Tuesday, December 27, 2011

Image Quality

Recently Luminous Landscape published a comparison of the IQ180 top of the line digital back from PhaseOne with 8X10 colour film. It seemed odd at the time that the fellow setting this up reasoned that one could scan 8X10 film at 750 pixels per inch and get all the information that was available in the film.

It seemed odd, because if one uses the same emulsion in 35 mm. film, scanning a slide or colour negative at only 750 pixels per inch would be a disaster, showing only a small fraction of the information in the original.

Tim Parker and friends have taken on the daunting task of doing a repeat and extension of this comparison, adding 4X5 film, and the older P45 back (?39 megapixels vs. 80 for the newest), as well as Canon 5D2 (of great interest to me) and the Sony 900.

The results of the studio shots showed a huge advantage to the 8X10 film, and even to 4X5 and the Mamiya 7. A shot out in the wild however tended to even things out. Despite very windy conditions, they continued to show a huge resolution advantage to the 8X10 transparency film, but when it came to looking at the darker areas of the image, a whole other story came out.

You must click on the image above to see it at proper size. As you can see, the amount of detail in the IQ180 on the right is huge, however if one is honest, there is over sharpening and in the areas of the left that are adequately exposed and standing still, there is a lot of detail.

This example above was deliberately selected to show the film results at their worst - in shadowed areas and dealing with more wind than most of us are willing to put up with.
Again, click to see at original size - and the sharpening is the same as in the shadow image. There is a tremendous amount of information in the distant trees and buildings and bridges beyond that is simply gone in the digital image.
A different image of the skyline shows more detail in the film image no matter what sharpening is applied to the digital image, though with a huge amount of sharpening (6 pixels worth) you can see at least some of what the film saw, but that amount of sharpening destroys the rest of the image).

Bottom line is under ideal circumstances, optimal  stop, no wind, rock steady tripod and great lenses, 8X10 still very nicely remains King Of The Hill.

Under real circumstances, it isn't nearly as clear - more of a matter of losing on the straightaways and winning on the corners. This would explain Hans Strand's comment that since switching to a Hasselblad 50 MP camera, he has seen a significant increase in quality of his images - real images in real situations.

For those who carefully select their situations, use a massive tripod and a low contrast lighting situation, and who then use careful unsharp masking in their printing, 8X10 is still capable of the ultimate in quality in 2011. This explains why people like Christopher Burkett are still willing to lug around his 15 lb. Calumet view camera. For those who climb active volcanoes, or fly over river deltas or climb into caves, like Hans, he is simply more successful with digital.

The original Tim Parkin study is available free at On Landscape and I encourage you to read it carefully, and possibly play with the images there for yourself. Although this online magazine leans towards British Landscape Photography, I note the inclusion of more international work since its inception and I'm going to subscribe.

2 comments:

Sandy Wilson said...

Hi George,

I read the Tim Parkin article, which was very interesting and enlightening.

I know most of the contributing photographers. Their vast knowledge and experience in landscape photography leaves little to be desired.

My friend David Ward put forward a very convincing case for still using film, particularly the cost aspects of changing to digital high end digital backs.

I use a Sony A900 full size sensor DSLR camera and the cost of that was quite a lot for a retired pensioner to fork out.

It has to be remembered that analogue film photography has had a 170 year start over digital, which in my opinion is still in its infancy.

However at the rate and speed of new digital developments being made practically every day who knows where it will be in two, five, ten or fifty years time.

As the pixel count increases so does the file size and we will need considerably more powerful computers to handle them. To say nothing of the problems of storing these large files.

Somewhere in the plethora of technobable the basic contributing factor of photography seems to have got lost. I know we need to know all this to produce high quality images, but what about VISION and SEEING the images in the first place. Surly this takes precedence over pixel counts etc.

The conversation everywhere where the topic of photography is discussed seems to be Photoshop, resolution, colour management, pixel counts,which gets a bid boring after a while. Nobody seems to want to talk about making images any more, either at club level or any other level of photography. SAD VERY SAD.

I suppose this is progress, but can we keep up with whirl wind technological progress at a detrimental cost of the artistic side of photography.

A final word in recent years I have come across many fine photographers who seem to struggle with digital technology in general, and some have returned to using film, where they feel more in control of their image making.

I will now await the flack from all the digital experts our there.

Tim said...

Sandy,

I've heard all that before and don't disagree that pointing the camera in the right direction is of foremost importance.
However, having gone to some lengths to achieve that in a given photo-shoot, why would I want to be let down by either my equipment or my knowledge or the amount of image-data captured at the scene? I contend that one has to place these things on an equal footing, and if you want a discourse on the art of composition, don't look in a photoshop forum...

For me, digital has introduced new ways of thinking, in terms of an image, a flexibility of working that is not limited to some Fujifilm engineer's idea of what shade my terracotta plant-pots should be, making it a priority to populate the final rectangular *image* the best way I can in a formalised workflow.

I've done plenty enough film myself and the smell of fixer loses its romance.