in your signature) . . and this old goat, can avoid getting funny colours in their pictures.

 

Of course Lucy - being young and sprightly and excellent at multi-tasking you won't have this problem.

 

More seriously, it is much the easiest option to get all your lenses coded, and a filter for each one.

Link to post
Share on other sites

If all of your lenses are coded, and you keep a filter on each lens, then you will only have to set the menu once though. :)

 

But keeping the filters on the lenses will give me an other problem them, strange looking colors on the pictures I take with my M6.

 

But as soon as I receive the the rest of my filter, which should be any day soon, I will probably keep them on most of the time and take them off when I use the M6.

 

If one should believe the rumors, I can sell all my filters when the M9 arrives though, but I guess the marked for them will collapse then.

Link to post
Share on other sites

That's very useful, I definately would have forgotten to tell the cam about the filter.

I'm just going to have this 50 for a while and then decide if i need 24 or 28 to go with it. Just the one lens keeps things simple for the mo, i'll definately look into coding later though. Thankyou!

Link to post
Share on other sites

But keeping the filters on the lenses will give me an other problem them, strange looking colors on the pictures I take with my M6. ...

Why would an IR blocking filter produce strange looking colours on film? The filter's only blocking infrared rays that your film couldn't record anyway.

 

Pete.

Link to post
Share on other sites

Why would an IR blocking filter produce strange looking colours on film? The filter's only blocking infrared rays that your film couldn't record anyway.

 

Pete.

Because oblique rays hitting the filter will be more heavily filtered than the central rays, so they will have a deficit of red and the corners of the picture will have a cyan colour shift -- even on film!

 

But the axial part of the image will look OK on film, while there will be 'funny colours' all over on digital, especially with black synthetics and leaf green

 

The old man from the Age of Cyan, Magenta and Yellow -- and Black

Link to post
Share on other sites

Why would an IR blocking filter produce strange looking colours on film? The filter's only blocking infrared rays that your film couldn't record anyway.

 

Pete.

 

Well, according to Leica it will produce strange colors, but who knows, maybe they don't know what they are talking about ;)

 

Quote from the folder supplied with each and every UV/IR from Leica:

"Because of the blocking effect of the filter, when using analog color film there will be undersirable color effects in the corners of the pictures; the filter should therefore not be used with such film"

Link to post
Share on other sites

Fair enough then, I can't deny what 'it says on the tin' but it defies logic for me because the filter is not blocking visible light, only infrared radiation and silver halide used in film emulsions (except IR film of course) is not susceptible to wavelengths above 700 nm.

 

Pete.

Link to post
Share on other sites

Fair enough then, I can't deny what 'it says on the tin' but it defies logic for me because the filter is not blocking visible light, only infrared radiation and silver halide used in film emulsions (except IR film of course) is not susceptible to wavelengths above 700 nm.

 

Pete.

Pete, this has nothing to do with IR. The interference layers of the filter are calculated so that they absorb nothing but IR, as long as the rays hitting the filter are more or less perpendicular to it. Visible light is not affected, and the filter looks completely clear.

 

But the interference that kills long-wave IR radiation is angle-dependent. Increase the angle and the filter starts filtering out visible red too. This deficit of red in the corners of the image leads to a relative surplus of the complementary colour, which is cyan. Hence the cyan shift. Q.E.D.

 

If you don't believe me, you can convince yourself by a simple experiment. Look at a piece of white paper through the UV/IR or 486 filter, holding the disc at a right angle to the direction of view. The paper looks white, as it should. Now slowly slant the filter and see what happens. -- This by the way is the cause of the famous 'red eye of Mordor' reflex effect seen with a UV/IR filter on the camera. The visible red that is filtered away is not annihilated by absorption, as with a green filter. It is kicked out the way it arrived, because the filter works on the principle of repeated reflection between coating layers. What does not go in, goes out. It's called 'conservation of energy'.

 

The old man from the Age of the Yellow Filter

Link to post
Share on other sites

Lars,

 

Thank you for your, as always, lucid and complete explanation - and, yes, I believe you.:D I wasn't familiar with the workings of interference filtering and its limitations but it appears that Mordor is alive and well and living in my UV/IR filter.

 

Pete.

Link to post
Share on other sites

Since we are talking about a 50mm lens I suggest fitting the B+W 486 UV/IR filter and don't worry about coding it at the moment as on a 50 you will not get any noticable cyan fringing. If you are using coded leica lenses as well simply leave your menu setting as 'lens detection on with UV/IR' which will work with the coded lenses and then will ignore the 50 when it doesn't detect a code present.

Link to post
Share on other sites

Archived

This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...