Question about back tilt on 69

[BernardLanguillier]

Michael,

Congrats on your new system, I wouldn't mind playing with that one, although the Linhof is a bit too heavy for my type of shooting.

Anyway, one question for you.

You mention that using back tilt to modify the plane of focus is an option that doesn't affect much image circle. That is correct, but back tilt typically results in the clear underexposure of the foreground since the distance the light has to travel to reach the sensor becomes longer for the upper part of the image than it is for the lower part of the image.

How much it differs is a function of the angle, but also of the absolute distance between the lens and sensor plane.

The effect will be stronger with a 69 back than it will be with a 4*5 camera, since the lenses will be wider, and the absolute distance between sensor and lens will be shorter.

I use back tilt a lot on my Ebony, and can already clearly see the effect when using a 110 m Schneider lens as soon as I use significant back tilt. I would think that it would really show a lot on your 69.

Have you witnessed any such effects?

Thank you in advance,

Regards,
Bernard

[michael]

For landscape work the amount of swing or tilt isn't that great. Closeup it would be an issue though. A simple gradient correction in Photoshop is all that's needed if it becomes an issue.

Michael

[Anon E. Mouse]

The effect will be stronger with a 69 back than it will be with a 4*5 camera, since the lenses will be wider, and the absolute distance between sensor and lens will be shorter.

Not really because you won't end up using a greater tilt and you are dealing with a smaller format. Focal length is not the issue as what you are doing is intersecting planes - object plane and plane of focus. While you may think the difference between two specifics points on the image plane may be greater with a shorter focal length lens, it is not true as the film size is different as well. So basically focal length will not affect the degree of fall off between two different format cameras have the same angle of view.