PDA

View Full Version : Which movements will fix this?



atlcruiser
25-Apr-2011, 19:49
Hi All,
just smack me if I ask too many questions :)

I took yet another frame of the famous test shed. I had a very small ft tilt and maybe a teeny tiny left swing. The rear standard was tilted forward a bit, then backward yet I never could quite the shed to not lean. The ft tilt was very little and I dont think that explains the "leaning tower of shed" i have going on here.


810 deardorff
240/5.6
foma in rodinal 1:50 8 min

What movements would make this better?

thanks!

http://farm6.static.flickr.com/5225/5656333696_e8dc9aaee2_b.jpg (http://www.flickr.com/photos/53092319@N04/5656333696/)
cc mid367.jpg (http://www.flickr.com/photos/53092319@N04/5656333696/) by urbanlandcruiser (http://www.flickr.com/people/53092319@N04/), on Flickr

Bill_1856
25-Apr-2011, 20:03
Suggestion: Put a grid over your ground glass so you can see what you're doing instead of shooting films.
Other suggestion: Buy and use a carpenter's level.
One more: What you need here is rise/fall, not tilt/swing.

Thom Bennett
25-Apr-2011, 20:10
Get the rear standard parallel to the shed (i.e. level the rear standard). Level the front standard as well. This image does not need any tilt or any swing. Depth of field is what you need in this case: Focus on the farthest point of the shed you want in focus. Make note of where your standard is. Focus on the closest point of the shed you want in focus. Make note of where the standard now is. Refocus halfway between these two points and begin stopping the lens down. At the appropriate aperture both far and near will come into focus at the same time. Hope this explanation helps.

atlcruiser
25-Apr-2011, 20:18
Suggestion: Put a grid over your ground glass so you can see what you're doing instead of shooting films.
Other suggestion: Buy and use a carpenter's level.
One more: What you need here is rise/fall, not tilt/swing.

thanks for the info

the GG has a grid...faint in places but a grid. I do need a new one

The camera was level...I have and use the carpenters level

I wnated a deep sharp foreground that is why I tilted just a bit

atlcruiser
25-Apr-2011, 20:19
Get the rear standard parallel to the shed (i.e. level the rear standard). Level the front standard as well. This image does not need any tilt or any swing. Depth of field is what you need in this case: Focus on the farthest point of the shed you want in focus. Make note of where your standard is. Focus on the closest point of the shed you want in focus. Make note of where the standard now is. Refocus halfway between these two points and begin stopping the lens down. At the appropriate aperture both far and near will come into focus at the same time. Hope this explanation helps.

thank you

I do know that technique and use it often. I wanted the foreground sharp..could I do it the way you described?

I think I might just want to tilt/swing just cuz I can :)

Ari
25-Apr-2011, 20:22
I must uber-emphasize what Bill said; get a good bubble level.
Keep all movements zeroed until absolutely necessary.
I don't trust the grid on the GG, as the GG could be slightly out of line with the camera; I trust the level.

Gem Singer
25-Apr-2011, 20:32
Tilting the back changes the perspective.

Tilting the front would have brought the grass into focus (what you were trying to accomplish) without changing the perspective..

jeroldharter
25-Apr-2011, 22:28
I think that a little front rise would eliminate the unnecessary, out of focus grass in the foreground and make a more balanced composition. Then stop down like others have said. If you tilt, you will have issues with the vertical shed which is right in the middle of the image. If you really stop down, you might be able to compensate for that.

Jack Dahlgren
25-Apr-2011, 22:31
thanks for the info

the GG has a grid...faint in places but a grid. I do need a new one

The camera was level...I have and use the carpenters level

I wnated a deep sharp foreground that is why I tilted just a bit

The point about the level is not that the camera is level, but that the back is vertical.

For an image to show up with no convergence the film plane needs to be parallel to the subject plane.

Frank Petronio
25-Apr-2011, 23:25
Stop tilting the damn thing.

davemiller
26-Apr-2011, 00:23
It's a very nice shed. :D

rdenney
26-Apr-2011, 05:02
You don't really need lens tilts for this picture. You could probably bring the foreground to acceptable sharpness using only depth of field. A very slight front tilt might give a little boost in the right direction, but that's not what's making the shed lean to the right.

If we think of the movements of an airplane, where we have pitch (nose pointed up or down), roll (wing tip high or low compared with the opposite wing tip), and yaw (nose pointed left or right of the direction of travel), then what you have in this picture is a bit of roll. I like these terms because they apply to the camera at large rather than to the movements within the camera. If the camera with all the movements zeroed is not level and plumb, then correcting the issue with movements is either more difficult than it needs to be or impossible. The only way to correct the issue I see here is with a rotating back (or a little rotated cropping).

Apply movements to adjust the projection of perspective convergence, or to adjust the focus plane. Don't apply them to correct a problem in where and how the camera is pointed.

Rick "whose garden shed will make a mockery of a bubble level--give me the grid lines any day" Denney

Thom Bennett
26-Apr-2011, 06:16
"I think I might just want to tilt/swing just cuz I can."

Yeah, this is where lots of people get themselves all twisted up with a view camera. (pun intended) Movements are nice to have but sometimes all you need to do is get the camera level, apply a little rise or fall to get the composition where you want it, set the appropriate aperture, take the picture and move on.

atlcruiser
26-Apr-2011, 06:34
Frank....most of this is your fault!

OK...the general concensus is that movments will not fix this and probably caused this in the first place!

I will really level the big thing and stop myself from moving too much!

Rick....very good explination

Thom....I was about to send you an E mail...David here from the NO workshop

ic-racer
26-Apr-2011, 10:14
If you want the 3 visible vertical edges of the shed to be all parallel then the camera back has to be parallel to the shed.

I'll bet the people who built the shed made the 4 edges paralell to the pull of gravity. If you do the same with the back (make it parallel to the pull of gravity) you will be assured of success.

Manipulations to the front standard will have no effect and swing or rise/fall of the rear will have no effect.

Bob Salomon
26-Apr-2011, 11:34
Too many answers making a simple answer more complicated.

First rule: Tilts and swings on the back always control the shape of the subject.
Second rule: Tilts and swings on the back also control Scheimpflug (plane of sharp focus).
Third rule: Front swings and tilts also control Scheimpflug (plane of sharp focus).
Fourth rule: Tilts and swings on the front never control the shape of the subject.

Fifth rule: Perspective is changed by changing the angle of the camera to the subject. Not by adjusting the camera controls.

So. Use back movements to correct the shape of your shed.

First use a good level to level your camera to the shed.
Then use the same level to get your back parallel to the shed.
Then use that same level to make the lensboard parallel to the camera back.
Now there are no converging vertical lines.
Should you have converging horizontal lines swing the back so it is parallel to the shed and the lens so it is parallel to the back.

Want to change the plane of sharp focus? Tilt or swing the front so you don't change the shape of the subject. Need more in focus? Stop the lens down enough to get the desired DOF without going into diffraction.

Vaughn
26-Apr-2011, 12:00
IMO, either the shed or the camera is not level...or both! I would trust the grid before I'd trust a level (like light meters, finding two levels that agree is difficult). Plus most LF cameras are not big enough for a decently size flat spot to measure the level accurately. Of course, YMMD.

The only true vertical edge I see on the print is the far right edge of the shed. Starting with the standards zeroed out and the camera roughly level, I'd use front rise/fall to frame up the image like I want. Then I'd get the nearest corner of the shed to the camera vertical first (visually, not w/ a level, by tilting the whole camera to the right or left), then move the back (tilt) until the other two corners of the shed were vertical. Then toss in a little front tilt and refocusing until I got the best focus possible, then close the aperture down to get everything in focus. But that is only how I would approach it and it would work just fine and dandy for me, with very little fussing around. It took me 10 times as long to write this than it would take to do it)

Vaughn

Lon Overacker
26-Apr-2011, 12:21
David,

Vaughn touched on something I was thinking about. Who says the shed is level and frame is vertical? From the looks of the ground, paver stones, etc. I'm guessing the owner probably didn't level the ground when putting in the shed? Having said that, it looks like the right edge frame is more vertical than the left edge, suggesting something not exactly as it seems with the shed in terms of vertical alignment and level. Converging lines due to camera back angle would produce an effect on both left and right vertical lines of the shed I would think. Just a thought. You should obviously consider the set up of the camera (zeroing everything to start,) as suggested, but also consider your subject. ie. Tall ponderosa pines aren't all necessarily growing exactly straight up!

I also agree that tilt is not necessary, although I can understand using a smidge of front tilt if you're really interested in the grass at the very bottom. HOWEVER, what you might be missing here when using tilt when you have strong verticals is potentially losing sharp focus at the very tops of your verticals (tree tops or potentially the bottom of the fence in back, etc.). As others have eluded to (I'm just saying in different words,) is that when you have a combination of near/far AND strong verticals (tall trees, buildings, etc.) then you're basically going to fall in to a simple depth of field exercise with teenie tilt or no tilt at all.

I've yet to make this public, but perhaps this guide (http://www.lonoveracker.com/pdf/planeoffocus_v100410.pdf)will help you. It's geared towards the beginner and not extremely technical, but hopefully it may shed some light for you. Please let me know what you think. And feedback from anyone else who happens to read this would be greatly appreciated.

Lon

cowanw
26-Apr-2011, 12:39
A ruler and pencil on the ground glass side of your GG will bring the grid up until you get a new one.

Ole Tjugen
26-Apr-2011, 13:00
Stop tilting the damn thing.

Best advice so far. Point the camera in the right direction, level the back, and then don't touch it unless you absolutely have to!

It looks like a classic example of yaw to me - the best way to solve it is to start over without movements. Corrections only make it worse, unless you're a mathematical genius who can do both Scheimpflug and Merklinger in your head. I can (although I'm not a mathematician), and when things start going off level like this I reset all movements and start over. It's much easier!

l2oBiN
26-Apr-2011, 15:35
1. reset the back and the front so they are vertically and horizontally level.
2. Experiment with only front standard movements and the image geometry will stay the same but the plane of focus will differ.

General advice

Movements of the front standard will alter the plane of focus without changing the image geometry, while moving the back will alter both.

atlcruiser
26-Apr-2011, 18:10
this really is amazing....thanks for all the help!