Hi to all, I am doing 35 mm, 645,4x5 (I have lens 210mm), I want to start 8x10 ,and take picture of faces of people in 1:1 size on the film, of course they won't like it , but I like it. And I don't want to have distortion like 210mm on 4x5 ,there is slight one. What lens will you recommend ? I like 100mm lens on 35 mm camera ,So it will be 600mm or 720mm on 8x10 ? Is there big difference on distortion between 600mm and 720mm? Please give me any advice Thank you very much.

-- Kazuhiro Tsuji (semua@earthlink.net), June 11, 2000

Answers

A 600mm or longer would be great for portraits, but I doubt you have the bellows extension to get 1:1 with a 600mm lens. You will need a 1200mm bellows! You will probably need to use the longest lens that you can focus to 1:1.

-- William Marderness (wmarderness@hotmail.com), June 11, 2000.

If you are looking to do 1:1 head shots on film, I believe the size you want is 11x14 rather than 8x10.

-- Donald Brewster (dpbrewster@prodigy.net), June 11, 2000.

Are you concerned about lens distortion or are you confusing that with foreshortening which means that things closer to the lens are reproduced larger then things further from the lens?

that isn't distortion. All lenses of a given focal length will all do it equally.

-- Bob Salomon (bobsalomon@mindspring.com), June 11, 2000.

The deciding factor of how much "distortion" is apparent is how to minimize the differences in differences betwenn say the tip of a persons nose (point A) and the back edge of their earlobe (point B) , and the lens nodal point (point C). This is solved by finding a working distance where the differences between "A to C" and "B to C" are minimized and then choosing a lens which best fills your format. You'll then need to select an f/stop which will render a sharp image of the back of the ear and the tip of the nose -- if that depth of field is what you are looking for.

From the point of view of the audience how much the 3D object that has been photographed appears to be "distorted" in the final image by its rendering in 2D is determined somewhat by viewing distance.

For more info on this see Ansel Adams' book The Camera.

-- Ellis Vener (evphoto@insync.net), June 11, 2000.

A friend of mine did a series of very tight portraits at 1:1 with an 8x10 using a 14" Commercial Ektar lens. The results were very pleasing. Bear in mind that a whole adult head won't fit on 8x10 at actual size-- you'll be getting tightly cropped 'face shots' this way. Also, depth of field will be very limited.

---Carl

-- Carl Weese (cweese@earthlink.net), June 12, 2000.