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Archive 2014 · 17mm TS-E at Full Shift Question

  
 
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p.1 #1 · p.1 #1 · 17mm TS-E at Full Shift Question


Is there a way to minimize the softness at the edges when I use the lens at full shift?
I realise it's something I have to live with when using a TS lens.
I'm using a tripod at full extension with a remote release.
Unfortunately, I'm not 20ft tall, so when I have to, I need to be at full shift.

Is there anything that can help? Maybe really small apertures (beyond f11), refocusing for the edge, or any PP techniques?

Thank you



Oct 19, 2014 at 07:07 AM
jcolwell
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p.1 #2 · p.1 #2 · 17mm TS-E at Full Shift Question


Fred made some relevant comments about best practise for focusing the TS-E 17/4L in a 17mm/18mm image comparison thread that I posted early this year.

Fred Miranda wrote:
...It does not seem you are taking in consideration field curvature. The TS-E 17mm has a mild field curvature and therefore you need to focus on the center to evaluate center resolution and extreme edges to evaluate that area....


https://www.fredmiranda.com/forum/topic/1267345/2#12075780



Oct 19, 2014 at 08:12 AM
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p.1 #3 · p.1 #3 · 17mm TS-E at Full Shift Question


jcolwell wrote:
Fred made some relevant comments about best practise for focusing the TS-E 17/4L in a 17mm/18mm image comparison thread that I posted early this year.

https://www.fredmiranda.com/forum/topic/1267345/2#12075780


Thank you very much



Oct 19, 2014 at 08:52 AM
Gunzorro
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p.1 #4 · p.1 #4 · 17mm TS-E at Full Shift Question


Also, an old trick from the view camera days photographing skyscrapers with maximum rise on UWA lenses such as 65mm (equiv. to around 18mm in FF format):

It somewhat goes against logic, but tilt the lens opposite the plane of the subject, in order to allow more of the image circle to cover the sensor (or film) rather than using the peripheral area at the edge of the image circle which is always the poorest resolution and darkest (penumbra). This maneuver throws a significant amount of the image out of focus, so use maximum (or near) depth of field to cover the loss off sharpness. With DSLR lenses, this might mean stopping down to f/16 or f/22.

You need to carefully jockey the tilt/aperture combination for maximum benefit. It may require adjusting the lever of the camera body due to distortion in the image plane due to the tilt being introduced.

This technique is the opposite of the Scheimpflug Rule of tilting the lens to obtain the greatest DOF along a flat plane, ans is most often used in portrait photography to define an extremely shallow DOF.

A little tilt goes a long way! Using LV, you can see the edge of the image brighten up when "reverse-tilt" is introduced. Use the minimum amount and readjust the focus each time.

Here's a quickie diagram showing the lens on the right, the projected image circle, and the sensor on the left.







Oct 19, 2014 at 10:15 AM
Photonadave
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p.1 #5 · p.1 #5 · 17mm TS-E at Full Shift Question


My vote would be to shoot at f16 using a 16 ft. tripod while standing on a 16 ft. ladder.

I would think stopping down would help at the expense of lens center resolution.

Since I don't have this lens yet I'm looking forward to other posters hands-on experience (not involving tall tripods & ladders of course).
PS. I do have the TSE-24 II (love this lens) & before that the original version.



Oct 19, 2014 at 10:22 AM
RobertLynn
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p.1 #6 · p.1 #6 · 17mm TS-E at Full Shift Question


jcolwell wrote:
Fred made some relevant comments about best practise for focusing the TS-E 17/4L in a 17mm/18mm image comparison thread that I posted early this year.

https://www.fredmiranda.com/forum/topic/1267345/2#12075780


Another dog in the corners is the 16-35ii, and I wonder how much of that is field curvature.



Oct 19, 2014 at 10:36 AM
Photonadave
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p.1 #7 · p.1 #7 · 17mm TS-E at Full Shift Question


Gunzorro wrote:
"distortion in the image plane due to the tilt being introduced."

This got me thinking!

If there's any undesirable leftover perspective distortion, probably minimal in this case, due to the tilt it can be removed on PP.

On that note you can also just shift less keeping subject plane parallel to sensor or at your originally intended angle. This is probably not as effective as Gunzorro's technique up front however maybe easier and then correct to taste in PP.

IMO correcting a minor distortion in PP after using a tilt/shift lens's extreme movements that don't quite get you there is way better than correcting extreme distortion in PP from not using a tilt/shift lens in the first place.



Oct 19, 2014 at 10:55 AM
Gunzorro
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p.1 #8 · p.1 #8 · 17mm TS-E at Full Shift Question


Photonadave wrote:
This got me thinking!

If there's any undesirable leftover perspective distortion, probably minimal in this case, due to the tilt it can be removed on PP.

On that note you can also just shift less keeping subject plane parallel to sensor or at your originally intended angle. This is probably not as effective as Gunzorro's technique up front however maybe easier and then correct to taste in PP.

IMO correcting a minor distortion in PP after using a tilt/shift lens's extreme movements that don't quite get you there is way better than correcting extreme distortion in PP from not using a tilt/shift lens
...Show more

Absolutely!

I use LR's perspective correction tools and angle/crop adjustment all the time, with or without TSE lenses.

You are right about the possibility of intentionally leaving a slight tilt -- that is an often included addition to the technique I mentioned. Especially for buildings, they looked unnatural if absolutely ALL vertical distortion is removed -- look unnatural like they bevel outward if left perfectly straight sided.

If you are not using TS lenses and want to use PP to correct, make sure you leave an abundance of extra room on the sides (i.e. using a wider lens or moving further away), as it gets eaten up when the straightening begins. But that is certainly a valid method of correcting perspective "distortion".



Oct 19, 2014 at 11:04 AM
Jeff Donald
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p.1 #9 · p.1 #9 · 17mm TS-E at Full Shift Question


RobertLynn wrote:
Another dog in the corners is the 16-35ii, and I wonder how much of that is field curvature.


The 17mm TS-E is not really a "dog in the corners" when in the centered position, like the 16-35mm, i.e. not shifted. However, when shifted/and or tilted to the extreme, the corners may exhibit softer tendencies than when centered.



Oct 19, 2014 at 11:15 AM
Photonadave
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p.1 #10 · p.1 #10 · 17mm TS-E at Full Shift Question


Gunzorro wrote:
Absolutely!

I use LR's perspective correction tools and angle/crop adjustment all the time, with or without TSE lenses.

You are right about the possibility of intentionally leaving a slight tilt -- that is an often included addition to the technique I mentioned. Especially for buildings, they looked unnatural if absolutely ALL vertical distortion is removed -- look unnatural like they bevel outward if left perfectly straight sided.

If you are not using TS lenses and want to use PP to correct, make sure you leave an abundance of extra room on the sides (i.e. using a wider lens or
...Show more



PS. I also still have my old Sinar F, 3 lenses, Bags Bellows and all. That was way before digital editing! Back then I was getting in the last bit of correction tilting the printing easel and using Rube Goldberg-esque modifications tilting enlarger lens boards and such.



Oct 19, 2014 at 11:19 AM
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p.1 #11 · p.1 #11 · 17mm TS-E at Full Shift Question


Thank you all very much


Oct 19, 2014 at 12:06 PM
jcolwell
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p.1 #12 · p.1 #12 · 17mm TS-E at Full Shift Question


RobertLynn wrote:
Another dog in the corners is the 16-35ii, and I wonder how much of that is field curvature.

Jeff Donald wrote:
The 17mm TS-E is not really a "dog in the corners" when in the centered position...


Nor is the 16-35/2.8L II.




Oct 19, 2014 at 01:38 PM
SteveF
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p.1 #13 · p.1 #13 · 17mm TS-E at Full Shift Question


The few times when the fully shifted edges / corners of the 17tse bothered me in terms of their softness I used focus stacking to fix it. I think this goes along with field curvature being the issue.

Lately I've been more in the camp that it is only me and other obsessed photographers that care that the edge pixels are 0.002% fuzzier and just left well enough alone. But that is another topic.



Oct 20, 2014 at 07:46 PM
Gunzorro
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p.1 #14 · p.1 #14 · 17mm TS-E at Full Shift Question


SteveF wrote:
The few times when the fully shifted edges / corners of the 17tse bothered me in terms of their softness I used focus stacking to fix it. I think this goes along with field curvature being the issue.

Lately I've been more in the camp that it is only me and other obsessed photographers that care that the edge pixels are 0.002% fuzzier and just left well enough alone. But that is another topic.


Cool solution, Steve!

**********

I just wanted to add a note to my earlier diagram of tilting the lens: The amount of tilt to clear up the edge of the image circle is very minute, not like the exaggerated full tilt coverage I show in the diagram. In LV, you will see the edge brighten with a tiny tweak of the lens tilt, as the penumbra is moved out of the imaging area. I didn't want anyone thinking this was a difficult or extreme maneuver.



Oct 21, 2014 at 10:59 AM





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