Effect of UV/IR filter on M240

[newnew]

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Hi all. I just acquired a lens that came with an UV/IR filter. It was probably used with M8 before. Do you know what is the effect on the colours of the IR component on M240 ? Should I rather get a UVa filter ? Thanks for your replies.

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[Ko.Fe.]

Get clear, protective filter. Everything else is unnecessary and only degrades IQ.

[lct]

Depends on the focal length. On WA and UWA lenses i could cause some cyan shift in the corners. Otherwise it can be useful to cut IRs on some foliage and black fabrics as the M240 is not the best at that. 

[adan]

Hold up the UV/IR filter and look through it. Then turn it side to side and you'll see its color changes as you look through it at an angle, getting more green/cyan when viewed at an angle. This is what will cause the cyan shifts in corners with wide angle lens (more and more, the wider the lens). Which also "look through" the filter at an angle near the picture corners. \ /

This is specific to the UV/IR filter, which blocks infrared light (and a bit of visible red). A regular UVa filter does not affect the red end of the spectrum.

The Leica M8 has specific computer corrections in the camera for this cyan-edge effect. Later cameras (M9/240/10) no longer provide that, and using UV/IR filters in not recommended by Leica (although many people try it).

Used with lenses 50mm-135mm, this effect will be minimal to nonexistent - and you may get slightly cleaner, purer colors overall by blocking infrared light (foliage/grass less brown/yellow and more green, less overall reddish tint). The post-M8 Leica cameras have about 1/50th the IR sensitivity as the M8 (thicker IR-blocking filter built right into the sensor package). But they still leak a little IR.

[jdlaing]

Is it a UV/IR or a UV/IR Cut filter?

[newnew]

Thanks for your responses. It is Leica 13421 and is used on a 24mm.

 

[Jean-Michel]

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3 hours ago, newnew said:

Hi all. I just acquired a lens that came with an UV/IR filter. It was probably used with M8 before. Do you know what is the effect on the colours of the IR component on M240 ? Should I rather get a UVa filter ? Thanks for your replies.

Hi, since you have the filter, simply do your own comparison, and perhaps share your results with the Forum. FYI, you can read some information on the filter for use on the M8 and M9 at https://lavidaleica.com/content/uvir-filters

On occasion, I have seen some IR contamination on some of my M9 images, but none on my M-P (240) images.

A UVa is all you need for protecting the front element. The one lens that I do not use a UV filter on is the 90 Marcro-Elmar.

[newnew]

Thanks Jean Michel. As the filter came together with the lens I thought I did not need to buy a new Series VII UVa, but from what I read, I need to to take it away and get just a clear filter, which may be difficult to find in Series VII. Maybe B&W has one; I need to check.

[a.noctilux]

Hello Ali,

you can buy new model UVa II (Leica Filter UVa II, Serie VII, black ref. 13044), check here

 

[darylgo]

Keep the uv /ir filter, you’ll get better color on a M240. Leica has a thin ir filter on all M digital cameras including the new M10 series, they all are effected by ir contamination. The SL by contrast has no leakage. Theoretically you might get corner change as suggested with wide lenses but I’ve never seen it, and it should easily be removed in post.  Try a few shots to check your corners, if you see cyan color then consider a change, if not keep the filter as I’ve found these to be excellent quality. 

[newnew]

Thanks Darylgo. Interesting suggestion. I need to check all these effects before getting rid of it. Anyhow I have also ordered a ND filter that should give the protection function   

[Jeff S]

5 minutes ago, newnew said:

Anyhow I have also ordered a ND filter that should give the protection function   

An ND filter is for specialty needs, not general protection.

Jeff

[newnew]

Agree. But when it just reduces 2 f stops on a Summi. Not a great deal till I need more than 3000 Iso