Monday, August 23, 2010

Archiving Images Part 1: Digitizing Slides

I began shooting slides for stock photography purposes in the early 1980s.  I freelanced as a motorsports photographer and did some portrait photography back then, but whenever I had the chance I was out "shooting for stock," I called it, hoping that I'd be able to market my images and make some money off them that way.  Over the years, as a result of this practice, I accumulated thousands of slides on a wide variety of subjects.  By the late 1980s I recognized the need for an improved method of retrieval so I came up with a simple date code using six digits: the first two were the year and the last four were the sequence in which they were taken during that year. I figured I wouldn't have a year where I shot more than 9,999 images. Heh. That was before digital, obviously. So except for my most recent slides, I have thousands cataloged in archival sleeves by number.  As it turns out, as time consuming as that process was, assigning numbers and putting them in sleeves was the easy part of the process.  Digitizing the slides and then building a database for them, as well as for all my other images, are the true time consuming parts of this process.

The process I will be outlining in this and the next few articles is where the images will be archived to DVD.  Since these will be archives, and since all this process is quite time consuming, it will behoove you to buy good, archival quality DVDs.  Very short lifetimes have been well documented with cheap DVDs. Archival quality ones should last for decades.

Modern digital photographers talk a lot about "workflow" these days and now that I have a DSLR and have become fairly active with it, I can see why. Because of the deluge of digital images that can be produced one needs to have a workflow design such that ones time is used most efficiently. Otherwise many hours can be spent needlessly spinning ones wheels. So I've spent a fair amount of time just thinking about this whole "workflow" business, and what I'll need to do to archive my images. Even more important than archival process is how my images will be organized, and how easy it will be to retrieve any given image. It is this latter point that will cause the initial setup of images to be a lengthy process. But once it's done, then the workflow becomes much more efficient in its operation.

So first off, I decided to start in on my slides.  While it is true that they are archived in the sense that I have them stored in archival sleeves, they were not archived digitally, so not easily retrievable and transmittable.  Assembling a quality digital archive of my slides has ended up being a long and laborious process, mostly because when I started out digitizing them I knew much less about the whole process of digitizing slides than I do now. I started out by scanning slides on my Epson 3170 flat bed scanner at 3200 pixels per inch (ppi). The 3170 began showing some color streaks in some of the images, thus degrading image quality, and I felt that the scans could have been sharper, so I upgraded to an Epson 4990. The 4990 is definitely a better scanner, but only by an incremental amount. Then a friend gave me an HP S-20 dedicated film scanner, so I gave it a try and found it to be on par with, or perhaps just a bit sharper than, the Epson 4990. But the Epson has a better Dmax than that HP so I felt it to be a toss-up between the two.

 Epson Perfection 4990

Still, I wasn't happy with the results I was getting because I could examine my slides with a decent loupe and clearly see more detail than any of my scanners were capturing. And then I found out about "digital" slide copiers. A digital slide copier is designed to mount to the front of a DSLR's lens, kinda like this:


In order for the lens to focus properly, the copier has an interior element, which can also be used as a close-up diopter lens for macro photography.  The element is reasonably well corrected, and the setup takes decently sharp photos.  Clearly sharper than those I was getting with my Epson or HP scanners.  But it was something of a pain in the butt to use, which I was willing to put up with, but I found upon close inspection with a loupe that there was still detail in the original slide that wasn't being transferred. 

I liked the slide duplicator idea, though, but in order to do it right, I began to suspect one needed to do things the old school way, like with one of these jobs:
The above is a proper bellows with a macro lens attached to the front and with a slide duplicator accessory attached to the front of the macro lens.  However, unless one has a full-frame DSLR (and most folks don't), slides will be cropped because of the magnification that occurs when using a "crop body" camera with 35mm-format lenses.  So that's out for me, at least, with my APS-C sensored Canon EOS DSLR.

So I started playing around with what I had, which was my digital slide duplicator and some other close-up stuff.  I wound up with a combination of the slide duplicator tube, a Nikkor 55mm f/3.5 macro lens, and a 10mm extension tube, plus a Nikon-EOS adapter so I could fit this contraption to my camera.  The setup in the following picture shows both the slide carrier and the roll film stage at the bottom.  I scavenged both of these off a 1980s-vintage zoom slide duplicator.
Finally I had an outfit that was capable of recording images that were critically sharp with my 10 megapixel DSLR.  This rig is clearly superior to any other device I've tried for digitizing slides. 

So now that I had the hardware straightened out, then I had to turn my attention to the method of capturing the images.  At first, I just took my slides outdoors and used a piece of poster board as a reflector and pointed my duplicator outfit at the poster board.  But I found that I was restricted to doing this at mid-day only, or else the color temperature drifted and then I had to try and color correct the slides, which wasn't always as easy as one might think.  I found that on overcast days the time of day wasn't as critical and that I could just point the rig up at the clouds.  On balance, these methods worked well, but since I was restricted to mid-day hours, I decided to set up an off-camera flash rig and give this a go.  I don't have any of the fancy TTL cables and off-camera adapters, or TTL flashes for that matter, that will provide TTL flash with my EOS DSLR.  So I just used another flash I had that has variable power settings, set it to its lowest setting, and just used standard PC-sync cabling and a single-contact off-camera hot-shoe adapter.  I was able to find out the optimum distance between the duplicator and the flash after only a few tries, and found that with some slides in which the exposure may have been a bit off, I could even adjust it somewhat by moving the camera either closer or farther away from the flash to correct for this somemwhat.  This was the easiest method by far, and provided me with images that had perfect color balance.

So then it was a matter of staving off feelings of drudgery, really.  Periodically, I would check the focus of the lens with a slide of known sharp focus using the camera's Live View feature.  I had to pay attention to horizon lines in the images and see if I could correct for them if they were somewhat off, if at all possible, by rotating the front of the duplicator tube.  I needed to insure that the slides were each pushed into the duplicator stage the proper amount, all the while trying not to bump the focus.  And repeat the process several thousand times!

Of course, I had my camera set to record the images in raw mode, which provides me with about 800 ten megapixel images with an 8 gb memory card.  Once the card was full, I downloaded the raw images to my computer's hard drive as temporary storage, emptied the card, and filled it back up again with more images.  Lather, rinse, repeat.

During this process, it might be worth your while taking some notes.  For example, I have my sleeved slides sorted according to subject, and when I shoot digital duplicates of them, I keep to that order.  I don't change the digital file names -- it would be way too time consuming to do so.  Instead, I record a raw image's file name at the beginning of each subject, which makes it easier to keep track of the various subjects when it comes time to transfer the images to DVD.  What I do is create a separate folder on the DVD for each subject and then dump all the files pertaining to that subject into its folder.  But before doing so, I will still double check that I've started the file count at the right file name.

After burning the DVDs, I use a Sharpie Marker and record the subjects of the folders the DVDs contain and any other information I consider pertinent.

In my next article I'll discuss archiving negatives and how they offer an entirely different set of problems.

Sigma DP1s -- What's all the Excitement About?

I was given the opportunity to try out a friend's brand new DP1s, and was mildly interested because its minimalist looks appeal to me.


Sigma DP1s

Its 16.6mm lens is the equivalent to a 28mm in 35mm format. So this camera is a dedicated wide-angle tool. Good for quick landscape and architectural shots, and perhaps even street scenes. Its APS-C sized Foveon X3 sensor is highly touted -- providing 14.6 megapixels of resolution and all -- as is its well-corrected 16.6mm f/4 lens. The DP1s is deceptively simple. No viewfinder, a modest-sized LCD screen, a couple of wheels and buttons on the top cover, along with a hot-shoe -- something you don't see often on a P&S digicam, and it has a few more controls on the back. It even uses a pop-up flash for a proper retro look, reminiscent of the Canon AF35ML and some Minolta Hi-Matics. But under the skin, the camera has an admirable level of flexibility and complexity. It shoots in raw mode, for example. It has different metering patterns and AF modes, and one can select between single and continuous frame shooting. It also has a movie mode and an audio setting that allows the photographer to make a 10-second comment at the end of each photo. Its ISO range is 50 to 800. 50 is somewhat unusual for a camera like this and a welcome addition if the photographer is interested in minimizing all traces of noise.

But all this comes at a hefty price. The DP1s lists for about $800.  Yikes! Street prices are under $300, though. But still, that is rather pricey for a digicam. And I'm sorry, but I just can't resist asking myself if it's worth it. So I decided to make a quick and dirty comparison between the DP1s and the only other halfway decent digicam I had handy -- my daughter's Canon A1000IS, a model that has been discontinued for a while now -- but so what else is new, in the world of consumer digicams? She bought her A1000IS for about $125 two years ago. It has 10 megapixels compared to the DP1s's 14.6.


Canon A1000IS

But -- and this is a big but -- the Foveon is a three layer sensor, each layer being "tuned" to a particular color: red, green, and blue. Supposedly this provides for more faithful color rendition, but another result is that 14.6 mp isn't as many as you might think. The maximum image size produced by the DP1s is 2640x1760, whereas the max image size with the lowly A1000IS is 3648x2736. That's a 38% larger image from a camera with a 31% smaller sensor, megapixel-ly speaking. But how about image quality? Surely the Sigma's must be vastly superior, or so one might think. Let's take a look shall we? I went out and shot a few pics with each camera, each set to its max resolution and ISO 100. I could have set the Sigma to raw mode, but since the Canon doesn't have this feature, I felt it was only fair to compare like with like, so both cameras were set to capture images in .jpg format.

Here we have a couple of photos of my beloved Volvo V90. The first image was taken with the Sigma DP1s, and the second with the Canon A1000IS. Cliick on the images to view them at a more convenient 900 pixels horizontal size.


Sigma DP1s: Volvo V90


Canon A1000IS: Volvo V90

Well, a couple of comments -- first, I should have stood back farther away from the car when I took the shot with the Canon. I wasn't taking into account the wide-angle nature of the Sigma's lens. Second, for valid comparison purposes, I did not do any post processing to the images at all, other than reducing them in size for viewing on the web. And then WordPress reduced them even more, but you can click on them to view the 900x600 or x675 images that I originally uploaded.

You'll probably notice right off that the Sigma's colors are more neutral, whereas the Canon's colors have a bit more of a yellow cast. I'd have to say that this is a "feature" of the Canon, since it was close to mid-day when I took the photos, thus the color temperature of the sunlight shouldn't have caused any yellow cast. So +1 to the Sigma for color accuracy. As for lens sharpness, with these rather small photos it's hard to tell. So here are a couple of 100% crops -- well almost. To show the Canon's image at the same size as the Sigma's, I had to eyeball the Canon's crop so that it covered the same area of the image as the Sigma's 100% crop, then I reduced the Canon's crop to the same size as the Sigma's. Got all that? Click on each image for a larger viewing size.


Sigma DP1s: 100% Crop


Canon A1000IS: 100% Crop

The two images appear to be very close, don't they -- color differences aside, that is. In fact, after close inspection, I'd have to give the nod to the Canon. Notice the small scratch on the bumper visible in the Canon's photo, but which is almost undetectable in the Sigma's? Also, there seems to be a bit better definition in the headlight lens patterns with the Canon's image. But then I ask myself, is this a sharpness difference, or is it exposure? Because the more I look at it, the more it looks to me as if the Sigma is overexposing just a bit, and as a result, blowing out some detail in the highlight areas. So + 1 to the Canon for having better exposure control. Actually, with a few subsequent shots I took with the Sigma, I found that I had to adjust the camera's exposure compensation (the AV button) to reduce a tendency to overexpose in bright sun.

Next, I took some shots of trees in the front yard. Once again, in this pair of pics you can see that the Sigma's exposure is a bit lighter than the Canon's, although it doesn't appear excessive in this case.


Sigma DP1s


Canon A1000IS

I haven't posted 100% crops because there's no point. I couldn't tell a bit of difference in terms of sharpness or correction of lens aberrations in either photo. With the Canon's image resized to that of the Sigma's and a bit of brightness/contrast adjustment done, I doubt if anybody could tell the two apart. Well, except for the fact that the Sigma's image format is the standard 3:2 proportion whereas the Canon's is closer to a TV screen's format at 4:3.

Next, I decided to take some close-ups. Flowers are always a good candidate for this. But the weather here in Houston is pretty brutal in early August, so I could find only a single rose in my wife's garden that was barely hanging in there. It would have to do. One thing I noticed right off with the Sigma -- with some disappointment -- is that its 16.6mm f/4 isn't really a close-focus lens. Minimum focusing distance is about 1.3 feet. And given its wide-angle nature, this is kind of far away for macro work. Sigma must have already taken this into account because they didn't even bother with a macro icon anywhere on its dial or controls. So macro shots might not be all that fair of a comparison, but here goes anyway. The first is the Sigma's, cropped to 100%, and the second is the Canon's. But this time, instead of sizing the Canon's image so that it's the same size as the Sigma's, I decided I'd show the Canon's shot at 100% also, just to show what is being missed with the Sigma.

This is the entire scene taken with the Sigma.


Here are a couple of 100% crops, first the Sigma, then the Canon. Each photo was taken at each camera's closest focusing distance. Click on each image for a larger viewing size.


Sigma DP1s: 100% crop of the yellow rose


Canon A1000IS: 100% crop of yellow rose

Okay, it's worth making the comment at this point that Sigma does produce a AML-1 close-up lens that lists for a hefty $125 and sells at a still respectable $80 street. This close-up lens provides the user with a magnification ratio ranging from 1:8.2 to 1:14.9. Not exactly anything to write home about, but nonetheless an improvement. Given that its front filter size is 46mm, which is a reasonably common size, one can buy a name-brand close-up filter set, which typically includes a +1, +2, and +3 filter, for about a third of the price of the single Sigma filter. A good quality set might provide one with a halfway decent macro capability, but it would have been nicer if the lens were designed to focus closer to begin with.

As long as I'm in gripe mode, I guess I find myself wondering just how wise it is to offer this camera with a single focal length lens only. True, for another large outlay, one can buy a DP2s, which has a 24.2mm f/2.8 lens (equivalent to a 41mm lens in 35mm format), but that's not much variety for a quite sizable pile of semolians. And it's also worth mentioning that other series of P&S cameras with an almost cult-like following: the Canon G-series. Earlier G-series cameras, like the G7 and G9, have 5x zooms that are equivalent to 35-210mm with a 35mm camera, but the G10 and G11 have 5x zooms that have the same wide-angle capability as the Sigma DP1s plus a still respectable 140mm equivalent on the tall end (i.e., 28-140mm equivalent). While it's true that a new G11 will set you back roughly $150 more than a Sigma DP1s, honestly, which would you rather have? Be honest now. Besides, the G-series look pretty cool in their own way too.


Canon G10

Oh, and it bears mentioning -- probably fairly frequently given the Sigma's rather slow f/4 maximum aperture -- both the Canon A1000IS and the later G-series have internal image stabilization, which provides the user with extended hand-held capabilities in low-light scenarios.

So I ask once again -- regarding the Sigma DP1s, what's all the excitement about? I'm reminded of the Konica Hexar AF, which was a totally cool fixed lens 35mm P&S camera, and which also had a cult following. Still does, in fact. Given Konica's almost total lack of promotion of the camera, the Hexar AF remained in production a surprisingly long time -- about five years. Is the Sigma DP-series destined for a similar status and fate?