Tilt Shift vs. Photoshop

[Buckster]

For those among you lucky enough to have and use a true tilt shift lens AND Photoshop (so that you can actually make out any actual differences), what exactly ARE the differences please?

I want a T/S lens badly for architecture shots to straighten out the parallax when I can't get far enough away from the structure. When I do it in Photoshop (CS6), it works, but it still looks a bit wonky because there's no magic bullet to elevate my position to where it would have to be to actually get that "straight on" shot and the look of it. So my brain looks at the parallax-straightened shot and knows something's not quite right with it.

It would seem to me that the same problem would come from a t/s lens. While it would straighten the verticals' parallax problem, the POV would still be wrong for what we're seeing.

I'd love to hear from you lucky folks experienced with both to better understand the real differences.

Thanks!

 

[Robin_Usagani]

I cant add anything since I have never used one. I just want to say if you do want one, Samyang is coming out with one really soon that is easy on your wallet. I think it is a perfect lens to buy for a Samyang since they usually produce manual lenses. Canon T/S lenses are manual anyway.

 

[Buckster]

I cant add anything since I have never used one. I just want to say if you do want one, Samyang is coming out with one really soon that is easy on your wallet. I think it is a perfect lens to buy for a Samyang since they usually produce manual lenses. Canon T/S lenses are manual anyway.

Thanks Robin. That's good info to have. I'll have to keep a lookout for them.

 

[amolitor]

I think the biggest actual difference you'll find is that where with a T/S you have more control over the actual plane of focus. You can place the plane of focus on the front of the building, and use the shift to get the entire building into the frame without disturbing that. With the photoshop solution, you need to use DoF to cover the entire building (the plane of focus is NOT vertical, it will be parallel to the film plane, which is tilted).

This may or may not be an issue for you.

 

[Buckster]

I think the biggest actual difference you'll find is that where with a T/S you have more control over the actual plane of focus. You can place the plane of focus on the front of the building, and use the shift to get the entire building into the frame without disturbing that. With the photoshop solution, you need to use DoF to cover the entire building (the plane of focus is NOT vertical, it will be parallel to the film plane, which is tilted).

This may or may not be an issue for you.

Good point. I would tend to use hyperfocal techniques in the PS solution, so it's covered, but there's still the problem of stretching the top of the photo to get the parallax in line in post, which can't be good for resolution.

 

[Mully]

Years ago Nikon made a PC Nikor that would correct building perspective but not far enough so I would just use 4x5 and correct that way... have not used PS for this but maybe someone who has will chime in

 

[Robin_Usagani]

If I have to guess (without that much knowledge in lens science) when you tilt it, you are making the focal length a variable. So on one side of the tilt you are "zoomed in", and the other side is "zoomed out". The middle will be whatever focal length the lens is. If I do have one, I probably use it with a live view and see what moving the lens does. I probably use a tripod. Some people use it at weddings just to give that blur effect. I am hoping I can get one. They look pretty sweet.

Samyang to show 24mm F3.5 tilt-and-shift lens at Photokina : Digital Photography Review

 

[Ysarex]

I don't have a shift lens now for my DSLR, but I used to use one on a 35mm film Nikon years ago and I have extensive experience using a view camera to do the same. It was Photoshop's ability to alter an image that finally convinced me to sell my last view camera. Apart from placing the focus plane, Photoshop will do the same thing as a shift in the front lens board accomplishes.

Amolitor's observation about the placement of the plane of focus is valuable, but as you noted, DOF, especially with a small format camera, will typically serve. Another point often missed is that tilting the camera not only keystones the subject but it also stretches the subject. After using software to straighten the verticals I also scale the photo to compensate for the stretch. That one's tricky as you have to work from memory of what the subject really looked like. With those two software adjustments in place you have the same image that a TS lens would give you.

The perspective problem is unsolvable and that's the reason I wouldn't allow my students to use the term perspective correction when I used to teach view camera practice. Perspective is a given determined by camera palcement and can't be corrected -- it can't be wrong in the first place. What you're talking about is a uniquely photographic phenomena in which a photograph can seemingly contain contradictory vanishing points. There's a 15 story hotel near one of the campuses where I teach and it has a large overhanging canopy covering the front entrance. I used to take the class there to photograph that specific building with a view camera because of the canopy. From a position across the street we could frame the entire 15 stories and render the verticals straight which of course, without a view camera would require us to be 7.5 stories up in the air. That would also give us a photo where we were looking down on the top of the canopy, but yet in our photo from ground level we're looking up at the underside of the canopy. The contradiction is inherent in this type of photo -- as photographers we really can be in two places at once?

So a TS lens won't solve this problem -- you end up with the same thing you get from Photoshop -- a somewhat schizophrenic rendition of a structure that has this odd feel to it. Some photographers refer to straightening verticals as removing distortion when in fact they're really replacing one distortion with another.

Joe

 

[Buckster]

Thtat's exactly the kind of experience-based info I was hoping for. Thanks much Joe!

 

[Rick58]

I have the Nikkor PC and have never used it. I always looked at it as an expensive toy that will never perform as well as a view. (Yeah, I know, why did I buy it then?)
If I needed PC I used the Omega 45.

Nice explanation Joe.

 

[bratkinson]

This discussion has me really considering renting a T&S for a weekend and simply 'playing with it', for lack of a better description. At least with the details above, it won't be 'blindly playing with it'. I'm sure my photography friend nearby would like to play with one as well, and split the cost, but he shoots with a Nikon...