HTS - how much tilt

[giulioz]

Hello,

I recently ventured into Hasselblad territory and acquired a H5D-40, three lenses and the HTS. I am a landscape photographer I am mainly interested in having sharp images from back to front. I am using the HTS mainly with the 24mm. My question is how much degree of tilt should I apply considering that I am using a tripod roughly tall 1,75 meters?

Thank you, Giulio

[jerome_m]

Tilt down about 1.5°.

[giulioz]

Thank you. Shall I focus at one third from the foreground or on the most distant object?

[paulgrundy]

Hello Giulio,

I recommend you google "Scheimpflug principle" which is what tilting the plane of focus is called. There are lots of diagrams etc. that explain how it works.

Paul

[jerome_m]

I recommend you google "Scheimpflug principle" which is what tilting the plane of focus is called. There are lots of diagrams etc. that explain how it works.

From that principle, you'll find out that, for the typical landscape picture, where you want the ground to be sharp from front to end, the tilt angle is defined by atan(f/h), where
-f is the focal length (lens + HTS, so 35m for the 24mm on the HTS) and
-h is the height of your tripod over the ground
It is a simple geometrical construction, where the plane of the ground, plane of the sensor (which is supposed to be vertical) and plane of the lens should meet right below the tripod. For the values of f and h given, you will find a bit less of 1.5°.

Shall I focus at one third from the foreground or on the most distant object?

If you are doing that, you don't need any depth of field for the ground and you will find out that all points on the ground are in focus (close and far away). You will need depth of field for objects not in the plane of the ground (like the top of nearby trees, etc...), but this depends on each particular picture.

In the particular case of the 24mm mounted on the HTS, you will also find out that:
-AF is deactivated
-it is almost impossible to estimate focus in the viewfinder (the lens is too slow and too wide angle)
-the distance indications on the lens barrel are no help
-the camera LCD is unreadable in sunlight outside, so reviewing your pictures is not really an option.

In practice, I focus by eye at my best estimate and use f/11 or f/16. That works.

[Wail]

I have just migrated from Nikon to Hasselblad, purely for the T/S attachment that is just marvellous; got fed-up of the Nikon lenses that just don't work so well with the D810 (worked well on my D3x).

With the lack of LiveView on the H5D-40, which is what I have, I was going to do a series of test to see what degree of tilt I'd need to get sharp edge to edge; as I could never workout the mathes in the Scheimpflug principle.

But the replied here have saved me a HUGE learning process that I was going to apply ...

Tilt down about 1.5°.

Straight to the point ... thank you for this.

I recommend you google "Scheimpflug principle" which is what tilting the plane of focus is called. There are lots of diagrams etc. that explain how it works.

From that principle, you'll find out that, for the typical landscape picture, where you want the ground to be sharp from front to end, the tilt angle is defined by atan(f/h), where
-f is the focal length (lens + HTS, so 35m for the 24mm on the HTS) and
-h is the height of your tripod over the ground
It is a simple geometrical construction, where the plane of the ground, plane of the sensor (which is supposed to be vertical) and plane of the lens should meet right below the tripod. For the values of f and h given, you will find a bit less of 1.5°.

Shall I focus at one third from the foreground or on the most distant object?

If you are doing that, you don't need any depth of field for the ground and you will find out that all points on the ground are in focus (close and far away). You will need depth of field for objects not in the plane of the ground (like the top of nearby trees, etc...), but this depends on each particular picture.

In the particular case of the 24mm mounted on the HTS, you will also find out that:
-AF is deactivated
-it is almost impossible to estimate focus in the viewfinder (the lens is too slow and too wide angle)
-the distance indications on the lens barrel are no help
-the camera LCD is unreadable in sunlight outside, so reviewing your pictures is not really an option.

In practice, I focus by eye at my best estimate and use f/11 or f/16. That works.

What a great detailed reply. Thank you so So SO much for this. It all makes sense to me now.

[giulioz]

Many thanks for all your reply, very helpful.

Giulio

[jerome_m]

You are almost embarrassing me. This stuff is actually not very complex, only misguided Internet fools make it appear to be so. Most of the time computations are not needed and tilt can be estimated by eye. OK: on the HCD24, it is difficult because the lens is slow and very wide-angle, but you can practice a bit with the HC80 first to get a feel on how the focus reacts to tilt. It will directly show in the viewfinder.

Even better: you could probably borrow an old view camera and try movements for an hour or so. You don't even need to put film in it and it will be easier to see what happens on a large ground glass.

[Wail]

You are almost embarrassing me. This stuff is actually not very complex, only misguided Internet fools make it appear to be so. Most of the time computations are not needed and tilt can be estimated by eye. OK: on the HCD24, it is difficult because the lens is slow and very wide-angle, but you can practice a bit with the HC80 first to get a feel on how the focus reacts to tilt. It will directly show in the viewfinder.

Even better: you could probably borrow an old view camera and try movements for an hour or so. You don't even need to put film in it and it will be easier to see what happens on a large ground glass.

Coming from Nikon to the H5D-40, it's a whole different world.

With the Nikon, I would focus on my subject, tilt the lens a bit, use LiveView to zoom in 100% to the bottom of the screen to see if that's in focus (if not tilt slightly some more), then zoom in 100% to the top of the screen and do the same.

Coming to the H5D-40, I don't have LiveView, and my immediate mistake was to take out the HTS for its first run with the 24mm lens; being so wide it's so hard to tell what's in focus and what's not.

Your advise on testing it first with the 80mm makes good sense

[NickT]

This was posted to your thread on Luminous Landscape:

http://www.snapi.org/snapi/Tilt_Calculator_Tutorial.html

I downloaded it and it looks great, going to test it with the HTS and see how it compares with my technique of standing the side of the camera and waving my arms about

[Wail]

Thank you, NickT; an excellent read. I've had that iOS application for some time now, but have always struggle with the mathematics for tilting.