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David
Joined: 13 Apr 2011 Posts: 1869 Location: Denver, Colorado
Expire: 2013-01-25
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Posted: Sat Feb 15, 2014 7:22 am Post subject: Brainstorming |
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David wrote:
A few weeks back I made an adapter out of a reverse ring and custom-sanded plastic piece so I could mount my Pentax bodies on my 4X5 camera. That makes the 4X5 a pretty extreme T-S macro bellows.
It got me thinking, though, what if I could make an articulating mount that would allow me to take a couple-dozen photos and use my DSLR as a 4X5 medium.
I saw some on eBay that allow the DSLR to move left and right for panoramas, but that seems like a pretty weak use of perspective control. I'm having trouble figuring out how this thing could be made such that the camera would stay on the same plane regardless of location. Maybe some kind of pantograph? A bearing seat of some kind?
Any ideas? The sensor, of course, has to be on the same X-Y plane the whole time. _________________ http://www.youtube.com/user/hancockDavidM |
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dan_
Joined: 05 Dec 2012 Posts: 1058 Location: Romania
Expire: 2016-12-19
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Posted: Sat Feb 15, 2014 9:53 am Post subject: |
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dan_ wrote:
Probably something like I've done here:
http://forum.mflenses.com/diy-shift-adapter-for-ff-lenses-on-nex-cameras-completed-t60109.html
It works very well.
Fore more shift you could use a front standard from a 4x5 camera (mine is made with one from a 6x9 camera).
For much more shift (as you requested) a microscope mechanical stage with geared controls like this could be adapted:
http://www.surplusshed.com/pages/item/m1527d.html
You could fix a part of it on a 4x5 metal film holder and on the other part (the shifted one) you could mount the camera.
I've got one to make a (extreme)shift adapter for medium&large format lenses on NEX and it's quite adequate for the purpose.
Of course, it's not an easy task (and not a priority for me wright now - the one I already made is working very well).
For a quick panorama adapter you could use a 4x5 metal film holder. Make a longer dark-slide to fit it, grid the film holder to remain only a frame which accepts the slide to pass through all the way and on the dark-slide mount the camera.
You could adapt a sliding 4X5 back as well but they are quite expensive. |
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araucaria
Joined: 16 Jan 2014 Posts: 63
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Posted: Sat Feb 15, 2014 1:57 pm Post subject: |
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araucaria wrote:
I am gathering the parts to do a full 6X7 area shift plate for 35mm nikon DSLR. I fell in love with my nikon pc 85mm and fullshift stiching, when you are working with so much resolution it seems like tonality gets a lot better (and also bokeh looks much better on prints)
So this made me look for some medium format shift lenses to use on my nikon with the a mirex tilt and shift adapter (400€, most nikon versions don't have tilt, not enough space), and while looking for it I came up with a shift plate for mamiya 645 to Sinar on ebay. Since all shift adapters are limited to one direction and are extremly expensive, and DSLR to 4x5 sliding backs are even worse, I placed a "very high" bid at the last moment since I couldn't find any place to buy this thing and compare prices. In the end it was something like 210€. (christmas money going down the drain)
http://s1.postimg.org/ftd07xwgf/image.jpg
http://s1.postimg.org/q25hdrki7/12_1.jpg
It has a 72x72mm square hole and shifts 20mm in all directions.
So you will end up with
X axis= (36+20+20)mm=76mm
Y axis= (24+20+20)mm=64mm
so I can get away with shifting X 2 times (36+36, with 2mm overlap this would make 68mm) and Y 3 times (24+24+24, but with 4mm overlap each, 64mm), 68x64mm, in landscape mode. In portrait mode I could make a fast panorama with only Y' axis shifts like on the zorkendorfer which would give me 68x36 max, something between 4:3, 3:2 image ratio, more horizontal than 645 but less vertical.
The next step was to find a sinar standarte, I found one for 20€ (it's still on its way). I will put this one on the tripod (just remove the whole tilt stuff) to put the adapter onto without gluing/soldering/destroying the sinar plate.
What is left is to get some adapters to put the camera onto the plate (this will involve some glue, What do you think would be best to get little as possible alignment problems?)
Then I'm left with two options, just get a lens plate and glue some MF mount adapter to it (I can't buy a standart one because I need it recess into the plate because of the shitty flash casing on my camera which leaves me little distance for 67 mounts) to put on the other side of the sinar with just shifting, or getting a whole sinar to also use tilt. (the last option is limited to very long flange distance lenses). But I am on hold because I went out of cash...
From what I have seen this is the best way if you want to scan the whole 7x7 area. |
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dan_
Joined: 05 Dec 2012 Posts: 1058 Location: Romania
Expire: 2016-12-19
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Posted: Sat Feb 15, 2014 5:25 pm Post subject: |
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dan_ wrote:
araucaria wrote: |
...or getting a whole sinar to also use tilt. (the last option is limited to very long flange distance lenses). |
Better get a whole Sinar and you can use it on film too.
If you'll use Mamiya 6x7 lenses you'll have enough flange distance for tilt. I have adapted a Bronica tilt/shift bellows unit to Pentax 645 and with Mamiya 6x7 lenses I can have plenty of tilt.
If the tilt is made on the camera side and centered then you don't need a lens with more coverage.
When making such a shift adapter in my opinion the first things to think at are:
1- how much resolution you really need,
2- how much resolution will deliver the lens/lenses you'll use.
With a 32Mpix image you can make perfect A1 enlargements. With 50-60 Mpx you'll make very good A0 enlargements.
Do you really need more?
A medium/large format lens usually has less resolution than a 23x36 one (there are exceptions, but usually very expensive). That will make the real resolution of your image to be less then expected.
Making many exposures will increase the risk of little movements of the subject and tripod or changes in light.
I think that trying to scan an area larger than 6x4.5 cm will be increasingly less effective and too much trouble.
But, of course, others may have different opinions. |
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araucaria
Joined: 16 Jan 2014 Posts: 63
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Posted: Sat Feb 15, 2014 8:26 pm Post subject: |
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araucaria wrote:
You are right, mf lenses arent that great but color gradations, and noise will be a lot less. I only will use this for static buildings and landscapes. It will be more than 100mp, its for a project that will take me a long time and if it turns out well I will print as big as a wall.
Anyway, I have some mint elpros coming my way for some tests, did you get my MP? |
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CuriousOne
Joined: 31 Dec 2013 Posts: 669 Location: Home
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Posted: Sun Feb 16, 2014 9:57 am Post subject: |
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CuriousOne wrote:
This might appear a bit brutal, but it should work:
http://www.amazon.com/Shop-Fox-D2731-4-Inch-Sliding/dp/B0000DD1S8/ref=sr_1_1?ie=UTF8&qid=1392544621&sr=8-1&keywords=cross+slide+vise _________________ I have nothing to compensate with lens |
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David
Joined: 13 Apr 2011 Posts: 1869 Location: Denver, Colorado
Expire: 2013-01-25
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Posted: Mon Feb 17, 2014 2:40 am Post subject: |
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David wrote:
Thank you, everyone, for the insights. That one sliding back is exactly what I was trying to picture. I may need to just pick it up myself.
As for resolution, some of the things I could photograph will be tradeshow booth displays, so figure 6X10 feet or more. For that, I need something in the 110+ megapixel range. That said, when I do those shots I just stitch the images together. Here I'm just looking for a way to make the most of a 4X5 camera's movements without buying a digital 4X5 back. _________________ http://www.youtube.com/user/hancockDavidM |
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