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Author Topic: Question for tilt-shifters  (Read 2290 times)

allegretto

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Question for tilt-shifters
« on: November 29, 2013, 10:33:29 am »

just had my first day with the Canon 24mm ts-e... wow, what an instrument! Was able to blow my Zeiss 21mm out of the water on DOF. Quite a tool.

The set up was my family about 30 ft in front of the camera and about 1000 ft of mountain a couple of tenths of a kilometer behind them. What was interesting to me was that at about 40-50% of available shift the entire scene, from people to the mountain peak were all in crisp focus by 5.6 and very pleasing to about f8. After that diffraction effects were getting more pronounced. By comparison, the Zeiss never covered it all at any f-stop and also ran into trouble in the f8-11 range.

An added bonus was that the mountain peak was more pronounced and properly keystoned vs. the 21. As said... what a tool

Now when I went much past 50% of available tilt, I began to lose focus of the peak and progressively down the mountain as tilt increased. This made sense since I sort of view the tilt as "laying back" the plane of focus. So maximal tilt decreases the vertical focus zone.

My question to you experienced folks is; suppose instead they were at the edge of a canyon and I wanted to keep the canyon walls in focus as far down as possible but still get the people in focus? Would this be a case for maximal (or at least significantly more) down-tilt? Or just the opposite? I will be trying this soon and get my answer, which I suspect is the former (increase tilt), but a quick answer will save me some time fumbling in the cold mountains for me and the family.

Thanks in advance
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Rob C

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Re: Question for tilt-shifters
« Reply #1 on: November 29, 2013, 11:14:41 am »

just had my first day with the Canon 24mm ts-e... wow, what an instrument! Was able to blow my Zeiss 21mm out of the water on DOF. Quite a tool.

The set up was my family about 30 ft in front of the camera and about 1000 ft of mountain a couple of tenths of a kilometer behind them. What was interesting to me was that at about 40-50% of available shift the entire scene, from people to the mountain peak were all in crisp focus by 5.6 and very pleasing to about f8. After that diffraction effects were getting more pronounced. By comparison, the Zeiss never covered it all at any f-stop and also ran into trouble in the f8-11 range.

An added bonus was that the mountain peak was more pronounced and properly keystoned vs. the 21. As said... what a tool

Now when I went much past 50% of available tilt, I began to lose focus of the peak and progressively down the mountain as tilt increased. This made sense since I sort of view the tilt as "laying back" the plane of focus. So maximal tilt decreases the vertical focus zone.

My question to you experienced folks is; suppose instead they were at the edge of a canyon and I wanted to keep the canyon walls in focus as far down as possible but still get the people in focus? Would this be a case for maximal (or at least significantly more) down-tilt? Or just the opposite? I will be trying this soon and get my answer, which I suspect is the former (increase tilt), but a quick answer will save me some time fumbling in the cold mountains for me and the family.

Thanks in advance


Would have been interesting to see the picture you made, especially a before and after tilting/shiting...

I'd thought the 21mm was meant to be excellent. I end up believing less and less about anything I read on the 'net, which is a bit of a sorry pass, when you think about it.

;-)

Rob C

allegretto

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Re: Question for tilt-shifters
« Reply #2 on: November 29, 2013, 11:22:41 am »

Be happy to post when I figure out how to do that on this forum. Will soon

Oh, the Zeiss 21mm is excellent in every way. But for DOF and keystoning the ts-e is a whole different thing




Would have been interesting to see the picture you made, especially a before and after tilting/shiting...

I'd thought the 21mm was meant to be excellent. I end up believing less and less about anything I read on the 'net, which is a bit of a sorry pass, when you think about it.

;-)

Rob C
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Eric Myrvaagnes

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Re: Question for tilt-shifters
« Reply #3 on: November 29, 2013, 11:28:10 am »

You are correct in thinking of the plane of focus being tilted. And what follows is that depth of field must be measured perpendicular to that tilted plane, not just fore and aft as with a non-tilting lens. That's why the peak lost focus as you tilted more.

Yes, please post some of the pictures.
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Jeremy Roussak

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Re: Question for tilt-shifters
« Reply #4 on: November 30, 2013, 03:41:44 am »

I end up believing less and less about anything I read on the 'net, which is a bit of a sorry pass, when you think about it.

Indeed: http://www.theonion.com/articles/factual-error-found-on-internet,102/

Jeremy
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Rob C

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Re: Question for tilt-shifters
« Reply #5 on: November 30, 2013, 04:22:32 am »

Indeed: http://www.theonion.com/articles/factual-error-found-on-internet,102/

Jeremy


Saturday morning devastation has set in; those old certainties I held dear are no more.

Do I light the wood-fire or wait unti it rains; if I wait and it rains in the afternoon, is it worth the hassle of lighting up late and thus having to clean out the ash on a Sunday morn for such meagre reward? Is it less expensive to burn wood or keep on with the electrical devices? Shall I do my accounts today, or wait until tomorrow when I shall feel the energy of a new month coursing through my veins? But then, will I have exinguished that rejuvenating flood with the realisation of the inevitable decline and fall of resources in a non-interest-paying conspiracy of banks? Can I strike a deal with that kid in Monaco?

Should have stayed in bed.

;-(

Rob C

WalterEG

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Re: Question for tilt-shifters
« Reply #6 on: November 30, 2013, 05:17:51 am »

Allegretto,

Welcome to the wonderful world of the 24mm Tilt/Shift.  I have used one for years and, at one time, I had the full set of siblings (45mm and 90mm at the time).

Attempted to accurately place an optimal plane of sharp focus is something the requires a great deal of practice — the issue is NOT the lens but the 35mm reflex viewfinder.  Perhapos live-view is a game-changer.  I don't know because I have not had a chance to dabble.

I came to DSLR photography nearly 10 years ago after 40 years of large format view cameras.  Lesson 1, page 1, paragraph 1 is that a tilt/shift does not a view camera make.  (For all sorts of reasons.)  It helps with the T/S and DSLR that I have an intuitive understanding of what is happening optically but it is still no walk in the park.

A good start is to get to grips with the fact that Depth of Field has nothing to do with altering the plane of focus and it is unfortunate that, for the sake of making sales simply, the camera brochures cloud the issue by applying incorrect terminology.

With regard to your alternative scenario, it is easiest to get a clear idea by realising that what you are dealing with is geometry — when you look at a scene you need to imagine lines through the scene and the angles of those lines and then start to set the tilt (or swing).  I suggest some practice time playing with receding ground or walls to get a feel for what is happening and, quite often, how little adjustment is called for.

Best wishes,

W
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Eric Myrvaagnes

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Re: Question for tilt-shifters
« Reply #7 on: November 30, 2013, 09:17:47 am »

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allegretto

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Re: Question for tilt-shifters
« Reply #8 on: November 30, 2013, 03:57:53 pm »

Oh yes…!!!

In designing the comparison of the Zeiss 21 to the 24 ts-e I have had several revelations in terms of understanding. And among the most relevant is that this is not a change in DOF magnitude. Or at least the "depth" is fairly unaltered. It is instead a shift of what I learned to envision as the "horopter". That is, the plane that is in best focus.

Second is that the "formula" for determining the proper amount of shift is a kind of "feel" rather than a quick and simple calculation. Though I'm sure there are approximating algorithms that someone can point out. But since you do have some great experience let me ask you; as I view different scenes and try to cover them with the lens, it strikes me that it's kind of log in that as I get to greater degrees of shift the delta between the effect of "one-mark" of change on the scale changes more as I advance on the scale. So the delta from 2-3 in change is smaller than the shift induced by 5-6

True?


and thanks for the welcome Do I read that you don't have the other focal lengths anymore?



Allegretto,

Welcome to the wonderful world of the 24mm Tilt/Shift.  I have used one for years and, at one time, I had the full set of siblings (45mm and 90mm at the time).

Attempted to accurately place an optimal plane of sharp focus is something the requires a great deal of practice — the issue is NOT the lens but the 35mm reflex viewfinder.  Perhapos live-view is a game-changer.  I don't know because I have not had a chance to dabble.

I came to DSLR photography nearly 10 years ago after 40 years of large format view cameras.  Lesson 1, page 1, paragraph 1 is that a tilt/shift does not a view camera make.  (For all sorts of reasons.)  It helps with the T/S and DSLR that I have an intuitive understanding of what is happening optically but it is still no walk in the park.

A good start is to get to grips with the fact that Depth of Field has nothing to do with altering the plane of focus and it is unfortunate that, for the sake of making sales simply, the camera brochures cloud the issue by applying incorrect terminology.

With regard to your alternative scenario, it is easiest to get a clear idea by realising that what you are dealing with is geometry — when you look at a scene you need to imagine lines through the scene and the angles of those lines and then start to set the tilt (or swing).  I suggest some practice time playing with receding ground or walls to get a feel for what is happening and, quite often, how little adjustment is called for.

Best wishes,

W
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CptZar

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Re: Question for tilt-shifters
« Reply #9 on: December 01, 2013, 04:44:54 pm »


The set up was my family about 30 ft in front of the camera and about 1000 ft of mountain a couple of tenths of a kilometer behind them. What was interesting to me was that at about 40-50% of available shift the entire scene, from people to the mountain peak were all in crisp focus by 5.6 and very pleasing to about f8. After that diffraction effects were getting more pronounced. By comparison, the Zeiss never covered it all at any f-stop and also ran into trouble in the f8-11 range.

Now when I went much past 50% of available tilt, I began to lose focus of the peak and progressively down the mountain as tilt increased. This made sense since I sort of view the tilt as "laying back" the plane of focus. So maximal tilt decreases the vertical focus zone.


So are you talking about shifting or tilting? The hyperfocal distance with f8 is 3.68m, about 12ft. That would make your picture sharp.  I am not sure what trouble you encountered at F/8-11. That is where landscape is usually done.

Have a look at http://www.cambridgeincolour.com. There is nice tilt/shift tutorial.

Hth

Jan

« Last Edit: December 02, 2013, 03:39:54 am by CptZar »
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Tony Jay

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Re: Question for tilt-shifters
« Reply #10 on: December 01, 2013, 10:33:31 pm »

I am also a bit confused.
Shifting does not change depth of field in any way.

With regard to what happens to depth of field with tilting that is slightly more complex.
It is true that tilting changes the plane of focus from vertical to another angle that is dependent on the amount of tilt employed.
However, the depth-of-field zone changes shape as well.
With no tilt it is bounded by parallel lines.
Once tilt is employed the depth-of-field zone becomes cone-shaped - narrowest close to the camera (and lens) and becoming progressively wider as one moves away from the camera.
Somewhat strange effects then become possible with a tall vertical object close to the camera such as a telephone pole where it can be possible for the middle parts of the pole to be in sharp focus and the top and bottom of the pole to be blurred. This is especially noticable if the tilt employed has altered the plane of focus to be parallel to the ground (assuming it is roughly flat).
Poles of the same height situated further away from the camera might be completely in focus.

All in all the Canon 24mm TS lens is a very good bit of glass and its performance, compared to the Zeiss 21mm lens might be reflected in your observations irrespective of its ability to tilt. It is also possible that your particular Zeiss 21mm lens may be a dud.

Tony Jay
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uaiomex

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Re: Question for tilt-shifters
« Reply #11 on: December 02, 2013, 12:58:01 am »

Canon TSE lenses make my cravings for digital medium format totally bearable. The super sharp optics of the new 24 and 17 approach bigger formats IQ and if i stitch, there's not much left to be desired.
But the best part is being able to shift and tilt like a field camera. T&S totally overrides any craving this side of an slr digital medium format. Pancake technical cameras are in another league but the whole package with lenses and back cost 10X.
Eduardo
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NancyP

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Re: Question for tilt-shifters
« Reply #12 on: December 02, 2013, 11:47:17 am »

Zeiss 21mm f/2.8 is a really lovely lens, but.....it doesn't tilt or shift. Comparing the depth of field of a shifted 24mm TS-E to a standard non-T/S lens, whether it is a Zeiss 21 or a 40 year old Vivitar 20mm lens, will always favor the TS lens - rule of optics.
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Rob C

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Re: Question for tilt-shifters
« Reply #13 on: December 02, 2013, 11:58:52 am »

Zeiss 21mm f/2.8 is a really lovely lens, but.....it doesn't tilt or shift. Comparing the depth of field of a shifted 24mm TS-E to a standard non-T/S lens, whether it is a Zeiss 21 or a 40 year old Vivitar 20mm lens, will always favor the TS lens - rule of optics.



Well, Nancy, in film days I'd have agreed with you; today, with the apparent penalties that sensors stick onto lenses that stop them being much use down smaller than f8, maybe a 21mm with film will be a better bet!

I used to have a 35mm PC NIkkor, and it did the rise/fall thing perfectly; all I had to do was stop down quite far and everything was solved. No tilt available or, really, needed for the few houses/apartments I shot. If Nikon made a straight 24mm PC or 17mm PC (without tilt) I'm sure it would be rather a useful gadget... I bet the existing Tilt/Shifters are often used that way too. I've thought of their old 28mm, but apparently it has a lot of CA problems with digital, and isn't really quite wide enough to be worth the bother.

Too late: the huricane shelter is now locked down.

;-)

Rob C
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