Depth of field

[mathrafal]

I have been working for some years with 360 x 180 degree panoramas, using standard equipment, including 10,5 and 8 mm lenses.

However, I have recently been trying to develop techniques for using longer focal lengths. At the moment, this has been relatively successful with a 70 mm mosaic image (http://tactus360.com/panos/tylldal/index.html), but less successful with anything longer (http://tactus360.com/panos/roros/index.html). The problem is one of focus and depth of field. In the latter example, I refocused the camera for each row (I seem to remember that as 6 rows), and stupidly focused on infinity for the last two rows. These are clearly not in focus.

Since I have most often used fisheye lenses in the course of my work, I have never encountered depth of field problems, but here I feel out of my depth completely.

With each image that I provided above, I was using the lens at its sharpest aperture, which with the 70 was at F9 and with the 105 at F11. Any smaller than that and I am opening up myself for a soft image and also the biggest drag of them all . . . internal dust. However, this has cut down the hyperfocal length considerably.

Has anyone any tips they can give to help me sort out how and what I should be doing to overcome this dof problem?

Mathrafal

[FrankMi]

Hi Mathrafal. I don't know if it would help your panoramas, but for increased DoF I would try taking multiple shots of each view with several different focal points and combining them to get the greatest DoF, balanced colour tone, and exposure before stitching the images into the panorama. In Post #42 of Project 52 by Frank Miller, I tried this technique with 13 images before I created the panorama and it seems to have worked on this indoor shot. I'd need to play with this approach on a composition like yours to know if it is applicable to your work. That might be a good idea for a future Project 52 week. Thanks!