Bellows extension, portrait capability.

[Bill Ballhorn]

I have a Calumet 45N which has ~430mm of bellows draw from front of lens board t o the film plane. Will this be enough draw for a 300mm lens to do a head and sho ulder portrait? I'm reluctant to purchase a shorter lens for portrait work and s uggestions would be appreciated.

[John H. Henderson]

I haven't the experience but do have the math. 300mm lens with 430mm of bellows draw will allow you to focus as close as 992mm (call it a meter). At a meter, the long dimension of the film will capture about 11.5 inches of object. (I pull out a ruler and hold it to my head.) You'd get a nice, close picture of my head. So you can even back out a little. Math says you can do it (if I did the math correctly).

[Chris Ellinger]

A 300mm lens and 430mm of bellows should produce a magnification of approximately 0.45, which is more than enough for head and shoulders.

[Ken Burns]

Bill: As a rule of thumb, when the lens extension is 1.4 (that's the square root of 2)times its focal length, the image will be 1/2 life size and a 1-stop increase in exposure is necessary. Therefore your 300 will give an image about 1/2 life size when extended 430mm. It should work beautifully for head and shoulder portraits with less extension than that. With that much extension, you can probably move in close enough for a really tight face shot, though at 1/2 life size the lens will be only about 4 focal lengths from the subject (in this case, about 4 feet).

[Wayne]

"though at 1/2 life size the lens will be only about 4 focal lengths from the subject (in this case, about 4 feet)."

And they better have a really small face if you expect to get it on 4x5 at 1/2 life size