I need to shoot some panoramas. Rather than rent a panoramic camera (i.e. a 6x17) for this I thought it better to get a wide angle lens for a 4x5 and crop to the same proportions. What would be a good focal length for this? I want to minimize distortion as much as possible. Right now I'm thinking of a 75mm or a 90mm. Any opions as to what is better for this application?

-- frank miller (fmiller4@acsu.buffal.edu), September 28, 1998

Answers

If you get a good lens, there will be no distortion visible on "ordinary" shots. 90, 75, 72, 58, 47, whatever you need to cover the required angle.

But I suspect that what you call "distortion", I call "perspective". If you make a print with a given lens, and then don't view the print at the correct distance, your picture will have false perspective.

For example, use a 90mm lens, and enlarge x2. The "correct" viewing distance is then 180mm. With a 47mm lens, enlarged x2, the correct viewing distance is only 94mm. If you can't squint that close, but hold the print 300mm from your eyes, you will get a false perspective, and three-dimensional objects will appear "stretched" away from the picture centre.

So if you don't want this effect, just work out the degree of enlargement and the viewing distance (200-300mm for prints, more for gallery walls), and choose your lens accordingly. Bear in mind that we tend to look at pictures at a distance roughly equal to the picture's diagonal, which is why "standard" lenses are equal to the film's diagonal (because they don't give this false perspective).

So to be really picky, suppose you want to crop a 5x4 negative down to 6x17 format. The usable part of the negative will be 5x1.77", and the diagonal will be 5.3", or 134mm. So a 135mm lens will be the "standard".

-- Alan Gibson (gibson.al@mail.dec.com), September 28, 1998.

According to the table published in the March/April 1998 issue of View Camera, if you are comparing the longest film dimension (length NOT diagonal) a 75mm lens on 4x5 will give you the same horizontal coverage as the 105mm lens on the Fuji G617. Both are equal to a 23mm lens on a 35mm camera. If you are using a 90mm on a 6x17cm format camera you will need the 58mm Super Angulon XL or a 65mm (90mm on 617= 19mm lens in 35mm; 58mmXL= 17mm in 35mm; 65mm= 19mm in 35mm). How wide you might need to go will be determined by your subject matter. With some subjects, a 300mm lens on a 6x17cm is panoramic. Which is why I shoot with a V-Pan and look forward to the Lotus Camera 6x17cm back later this year. Your crop on a 4x5 piece of film will be approx 1.65 inches x 5 inches.

-- Ellis (evphoto@insync.net), September 28, 1998.

One issue that neither Alan or I addressed in our earlier answers is the change in apparent near/far relationships caused by using different focal length lenses. To fill the frame with a 75mm lens or 65mm(on 4x5) will require you to get closer than you need to with a 105mm or 90mm lens (on a 6x17cm camera). This will enlarge objects in the foreground in relation to the background. Perhaps this is what you mean by distortion? Because of how much you are going to have to crop, you might consider rental or purchase of a 6x12cm back along with the wide angle len(es) if you are going to be shooting several panoramics. The equivalent focal lengths change slightly.

-- Ellis (evphoto@insync.net), September 28, 1998.