Canon Tilt-Shift lenses

[davidpalermo]

Hi all,

 

I bought a 24TS lens for doing interior work. I also shoot a lot of hotel

exteriors with it. Sometimes if the building is very tall or if I am very close

to it the 24mm TS lens makes the upper portion of the building look strange -

sort of wider than it should be. Hard to explain. I am wondering if I should

buy a 45mm TS or even a 90mm TS lens for doing exteriors? Do any of you have

any experience with the 45mm TS or 90mm TS lens?

 

Why use a 45mm TS over a 24mm TS? Why get a 90mm TS lens at all? My guess is

so that I can photograph a tall building from a bit farther than I would with my

24mm TS lens. I guess the building would have less of a "falling over" effect

using a 45 or 90mm TS lens than it would with a 24mm TS? Is that true?

 

Any input is very much appreciated!

 

Thanks,

 

David

[john_downie1]

What about tilting less and/or angling the camera up a little to develop a little convergence?

[davidpalermo]

I don't want any convergence if possible.

 

Thanks,

 

David

[mark u]

Which body are you using? You may find it useful to use a screen with grid markings when adjusting the degree of shift, and also ensuring that the camera is properly levelled when mounted on the tripod using a twin axis bubble level in the hotshoe. A longer focal length may not be helpful, as you would need to shoot from further away which might not be possible. What you describe suggests that you are over correcting with too much shift, so the aids will help you get it correct.

[colin carron]

David - the reason the top of the building looks wider than it ought in your corrected shot is because the eye is expecting a degree of convergence. A common technique in large format work is to leave a degree of convergence as this looks more natural.

[davidpalermo]

Never thought of that Colin. I guess I just want the lines to be as straight as possible with no convergence. I always see perfectly straight buildings and want to get as close as possible to being able to do that so I thought maybe a longer Tilt Shift lens might help if I can get back a little further from the building - can't always do that though.

 

To answer Mark: I use a full frame Canon 5D. Yup I have the focusing screen with grid lines and yes I use a tripod.

 

So leave a degree of convergence... hmmmm really? ok I will try that but that is sounding like using a regular non shift lens and photoshop - so what is the advantage of this TS lens again?

 

; )

 

David

[andykowalczyk]

I know this is going to the other extreme to solve your problem, but look here <a href = "http://www.rokkorfiles.com/funwithfisheyes.htm" > http://www.rokkorfiles.com/funwithfisheyes.htm </a> to see an example "de-fishing" a fish-eye lens photo of buildings.

[a._karalius]

David- I don't have TS lens, but from my experience when I'm trying to correct convergence in photoshop I always loose some sharpness which I guess can be avoided if you use TS lenses.

[davidpalermo]

A. Laralius - That is correct. That's why I bought this lens in the first place. It's nice to be able to "get it right" in the camera and then use Photoshop only if I have to.

 

Andrew: Thanks but that is what I want to avoid. I am very familiar with DeFishing. I do it in my day to day work. (I shoot high definition virtual tours.) DeFishing is fine for Web work. No so good for enlargments and picky architects!

 

Here is some of my work in case any of you are interested:

 

http://www.worldvr.com

 

and

 

http://www.davidpalermo.com

 

Thanks,

 

David

[cliff_henry]

WOW! Impressive site and work.

 

I did a little contract VT work for a local company several years ago - mostly residential real estate. They used Ipix system. I had problems with dark interiors and bright windows because we took two 180 degree shots and we could not adjust exposure between shots.

 

I visited Smithsonian Air Museum first summer it was opened. You must know some "heavy weights" to get that kind of access. Love the shots.

 

Cliff

[davidpalermo]

Thanks Cliff! Ipix didn't have the quality I wanted. I guess that might be the reason they are out of business now. ; )

 

I have been doing virtual tour work since 1993 or so. The Smithsonian work was a lot of fun for the most part. I spent a year in VA to do that work. It had its challenges - some of which are still not resolved but I am getting there.

 

David

[znabal]

The problem is that your eye still sees that your line of view is up, so even though the building is straight, as you go higher and higher up, the windows although they stay the same width, they get "shorter". I attached an example of a statue on a building I shot...<div></div>

[colin carron]

David, my LF experience - amateur architectural work using LF - is that a fairly wide angle is usually required both for interiors and exteriors. On 4x5 I used a 90mm (roughly a 28mm equivalent on 35mm) or a 65mm (roughly 21mm on 35mm). The 24TSE would fit between these. I find that the 'strange' effect varies a lot from shot to shot. The only thing I can suggest is now that you are aware of the effect you can look for it and see whether it looks strange or not.

 

Here is an instance when I have used a front shift to remove convergence and it looks OK (to me!). Maybe the strong verticals help :

 

http://www.photo.net/photo/1996700

 

In this example I have left a bit of convergence as it seemed to look better that way.

 

http://www.photo.net/photo/1996700

[colin carron]

Sorry that second one should be :

 

http://www.photo.net/photo/1868830

[colin carron]

For comparison here is that second one fully straightened in PS.<div></div>

[jeff_conrad]

It's exactly as Colin said. A general rule of thumb in architectural

photography is to allow some convergence if your line of sight is more than

about 20 degrees above the horizontal. The “proper” amount of

convergence is largely personal preference, and varies with the type of

shot; you set it by eye so that the top of the building doesn't look like

it's bulging.

<p>

Jeff L. also is right—although you can prevent convergence, you

cannot alter the point of view. One approach is to photograph a tall

building from an elevated location (such an upper floor of a building

across the street) if possible. If you do so, of course, the elevated

location is obvious to the careful observer—you're looking down on

details at ground level, and up at details such as the nose in Jeff's

example.

<p>

The 45 mm TS-E is useful for a less-extreme perspective that will partially

address the original question. It's even more useful for allowing a shot

from a sidewalk rather than the middle of busy street.

<p>

The 90 mm TS-E is less useful for architecture, but the angle of the line

of sight above the horizontal is the key—if there are straight

vertical lines near the edge of the image, the convergence will be obvious

when the line of sight is pointed up even with a 90 mm lens.

<p>

The 45 mm and 90 mm lenses are perhaps most useful for landscape work (or

anything else that fits a wedge-shaped depth of field); this is something

you can't implement in Photoshop.

[davidpalermo]

Colin: The image on the following link looks like it was straightened:

 

http://www.photo.net/photo/1868830

 

The vertical lines on both the left and right look much straighter than the vertical lines on the image above.

 

You guys are a wealth of knowledge. Aside from the vignetting I like the 24mm TS for interiors: http://www.davidpalermo.com/mobile/content/IMG_2838_large.html

 

Here is another example of the top portion of a building looking larger than it should... http://www.davidpalermo.com/mobile/content/IMG_2848_large.html

 

I guess I will try leaving some convergence in to make the top part of the building look more realistic. Something is a bit "off" with this image.

 

I am thinking of buying a 90mm TS lens for portraiture. I like throwing the focus off and could be interesting for portraiture.

 

There is an ad for the HBO special "Bury My Heart At Wounded Knee" that has some very nice old - type portraiture that I am wondering if they were shot using a TS lens or done in post in Photoshop. Very nice. I saw it in the June issue of Vanity Fair. I like that look. I could not find it online to show you. Sorry.

 

 

David

[davidpalermo]

Colin: By the way I really like the image inside the church:

 

http://www.photo.net/photo/1996700

 

I am not sure I can do that with a 24mm TS lens. That'd be interesting to see if I could!

 

David

[colin carron]

David, thanks. the church interior was right at the edge of what i could get on the 65mm lens (21mm equivalent) so maybe a 24TSE could not replicate it.

 

Looking at your 'strange' shot of the tower with a grid imposed you will see that the right hand side of the tower is slightly leaning outwards. So there was a little too much shift applied when you took it. Correcting to vertical in PS it looks as below (hope you don't mind my copying and playing with it!).

 

It is difficult to judge these things at 35mm size (I could not get it right with a gridded screen and a magnifier but my eyes are not what they used to be.) I think your best bet will be to apply the tilt/shift in the original capture to your best guess then adjust in PS for the final effect. This will allow you to get a better shot than just using PS.<div></div>

[davidpalermo]

No I don't mind at all. That is just a test shot. I took the 24mm TS lens out while I was in Mobile, AL for work and walked around one afternoon to get accustomed to it. I will need to pay more attention to the subtleties of using the shift feature. It does look like I over compensated.

 

Thanks Colin! I guess on some shots I will have to rely on Photoshop for some correction. I was hoping not to to preserve the image quality as best as I can. But I guess you can't really tell unless you make large prints. That's somewhat a relief.

 

David

[davidpalermo]

I have been using my 24mm shift lens and I notice that one of the nobs is way too tight to

turn. It's the knob that prevents shift or tilt from slipping. There are 2 of them. I tried pliers

and scraped some of the black paint off but still couldn't get it to budge! Sheesh this lens is

brand new.

 

Anyone have this problem?

 

David