Leica M8 / 8.2 With/Without IR Cut filter

Sonnar Brian

Sonnar Brian

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These are with the Leica M8, will add some more from the VNIR cameras as I get a chance.

Canon 85/2 on the M8, Wide-Open at F2:

Direct Sun, max reflection of IR.

Without:
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Heliopan IR Cut filter:
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Without, off-angle, not as much direct reflection:
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With Filter:
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I chose green leaves for the Chloropyll, which is a strong IR reflector. The FIltered images have a much more accurate color rendition of the original.
 
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The OOF area blue color in the second two is also different as one would expect. IR contamination isn't limited to highly reflective surfaces.
 
can anyone show the improvement in sharpness people are talking about?

Edit: I am shooting an M8 filterless at the time but mostly do b&w. I am interested in the sharpness gain though.
 
The sharpness gain depends on what camera you use. The quickest indicator is the IR focus mark on the lens. Lenses with an IR mark at F2, such as the Summicron, will not be much of a different. Lenses such as the Sonnar, with IR marks close to F5.6 and F8, will have more smear.
 
very interesting

very interesting

if your target is b/w, can you shoot unfiltered in color mode and have one or more of the 3 channels unaffected by the near ir shift?

I still haven't seen it, and am not yet sold on using filters for increased sharpness, especially in b/w, but I can understand why there may be some IR focus offset without a filter or enough filtering ... will have to try the J8 with and without IR filter to try to see differences now that I have a good focusing one.

I thought the marking space differeces on lenses of same length/speed were related to differences in films (750nm vs 850nm, Kodak or Konica) but the differences are in designs of the lens wrt IR too?


Brian Sweeney said:
The sharpness gain depends on what camera you use. The quickest indicator is the IR focus mark on the lens. Lenses with an IR mark at F2, such as the Summicron, will not be much of a different. Lenses such as the Sonnar, with IR marks close to F5.6 and F8, will have more smear.
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The 5cm lenses will not pick up any of the detrimental effects of the IR "hot mirror". I would not use it for night photography with streetlamps in the FOV, with film or digital.
 
I wouldn't

I wouldn't

use any filters with film, but I'd use a UV over a UV/IR cut, even though the film you use isn't likely to be sensitive to the wavelengths cut.

Lens make a difference as well, each lens lets in different frequencies of light, which is why the IR position marks on lenses vary.

UV transmission also varies. For example, I can use a UV light in a dark room and see the invisible band on US currency with a J8 (not sure of elements, Brian S. swapped them out from original), where a more modern lens like a CV 40/1.4, I cannot see the band with same procedure.

So a lot of the examples in this thread, the reason why I don't have these variances, is I don't use or have a lot of the lenses that are passing UV.

An interesting test would be, tripods, notation of lens, M8, without filter, with UV only filter, with UV/IR cut filter (and model noted, e.g. Leica, BW 486, etc.).


PAN F said:
Although I don't own a digital rangefinder camera at the present time,sometime in the future, I would like to purchase either an M8 or M8.2 in good secondhand condition.Bearing this in mind if I currently fitted my 5cm Summar and Fujinon with B&W UV/IR cut filters rather than standard UV filters (to guard against UV/IR filters being unobtainable in years to come in size 34mm and 40.5mm now that the M9 doesn't require their use) will they still be usable at present as ordinary UV's with colour film stock?.
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