Digitising large format negative at high resolution with a DSLR

Adrian Lambert

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I’m new to this group and as part of my intro I mentioned my digitising station set up. I thought I might share more about it here in case it’s of interest.

Like many I’m digitising my negs with DSLR. I’ve done this a lot and it has always worked well with my 100mm macro on a Canon DSLR body. Recently after discussions with a friend I decided to take multiple images of parts of the neg and stitch them together to create a very high res image. The first attempt went very well and I ended up with a 1.5m high image at 300dpi. The discussions continued and we felt that the aberrations, distortion, an CA in the 100mm would be repeated through the frame. So I started looking at large format process lenses so that there was only 1 layer of optical inaccuracies. I acquired a Fujinon 240mm A lens in good nick and with multi-coating. The DSLR is mounted on a sliding back adapter on my Sinar f with p rear standard. I use the rear standard to shift only the canon body. It’s early days yet and I found the cheap adapter actually shaded the sensor. So today I’ve managed to Dremel and file the adapter and it’s currently in the cellar having been repainted Matt black having already been tested and confirmed to clear the sensor. Tomorrow I’ll add some flocking then we will see what we can achieve.


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Ian Grant

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Two questions come to mind. First what's the sensor specification of the DSLR and then how many sections of the negative are you scanning.

An answer to something you raised in another thread would be to find the frame from an old De Vere 54 enlarger (pre 504) and use this as a copy stand. I used a De Vere monorail camera (Whole plate/Half plate/5x) mounted on one as a copy camera for some years, very rigid so ideal for what you're after. I had a 54a enlarger and the ship mounted frame, the normal frame sits in an outer frame with thick rubber spacers to cope with vibrations and I bolted this to a wall.

You sometimes see these frame on Ebay. Mine was spare as I'd used the rest to make a horizontal enlarger.

Ian
 

Ian Grant

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Probably a touch expensive for it's condition, might be worth an offer though.

Ian
 

Adrian Lambert

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Thanks for the advice. The only other options are one with a baseboard and wall brackets for £330 delivered but in good condition but no head (not sure if one is needed). I've said to the seller of this dusty old one that I'd like to pay no more than £150 delivered and things are sounding hopeful. I'd prefer not to have a baseboard because I'd only trim down to the size I need as space is limited. BTW another test today with the full rig gave me a 2m high 4x5 scan at 300dpi. Way past my expectations as the resolution of the fomapan200 and lens combo of the camera seem to be short of this sort of quality. But an exciting milestone.
 

Ian Grant

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My misgivings are it looks like the tripod head can swivel, so could move the camera from being parallel to a base board. I'd fixed my rail to tripod mount onto a steel plate.

A radically different approach might actually be to use an LF enlarger as a copy camera, this could be relatively easy if you already have a pre-existing enlarger, and save space and money. That going to depend on how the light source fits of course, as you'd need to be able to add your DSLR adaptor.

Ian
 

Adrian Lambert

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My misgivings are it looks like the tripod head can swivel, so could move the camera from being parallel to a base board. I'd fixed my rail to tripod mount onto a steel plate.

A radically different approach might actually be to use an LF enlarger as a copy camera, this could be relatively easy if you already have a pre-existing enlarger, and save space and money. That going to depend on how the light source fits of course, as you'd need to be able to add your DSLR adaptor.

Ian
I'll stick with my Sinar as I don't have a LF enlarger plus I've bought the adapter for the dslr to fit to a graflok system, plus the 240mm process lens and lens board. The system needs to shift the dslr to cover the image circle too which the adapter handles easily in one plane and the Sinar standard handles in the other. The system up to this point is good and stable enough to be sharp. I just need to make it a bit more stable and as compact as possible which the wall mount should do.
 

Ian Grant

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De Vere make a copy back for their Horizontal 10x8 enlarger but I think it would be very easy to make something. Actually thinking about it I have two De Vere copy backs but they arent Graflock.

My thoughts are that the De Vere copy stand with a camera fitted would take the same space as an enlarger, I was thinking of using an existing 5x4 back like the Sinar's, I have quite a few options. Cost wise you could be under the£150 mark - a De Vere 54 with a cold cathode head sold for £100 recently.

Ian
 

Adrian Lambert

New Member
Registered User
De Vere make a copy back for their Horizontal 10x8 enlarger but I think it would be very easy to make something. Actually thinking about it I have two De Vere copy backs but they arent Graflock.

My thoughts are that the De Vere copy stand with a camera fitted would take the same space as an enlarger, I was thinking of using an existing 5x4 back like the Sinar's, I have quite a few options. Cost wise you could be under the£150 mark - a De Vere 54 with a cold cathode head sold for £100 recently.

Ian
A copy back sounds like a great idea. I'm a long way down the track now and it's all coming together. I think a monorail camera with a small baseboard will take up a little less room than a large format enlarger but it won't be a huge difference. I'll keep a look out for a large format enlarger but just storing it would be a challenge at the moment.
 

Alan Clark

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I'm not sure that I entirely understand what you are trying to do. What I think you are doing is taking several photos of separate parts of a 5x4 negative with a digital camera. Then stitching these together to get a big file of the complete 5x4 negative.
To achieve this you are experimenting with a rigid system to hold the camera that will also let you move the camera to photograph the separate parts of the 5x4 negative. I hope I've got this right!
Why not simply use a copy stand to hold the camera still, and move the negative?

Apologies if I've got this all wrong.

Alan
 

Adrian Lambert

New Member
Registered User
I'm not sure that I entirely understand what you are trying to do. What I think you are doing is taking several photos of separate parts of a 5x4 negative with a digital camera. Then stitching these together to get a big file of the complete 5x4 negative.
To achieve this you are experimenting with a rigid system to hold the camera that will also let you move the camera to photograph the separate parts of the 5x4 negative. I hope I've got this right!
Why not simply use a copy stand to hold the camera still, and move the negative?

Apologies if I've got this all wrong.

Alan
Mostly right. Yes several images stitched to cover the whole neg to achieve a higher resolution digital file. I started with what you are describing but felt that multiple images meant multiplying the inherent taking lens flaws such as diminishing lpm from the centre to the edge of the image, plus barrel distortion, chromatic aberrations, and vignetting. All these errors would have to be corrected before stitching (and not all are correctable). So I purchased a process lens as these are tuned to this purpose and have far far less of the aforementioned errors. This lens (a Rodenstock Apo-Ronar f/9 240mm multicoated) projects the image at roughly a 1:1 ratio to the film plane of the repro camera. I then adapt the back of the repro camera to mount a dslr - in this case a canon 5Ds, which then shifts from one section of the projected image to the next. So the repro camera, it’s lens, and film plane are fixed and only the sensor in the 5Ds shifts until the whole image is captured and stitched with far less digital processing required to achieve this. In my mind the resultant digital file is now equivalent to a using a digital back that covers the whole of the 4x5 image. Diminishing returns and all that but it fits much better with the tried and tested methodology of film to film duplication using only optical and mechanical means.


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JimW

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Don't arca swiss make something that does this? No chance of it being cheap tho.....
 

Adrian Lambert

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Yes the universal camera but I already had a Sinar so I’m using that. Not sure if the AS camera could do the extension required either. It’s a nice unit though and if money was no object...
 
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