I am looking at a fuji lens for my 4x5. The lens has an image circle of 213. Do you think that would be generally acceptable? I want to do some portraits as well as urban work. Thanks.
Alexis
I am looking at a fuji lens for my 4x5. The lens has an image circle of 213. Do you think that would be generally acceptable? I want to do some portraits as well as urban work. Thanks.
Alexis
Alexis
Sinar F1
Toyo 45AX
Chamonix 45N-2
too many others
213mm will cover the 4x5 format and give you the ability to use some tilt and swing without being excessively limiting. You don't mention focal length which would be a consideration with portraits. Consider the distance you will be working at for your desired objective (head and shoulders, full-length, "environmental" portraiture).
Hi Alexis,
The full diagonal of 4x5 is 163mm.
Your 213mm ic should cover that easily, but...
It depend entirely on how that ic is defined. Image circle is not a fixed value.
It will be smallest when the lens is focused at infinity and the aperture is fully open.
Focusing closer and/or closing the aperture will increase the ic.
Some lenses give the ic diameter when wide open.
Others give a value when stopped down (by two stops or to f/22 or ???), which will be larger.
You must review the lens' datasheet carefully.
Urban scenes are most sensitive to ic because you have fine detail throughout the field of view.
- Leigh
If you believe you can, or you believe you can't... you're right.
Sorry. the focal length is 300mm. I anticipate casual portraits generally half length or perhaps a full length outdoor/environmental shot. Thanks.
Alexis
Sinar F1
Toyo 45AX
Chamonix 45N-2
too many others
OK Leigh, so for example, if I were to have the subject about 5 feet away at an aperture of f8, that would have more of a image circle than a subject 15 feet away at an aperture of f 48?Originally Posted by Leigh
Alexis
Sinar F1
Toyo 45AX
Chamonix 45N-2
too many others
Hi Alexis,
That's correct.
The image circle is a cone with its apex at the rear node of the lens.
The rear node is in front of the film by a distance equal to the lens focal length when focused at infinity.
In fact, that's the definition of lens focal length.
To focus on a closer subject you move the lens farther from the film.
Envisioning that cone, as the lens moves forward the diameter of the cone at the film plane increases.
- Leigh
If you believe you can, or you believe you can't... you're right.
Re coverage a near distances given coverage at infinity, see post #3 in this http://www.largeformatphotography.in...-lens-coverage discussion.
Leigh, isn't 4x5's image area's diagonal much closer to 150 mm than to 163?
Hi Dan,
The geometric diagonal of a 4" x 5" rectangle is 163mm.
The actual area on which light impinges when used in a regular film holder is likely closer to 150 than to 163.
As you approach the edge of coverage, light intensity drops gradually, not instantly.
I always use the larger number as a way to compensate for makers' fudge factors and "allowable" light falloff.
There's no way to tell what that fudge factor is/was.
And no way to tell how critical the corners are to a particular scene or shooter.
And as I stated earlier, the number is just a number supplied by the lens maker.
Its real value can vary both + and - for many reasons with any particular shot.
- Leigh
If you believe you can, or you believe you can't... you're right.
You don't need a large image circle for portraiture.
Is it the Fujinon 300T?
Your stated IC seems quit small for a 300mm non-Tele.
If it is the 300T, it may not be the best lens for movements due to the position of the nodal point.
Lachlan.
You miss 100% of the shots you never take. -- Wayne Gretzky
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