defektive
Aussie
I read somewhere that there was no benefit in using an ir cut filter on the summicron 90mm asph. Is this also the case with the E55 pre-asph summicron 90?
And is the E55 thread just the standard 55mm filter thread or do I need special filters?
Cheers,
Sam
And is the E55 thread just the standard 55mm filter thread or do I need special filters?
Cheers,
Sam
LCT
ex-newbie
You mean on M8 or M8.2 i guess. If so you will need IR-cut filters on every lens no matter their focal length can be.
Shade
Well-known
Yea if you're on the m8 or m8.2 you'll need the ir cut filter no matter the focal length..
jbr
Established
The sensor in the M8 has no (or not sufficient) IR-Filtering in front of it, so the IR-problem is independent of the focal length of the lens.
You may be referring to the 'magenta corners' which appear when using uncoded wide angle lenses; with coded lenses, this aberration is compensated by the firmware. With longer lenses there is no need for that so you can use them uncoded.
You may be referring to the 'magenta corners' which appear when using uncoded wide angle lenses; with coded lenses, this aberration is compensated by the firmware. With longer lenses there is no need for that so you can use them uncoded.
Roger Hicks
Veteran
It's possible to overstate the problem. Foliage, and black synthetic fabrics, will look better with a filter. Many other subjects won't show any problems at all. This is not theory: I have used my pre-aspheric 90/2 on all the digital Ms since they came out.
And yes, it is a standard thread.
Cheers,
R.
And yes, it is a standard thread.
Cheers,
R.
The M8 has a 0.5mm thick IR absorbing glass filter in front of the CCD. It gets rid of ~95%? When an object is dark in visible, but very bright in IR- the problem arises.
This case is all-black in visible.
This picture is with a modified Nikon Coolpix that is "full-spectrum", clear glass in place of the IR filter.
You get two artifacts introduced into the image: 1) the color shift, 2) a secondary image that is somewhat out of focus. Most lenses are not corrected for IR, and you get a blurred image as a result.
APO and Mirror lenses are corrected well enough for IR that this second problem does not show up. SO- on the 90 APO, color shift but no secondary image that blurs the picture.
Canon 85/2 on the Leica M8 without IR cut filter:
WITH IR Cut Filter.
Chloropyll in plants is a reflector of IR, so what is "green" in visible is white in IR.
This case is all-black in visible.
This picture is with a modified Nikon Coolpix that is "full-spectrum", clear glass in place of the IR filter.
You get two artifacts introduced into the image: 1) the color shift, 2) a secondary image that is somewhat out of focus. Most lenses are not corrected for IR, and you get a blurred image as a result.
APO and Mirror lenses are corrected well enough for IR that this second problem does not show up. SO- on the 90 APO, color shift but no secondary image that blurs the picture.
Canon 85/2 on the Leica M8 without IR cut filter:
WITH IR Cut Filter.
Chloropyll in plants is a reflector of IR, so what is "green" in visible is white in IR.
Last edited:
defektive
Aussie
Thanks for the info everyone.
Brian, it must be the APO function of the newer 90 that reduces the necessity of using a filter on it which means I will look at getting one for my version of the lens.
Brian, it must be the APO function of the newer 90 that reduces the necessity of using a filter on it which means I will look at getting one for my version of the lens.