Oteck's Arca swiss style setup

Which equipment do you use for 3D-scanning?
Oteck
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Re: Oteck's Arca swiss style setup

Post by Oteck » 17 Nov 2016, 16:05

the current zoom i started with was a 2.8-8mm 1/2.7" so the scale doesn't really work for me. I'm not sure but i believe cs and c share the same type of sensor with the difference of flange distance to the sensor. With a 5-50mm 1/3" on the way I'll have a more accurate scale to work with but ideally prime lenses are the only way but the sizes i'm after doesn't exist or are super expensive designer ones.

I use to remember a site that does all this type of calculation but i can't remember anymore. the sensor size and Focal length is just screwing with me. There are 2 more lenses coming to me at 12mm and 16mm but they are fixed iris so they might not do me much good but $5 isn't much at this point but i really need to do more homework on glass selection.

We ought to move some of this thread to a different post that's more optic oriented, I'm still trying to figure out how to mount a up close lens on the k132

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Micr0
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Re: Oteck's Arca swiss style setup

Post by Micr0 » 18 Nov 2016, 16:08

Oteck wrote:
We ought to move some of this thread to a different post that's more optic oriented, I'm still trying to figure out how to mount a up close lens on the k132
I got one of the cheap vivatar filter packs that are sold on eBay and took one of the star filters (who uses those things?), removed the lens and epoxied the threaded ring to the lens bezel of my projector.


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Last edited by Micr0 on 18 Nov 2016, 16:13, edited 1 time in total.
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Micr0
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Re: Oteck's Arca swiss style setup

Post by Micr0 » 18 Nov 2016, 16:13

FWIW lens focal length can really become a problem when you move into the larger sensor high definition cameras. The selection of lenses with OTF suitable for high def cameras is very limited. I wound up with lenses that forced me to place the cameras behind the projector or lose a significant portion of the projected image.

P.S. I really like the vertical set up.

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Oteck
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Re: Oteck's Arca swiss style setup

Post by Oteck » 18 Nov 2016, 16:27

I think the moment you start using higher resolution is when you start using MFT, SLR, and mirrorless camera glass.

Recently i picked up a pair of 25mm c-mount for a 1:1 2.8" but it's way too narrow. it may be good for macro but this would require some hefty up close lens for the projector. Is there a specific distance this has to be placed on the projector lens?

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Micr0
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Re: Oteck's Arca swiss style setup

Post by Micr0 » 18 Nov 2016, 17:24

Oteck wrote:I think the moment you start using higher resolution is when you start using MFT, SLR, and mirrorless camera glass.

Recently i picked up a pair of 25mm c-mount for a 1:1 2.8" but it's way too narrow. it may be good for macro but this would require some hefty up close lens for the projector. Is there a specific distance this has to be placed on the projector lens?
I tried using SLR lenses with mixes results. Part of the problem is that to get a decent lens (bright with little distortion) you have to spend nearly as much as you do to get a high definition machine vision lens. Also with SLR lenses, one needs very wide angle lens (<20mm). Again to get one that has low distortion you are into an expensive lens (even used).
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Oteck
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Joined: 11 Nov 2016, 21:21

Re: Oteck's Arca swiss style setup

Post by Oteck » 21 Nov 2016, 05:39

Micr0 wrote:
Oteck wrote:
We ought to move some of this thread to a different post that's more optic oriented, I'm still trying to figure out how to mount a up close lens on the k132
I got one of the cheap vivatar filter packs that are sold on eBay and took one of the star filters (who uses those things?), removed the lens and epoxied the threaded ring to the lens bezel of my projector.


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Is there a specific distance to mounting it?

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Micr0
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Re: Oteck's Arca swiss style setup

Post by Micr0 » 21 Nov 2016, 14:53

I just glued the ring on where it fit and it works. Don't over think it.
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Curiousjeff
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Re: Oteck's Arca swiss style setup

Post by Curiousjeff » 21 Nov 2016, 14:54

I am a bit confused.

I was under the impression that focal length was not very important, as long as it was a quality lens.

I use the Canon 60 mm macro on the GH4 and I did not notice any specific problem.

Of course, I cannot keep the camera aligned with the projector. The camera has an extra rail to move back and forth.

I try to frame the camera and the projected image a little outside the borders of the calibration pattern.

Do you believe that there is an "ideal" focal length to obtain the best scans ?

Jeff
P.S. I also use the Vivitar Close up lens but they provides too much distortion if I try to get close to the 30 mm pattern.

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Micr0
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Re: Oteck's Arca swiss style setup

Post by Micr0 » 21 Nov 2016, 16:04

There is no ideal as far as scan quality goes. However with neutral lenses (50mm in the SLR world) you would have less lens distortion organically. Also, the problem I had was that slightly telephoto lenses forced me to mount the cameras behind the projector which caused other problems.
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Oteck
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Re: Oteck's Arca swiss style setup

Post by Oteck » 21 Nov 2016, 18:12

I believe the ideal focal lengh is to be greater than the optics on the projector but we will never know that.
I've come to realize that the projection is skewed by the key stone so the moment it left the lens it's already off the angle so if i were to place one on my k132 it would have to be angled at 15deg after mounting it but i may be thinking to hard on this

If i were to replace the lens would that remove the keystone entirely? or is it how the LCD is mounted inside

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