Titlt/shift focussing methods

jerry12953

jerry12953

Suspended / Banned
Messages
12,421
Name
Jeremy Moore
Edit My Images
No
I've just got a Canon TS 24mm v2 lens off ebay at a reasonable price.

I've been reading up on the technicalities of focussing TS lenses and it looks like there's quite a steep learning curve involved.

Until I get the hang of it, can I avoid the risk of getting things wrong just by using a small aperture?
 
jerry12953 said:
I avoid the risk of getting things wrong just by using a small aperture?
Click to expand...
•


If you don't force anything. you can't damage anything.

Making mistakes is surely the best way to learn.
Search for "Scheimpflug effect"

Using a small aperture is not the right way to do it though
it won't damage anything either.
 
jerry12953 said:
Yes, I've read about the Scheimflug effect but until I get my head around it, I could with a quick and easy way of "getting it right"!
Click to expand...

There isn't a quick and easy way I'm afraid, practice is the answer. I've shot a half dozen boxes of sheet film on my 54 and still miss focus and thats with the (relatively) giant gg to aid focusing. At least with a digital t/s lens you can cheaply practice and bracket so you'll at least get something from your labours.
 
jerry12953 said:
I could with a quick and easy way of "getting it right"!
Click to expand...
Have you got a specific example in mind? - it's always easier to figure out a concept with a concrete example rather than in the abstract.

It took me a while just to get my head around which way to tilt a lens to get the effect I wanted - the plane of the front element lies between the plane of the sensor and the intended plane of focus.

i.e. if your intended plane of focus is horozintal along the floor like this ____ and your camera is being held horizontal with the sensor plane like this | then the lens front element will tilt forward like this \


focus plane _____ \ front element | sensor <----- shooting right-to-left


Edit: and focus peaking makes it so much easier...
 
Last edited:
steveo_mcg said:
There isn't a quick and easy way I'm afraid, practice is the answer
Click to expand...
•


My sons would certainly not agree with this statement!
True, they have a teacher at home but getting the right
instructions is key, that's the first homework.
 
The sort of thing I have in mind is to make the foreground more prominent in the image while retaining focus there and at infinity. Is that what's described as "looming"?

I like the way you've used the keyboard symbols to show what you mean. Would I be correct in believing that the slash symbol at the end is at a more vertical angle than the lens would be in reality?

In other words the lens tilt is not that steep?
 
Last edited:
when you tilt a lens You are shifting the plane of focus.
The depth of field effect also shifts, and is at 90 degrees to the plane of the focus.
For example... if the new plane of focus is along the ground extending into the distance, at wide open the base of a tree might be well focussed, but the trunk and the top out of focus.
As you stop down the tree will become progressively in focus from the base up.

This is exactly the same as with front movements in large format.
 
Kodiak Qc said:
•


My sons would certainly not agree with this statement!
True, they have a teacher at home but getting the right
instructions is key, that's the first homework.
Click to expand...

Yeah perhaps it's easier when someone shows you where you're going wrong or can explain it in enough different ways for it to click.
 
steveo_mcg said:
If you're going to stop right down you don't really need the t/s it's just further complication, you could get front to back focus at f16 any way with a 35mm, can't you?
Click to expand...

Stopping down to F16 does not change the point of maximum focus. it only increases the apparent depth of field.

Swinging a lens changes the plane of focus so that that entire new plane is at maximum focus.
 
steveo_mcg said:
If you're going to stop right down you don't really need the t/s it's just further complication, you could get front to back focus at f16 any way with a 35mm, can't you?
Click to expand...


Isn't tilting a method of bringing the foreground up into the image more than it otherwise would be? A bit like using the perspective controls in your software but retaining the quality?

That's the sort of thing I'll be looking for.
 
Last edited:
Terrywoodenpic said:
Stopping down to F16 does not change the point of maximum focus. it only increases the apparent depth of field.

Swinging a lens changes the plane of focus so that that entire new plane is at maximum focus.
Click to expand...


That's the sort of thing I'm having real difficulties with understanding at the moment, not having used the lens yet. Nor have I used a large format camera.
 
jerry12953 said:
Isn't tilting a method of bringing the foreground up into the image more than it otherwise would be? A bit like using the perspective controls in your software but retaining the quality?

That's the sort of thing I'll be looking for.
Click to expand...

You can use tilt for a couple of things, mostly its used for front to back sharp focus on LF cameras where the dof is literally mm thin at usual apertures. You can also use it to de/emphasise elements in the foreground relative to the back ground, for example making a small flower in the front part of the image seem much larger than it otherwise would. I'm not sure how you'd manipulate perspective with a t/s lens I'd use the rear tilt on my 54 to do that.

Tbh I'd just get out and shoot with it, make mistakes try stuff you'll learn much quicker than hypothetical discussions.
 
steveo_mcg said:
You can also use it to de/emphasise elements in the foreground relative to the back ground, for example making a small flower in the front part of the image seem much larger than it otherwise would.

Tbh I'd just get out and shoot with it, make mistakes try stuff you'll learn much quicker than hypothetical discussions.
Click to expand...


That's the sort of thing......

I just wondered if there was a quick and easy rule of thumb to maximise depth of field/focus while I get to know the lens.
 
Terrywoodenpic said:
Stopping down to F16 does not change the point of maximum focus. it only increases the apparent depth of field.

Swinging a lens changes the plane of focus so that that entire new plane is at maximum focus.
Click to expand...

for the majority of cases these things are fungible. (Hyper) Focus point and small aperture will get a front to back sharp image with a miniature format if thats all you want. Adding tilt if all you want is f-b is largely an academic exercise for most folk round here.
 
jerry12953 said:
That's the sort of thing......

I just wondered if there was a quick and easy rule of thumb to maximise depth of field/focus while I get to know the lens.
Click to expand...

F8 and be there :)


More seriously though you'll find the number tilt really helps with focus is limited, all it takes a large tree in the mid field to be a bit higher than the focus plane and you've got f-b sharp image with an oof tree top etc.
 
Last edited:
steveo_mcg said:
make mistakes try stuff you'll learn much quicker than hypothetical discussions.
Click to expand...
•


+1

…working tethered is certainly an asset!
 
jerry12953 said:
Live view must be handy.........
Click to expand...
•


Not really as the picture lacks the quality of a shot in a converter.
A test shot and you know and see all you need!
 
jerry12953 said:
That's the sort of thing I'm having real difficulties with understanding at the moment, not having used the lens yet.
Click to expand...
I only use tilt adaptors with regular lenses rather than a dedicated t/s lens. I found setting myself specific challenges and then attempting them was the best way to understand the theory I was reading.

As a very quick example of an exercise I set myself, two books on a table top both angled away from the camera but in opposite directions. Without moving the camera only altering the tilt moving the focus along one book spine and then the other..






What I should have then done is a third tilt in a different plane to place the focal plane along the flat of the table...
 
ST4 said:
I only use the shift movements to help correct verticals. I would focus with the lens unshifted in live view manually, then shift it then fire the shutter.
Click to expand...

I take it you're working at fairly small apertures?
 
Sheimpflug isn't a complete answer with a TS lens, which only affects the front standard, but still well worth getting to grips with.
For your purpose, you're only using the tilt function, and you're only shooting on digital, which makes it all very easy.
Your lens will be wide open for focussing, so just focus with the lens tilted at the angle that either lies along the plane of sharp focus (if you want to extend the plane of sharp focus) or the opposite, if you want to de-focus most of the image, then stop down to get the effect you want.
My own tilt/shift is 80mm, which I use for product photography, I have no experience of using your 24mm lens but I'm guessing that due to the short focal length, which makes the effective aperture much smaller, the dof will be pretty deep even without the tilt, so I don't really see a problem unless you're shooting from realy short distances.

The fun begins when trying to photograph a deep subject, at an angle, with an 80mm lens with what is, compared to the movements on a LF camera, a very limited shift. This is where a tilt/shift comes into its own but sometimes it's still necessary to shoot with the subject at a less than ideal angle.
 
Last edited:
jerry12953 said:
Alastair..... it looks like you deliberately tried to get your depth of field to an absolute minimum in those shots?
Click to expand...
Purely to exaggerate the effect and make it easier to see the effect of the tilt. I could have shot them at f/16 but it would have been harder to distinguish the tilt effect rotating the plane of focus from the DOF extending the depth of acceptable focus either side of that plane.

The other benefit of that exercise was defining the limits of maximum tilt, just how far could I rotate the plane of focus from the plane of the sensor. The answer was, "Much further than I thought". You an see that the angle between those two book spines is a lot less than 90 degrees.

FWIW, those shots were with a CZJ Flek 35/2.4. There are faster primes that would reduce the DOF further.
 
I do not quite understand why but even when presented with a monorail with a full compliment of movements, few people today ever get to grips with using them.
Up to the 70's most professionals used movements on a daily basis and thought nothing of it. Setting movements was a basic function of setting up any large format camera, and took only moments.

On small cameras the shift function is by far the most useful and is easy to use, but as you are using the extremes of the lenses image circle the aperture needs to be quite small to compensate for the poorer quality found at the extremities.
As back movements are not available, the front swing or tilt is of little practical value. On large format back and front swings and tilts are almost always used in combination. The one to correct for distortion and the other for focus.
 
Kodiak Qc said:
There were no choice since the larger format had greatest flexibility but less DoF

DoF that is as it just focus as well as any other thing!
Click to expand...
We used movements for 2 reasons
1. Because we had them
2. Because we produced a very high standard of work. For example, for both product and architectural photography, we'd use shift all the time, drop front for product photography to show the top of the product without distortion, with tall buildings we'd raise the front to get all of the building in shot, in both cases the film would be square on - today's photographers think it's OK to tilt the camera for both and "correct" it in PP.
Kodiak Qc said:
DoF that is as it just focus as well as any other thing!
Click to expand...
Well, not for correcting focus, DOF is governed by the immutable laws of physics and tilting the lens doesn't change physics, what it does do is to change the PLANE of sharp focus, to run either along the top or the side, instead of being at one fixed point of sharpness with some other parts of the subject being not so far out of focus for people to notice.
 
Kodiak Qc said:
There were no choice since the larger format had greatest flexibility but less DoF

DoF that is as it just focus as well as any other thing!
Click to expand...

For a number of years I specialised in Shop photography, interiors, exteriors, windows, and fittings and components.
Mostly I used a monorail with full movements. I never once had a problem achieving the necessary depth of field or distortion correction, either on location or in the studio.
Virtuall all of the better large format lenses have massive image circles and tiny minimum apertures. Diffraction on large format is almost never any sort of problem. Maximum movements are easily accommodated.

Tilt shift lenses are a very poor relation to the real thing.
 
Terrywoodenpic said:
Tilt shift lenses are a very poor relation to the real thing.
Click to expand...
•

You got that right for sure :) but I have to do
with the 24 and the 85 as it is the only way
to approach the wanted results in FX.
 
Alastair said:
I only use tilt adaptors with regular lenses rather than a dedicated t/s lens. I found setting myself specific challenges and then attempting them was the best way to understand the theory I was reading.

As a very quick example of an exercise I set myself, two books on a table top both angled away from the camera but in opposite directions. Without moving the camera only altering the tilt moving the focus along one book spine and then the other..






What I should have then done is a third tilt in a different plane to place the focal plane along the flat of the table...
Click to expand...

Had you placed the plane of focus along the plane of the table, and about a centermeter or so above it, and set a moderate aperture all the books and table surface would have been in focus. Everything above and below would have been out of focus.
 
jerry12953 said:
I'm beginning to wonder if the lens can do what I want it to do !

Time to go out and have a play, methinks. :)
Click to expand...

I'm certain it can, I just can't visualise the way to set the camera up to do so.

I suspect you need to treat the body as the rear part of the LF camera and tilt the base towards the object you want to emphasise and then use the lens to correct the view.
 
Last edited:
You must log in or register to reply here.
Back
Top