Just wondering if using IR cut filters with the M9 has any impact on how crisp the shot comes out? Does it have any negative side effects?I kept the M8, after getting the M9 and M Monochrom. It has 1/8000th shutter speed which is great for using lenses wide-open. Used with the IR cut filter, The images are "crisper" than the M9. It usually has a C-Sonnar on it, but for these shots- the Jupiter-9. At low-ISO, the images are very clean. With LR4: ISO 1250 is very good on mine, and I'll use it at 2500 with decent results.
CheersThe M8 has a 0.5mm IR absorbing filter over the sensor, the M9 has a 0.8mm filter which is probably more efficient at absorbing IR. The latter also blurs the image a bit, like a weak AA filter.
The M8 with an IR cut filter does knock out more IR than the M9 without the filter over the lens, but the difference is very small. I did a test using the Wii light bar.