I guess (according to your "opinion") there are theories other than physics then.
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CAMBO WRS 1600 or Alpa STC or any other suggestions?
- Thread starter algrove
- Start date
voidshatter
Member
I'd agree with Doug.
You could post some real world comparisons to support your claim. (Yes, that means you'll need to have access to something you think is doing the tilt right, and at the same time, something like Alpa.)
dougpeterson
Workshop Member
*Shrugs* All I can do is give you the correct information. You're free to ignore it or mischaracterize it as opinion. Though I do find your statement here mildly personally insulting, and don't find it's tone appropriate for this forum.
In any case, one more way to think through this topic is to say that in any camera system the body is a light tight box that functions to hold a lens in a specific position. That position is the only thing that affects the projected image. In two camera systems if you end up holding the lens in the same spot it is not important what gears/knobs/process is used to get there (other than ease/order of workflow), the projected image will be identical.
For example with some gear combinations tilt you will need to tweak focus after. In others you will not. The end result is the same.
Though I do find your statement here insulting to physics theory, you are correct in stating that "That position is the only thing that affects the projected image". If the position is not correct according to officer Scheimpflug's principal, the image will be distorted. Thanks for bringing the subject up. I'm out!
In Defense of the STC or WRS I head off to Lofoten tomorrow with my wife the chief extra lens holder, umbrella holder, bag holder.... well you get it. I expect winds of 20mph or more which will force me to use my STC. I leave three lenses in Alpa mount (60mm, 100mm, 150mm) just for these situations. As much as I love my Cambo DB+ it would do poorly with 20mph winds. Even the STC will be challenged but less so than the Cambo. A 180mm lens + bellows on a Cambo with a 20mph wind may as well be a kite in the wind. Will see how it goes.....
Victor
Victor
voidshatter
Member
This is correct. As a physicist one should easily understand this if he understands frame of reference.
With either system, the lens can be held in exactly the same location pointing towards exactly the same direction. It's just the digital back that is getting tilted, and it doesn't really matter which axis it's tilted along.
Only.... that you can't hold a lens in a constant position unless you tilt it or swing it by its entrance pupil...
voidshatter
Member
You can, if you adjust your tripod height, ballhead angle, tilt angle and shift amount at the same time (with whatever tilt system you have, not necessarily tilt by entrance pupil). The lens can remain in exactly the same spot and pointing towards exactly the same direction.
Thanks for confirming that "keeping the lens in the correct position can only happen if one swings it or tilts it by its entrance pupil"
Tripod has nothing to do with the subject if a technical camera is involved that applies the movements, positioning the lens correctly on the tripod's swing axis, will still induce the same errors by the camera itself if swing or tilt movements are applied (by the camera) on the lens.
EDIT: Obviously the errors induced by the camera, are a relation to lens position with respect to image area, tripod has nothing to do as to correct that relation.
GrahamWelland
Subscriber & Workshop Member
I agree with this. There definitely are scenarios where the solid pancake camera has an advantage and struggling in bad weather to put it together in the field and wind on the bellows too (although on a long Alpa lens there's a lot of barrel hanging out there too).
For an Actus DB type camera live view is mandatory and hence only practical with a CMOS back today.
voidshatter
Member
If you have difficulties doing it right, you can mount the lens body (of an Alpa camera) directly onto the tripod, and let the lens be held in a fixed spot pointing towards exactly the same direction. This spot and direction is fixed as the same as whatever "correct position" you define or get from whatever tilt system you think is superior. When you operate the tilt (of an Alpa camera) you don't touch/move the lens at all, because it's fixed directly onto the tripod. Any tilt/shift operation would only cause the camera body/digital back to change spot/direction. The end result is the same as what you get from whatever tilt system you think is superior.
If you are clever enough, you would be now able to mount the (Alpa) camera body instead, and still be able to achieve the same spot/direction for the lens, with the help of compensation from tripod height, ballhead angle.
I do wonder what is that you can't understand here... Is it that if the tilt or swing mechanism of the camera itself will set the lens "off center" with respect to the image area if the entrance pupil of the lens is not correctly positioned with respect to the center of the tilt radius and swing axis of the camera itself?
Tripod positioning has nothing to with the errors that will be induced by the camera itself!
voidshatter
Member
Do the following as I draw:
The blue is what you think is superior, and the red is what you think is inferior. Do you know how to make the red overlap with the blue? The answer is simple: shift and focus!
Again, not relevant with distortions! this is "parallel planes" that correct for sheimpflug principal of planes focused, but not for distortions!Do the following as I draw:
The blue is what you think is superior, and the red is what you think is inferior. Do you know how to make the red overlap with the blue? The answer is simple: shift and focus!
View attachment 125491
Distortions are a matter of camera operation, nothing to do with tripod... I think you confuse "panoramic stitching" with distortions induced by wrong implementation of technical cameras by the makers!
voidshatter
Member
As long as there always exists a way to make the red overlap with the blue (with shift and focus), I don't care how you place the lens or where you place the blue. This applies to both distortion and Scheimpflug principle. However you place the lens and blue to correct distortion, I just make the red overlap with your blue. Simple!
I thought you got it wrong in the first place... You can't overlap the "red plane" with the "blue plane", if the entrance pupil of the lens is not kept constant when tilting or swinging the lens on the camera!
voidshatter
Member
As I said, you can mount the lens directly onto the tripod - simple! :clap: My duty is only to prove that there always exists a way to make the red overlap the blue.
OK... I'm off to bed now. Good point but it would make most of the lenses unusable and a "special" bellows required for each lens. Never the less there is a POV that can make every idea a "great" one!
voidshatter
Member
Not sure why you think most lenses would become unusable, unless you mean the Copal 0 shutter cannot bear the weight of digital backs.
In reality you won't need to have a special collar for each lens. I'm just illustrating that there always exists a set of parameters to make the red overlap with the blue, and this set of parameters would not cease to exist when you choose not to mount the lens directly to the tripod.
drunkenspyder
Well-known member
New member here. Just wanted to thank everyone for the amazing amount of info and the great "tone" of the forum. I was, maybe still am, on the fence on this very camera selection question, and this was easily the most useful info I found on the net, along with the Luminous STC review and Mark Dubovoy's praise of the WRS-1600.