Friday, January 10, 2014

Sigma Merrill Cameras- Digital Film?

Burnt Building - Boron, California
In my review of the Sigma DP2 Merrill I wrote, "The DP2M at [ISO 100] can reach the fine grain of [Agfa Pan 25 and Ilford Delta 100] films, including the Ilford Delta 100 in medium format." I also said, "The DP2M retains a large amount of fine details within highly saturated images. It is possible to replicate the look of saturated transparency films with images captured on this camera!"

I've been asked more than once now to expound on this. Are Sigma Merrill cameras really the digital equivalent of film? Can Sigma's Foveon sensor really deliver film-like results?
A Light In The Dark - Tehachapi, California
The answer to those questions is not easy because there are a lot of different films out there. There are many choices for both color and black-and-white. Each one has different advantages and disadvantages. Each one has a different look. So right off the bat I can say that Sigma Merrill cameras do not replicate exactly any one film.

But that does not mean that the cameras aren't "close enough" to some different films to draw comparisons.

Autumn Tree Leaves - Tehachapi, California
Sigma Merrill cameras are known for their rich colors, something that digital cameras struggle with in general. Digital cameras tend to over-saturate easily, and by over-saturate I mean that there is not enough color depth to retain fine details in highly saturated areas in an image. At low ISO, the Foveon sensor is able to retain details in highly saturated images much better than Beyer sensors.

Fuji Velvia 50 is the comparison everyone wants to see, because this film is the absolute best for saturated colors. The colors are just so vibrant, and fine details are very well retained. The grain is incredibly fine, and if paired with a sharp lens, there isn't anything that can touch it. Not even Sigma Merrill cameras. At ISO 100, however, the Foveon sensor is close enough to Fuji Velvia 50 (in 35mm format, anyway) that you may find it acceptable as a digital doppelganger.
Frozen - Stallion Springs, California
A closer comparison would be Kodak Ektachrome E100VS. This is basically Kodak's version of Velvia 50. E100VS doesn't quite have the same fine grain as Velvia 50, and the colors are not quite as vibrant (but pretty close). The Merrill cameras get pretty darn close to E100VS, in my opinion.

Now these two films have different hue casts (Fuji is "cooler" and Kodak is "warmer"), and either one could be easily replicated by manipulating the white balance on the Sigma images.
Color Lamp Abstract - Bakersfield, California
There are many other 35mm color films that could be compared, and perhaps even replicated with the Sigma cameras. The comparisons could go on and on and on. The larger point here is that film still blows the socks off of digital when it comes to pure image quality, but, at low ISO, the Sigma Merrill cameras close the gap.

Black & White
On A Brighter Day - Tehachapi, California
The two films that I mentioned in the quote at the top are Agfa Pan 25 and Ilford Delta 100. At ISO 100, the digital noise and fine details of the Sigma Merrill are a pretty close approximation of the silver grain found on those films. Perhaps not quite as fine as Agfa Pan 25 in 35mm format, but definitely as fine as Ilford Delta 100. In fact, even in medium format, there is not a significant difference between Sigma Merrill cameras and Ilford Delta 100.

One area where the Sigma Merrill cameras cannot touch most black-and-white films is dynamic range. I've found that the dynamic range weak point in Foveon sensor cameras is in the shadows. The cameras actually retains details in highlights very well, but not in shadows. By overexposing by one stop and recovering in post processing, the dynamic range can be increased. However, it still does not quite match the dynamic range of film.
Rolling Dough - Tehachapi, California
One can get a more "gritty" look by using higher ISO films because the grains of silver are larger. Increasing the ISO on Sigma Merrill cameras replicates this, although you cannot go much beyond ISO 400 before image quality degrades to an unusable level. With some effort in post-processing, ISO 800 is usable and gritty, but it does take some work to make it look good.

On a side note, the way the Foveon sensor works is that it has three layers: one that captures red, one that captures green and one that captures blue. Since the entire images is captured with each color, one can adjust the color channels to simulate black-and-white filters without degrading image quality. Want a red filter effect? Simply use the red color channel.
Abandoned Homestead - Tehachapi, California
Interestingly enough, you can actually use colored filters meant for black-and-white film on Sigma Merrill cameras. And Sigma DSLRs can be easily converted to infrared by taking out the easy-to-remove IR filter.

Butterfly - Bakersfield, California
With film, there are a whole host of reasons to choose one over another, including contrast, hue, tones, grain, saturation, sensitivity, etc. With digital, much of that can be easily replicated and adjusted. There's software that will quickly make an image look like it was captured with any number of different films. But there are some things that even clever software cannot do.

Even the best software cannot keep fine details in highly saturated areas if the files are not capable. HDR might give the dynamic range of black-and-white film, but not without some trade-offs. You can decrease digital noise to replicate fine grain, but at the expense of sharpness.
Covered Bridge - Stallion Springs, California
Film is still superior to digital with regard to pure image quality. Sigma Merrill cameras bring digital a little bit closer, but it is still not equal.

So why do so many choose digital over film if film is better? Because digital is just so much more convenient. Sigma Merrill cameras are certainly not as convenient as most digital cameras, but at the same time most digital cameras can't match the image quality from the Foveon sensor at low ISO.
Abandoned Bathroom - Mojave, California
Each of these images were captured using a Sigma DP2 Merrill camera. I made no test shots. I did not do any side-by-side comparisons of images. Instead, I relied on over 15 years experience using film, including those mentioned in this post and many that were not mentioned, as well as about six months using a Sigma Merrill camera.

Test shots in controlled environments can be useful. However, there is nothing like real-world experience. There is nothing like working knowledge, which can never be replaced by controlled work in a lab.
Rusted Bolt - Loraine, California