Digital Backs on Wooden Field Cameras

//Digital Backs on Wooden Field Cameras

Digital Backs on Wooden Field Cameras

 

 

Photographer

 

 

Its amazing to think of how photographic technique has changed over the past 50 years. Even the last 10 years alone have seen amazing leaps in image quality and convenience.

Not that long ago film was the name of the game, and large format photography was the ultimate professional’s choice. I’m sure many could reminisce about the days of commercially shooting 8×10 chromes for publications and shooting Polaroids to check exposure.

As we all know film has largely been phased out and replaced with the convenience and practical superiority of its digital counterpart. 8×10 chromes have been replaced with high resolution medium format digital backs as the highest quality professional’s choice.There are still film photographers in the wild (I’m one of them), and there’s been a recent renaissance in film production and demand by artists and hobbyists. Film has a distinct organic look both in color rendition and grain structure that some find refreshing over digital’s generally clean, clinical look. Digital film emulation is big business these days for that very reason.

I’ve been shooting large format 4×5 film ever since I was in college and love it to death. Though I’ve always been curious what it would be like to use a digital back with my film camera. For the sake of sheer curiosity we made it happen and decided to take it out for a spin in our backyard: Rocky Mountain National Park.

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Challenges

Photographer

Using the highest resolution single shot digital back on the market (at time of writing) on a wooden camera made for film photography presents some (not unforeseen) challenges. Slight deviations in focus might slide when using film, but when using an 80 megapixel back with a 5.2 micron pixel pitch the line between acceptably sharp and unacceptably soft is razor thin. Therefore it’s extremely important, even more so than normal, to ensure that the camera is rock solid and locked down. This presents another challenge, as its very easy to wiggle the camera even with all knobs and hinges tightened because of its wood frame.

Of course the big benefit large format photography has always had over most other formats is the ability to use movements. My particular 4×5 model, the Shen Hao TZ45IIB offers several movements for studio or landscape photography, but none except focusing are geared. Front/back rise and fall as well as swing, shift, and tilt are all on tracks with only your best judgement and the holy spirit to put them in the exact location for critical focus. We’re talking about millimeters of adjustments with no click stops…

The next big challenge was glass. My two lenses- a Fuji 90mm f/8 SW and a Fuji 210mm f/5.6 W, were most likely made before I was born and are mounted in older shutters- one in a Seiko B and another in a silver ringed Copal 1 respectively. Lenses made for large format film were generally not designed for extreme resolving power, but rather for projecting a large image circle to allow for lens movements. Obviously sharpness was and is a factor in film photography, but the parameters were for film with grain sizes of ~10-30 microns. Put simply, something that looked sort of blurry on 4×5 film will look extremely blurry on a high res digital file.

Photographer

While we’re on the subject of lenses, its necessary to create a mode of communication between the back and the lens. After all, the back has to know when to turn itself on to take an exposure. Because the large format camera is nothing more than two wooden boards connected with light tight fabric with no electronics whatsoever, this is accomplished with a Phase One Wakeup Cable. This cable is easily attached to the 8-pin port on the back, and then to the PC-port on the lens. This cable has a button that, when pressed, wakes up the back and makes it sensitive to light. Once the shutter is triggered, a signal is sent from the PC port on the lens to the digital back relaying that the exposure has started, how long the exposure lasts, and when it ends so that the back can generate a black frame and map out noise. All of that sounds complicated, but its a simple two-step process. Wakeup and expose. Done. Not complicated as some would have you believe.

 

In The Field

Photographer

With the camera setup and ready to shoot, focusing proved to be a major hurdle. Our setup didn’t include a sliding adapter with a ground glass matched to the sensor plane of the digital back. This would have been a much easier solution. Instead, we tried to use the original ground glass to focus and then replace the ground glass with the graflok adapter and attached digital back. This was a massive failure as it turns out the focusing plane of the ground glass and the sensor plane of the digital back were at completely different locations, and thus resulted in an extremely out of focus image.

Photographer

In order to actually focus with the digital back on the 4×5, we resorted to using the digital back’s live view feature. The issue we found here was that the lenses we used introduced diffraction very early in the aperture range, which forced us to focus with a more open aperture. Though it was a slow process, this proved to be the best option and resulted in the sharpest image. On top of that, because of how easy it was to slightly jostle the 4×5 camera while focusing, each time we focused we would have to let the camera settle so that live view could offer a crisp view of what we were looking at without motion blur. Digital backs with CMOS sensors would offer a much more DSLR like live view, making focusing in this way much faster and simpler.

As I expected, the images we shot with my lenses were not the razor sharp images I’ve come to expect from medium format digital backs. Using the Fuji 90mm f/8 we stopped down to past f/16, but diffraction due to the high resolution digital back was so severe that we were forced to shoot at f/11 which turned out to be the sweet spot. Even so, the image was not what we wanted in terms of sharpness.

In order to achieve the sharpest possible image, we elected to use the back’s Sensor + feature. Sensor + combines four surrounding pixels into effectively one pixel, thus reducing resolution by 75%, but gaining ISO performance while still using the entire sensor area. This reduction in resolution leveled the playing field allowing the resolving power of the lens to more closely match that of the digital back which resulted in more apparent sharpness.

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Left: Shen Hao, Fuji 90mm, IQ260 full resolution (60MP) 100% crop

Right: Shen Hao, Fuji 90mm, IQ260 Sensor+ (15MP) 100% crop

Its true that you’re not getting the full benefit of the digital back (in terms of resolution) by using Sensor +, however I’ll gladly sacrifice 75% of my resolution for sharpness if that means I still get the large medium format sensor AND superior ISO performance. Plus, on top of that, its very easy to stitch images together using the large format camera’s movements. This creates an even larger image while still maintaining the sharpness and ISO performance using sensor plus. My typical experience is shooting with Phase backs on technical cameras and DF bodies, so I was impressed with how we were able to adapt the backs to shoot with the imperfect features of the 4×5.

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Shen Hao, Fuji 90mm, IQ260, Sensor +, 9 image vertical panorama

 

How it Stacks Up

Photographer

Together with the Shen Hao 4×5 I brought along a Phase One 645DF+ with an IQ 280, 35mm AF, and 28mm LS lens. The DF+ is an SLR that is made specifically for Phase One digital backs, and when paired with Schneider lenses, makes a beautifully sharp image. For this test, I switched out the IQ 280 on the 4×5 with an IQ 260. I did this because I wanted to play to each system’s individual strengths, and with the 260’s slightly lower resolution the images from the 4×5 would appear sharper even at full resolution than if it were paired with an IQ 280

 

Because of the crop factor of the digital backs paired with the 4×5 lenses, they appear much more telephoto than the lenses I had for the 645DF+. Interestingly, even though the digital back was using the sweet spot of the 4×5 lenses (right in the center), they still weren’t as sharp as the Mamiya and Schneider lenses on the DF+ at full resolution, even with the back on the 4×5 set to Sensor Plus.

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Left: Shen Hao, Fuji 90mm, IQ260 sensor+ (15MP) Full image

Right: Phase One 645DF+, 35mm AF, IQ280 (80MP) Full image

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Left: Shen Hao, Fuji 90mm, IQ260 sensor+ (15MP)  100% Crop

Right: Phase One 645DF+, 35mm AF, IQ280 (80MP) 100% Crop

 

One bright spot for the 4×5 lenses was the sharpness of the Fuji 210mm W. Even at full resolution on a 60 megapixel back, the lens performed admirably. Schneider Digitar and Rodenstock HR glass would still blow it out of the water, but still a sharp lens all things considered.

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Left: Shen Hao, Fuji 210mm, IQ260 Full Resolution

Right: Same Photo at 100% crop

And then of course we couldn’t wrap up the test without shooting some actual film. I’m a big fan of Ilford HP5 Plus 400. I like the tonality I get with HP5 as well as the grain size and structure. These film images are not meant to be an exact comparison to the digital files. A proper test would require lower ISO film with finer grain as well as a proper drum scan of the negatives. The film images do offer the tonality and grain structure that differs from the native Phase files, though in Capture One 8.2 Phase One has added a much more in depth film emulation module as shown below.

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Original Digital File (Import to Capture One 8 only)

Phase One 645DF+, IQ 280, Schneider 28mm LS.

Photographer

Film Image

Shen Hao TZ45IIB, Fuji 90mm f/8, Ilford HP5+. (Stand developed in Rodinal)

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Digital Black and White Conversion

Phase One 645DF+, IQ 280, Schneider 28mm LS.

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HP5+ 400 Film Grain Crop

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Silver Rich Grain module applied in Capture One 8

 

Digital Equivalent

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You might say the large format camera is to film as the technical camera is to digital. The technical camera is the modern day equivalent to the 4×5 camera, designed specifically for ultra high resolution digital backs instead of film, though some can use both. Technical cameras are extremely precise, highly crafted metal cameras optimized for digital backs with very tight tolerances for focus. These cameras are comparable to large format cameras in that many of them offer the same movements of a large format camera such as tilt, swing, shift, and rise/fall,

Phase One’s contribution to this kind of camera was to partner with Swiss technical camera maker Alpa to produce the Phase One A series. This is an elegantly crafted body with mounts for Phase One and Credo digital backs as well several attachment points for peripherals. For lenses, the Alpa mount uses modern day Rodenstock HR and Schneider Digitar technical camera lenses and comes with a choice of one of 3 different Rodenstock HR lenses that are all extremely sharp with very high resolving powers. These lenses hang their hat on their ability to maintain corner to corner sharpness extremely well- and they do so beautifully even at wide angles. Past that, a plethora of other lenses are available from Alpa- not just the ones included with the A series.

The A series body doesn’t offer rise or shift movements, but can can be paired with an adapter to introduce tilt or swing if the lens allows it. Other cameras in Alpa’s line offer shift or rise/fall depending on orientation such as the STC, or both like the Max or the XY. The movements of these cameras are driven by a much higher level of precision than is present on most large format cameras designed for film. Many of the best landscape and architectural photographers in the world put such cameras to use and rely heavily on their reliability and precision.

In addition, there are still modern view cameras being made specifically for digital backs. These view cameras are much smaller in size and weight than their large format counterparts, but still offer a variety of movements, albeit to a lesser degree as the tolerance for focus for a digital back is much tighter than for a 4×5 negative. Digital backs simply need less range of movement due to their high resolution and smaller sensor size.

 

Conclusion

4x5 Camera

4×5 Field Camera

 

Slapping a high resolution digital back on a wooden/aluminum 4×5 foldable field camera with film lenses is, honestly, best thought of as a novelty than a real imaging solution. That being said, if you already have a field or view camera just sitting around collecting dust and are looking for ways to bring it into the digital age, snagging a graflok adapter and putting an inexpensive digital back on it is a great way to breathe new life into some old gear. You don’t have to use an IQ 260 or 280 to make this work. In fact lower resolution backs, as demonstrated by the use of sensor +, will be more on par with film lenses and make for sharper looking images because of their lower resolution. They key is to find the best method for focusing, whether that’s with a sliding back, or a calibrated ground glass.

We’ve proven that its certainly possible to make photographs with a low-tech, large format body, however that ability must be paired with realistic expectations. Using lenses other than Schneider Digitar and Rodenstock HR is a dangerous minefield of quality and consistency. But as we’ve demonstrated, its not just the glass that could introduce lack of sharpness. Camera stability and solidity are paramount to getting both consistent composition and sharpness. The last thing you want is to be taking multiple images for an HDR or Panorama to find out later that one of the standards moved unintentionally.

In all, it was a fun exercise. It also gave me an appreciation for technical cameras and the rigorous quality control and manufacturing process that goes into making them. Its one thing to use a field camera for personal projects and experimentation, but when it comes to getting a job done right where money is on the line there’s no replacement for the right equipment.

For questions about Phase One digital backs, DSLRS, technical cameras, or anything at all please give us a call or e-mail us.

 

Zac Henderson, Support

zac@megapixelsdigital.com

Cell: 334-728-1465

Office: 303-774-0712

 

To learn more about technical camera and specifically the Phase One A-Series, Check out the video below

 

By | 2015-04-03T16:02:35+00:00 April 3rd, 2015|Cool Shit|0 Comments