Wednesday, February 2, 2011

80 MP medium format backs

I've been reading with great interest the field report of the new super high resolution Phase One medium format back done by Michael over at Luminous Landscape. This monster gives 80MP real resolution and Michael thinks it is equivalent to drum-scanned 8x10" film. This would be extraordinary if true. Looking at the 1:1 crop and counting pixels, the resolution appears to be similar to or slightly better than what I get stitching (see here, here or here) multiple images from my crop DSLR using my very cheapest kit lens. Of course getting that kind of quality in a single shot is far more convenient than my el cheapo solution as you can compose the shot far better. When I compose, I usually make a guide shot with an equivalent wider angle lens to the final stitched image's viewing angle. This works to a degree but is not perfect. I cannot exactly compose this way. My stitching solution also has trouble with very long lenses as the rotation between frames becomes very small so it works best for wide angles. All in all the new medium format backs are very interesting products. Of course I can't really afford such a machine (44k$ for just this new back, no body and lenses included!) which is probably why I don't get these cameras sent to me by Phase One or any of the other makers for testing. I'd be happy to put one through its paces though! Michael mentions stitching multiple shots from this camera. That concept just blows my mind.


  1. well, Michael was saying that a D30 Canon was equal to scanned 6x7 120 film at one stage, which I understood he's backed away from a tad.

    In the end it doesn't matter as so few have used even 4x5 let alone 8x10 that they'll never be able to make a comparison.

    With about $10 worth of glass and a light bulb you can make 8x10 prints (contact prints) of 8x10 in your bathroom which will have a texture which I'm dubious that the digital backs will have. Of course slide users will not know what it is they're missing

    I use my G1 for 90% of my photography because its quick and convenient and does a great job. But there is still stuff which makes me want to pull out a film camera with negative in it.

    Thanks for the post :-)

  2. My sarcasm about the claim didn't shine through enough it appears. I have done 4x5 and I have a friend who does 8x10 and larger film, both black and white and color (Velvia or Portia). The examples on the luminous website and my stitched images are nowhere near what you get from that. To see those 8x10 positives in real life is just extraordinary. An 8x10 from a fine-grained film like Velvia should be equivalent to >500 MP when scanned on a flat-bed if you look at the MTF curves and typical large format lens performance. You can get far more out of it on a drum scan but you're probably mostly imaging grain there. This is substantially more than the 80 MP Bayer arrayed (which cuts the real resolution down by 30-50% or so) digital sensor. I would say that this 80 MP back might be getting close to 4x5 film in resolution.

    Now if you compare dynamic range, it is quite a bit better than Velvia. However, there are much better color films than Velvia if you go for dynamic range that will give you something close to the claimed sensor DR.

    I should arrange a shootout sometime with one of my large format friends to compare the detail in a stitched shot with that in 4x5 film. My guess is that the film shot will be visibly better when scanned well. I do digital mostly for the convenience and the much lower weight I have to carry going up in the mountains. Some of the well known Colorado photographers that work with large format use llamas, donkeys or even human assistants to get their gear up. Or they simply drive to the location if that's possible.