Architecture. Shift lens compared to post processing test.

[John Crowe]

I have only done some quick and dirty tests with Hugin and PS CS6. I stitched a two shot image taken with a regular zoom at 70mm. One image with the horizon at the centre and one image slightly angled upward.

Hugin did a nicer job of stitching and repairing the converging verticals, but greatly reduced IQ over the entire frame. PS maintained the full resolution of the original images.

Then I used PS perspective crop to repair the converging verticals and while some of the central portion of the image was unaffected, much of the image experienced the same loss of resolution that Hugin caused.

A shift lens would avoid the loss in IQ. When I get out to an appropriate subject I will test my non-shift 50mm against my 50mm shift lens. Both are extremely high quality so it will be interesting to see. Will test with my 17 TS-E as well.

 

[Nigvo]

Interesting post! The two main benefits of t/s lens for me that you don't get in post are control over diffraction (I'd rather not stack images for DOF) and compositional assistance as a t/s is applied in real time while you frame vs in post at a PC. What say you?

The fact that you see the finished composition in the viewfinder. leads to much better composition, as you can adjust very precisely using vertical and diagonal shift.

This is difficult to understand, as we see in some posts in this thread, unless you have actually gone out and used one of these lenses to photograph architecture.

 

[Nigvo]

Today I took my 24mm TS lens to a local castle to see if there are any visual differences between using a shift lens, and correcting keystoning in post. The lens was on a tripod and in a fixed position. In one case the lens was shifted, in the other, shift was set to zero and the lens tilted to simulate a normal lens.

I looked at two cases: simple vertical shift and diagonal shift. I then made an approximate overlay of the images to get an idea of the differences.

Simple vertical shift is pretty close, with very minor differences probably due to my approximations. Diagonal shift does have some more noticeable differences.

I just wanted to do a geometrical comparison. The merits of using a shift lens compared to correcting in post are not the subject of this post.

“Everyone sees what you appear to be, few experience what you really are.”
- Niccolo` Machiavelli.

Please redo the test with a much greater tilt to the camera. And the best test would be trying to do this with a T/S and a non-tilt shift as T/S have better image quality characteristics to start with.

I used the TS for the keystone shots in my test to have a very well corrected lens for the comparisons. I wanted to see if keystone correction gave a different geometrical result. It does not change much in just vertical shift, but diagonal shift causes geometric differences.

I actually once shot a real life test image with my 24-120 to get the right framing. The distortions in the zoom played havoc with the keystone correction.

 

[Nigvo]

Hi,

I hope you are now convinced that perspective correction can reproduce the exact result of a T&S lens (in terms of geometry I mean).

I proved that for diagonal shift, it does not.

You prooved absolutely nothing, come on.

If maths don't lie, images often lie..

Each time I propose that you go to the scientific forum, you refuse. Why ???

You perfectly know you are not correct of course.

I proved with actual pictures taken with an actual camera that things do change.

I do not need armchair experts to huff and puff about things I can easily see and prove out in the field with actual pictures.

. Shifting does not distort .

Anybody (except you maybe) using a T&S lens knows that it creates perspective distorsion for 3D scene. How can't you see this ?

It takes 2 seconds to check, use maximum vertical + horizontal shift and look... It can work work more or less with simple architecture but as soon as there is relief like balconies) it is not good at all. Better to use it with moderation or step back when you can and not use it.

The highly corrected lens does not create "distortion". It faithfully records what is in front of the camera. If a very wide angle lens is used it gives results that are not good to look at. the photographer just has to use the right lens.

Here is the proof. Shot 1 24mm TS shot 2 45mm TS

--
“Everyone sees what you appear to be, few experience what you really are.”
- Niccolo` Machiavelli.
https://nigelvoak.blogspot.com/

 

[Nigvo]

In your examples the camera was not level. The look you want is achieved with diagonal shift.

You really need to read "View Camera Technique" by Leslie Stroebel or "The Camera" by Ansel Adams. You get to understand just what movements do and how the affect the picture.

 

[Nigvo]

Hi Mate, whats your thoughts on this thread

https://www.dpreview.com/forums/post/66218879

Ds

Well you are both right. I see some slight lens distortion in the other pictures too, but very old buildings here in Europe sag and bow with time.

My two pictures below show what happens when you use a zoom with barrel distortion and correct in post. A wonky building looks more wonky. Don't ask me why!

Here is a church that is 800 years old. It has survived at least a couple of strong earthquakes and the land in the mountains moves. My TS lens shows the bell tower leaning. But a test shot taken with a zoom shot and then corrected in post exaggerates the "Tower of Pisa" problems that this bell tower has. The wall on the left has problems too.

Tilt shift with the camera level

A test shot corrected in post









--
“Everyone sees what you appear to be, few experience what you really are.”
- Niccolo` Machiavelli.

NIGEL'S RAMBLES

nigelvoak.blogspot.com

 

[Dspider]

Hi Mate, whats your thoughts on this thread

https://www.dpreview.com/forums/post/66218879

Ds

Well you are both right. I see some slight lens distortion in the other pictures too, but very old buildings here in Europe sag and bow with time.

My two pictures below show what happens when you use a zoom with barrel distortion and correct in post. A wonky building looks more wonky. Don't ask me why!

Here is a church that is 800 years old. It has survived at least a couple of strong earthquakes and the land in the mountains moves. My TS lens shows the bell tower leaning. But a test shot taken with a zoom shot and then corrected in post exaggerates the "Tower of Pisa" problems that this bell tower has. The wall on the left has problems too.

Tilt shift with the camera level

A test shot corrected in post

cheers mate.

Ds

--
The confusion starts when the scientists can't agree amongst themselves. Henry F

 

[chrisfisheye]

In your examples the camera was not level.

The look you want is achieved with diagonal shift.

He had posted many times these pictures and you did not mention this at all, looks like you had not realised it was feasible until I added this information.

Strangely now you say that T&S and software corrections can match.. So when the result looks good you say that T&S can match but if the T&S result looks good then the software corrections can not !!!

Difficult to follow you...

 

[Reilly Diefenbach]

Hi Mate, whats your thoughts on this thread

https://www.dpreview.com/forums/post/66218879

Ds

Well you are both right. I see some slight lens distortion in the other pictures too, but very old buildings here in Europe sag and bow with time.

My two pictures below show what happens when you use a zoom with barrel distortion and correct in post. A wonky building looks more wonky. Don't ask me why!

Here is a church that is 800 years old. It has survived at least a couple of strong earthquakes and the land in the mountains moves. My TS lens shows the bell tower leaning. But a test shot taken with a zoom shot and then corrected in post exaggerates the "Tower of Pisa" problems that this bell tower has. The wall on the left has problems too.

A test shot corrected in post

How is this corrected in post? The whole left side of the pic is a blur and the tower is still racked.

It's not a tough fix.

Corrected in Post

 

[Nigvo]

You have over corrected and the shot has lost how it looked in reality

 

[Nigvo]

In your examples the camera was not level.

The look you want is achieved with diagonal shift.

He had posted many times these pictures and you did not mention this at all, looks like you had not realised it was feasible until I added this information.

Sure I know about diagonal shift with the TS and two way correcting in post.

Strangely now you say that T&S and software corrections can match.. So when the result looks good you say that T&S can match but if the T&S result looks good then the software corrections can not !!!

I said it can almost match with optical vertical shift but does not match with diagonal shift/ 2 way correction.

I posted example in the OP.

Difficult to follow you...

Not really.

 

[Reilly Diefenbach]

You have over corrected and the shot has lost how it looked in reality

Mmm no. The tower is absolutely no way racked to the right as you show it, otherwise it would have collapsed long ago.

I'm just glad you're not building my house :^)

 

[mfinley]

Today I took my 24mm TS lens to a local castle to see if there are any visual differences between using a shift lens, and correcting keystoning in post. The lens was on a tripod and in a fixed position. In one case the lens was shifted, in the other, shift was set to zero and the lens tilted to simulate a normal lens.

I looked at two cases: simple vertical shift and diagonal shift. I then made an approximate overlay of the images to get an idea of the differences.

Simple vertical shift is pretty close, with very minor differences probably due to my approximations. Diagonal shift does have some more noticeable differences.

I just wanted to do a geometrical comparison. The merits of using a shift lens compared to correcting in post are not the subject of this post.

“Everyone sees what you appear to be, few experience what you really are.”
- Niccolo` Machiavelli.

Please redo the test with a much greater tilt to the camera. And the best test would be trying to do this with a T/S and a non-tilt shift as T/S have better image quality characteristics to start with.

I used the TS for the keystone shots in my test to have a very well corrected lens for the comparisons. I wanted to see if keystone correction gave a different geometrical result. It does not change much in just vertical shift, but diagonal shift causes geometric differences.

I actually once shot a real life test image with my 24-120 to get the right framing. The distortions in the zoom played havoc with the keystone correction.

Thanks. I would love to see those results too if you ever post them.

 

[Nigvo]

You have over corrected and the shot has lost how it looked in reality

Mmm no. The tower is absolutely no way racked to the right as you show it, otherwise it would have collapsed long ago.

I'm just glad you're not building my house :^)

Ever seen the leaning tower of Pisa?

 

[Nigvo]

Today I took my 24mm TS lens to a local castle to see if there are any visual differences between using a shift lens, and correcting keystoning in post. The lens was on a tripod and in a fixed position. In one case the lens was shifted, in the other, shift was set to zero and the lens tilted to simulate a normal lens.

I looked at two cases: simple vertical shift and diagonal shift. I then made an approximate overlay of the images to get an idea of the differences.

Simple vertical shift is pretty close, with very minor differences probably due to my approximations. Diagonal shift does have some more noticeable differences.

I just wanted to do a geometrical comparison. The merits of using a shift lens compared to correcting in post are not the subject of this post.

“Everyone sees what you appear to be, few experience what you really are.”
- Niccolo` Machiavelli.

Please redo the test with a much greater tilt to the camera. And the best test would be trying to do this with a T/S and a non-tilt shift as T/S have better image quality characteristics to start with.

I used the TS for the keystone shots in my test to have a very well corrected lens for the comparisons. I wanted to see if keystone correction gave a different geometrical result. It does not change much in just vertical shift, but diagonal shift causes geometric differences.

I actually once shot a real life test image with my 24-120 to get the right framing. The distortions in the zoom played havoc with the keystone correction.

Thanks. I would love to see those results too if you ever post them.

Taken with a 24mm TS lens with a little diagonal shift, because I had a wall behind me and I could not centre on the door

Before

After correction in post



--
“Everyone sees what you appear to be, few experience what you really are.”
- Niccolo` Machiavelli.

NIGEL'S RAMBLES

nigelvoak.blogspot.com

 

[chrisfisheye]

Today I took my 24mm TS lens to a local castle to see if there are any visual differences between using a shift lens, and correcting keystoning in post. The lens was on a tripod and in a fixed position. In one case the lens was shifted, in the other, shift was set to zero and the lens tilted to simulate a normal lens.

I looked at two cases: simple vertical shift and diagonal shift. I then made an approximate overlay of the images to get an idea of the differences.

Simple vertical shift is pretty close, with very minor differences probably due to my approximations. Diagonal shift does have some more noticeable differences.

I just wanted to do a geometrical comparison. The merits of using a shift lens compared to correcting in post are not the subject of this post.

“Everyone sees what you appear to be, few experience what you really are.”
- Niccolo` Machiavelli.

Please redo the test with a much greater tilt to the camera. And the best test would be trying to do this with a T/S and a non-tilt shift as T/S have better image quality characteristics to start with.

I used the TS for the keystone shots in my test to have a very well corrected lens for the comparisons. I wanted to see if keystone correction gave a different geometrical result. It does not change much in just vertical shift, but diagonal shift causes geometric differences.

I actually once shot a real life test image with my 24-120 to get the right framing. The distortions in the zoom played havoc with the keystone correction.

Thanks. I would love to see those results too if you ever post them.

Taken with a 24mm TS lens with a little diagonal shift, because I had a wall behind me and I could not centre on the door

Before

After correction in post

And you omit to say thes 2 shots are not from the same position.

This tells a lot how rigourous you are in your tests !!!!

Everything is biased, these tests have simply no value. You have to shoot from the same position.

 

[Reilly Diefenbach]

You have over corrected and the shot has lost how it looked in reality

Mmm no. The tower is absolutely no way racked to the right as you show it, otherwise it would have collapsed long ago.

I'm just glad you're not building my house :^)

Ever seen the leaning tower of Pisa?

I have been up to the very top of the Tower of Pisa.

Where was your church shot taken? What town?

 

[Nigvo]

You have over corrected and the shot has lost how it looked in reality

Mmm no. The tower is absolutely no way racked to the right as you show it, otherwise it would have collapsed long ago.

I'm just glad you're not building my house :^)

Ever seen the leaning tower of Pisa?

I have been up to the very top of the Tower of Pisa.

Where was your church shot taken? What town?

Fivizzano in the Tosco Emilian Apennines

 

[Nigvo]

Today I took my 24mm TS lens to a local castle to see if there are any visual differences between using a shift lens, and correcting keystoning in post. The lens was on a tripod and in a fixed position. In one case the lens was shifted, in the other, shift was set to zero and the lens tilted to simulate a normal lens.

I looked at two cases: simple vertical shift and diagonal shift. I then made an approximate overlay of the images to get an idea of the differences.

Simple vertical shift is pretty close, with very minor differences probably due to my approximations. Diagonal shift does have some more noticeable differences.

I just wanted to do a geometrical comparison. The merits of using a shift lens compared to correcting in post are not the subject of this post.

“Everyone sees what you appear to be, few experience what you really are.”
- Niccolo` Machiavelli.

Please redo the test with a much greater tilt to the camera. And the best test would be trying to do this with a T/S and a non-tilt shift as T/S have better image quality characteristics to start with.

I used the TS for the keystone shots in my test to have a very well corrected lens for the comparisons. I wanted to see if keystone correction gave a different geometrical result. It does not change much in just vertical shift, but diagonal shift causes geometric differences.

I actually once shot a real life test image with my 24-120 to get the right framing. The distortions in the zoom played havoc with the keystone correction.

Thanks. I would love to see those results too if you ever post them.

Taken with a 24mm TS lens with a little diagonal shift, because I had a wall behind me and I could not centre on the door

Before

After correction in post

And you omit to say thes 2 shots are not from the same position.

This tells a lot how rigourous you are in your tests !!!!

Everything is biased, these tests have simply no value. You have to shoot from the same position.

They were taken from a distance of about a metre. But this difference is compensated for with the diagonal shift that I used.

The different shooting points changes nothing.

--
“Everyone sees what you appear to be, few experience what you really are.”
- Niccolo` Machiavelli.

NIGEL'S RAMBLES

nigelvoak.blogspot.com

 

[chrisfisheye]

The different shooting points changes nothing.

What can I say ?

We can not conclude anything from any of your tests. None of them are valid.