Mark Cassino Photography - Mark's Blog

Several essays on this blog have been concerned with the shift from film to digital. For photographers, that’s one of the key issues of the day. Digital photography offers a lot of advantages in terms of ease of use and workflow convenience, but as a relatively young and new technology, it still falls short of film in some critical areas.

One way to think about the performance of any photographic format is to consider the amount of area covered by each pixel in the photograph, either in terms of the original capture or a scanned image from film.

Right off the bat, this is a bit unfair to film in that in entails converting an analog recording of light (the exposed film) to a digital medium. But film is still able to hold its own even with that handicap.

Let’s compare the “stuff per pixel” for three photographic formats – a 6 megapixel digital capture, a 35mm film exposure, and a 6x7 cm medium format exposure.

A 6 megapixel digital camera produces an image file that is roughly 3000 x 2000 pixels in dimension. A 35mm exposure, scanned at 4000 dpi produces a file that is about 5500 x 3700 pixels in size, just over 20 megapixels. Finally, a 6x7 cm medium format frame, scanned at 3200 dpi, produces a file that is approximately 9000 x 7000 pixels in dimension, just over 62 megapixels in size.

(I picked those formats and scan resolutions simply because those are the ones I work with. I love speculation and mental experimentation as much as the next person, but ultimately count myself in the reality based population for most things and like to base comments on actual experience and tests.)

Now let’s assume that you are taking a head and shoulders portrait of person that is 2 x 3 feet in area – the portrait, that is, not the person.

With the six megapixel digital camera, each pixel in this digital capture represents a or square that is about 1/1000th of a foot, or 1/80th of an inch across. This should be more than adequate to capture fine detail in the subject.

With 35mm film, each pixel represents a square little less than 1/150th of an inch across. Even though the film grain interferes with some of this fine detail, this is clearly a leap ahead in terms of resolution.

With a 6x7cm the resolution takes another leap forward. Even scanning at a lower resolution 3200 dpi, a 6x7 exposure results in an image file where each pixel in the headshot captures a square that is 1/250th of an inch in diameter.

Despite this theoretical exercise, a lot of folks probably couldn’t see any difference between a head shot taken with the three difference cameras. Even though the medium format and 35mm exposures have the capacity to capture a lot more information, it really isn’t obvious in an 8x10 or smaller print.

The bottom line is that this kind of shot just does not have a great level of detail to record. Unless you are going to try to count individual hairs on your subject’s head, or blow the image up to billboard size, the benefits of film, even medium format film, are not obvious for this type of shot.

(That said – the one area where the difference can almost always be seen is in the smoothness of the tonal changes in the image. But this is a subtle distinction.)

On the flip side, assume you are taking a shot of a sweeping landscape, full of fine detail, and are using a wide angle lens to capture an area 100 yards across.

In this case, each pixel in the 6 megapixel digital exposure is sampling an area that is 1/10th of a foot – or 1.2 inches - square. The fine detail in this shot will clearly be compromised.

One the other hand, a 35mm film exposure scanned at 4000 dpi will result in a file where each pixel is about 2/3rds of an inch across. And a 6x7 cm medium format shot, scanned at 3200 dpi, results in a file where each pixel samples an area 0.4 inches across.

Obviously, in this kind of situation, the increased resolution of film is really an advantage. Since there is enough detail in the shot to for the viewer to see, the advantages of film for this kind of shot become clear.

Now consider the other end of the spectrum – an extreme macro, like a snow crystal shot. With snow flake photography I’m typically shooting at 4 to 8 times life sized on the film / sensor plane. That means that the projected image of the subject – in this case a snow crystal that may be 1/8th to 1/16th of an inch in size – is blown up 4 to 8 times that size.

In this case, with the 6 megapixel digital camera, each pixel represents a really minute area of the snow crystal – something on the order of a square 1/4000th to 1/8000th of an inch across! 35m film resolves even more detail, but as already noted, the interference of the film grain and lower acutance of film results in an inferior image. And so far, I’ve haven’t come up with a way to magnify a snow crystal big enough to take advantage of medium format film – so far now I’ll leave that in the ‘impractical’ column.

So what does this boil down to? If you think about your shots in terms of “stuff per pixel” you can quickly determine when you are better off shooting digital, 35mm, or medium format. You can also figure out when a lower megapixel camera will work fine, and when you need step up to a higher megapixel platform. Basically, if you think about how small the relevant details in your shot are, and how those details will relate to the total area you are exposing, it’s simple and intuitive to see when the higher resolution of film is needed, and where digital is better able to do the job.

Here’s a simple shot of Point Iroquois, a northern Michigan lighthouse that sits on the south shore of Lake Superior. This shot was taken under the clear azure skies of deepest summer and a polarizer was used to enhance the colors.

It took me over an hour to take this photo. As I stood there, camera on tripod, many a tourist passed by and took a shot, and at least three tripod bearing photographers set up, shot, and left. My wife toured the museum and gift shop inside the building, went up to the tower and peered at the Great Lakes freighters through the telescope up there, and ultimately wandered down towards the beach as I stood in place. I must of seemed awfully slow, but in fact I was standing under the still clear azure sky of deepest summer, and that dang flag was hanging limp like a washrag draped on the top of mop handle. But the wind always comes on even the stillest days (and it always pauses, even on the windiest) – and so after an hour’s plus wait, a desultory breeze wafted across the lighthouse grounds, and I was able to snap a shot with flag looking as a flag should. It’s not like capturing the decisive moment or anything like that. Rather, in this case it’s about craft. Its about paying attention to a detail, and investing the time and effort to get that detail right. Technical details – shot with a Pentax *ist-D, SMC FA 20-30mm lens, polarizer and tripod.

The internet has been a real boon to photographers. These days it’s easy to setup an online photo gallery and put your work out for the world to see. There are also all sorts of web based photo competitions and critique sites, and these can be excellent places to hone one’s photographic skill.

While there is a tremendous upside to the internet as a means of presenting photographs, there is also a downside. After all, the images on any website are so tiny that all but the most obvious aspects of the composition are diminished or lost. (The photos on this website are no exception.)

Most web images seldom exceed 600 to 700 pixels in size along the longest axis. Many are even smaller. If they were printed at the customary 300 dpi resolution, most web images are the equivalent of a two inch or smaller paper print.

The inevitable result is that a lot of information is lost, and more importantly, only certain kinds of compositions are effective at this size.

A few years ago I was fortunate to view a huge original print Ansel Adam’s “Moonrise, Hernandez, New Mexico” in an art museum. As I recall, the print was in the neighborhood of 6 x 4 feet in size. The lush detail was stunning, and the impact of the image was incredible.

I just hopped over to Google Images and pulled up some web shots of the same photograph. A lot of the fine detail that makes the shot is lost in low-res, web versions. Someone unfamiliar with this image, seeing it for the first time at internet size, may not be able to discern the cemetery and other key elements in the shot. In fact, at web size, the image really just breaks down into a few compositional elements – the moon, the band of clouds, the horizon, and the horizontal line formed by the town. The real essence of the image is gone.

Maybe it’s an example of the old adage that the medium is the message, but the more one relies on the internet as a means of presenting and viewing photographs, the greater the temptation to produce photos that work at internet size. That means taking photos with simple and uncomplicated compositions, and relying on that simplicity instead of on nuance, detail, and texture, to achieve the desired effect.

Compounding this tendency is that we are all confronted with hundreds of photos every day, and most of them are pitched at us with the intent of selling something. Advertising photos are most effective when they are simple and high impact. With advertising, the viewer might only see the image for a few seconds on a TV screen, bill board, or flipping through a magazine. Obviously, a simple, high impact shot has a greater chance of succeeding – getting the viewers attention – than does a more complex, subtle, or nuanced image.

Of course, there is nothing wrong with simplicity or impact. But photographers who allow those characteristics to become the primary measure of an image’s worth, are short changing themselves and their craft. Some subjects cannot be adequately explored with that approach, some messages cannot be conveyed in that language. And ultimately, that means that some images just won’t work when presented on the internet.

To me, this only emphasizes the importance of the physical print and the presentation of work as prints. One the most basic and fundamental decisions the photographer has to make when preparing a print is the simple question of how big (or small) to make the print. There are no rules, and bigger is not better. But I like to think that every image has its ideal size, and more often than not, that ideal print size will be significantly larger, and present more detail, than a web-sized image.

Here is an image that brings together a variety of experimental processes to achieve it’s ultimate effect. It was shot on an antique camera, using color negative film that was subsequently cross processed in exhausted Dektol, a highly active B&W paper developer. The result, in my opinion, is an interesting tonal range in a photo of a fairly common object – a bushel basket filled with kindling sticks.

So let’s talk about the processes used to take this shot. For starters, this is one of several recent images taken with an antique or toy camera. In this case a venerable Argus C-3 “Brick” rangefinder was used to take the image. The Argus is a fun and interesting early 35mm camera. It’s an incredibly fussy camera that requires multiple button presses and cocking before it will actually take a shot. The whole purpose of using toy or antique cameras is to deliberately introduce distortions, light leaks, vignetting and other optical elements.

There is also something magical about abandoning complete control over the photographic process and opening the door to randomness in hopes of the fortunate accident. The 50mm f 3.5 Cintar lens in the Argus brick is actually a pretty good performer, but still introduces enough character to the image to give it that different look and feel, especially wide open. For this shot, simply taking the image with the Argus was not enough of an experiment. I was also trying to use up some of my stockpile of 35mm C41 color film (see the essay on the number 396 in the “Film to Digital By the Numbers” series.)

So, I loaded the Argus with Fuji Superia 800 and over exposed the shot by a couple of stops. A few years ago I inherited a couple of packets of long expired Dektol developer. Although the foil packets seemed to be relatively in tact, the Dektol mixed up to form a brown liquid, more or less the color of black coffee or cola. I had developed a few rolls of film using this witch’s brew, following the times listed for D72 in some very old darkroom handbooks. The results with conventional B&W film were good - here are two examples:

I thought to try the concoction with the color negative film. The ultimate results were extremely dense negatives that require significant adjustment to scanning exposure in order to create a printable file. (I'm lucky that my 35mm film scanner allows me to directly adjust exposure.) I managed to get two interesting shots on this roll. I like the tonality, especially in “Sticks in a Basket,” and it’s a technique I plan to explore some more. As a closing note – here’s the other acceptable shot take from the same roll: 

As part of this blog I’m planning to comment on selected images. Of course – a photo has to speak for itself and it has to do that talking visually. Explanations about what a photo was intended to mean are pretty pointless. But there is still something to be gained by telling the story behind the photo, especially with ones like this that are less than completely self explanatory. The image that is (hopefully) to the left is exactly what the title says – a glimpse out of my west window. Click on it for a larger version. I like this shot because it captures the mood and feeling of a short, dark, and gloomy Michigan winter day – which is usually just the most recent of a long series of short, dark, and gloomy days. And to be honest, mornings are seldom bright times for me even when the sun is shining. This window happens to be in the bathroom and during the winter months is perpetually coated with condensation or frost, and the view of it here may not be objectively accurate, but it does capture the sense of heaviness I feel when looking out of the window. On an intellectual level, I like how the most obvious elements of the photograph are the least revealed - the tree is blurred, no detail to be seen. But the more subtle aspects of the image - the moisture and textures on the window - are the most clearly rendered. Lost in these tiny web images are the fine droplets of water hanging on the glass, the snakey imperfections in the dew formations, and cryptic characters Cali wrote in the steam just before snapping the image (all with one sweep of her tail at that.) At A3 of Super B print sizes, those artifacts start to glimmer in the image, adding a little more interest. And all the cars and their good people, sitting in the parking lot behind the little tree, are lost in this image, even though most of the light was bouncing up off them, so in some respect they are represented here… This will wind up in the “Around the House” subcategory in the miscellaneous images section of the main site. The photo itself was taken with a Canon T90 on Kodak 35mm Plus-x film developed in Rodinal. After scanning, the B&W image was ‘toned’ through channel adjustments in Photoshop. Rodinal was chosen in part because I wanted a bit of punch to the grain, and in part because it produces virtually no fog in somewhat stale Plus-X (unlike HC110 or D76.)

I read a lot of articles and blogs about film vs. digital, and which is “best.” In my opinion, that’s sort of like comparing a hammer to a saw, and asking which is best. The answer is that they are different tools and if you are going to build a house (or a photo portfolio) you’re best off using both. The trick is know which tool to use when.

One central problem that pops up in many of these discussion is a lack of clarity regarding the technical aspects of the photograph. One photographer may be perfectly happy with the results of his digital images, and that may be because his subject matter and technique play to the strengths of digital. Another may find digital to be unacceptable, precisely because her photos don’t play to the strengths of the platform. Until you define what factors affect image quality, you can’t analyze how well different platforms perform in light of those factors.

Fortunately, we don’t have to figure this stuff out all on our own....

In The Negative Ansel Adams outlines three factors that impact image quality. These are acutance, resolution, and grain (or ‘noise’ in the digital realm.)

Let’s look at each of these factors and see how digital and film perform in regards to them.

Acutance is the ability of the medium to record ‘sharp’ edges. So what is a sharp edge? A sharp edge is an abrupt change in contrast. Lay a silver razor on a black backdrop. The transition from silver to black takes place extremely abruptly. If you hearken back to your high school geometry days, and think of the razor and background as making up a plane (a two dimensional series of points), in theory the edge of the razor would be defined by a silver point directly next to a black point – 100% acutance.

Of course, it doesn’t work that way in the real world. No matter how good the optics of the lens, 100% acutance never happens, but excellent lenses can produce very high degrees of acutance.

And then there is the recording media. In broad terms, digital really out performs film in rendering high acutance images. In theory, pixels side by side, could make abrupt changes in contrast. However film, with its layers of silver halide crystals, can never render the same degree of edge sharpness. I saw this most clearly when I started shooting snowflakes digitally. Visually, snow crystals are very edge intensive, and acutance is an essential element creating high quality snowflake photographs. No matter what film I used – including many excellent emulsions like Fuji Velvia 50 or Kodak E100S - the degree of acutance was just not as high in the film images.

So in terms of acutance, digital generally beats film.

Resolution is the ability of the image to record fine detail. Let’s say you are shooting a wide-angle shot of a field of wheat. Think of the fine detail present in that shot: the thousands of wheat stalks, the seed heads topped with tassels. Even though digital cameras increase their megapixels daily, film still holds the edge in regards to being able to record fine detail.

I’m not talking about 35mm film here – even though even it has greater resolution that most digital cameras. But medium and large format film have a tremendous advantage over digital in terms of resolution. For example, a 6x7 cm medium format exposure, scanned at 3200 dpi, produces a digital file greater than 64 megapixels in size. These images have far more resolution for two reasons – they capture vastly more data, and the image projected onto the film is significantly larger (higher magnification) than a digital capture.

At the time of this writing (2006) even 35mm film has greater resolution that most digital SLR’s . Medium format film captures have significantly greater resolution, and large format is a whole order of magnitude greater yet.

So, in the resolution department, film wins hands down - but it only wins big if you are willing to step beyond the 35mm format.

Lastly comes noise or grain – which for the sake of simplicity I’ll just call “noise” from now on. Noise is defined as random changes in contrast and color independent of the subject matter in the exposure.

Both film and digital exhibit higher noise levels at higher sensitivity (ISO) levels. High speed films tend to be more grainy, and digital cameras set to their highest speed levels tend to produce very noisy images. In addition – small sensor digital cameras are generally noisier than larger sensor cameras, which is why digital SLR's generally outperform small format digi-cams.

Different types of film can produce markedly different levels of noise or grain. Some films – like the now discontinued Tech-Pan, Royal Gold 25, and Kodachrome 25 – had extremely fine grain. Others – like Kodachrome 200 or Royal Gold 1000 – were incredibly grainy.

While it’s difficult to generalize, I think it’s safe to say that at comparable ISO settings, digital SLR’s will outperform the best films in regards to noise. Again, I draw on my experiences shooting snow crystals, which have large areas of open space. The noise levels on shots captured with my Pentax *ist-D are significantly lower than the level of noise on exposures taken on Fuji Velvia 50. Similarly, I now routinely photograph close ups of botanical or insect subjects with the *ist-D set to ISO 400 – with noise levels comparable to what I used to see with ISO 100 transparency film.

The complication in understanding noise arises out of the concept of the “signal to noise ratio.” In other words, the more information presented in the photo – the greater the signal – the less noticeable the noise. The less information in the photo – the less the signal - and the more noticeable the noise. Practically speaking, that’s why you see the effect of noise or grain in a photograph of a clean blue sky, but notice it much less in a shot full of information – like the wheat field mentioned above. The upshot is that noise is less of an issue in some shots, based on the content of the image, than in other shots.

One final comment on noise: the grain in film, particularly certain Black & White films, can produce a pleasing and interesting effect. I think that to some extent that’s because we are used to seeing it, and we attach certain cultural connotations to old-fashioned photo grain. But I also think that film grain has a regularity to its pattern that makes it easy for the eyes to accept it and see past it. Digital noise, on the other hand, seems to be less regular and even. It seems to be more distracting that film grain, so it’s fortunate that it is less pronounced.

So, in the area of noise or grain, digital generally wins out over film, but with many caveats.

So how does all this come together?

As I see it, digital really shines in situations where low noise and high acutance are the essential elements of the image. Snow crystal photos are an extreme example of this type of image, but they really illustrate the respective advantages of digital media. In thse shots you have large areas of negative space, where noise can be really prominent. You also have lots of edges to the crystal structures, and those edges need to be as sharp as possible to make the shot work.

I also find that digital works very well with insect close ups. If you think about the structure of an insect, you have lots of edges - body segments, wings, antennae, etc - but not the degree of fine detail that calls for high resolution.

On the flip side, film really excels with high resolution, high detail subjects. This is particularly the case with medium and large format film exposures. Landscapes – especially those with lots of foliage or other fine details – are ideally shot on film. The weakness of film – high grain level – is minimized by the tremendous amount of detail in these sorts of shots. I really need to emphasize that when "a lot of detail" is indeed "a lot of detail." Seriously - photos of skyscrapers or houses, for example, don't dontain a tremendous amount of detail. Unless the paint is peeling or something like that. On the flip side, as subject like this ditch with all the srubby and brambly woods around it, really does have the level of detail to derail digital exposures.

So we come back to the question posed at the start of this rather long blog – which is “best”? Film or digital? The answer depends on what subject you are shooting. Personally, I utilize digital for close ups and most general shooting, but switch to medium format for landscapes and scenics. Capturing these diverse subjects are, essentially, different tasks. And so, it makes sense to use a different tool accomplish each. Just like using a saw for cutting, and a hammer for pounding.

64,938. Based on the counters on my digital cameras, that’s the number of digital exposures I’ve taken in the last 3 years. Those shots are split between a Nikon CoolPix 990 (which accounts for just over 24,000) with the balance being shot on a Pentax *ist-D.

By the standards of digital photography, I’m really quite a slacker...

I often talk to folks who claim phenomenal numbers of digital shots taken in very short time periods. Heck, 65,000 shots in a four and half year period (I bought the CoolPix in the summer of 2001) works out to just one shot every 36 minutes. Well, I shot a lot of film as well, so I wasn’t entirely goofing off…

The ability to photograph freely, without worry about the cost of film and processing, and the immediacy of the results, are two of the great strengths of digital photography.

No matter what you set out to do, the more you work at it the more your learn it. Whether you are learning to play the piano, hit a baseball, sail a boat, or take photographs – practice makes perfect. Digital provides the photographer with the ability to shoot, evaluate, adjust, and re-shoot (if need be.) And that adds up to learning how to take better photos.

Some folks have argued that digital actually hurts your ability to learn photography by making it to easy to take photographs. That strikes me as a pretty odd concept. You certainly don’t hear music teachers telling their students to practice less, or athletic coaches telling players to knock off the exercise.

Apparently, the perception is that running around, willy nilly, shooting everything in sight is unconstructive, and ultimately harmful to one’s ability as a photographer. The logic is that a disciplined, studied approach to the subject is more productive.

There is a grain of truth in that logic, in that taking a serious and studied approach to anything is usually the best way to learn it. But at the same time – just doing something is useful, even if the doing is unstructured and free form. You may not make it into the NBA by shooting hoops in your driveway – but you’ll learn more about shooting baskets by doing that than by sitting on your front porch.

And while some digital photographers do run around shooting willy nilly, many don’t. Some of us only spend part of our time in chaotic abandon, and actually pay attention most of the time. Shooting a high volume of shots does not preclude a thoughtful and studied approach. Having more experience does not mean that you learn less from it.

Above all, digital frees up the imagination and makes it easier to experiment with different ideas and approaches. If they don’t work – well, you learn something and delete the image. If they do work, you just may find that you’ve discovered something worth pursuing.

The real challenge lies in evaluating and editing your work. Of those 64,938 images, how many are really worthwhile? I don’t have a count, but it would be a slight faction of them to be sure.

What the world needs now is another photo blog.