A Day That Will Live in Infamy

Lady Byng, taken with my Mir-24

Lady Byng, taken with my Mir-24

I have always enjoyed playing with my Russian-made Mir-24 lens. It’s manual focus, so it can be difficult to catch fast-moving things like small dogs (I find myself setting the focus then moving the camera to get the subject in focus), but there’s a low-saturation retro feel to the shots.

It all started when I wanted a reasonably fast 35mm lens cheap, and I was willing to live without all the automatic stuff to save money. The key is to look for “preset aperture” — some lenses keep the aperture wide open to help focussing, then when you take the picture a mechanical linkage in the camera closes the aperture to the desired size. “Preset” means it lacks that linkage. Many lenses come with an M42 mount, which (with a cheap adapter) work great on my camera.

My copy of the Mir-24 lens isn’t really that great, but it works, and at f/2 it’s faster than the Zeiss lens it ripped off. The construction is solid. No regrets on that purchase whatsoever.

So why has it taken so long for me to search Mir M42 on eBay? Wait, what? A 65mm TILT lens? Oh, crap! Then I searched on Jupiter M42 (Jupiter is another Russian brand, related to Mir) and… aaarrrrgh! So… many… things…

To all my Eastern European friends: Go clean out your parents’ closets! I want me some Russian-made optics!

Old Glass

Some nights, when sleep seems like a bad idea, I drift through ebay looking at old camera lenses, mostly for educational purposes. There was a time in the 1970’s, for instance, where computerized lens design and super-high-tech coatings for the glass became common. Many very good lenses were created, only to be quickly outmoded by the autofocus revolution.

When Canon embraced autofocus, they took the opportunity to redesign their mount, making the hole bigger and farther from the film/sensor. This provided tangible benefits for super-high-performance lenses, but it meant that none of the pre-autofocus lenses were compatible with the new cameras at all.

With a few exceptions that don’t apply to everyday photographers, you can’t shoot old Canon glass on a new Canon body.

Nikon, meanwhile, kept the geometry of its older cameras so that old lenses would still work. Funny thing, though. According to the sources I read late last night, they way Nikon does light metering when one of those old lenses is attached really isn’t very good.

The sweet spot: Old Nikon lenses on a modern Canon body. The adapter costs only a few bucks and you can get a great lens for a song (though it’s a costlier song now that people are catching on). Apparently Tim Burton shot a whole movie (one even I had heard of) that way, with a variety of older Nikon lenses on Canon 1Ds. That has to make the brand snobs squirm a bit.

That Nikkor 50mm f1.2 AiS.C is looking pretty nice right now. Someday…

Rethinking Apertures

This is filed under the long-neglected ‘Get Poor Quick’ category, but the means of getting poor follows a discussion of camera lenses in general, with an emphasis on bokeh. Follow me and we’ll turn the whole industry on its head!

I was futzing around with the ol’ camera today, playing with my MIR-24, an older lens in which the Russians one-upped the prestigious German lens they were copying. I wasn’t trying for great photography, I was getting to know my lens by taking a bunch of pictures. It’s a fun lens when one has the time to manually get the focus just right. Here’s one of the shots I took (click to biggerize):

FR5A3546

One of the things I like about this shot is the way the fore- and background are interesting without being distracting. I took the shot with the lens wide open, which narrows the range that is in focus, and makes the foreground and background nicely blurry.

Different lenses will blur things differently; the quality of the blur is referred to with a word bastardized from Japanese, “bokeh”. Good bokeh is often described as “smooth”, while “jittery” is often used to describe bad bokeh.

But neither of those words actually describes what qualities make bokeh good or bad, just how it makes us feel. There is one generally-accepted reason bokeh is good or bad, and two others that are just as important but are not mentioned nearly often enough. I’m here to straighten that all out. You don’t have to thank me, it’s what I do.

So let’s think for a moment about what blur actually is. An image is blurred when light from one point in the subject covers more than one point in the image. Think about pictures where lights in the background turn into little circles. Or, if you don’t want to take the trouble to think, here’s an example:

FR5A0060

Note that points of light in the background of the above image are turned into circles. This is a projection of the aperture onto the camera sensor. If you look really closely, in fact, you will see that they are not quite perfect circles, but rounded octagons. The lens I was using has an eight-blade aperture control.

[Side note: When I’m watching TV now, I always take an interest in the shape of distant lights during night scenes. I bet an experienced cinematographer could tell you exactly what lens is being used just by that shape.]

Everyone agrees: the rounder the aperture, the smoother the bokeh. This is mostly true, but it’s far from the whole story. Here’s a look down the barrel of my MIR-24:

FR5A3574

The aperture is a hexagon, and not a terribly symmetric one at that. So, as the lens is stopped down (the aperture is closed) the bokeh will start to look edgy, and the dots from distant lights will be hexagonal. (The shot of the critters above was with the aperture all the way open; the blades are pulled out of the way entirely and the aperture is a nice perfect circle.)

Before we go on, let’s have some fun with aperture shapes!

Just because there’s an aperture control inside the lens, doesn’t mean we have to use it! Here I shoot with my beloved 85mm f/1.2, wide open in all these shots. But in the second shot, I’ve added my own homemade aperture in the shape of a triangle. (I wanted to do a fancier shape, but I’m not that good with the x-acto.)

You can get kits with all sorts of fun shapes, or you can get a camera lens with my new idea built right in. (Well, you might have to wait a while for option b.) Read on!

Back to bokeh. We have the generally-agreed-upon axiom that round apertures make better bokeh. But there’s another factor: The structure of the dots themselves. Some lenses produce nice, even dots, while others produce dots with a bright rim around the outside. And you can see that my homemade triangle aperture produced pretty significant ghosting. Both those things will add to the general unpleasantness of the blurry parts of your photos. So don’t assume that that old lens with the 20-blade aperture that’s nearly a perfect circle at any f-stop will automatically give you good bokeh.

Then there’s the one factor that no lens can compensate for (yet…). Sometimes the subject matter just doesn’t blur well. Here’s a picture that demonstrates a couple of annoying bokeh traits even when the lens is doing its job relatively well:

FR5A1629

The first bokeh annoyance is the fungus in the background. The fungus is very structural, but the way it blurs just doesn’t feel natural. Behind the fungus things get muddled but also don’t feel quite natural. To see why the blur came out the way it did, consider the blade of grass that goes diagonally behind the flower. It is blurred into a perfect, straight, well-defined, sharp-edged area of doubt and uncertainty. All the things that go into a traditional aperture to create “good” bokeh sometimes produce a result that doesn’t feel natural. Lines get exaggerated rather than softened. The line of the grass becomes a line of circles, the light evenly distributed.

The big distracting leaf in the foreground cannot be blamed on the lens, alas. You have no idea how many different crops I tried to get that MF-er out of there.

OK, we’ve finally made it to the get-poor-quick part of this episode. You see, I have come up with a way to control the aperture of the lens that solves ALL the above problems: the aperture can be perfectly circular at any f-stop, or it can have any shape the photographer wants.

The blur in a traditional lens has hard edges because the aperture has hard edges. Metal blades close and open to allow more or less light into the lens. But what if the aperture were not hard-edged? What if the hole that let light through tapered off in opacity toward the edges? Those circles projected onto the sensor would taper as well, softening the edges of the circles, and therefore softening the bokeh. It would look fantastic.

All we have to do is get rid of those dang metal blades and replace them with a ridiculously high-resolution grid of pixels that can be set on a continuum from completely transparent to utterly opaque. The rest is software.

I know that is easier said than done, and even with the march of digital progress the resolution required for this project (a couple of orders of magnitude better than what we could do now – getting down to an almost atomic scale) is a long way away. Or maybe, (better yet!), it’s not digital at all and an electric field could be applied to a film of material that controlled its opacity.

Eventually a system like this will be far cheaper to manufacture than a mechanism with servos and metal blades, and it will add a softness to pictures that can only be dreamt of today.

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Make Your Own Tilt Lens!

I first became aware of tilt lenses when I stumbled across the site for a company called Lensbaby. They have a whole bunch of specialty lenses, but they got their start making an inexpensive lens that you could tilt as you composed your shot.

Why in God’s Green Acres would anyone want to do that? Well, normally, one keeps the plane of the lens exactly parallel to the plane of the sensor, and out in front, everything at a particular distance is in focus. You can think of the volume of space that’s in focus as a rectangular solid with one face parallel to the sensor.

When you tilt the lens, the rules change. The volume of space that’s in focus tilts too (there’s a rough formula, but the math’s not important here). To illustrate, let’s take a look at figure 1. In this diagram, the lens and the sensor are parallel, and the zone in front of the lens that is in focus is parallel to them as well. The girl and the tree are in focus, but the dog is not.

Figure 1: diagram of a photo shoot in a park. The girl and the tree are in focus.

Figure 1: diagram of a photo shoot in a park. The girl and the tree are in focus.

Of course, dogs and girls are much more interesting than trees. How can we get them in focus, and get the tree out of focus so the shot doesn’t seem as cluttered? One way is to tilt the lens.

Figure 2: The same setup, but with a tilted lens.

Figure 2: The same setup, but with a tilted lens.

Lensbaby’s products cost substantially less than high-end lens systems, in part because they’re optically pretty low-grade. Still, a few hundred bucks for a set of flawed lenses (even if the flaws are embraced – more on that later), seems a little steep. After poking around a bit, I found sites for people who made their own tilt/shift lenses for just a few bucks. (There are plenty of other links where that one came from.) I decided to try my hand.

Medium-length section of macro extender tube set

Medium-length section of macro extender tube set

After considerable pondering, I realized that there were a couple of ways I could improve on the designs illustrated, at the sacrifice of a couple more bucks. All those designs involved drilling out a camera body cap to provide the attachment point to the camera. I opted for a cheap Chinese extender tube ($6) to give a much larger surface for mounting the bellows.

Next came the hunt for an appropriate lens. Many of the people who build these buy old, crappy lenses for SLR’s and partially disassemble them to allow clearance between the bellows and the camera body. Others use medium-format lenses, which generally are designed to be mounted farther from the film. Despite reports that these could be found on the cheap, I was not successful in my search. Eventually I stumbled on a Federal Anastigmat lens for $20 and decided that was an acceptable amount to risk.

I got really lucky.

The big investment - the lens.

The big investment – the lens.

I’m pretty sure the lens was originally intended for a photo enlarger rather than a camera, but hey, you need quality optics on that end of the processing, too. Where I really got lucky was with the focal length. I hadn’t given it much thought, but it turns out that lenses like this come in a pretty wide range, and 3.5″ turns out to be close to ideal for my lens design. See the end of the article for tips on how to find a similar lens.

Mini-plunger with bellows construction.

Mini-plunger with bellows construction.

The lens sat on my desk for a few weeks, but recently I decided it was time to get this puppy made. I went down to Home Depot and after a period of wandering found the plunger section. I wanted one that had a bellows style of construction, rather than the typical rubber dome. Happily I hit pay dirt (with a caveat).

I brought the plunger home and after considerable time pondering how best to attach all the pieces together, decided to stop thinking so much and just see what I could come up with. It was time for action!

I started by trimming off the part of the plunger bellows that was clearly too wide.

Trimming the plunger

Trimming the plunger


It turns out that that particular extender tube and that particular plunger fit together perfectly, though it took me quite a bit of fussing before I discovered the proper technique for mating the two. After futzing with screwdrivers and pliers (whose scars you can see in the final photos), I just put my weight into it and mashed the thing home.
The macro tube and the bellows mated.

The macro tube and the bellows mated.
You can see how much light comes through the plastic.


To attach the lens to the bellows I used a roto-tool and gradually enlarged a hole in the handle end of the plunger until the threads of the lens could bite and I just screwed the thing straight onto the plastic. It’s a lot more secure than I expected it to be.
The finished product!

The finished product!


And… that was all there was to it. But, alas, there is a problem. A lot of light gets through the plastic. The first pictures I took had low contrast and a decidedly orange cast to them.

Wrapping something dark around the bellows helped immensely. Here I am taking a tilt-shot with my neoprene knee brace pulled over the lens. Some orange still leaks in through the front plastic, but contrast was improved dramatically.

Taking a tilt-lens shot

Taking a tilt-lens shot


Once color-adjusted, the results are pretty interesting. In the following photo you can trace the volume of focus from the lower-left right back to the napkin holder in the upper right. One side of the glue bottle is in focus, while the other isn’t.
Tilt-lens photo with skewed focal plane

Tilt-lens photo with skewed focal plane

To be honest, I’m not sure exactly what I’m going to do with this thing now that I have it, but the first step is to take a whole ton of practice photos, so when the time is right I’ll be ready.

The biggest disadvantage to this setup is that it takes three hands to take a picture, and since you’re holding the lens steady with your fingers, fast shutter speeds are advised. Some of the lenses in the article I linked to lock down the lens at the desired angle, which would be handy. Lensbaby’s design is structurally pretty similar to mine; they have a version with screws that hold the lens in position.

Another thing about the “anastigmat” lens I used and the offerings of Lensbaby: My little lens is optically quite a bit better than Lensbaby offerings, for better or worse. Anastigmat was a name many lens manufacturers applied when they came up with ways to reduce the spherical aberration and astigmatism of early lenses. Lensbaby, on the other hand, embraces spherical aberration with gusto. This causes the focal zone in the illustrations above to be curved and the edges to be distorted, which can also be fun, and can really pin interest on your subject. The rear elements of my Federal lens can be removed, which I think will give me some pretty major spherical aberration as well. We’ll see. Lensbaby also has a variety of other ways to introduce distortion into photographs, but I’m not going to start experimenting with that until I get the tilting business well under control.

“Anastigmat” is also your key to finding the right glass if you want to follow in my footsteps. Just type that into eBay’s search and you will find a host of old lenses, some quite cheap. (At this writing there’s a nice-looking Rival for $22 and a sort-of-slow Federal for $10.) Choose a focal length in the 90mm range and away you go! (You can use longer macro tubes if you get a longer focal length. $6 gets you a set of three different lengths that can be screwed together.) Some lenses look like they’re only the front element (just one piece of glass); you should stay away from those.

Total cost: $30. When I got down to doing it, it was pretty easy. If you like to tinker, this would make a great Saturday project that could pay dividends with interesting photos for a long time to come. Give it a try!

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Bought a New Lens

It was love at first sight. I saw the lens, and had to make her mine.

I’d guess that I take more than 80% of my shots with my 24-105mm zoom. It’s an incredible piece of technology, combining versatility and really impressive image quality. In second place is my beloved 85mm, a lens that totally changes the rules when it comes to lighting, that I’m only just starting to master. My fishy-fisheye isn’t getting a lot of work these days, nor is my big ol’ 100-400 zoom.

I shudder to think how much money I’ve dumped into this hobby. (I have not done the math, nor will I.)

Since buying the new camera, I’ve bought two lenses. The first I will not describe now; that is for another episode. Today we’re discussing my new 135mm portrait lens, which is in the hands of the United States Postal Service and heading my direction from Baker City, Oregon as I type this.

Of course I did my due diligence before I bought the lens. I looked to see what other lenses with similar characteristics were going for. On ebay, there was one for less that had better numbers. The auction was young, however, and I wasn’t interested in hanging out to see what it finally went for. I was already in love, and it was purely physical.

I bought the 135mm prime f/3.5. I also bought an adapter to mount it on my camera. Total cost, including shipping: $46.

Yeah, baby.

The funny thing about my new, super-expensive camera: it’s manual-focus friendly. That means, within certain limits, I can mount a host of old glass in front of the state-of-the-art sensor. Ironically, old Canon lenses are not easily adapted on new Canon bodies. But ancient Pentax? Piece of cake. My new lens is by Vivitar. Here’s the link to the ebay listing: [Alas, the link didn’t work for the general public]. (I didn’t want to post the picture here, lest it undermine the drama in the previous scene.)

I have read (though I have yet to discern), that modern Canon lenses on modern Canon bodies create a look that can be distinguished by the trained eye. Same with Nikon and Sony. Not sure I buy that (there’s software between camera and viewer), but there’s a handful of photographers out there looking to bust loose by using old glass. Brand aside, the flaws in lenses before robots made them and lasers measured them adds a certain character to a shot. I like character, but to be honest, that’s not what motivated me. $46 for a 135mm prime lens (a lens I honestly think I can use to good effect) was only part of the story (but a meaningful part). It had to be this 135. Look at the picture in the listing and you’ll understand why.

OK, the link above seems to only work for me. Here’s the lens (click to biggerize):

My New Lens

My New Lens

Pinhole Fever

My favorite camera lens is a marvel of technology, an almost perfect example of science serving art. But lately my imagination has been captured by the other end of the lens spectrum: the pinhole.

The idea took root when I saw some russian plastic pinhole lens go on ebay for actual money. The sales pitch was, “recreate the look of this crappy old camera with your modern DSLR!” I agreed that would be a fun thing to do. We put distortion into electric guitar pickups and we dig lo-fi pictures.

But that’s selling the pinhole short. Last night I experimented with the lenses in my stable, determining the smallest details I could hope to resolve. I don’t have a true macro lens, but here’s the thing. A really good macro lens (hundreds or even thousands of dollars) will give you the ability to project images onto your film or digital sensor at a 1:1 ratio – if the thing you’re photographing is 1cm, it will be 1cm on your sensor. With a modern camera, that translates to a whole bunch of pixels.

But wait! With a pinhole, at the cost of maybe two dollars (10 bucks for better image quality) you can get a magnification five times that. Obviously not with the same fidelity, but seriously, five times the magnification means that you can still resolve some amazing details in your subject.

I think a pinhole would also be a better lens for observing the sun than any I currently have in my arsenal.

All that on top of cool vintage-looking shots in the “normal” range. Your subject has to be able to hold still for a while; the pinhole allows much less light through than a typical glass lens. You could argue that the primary function of the glass in lenses is to allow you to have a much bigger pinhole and still be able to focus.

And here’s a fun fact: All those numbers that we use when talking about a lens are actually based on pinholes. When we say a lens has a 50mm focal length, what we mean is that it acts like a pinhole 50mm from the film. The other numbers are similarly derived.

For a given focal length, there is an ideal pinhole size. (OK, that’s not exactly true, but there is an ideal pinhole size to optimize the shot for different preferences.) The goal is to have the light that comes from a specific point on the subject strike a particular point on the sensor. As you can probably imagine, the smaller the pinhole, the smaller the dot of light on the sensor from any given spot on the subject. (This dot is called, rather poetically, the “circle of confusion”.)

So the smaller the better, right?

Not so fast, Sparky! Just when you least expect it, light starts behaving like a wave, and the smaller the pinhole, the more pronounced that effect becomes, until diffraction causes the light from that single point outside the lens to turn into a bright central dot surrounded by fainter rings. The trick then is to minimize the distortion caused by both a too-big and a too-small pinhole, and find the happy balance. Others, happily, have done the math, though they don’t all agree.

I have a plan. I’m going to create two pinholes of different sizes, and mount them on the kind of cap you put on your camera body when you don’t have a lens on it. The caps are already made to attach the same way the manufacturers lenses do. I also intend to make an extension tube that mates with the camera at one end and with a lens cap at the other (using the cap that goes on the back of lenses for storage), and have myself a macro/zoom pinhole. The little pinhole can either go directly on the camera for a 46mm focal length, while the larger pinhole one goes on the end of the tube for telephoto. With the small pinhole on the extension tube, you’re ready for serious macro photography.

I’m fascinated now by the question, “what can a really well-engineered pinhole accomplish?” Besides just getting the size of the hole right, there are the challenges of getting the hole nice and round (irregularities will play hell with diffraction) and shallow. If the hole is too deep (drilled through too thick of material) the corners of the picture are cut off. The camera will quite literally have tunnel vision.

I intend to spend some hours in Father-of-Sweetie’s workshop, experimenting with drilling holes in metal. (I priced out copper sheet and then realized that drilling holes in money (pennies) would be much cheaper.) The first thing to discover is whether it’s merely difficult or completely friggin impossible to get a drill to stop when its tip is 0.09mm through the metal (for the smaller hole, assuming the standard 118º point angle of the drill’s tip), and if the resulting hole is round enough. If not, then micro drills are going to be required.

While I don’t mind spending a great deal of time building the thing, I’d like to come up with a process that can be repeated fairly easily. Because if people are willing to pay for a little plastic piece of poo, there might be a group of hobbyists interested in the Ridiculously Over-Engineered Pinhole System. If I can drill the holes efficiently, it might make a nice little cottage industry.

Bonus!

In between the time of writing and the time of posting, there was a time of doing! Here are some results with Quick and Dirty Pinhole 2 (pinhole 1 didn’t pass quality checks):

A few notes:
What I set out to do this morning was discover if I had any way to measure the size of the pinholes, and to see if they were actually round. I don’t have a fancy loupe, and the ones that can measure down to things that tiny are quite expensive. I do have a camera, however, and I figured if I could get close enough I could use an image to measure the size and shape of the pinhole.

I made a couple of pinholes in tinfoil. I used my fisheye lens to get down as close as I could to the pinholes (laid on top of a ruler app on my phone) and was able to roughly estimate their size. The first was definitely too big, the second seemed only a little bit too big. So I drilled a hole in a Canon body cap and taped in Quick and Dirty Pinhole 2.

Most of the exposures you see here are thirty seconds, at pretty high ISO to boot. the f-number for QDPH-2 is something like 48mm/0.3mm ≈ f/150. Remember how giddy I was to get a lens that went to f/1.2? Yeah, this is the opposite of that. Such is the way of the pinhole. The side effect of that is that just about everything in the universe will be in focus, including things that are really really close.

Yep, the best tool I have for measuring pinholes is… a pinhole, and the marks on the measuring stick are the pixels of the retina display itself (12.8/mm). I am stoked.

In the last macro shot of QDPH-1, you see some ghosting. I’m pretty sure that was caused by light bouncing back and forth between the two pieces of aluminum foil. In shots of the display only, there is no ghosting.

But, my sweetie asked this morning, what’s the point of all this? My answer: It’s fun, and also I think we can get some great vintage-feeling shots. As you can see in the still life, the focus is pretty soft – not appropriate for all the hard-edged items in the shot. I’ll be taking some self-portraits later to see how that goes.

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Oh, eBay, how would I know what to covet without you?

There will always be the Next Toy, but this one will probably never grace my camera bag. You might recall me writing about my Totally Awesome® 85mm f/1.2 lens. Man, I love that lens, though it definitely gets the best of me sometimes. That’s what practice is for.

But 85mm is a pretty long lens. It’s for zeroing in on one thing and making the rest of the world fade away. I’m starting to get some good results with it. But it’s not a lens for capturing a street scene, or for holding up over the windshield and grabbing a landscape while driving.

I’ve been mildly curious about the 85’s little brother, the 50mm f/1.2 lens. I looked on eBay last night and found them going for quite a bit more than I was ready to pay. Whew! No new lens lust.

Until I saw…

The Canon 50mm f/1.0 lens. It doesn’t seem like much, that difference of 0.2, and most of the time it isn’t. But the scale is logarithmic, so a difference of .2 down at this end of the scale can be huge in extreme circumstances. (Compare to other lenses that go down to f/2.8 or so and are considered pretty fast. 1.2 is way small, and 1.0 is nuts.) I read reviews from people taking pictures when it’s so dark they can barely even see. Street scenes coming to life at night. Ridiculous control of depth of focus.

Heavy. Not manufactured anymore. Very expensive. The lesser lens will handle almost as much, and even then it’s hard to justify paying less than half as much for the almost-as-good lens.

Still, a guy can dream (of spending thousands of dollars for a piece of glass he doesn’t need).

A guy can dream.

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