I want share with you some observations on sharpness for painting documentation in normal (visible) photography.
Mirror lock-up shutter mode considerably increases sharpness.Mirror-lock Up mode. First I want to introduce you to the mirror-lock up mode that professional DSLR (Digital Single lens reflex) cameras have. This is really useful and you must always use it to get more sharp pictures. Just a brief note on what mirror-lock up mode means. When you take a shot in SLR camera, the reflex mirror goes up, the shutter blade opens to expose the sensor and finally shutter blades close and mirror returns down. This process introduces vibrations.
This test was done with the following parameters:
- Camera: Nikon D800 (modified for full spectrum UV-IR) on tripod
- Lens: Nikkor-H 85 mm, F5.6, Shutter speed 1/13s
I was a bit skeptical the mirror-up mode could have any influence on sharpness while using the camera on a tripod but see the images below (100% zoom, detail of the AIC color checker)!
Sharpness considerably betters in mirror-up mode.Mirror-lock up mode is less important for long exposure since vibration dies in less than one second.
Aperture. Each lens has its sweet spot when it comes to aperture. Find the right one for your specific lens and work with it. For the lens used in this test – and so for the pic above – it is F5.6, Otherwise the image quality is badly affected, in particular for smaller F where chromatic aberration becomes overwhelming. See test images below shot in aperture priority mode.
series of shots in Aperture Priority mode. F5.6 is the best aperture for this lens.
Thank yo for this – really useful
Ciao Antonio, since I’m a passionate photographer myself I was wondering, why you didn’t light the picture with artificial light (flash or continuous)? It would bring your shutter in an area where you don’t have to worry about that anymore. You have the checkered color bar for calibrating the image afterward anyway so even if your light source is not perfectly neutral it is not a problem.
Hi Paolo,
thanks a lot for your comment! I actually do use lot of lighting already. The problem is that I do basically close up photography with a tele lens so i need lot of light. I also have limits on the intensity of lighting since I’m shooting fine art. So, I need some long exposure. Anyway, though counter intuitive it could be, vibration turns out to be a problem when you do short exposure, let say below 1/60. Indeed, the vibration dies quickly so it affects short exposure images while its contribution in long exposure images becomes proportionally less important with increasing exposure time. By the way, there are no drawbacks in using mirror-up mode, at least for who like me does mostly studio photography. Compliments for your photo portfolio!