I made a 4" digital back, and you can too

[Jim collum]

with an actual 4x5 camera & back, you'd have rise & fall ... which would accomplish the same thing with the sliding adapter.

I must not have explained what I'm doing here properly. The gizmo behind the DSLR is indeed a 4 way macro rail, as my post states. It has 10cm of travel both left and right and up and down. What I do is move the camera left and right and up and down taking photos in a grid pattern to cover about 4" x 4" (10cm x 10cm) and stitch the photos together on the computer. Photoshop even has an automated feature that does this with little user input. The result is a photo over 100 megapixels that covers almost what a 4" x 5" negative would.

Just to be clear, each of my sample photos isn't one picture taken with a DSLR mounted in a static position cropped out of the middle of a LF lens field of view, it's a series of photos stitched together that covers most of the view 4x5 would. That's the reason why I don't use the fotodiox adapter, they just let you slide the camera back and forth and use a small area.

[TomR]

My actual 4x5 camera that I have right here, which I took the rear standard off of to do this experiment, does not have 4" worth of rise and fall on the back. I wanted a solution that kept the rise and fall of the front standard for adjusting the image. Also the focus rails have quick adjustments. 1/2 turn of the knob moves the camera 15mm, so it's fairly fast to move the camera enough to cover the image.

[barnninny]

I think it's an interesting idea. I'll be following along to see how it progresses as you tweak it.

[TomR]

Thank you. Right now the biggest problem is the DSLR being too heavy for the cheap rail. It sags a little and I want to be sure the sensor stays aligned to the film plane, so I'm going to have to do something about that.

[barnninny]

Get a 2nd-hand, inexpensive mirrorless to experiment with?

[coisasdavida]

Your solution solves a major problem of the back adapters for DSLRs, the length they have in order to clear the hand grip of the camera. When using those adapter you end up using very long lenses.

A mirrorless camera, inside a recesser lensboard custom adapter in a Sinar P camera could be great.

[Amedeus]

TomR does have an interesting low cost approach although there are some mechanical hurdles to clear.

I've been using Phase One Flexadapter for Leaf MF back on my Sinar and also an inexpensive Chinese sliding camera mount for 4x5 for my Mamiya 645 to achieve same. Both have their pros and cons from cost and flexibility perspective as one doesn't get the full 4x5 coverage unless you use res and fall which is not an issue on most 4x5 cameras. OTOH, 6x9 results for me in 30"x45" prints easily and depending on subject and the work involved, all the way up to 48"x72" ... plenty for now.

Yes, sliding your camera across the back does add distance to the lens so there's a limitation on focal length of lenses you can use. Penalty is anywhere form 44mm to 89mm depending on the camera you use ... no-mirror camera should be in the 12-25mm range ... hence the reason some use Flex Adaptors or other sliding back arrangements, the latter are typically no different than using a film holder with it comes to impact on lens focal length.

Sergei ... I didn't get the comment on the nodal point shifting ... when properly done you're just scanning the film plane of the camera with the sensor, so nodal point wouldn't change as the lens is not changing or do I miss something ? LCC correction may be required though ...

[TomR]

I changed how I had the horizontal slide mounted. This places the stresses on it the way it was meant to take them, allowing it to work much better. My next step is to make a bag bellows that I can velcro around the DSLR. After that I guess I'll have to get a mirrorless camera if I want to use any wide lenses, as the mirrorbox on my DSLR is causing vignetting.

I did have to take of the rear standard and back from my camera to allow my DSLR to get close enough to the lens to focus properly. I'm guessing if you have a camera with a much wider range of movements than I have then you could have just taken the back out of the rear standard and stuck a digital camera in there. That would have been a lot less work, but I'm pretty happy with my results.

I don't think you have to worry about nodal points shifting, the lens stays fixed.


2013-679 by Tom Rintjema, on Flickr

[Peter De Smidt]

What's the advantage over using a dslr with a standard panoramic head?

[Ben Syverson]

What's the advantage over using a dslr with a standard panoramic head?

Since this is mimicking a virtual LF sensor, the advantages are LF's advantages; movements, great lenses, shallow depth of field, etc. You also wind up with a rectilinear image, whereas when you stitch images using a small format camera, you tend to end up with cylindrical or spherical projection images, which have a much different look.