Since I’ve been doing the slit scan photographs, I’ve been spending a lot more time using my tripods. Since I now use a tripod four or five times a day, I’m having more problems with various bits loosening up and occasionally falling off.

There’s a way to deal with most of these problems: compounds that are made to keep threaded parts in place. The most prominent set of products goes under the brand name Loctite. They been around since the 50s and may have invented the product category. In the early 60s when I was working in a summer job as assistant to a mechanical engineer, I used the stuff a lot.

In those days, we used Loctite to make sure that threads wouldn’t ever come undone; we considered it a permanent fix. Nowadays you can get Loctite with various degrees of permanence. There are only two – well maybe two and a half – that are of interest to photographers wanting to get control of their tripods.

The first is what the manufacturer refers to as Low Strength. This is the perfect material for keeping hand assembled things from coming undone. I use it on tripod feet. I don’t know about you, but I always use the soft rubber feet that the tripod comes with, never changing them out for the hard pointy things you use on rock surfaces, or the flat pucks you use in the studio. I just want the feet to stay where they are: without some help, they don’t do that. The low strength Loctite is a perfect way to make sure I come back from the field with all of the tripod feet that I left with. Why not the permanent Loctite? The little rubber feet might wear out someday.

The second is the medium strength material, which is great for attaching Arco Swiss receiver to ball heads, and, if you don’t change camera plates a lot, for attaching camera plates to camera bodies and lenses.

The half is the permanent stuff. I’ve never been in a photographic situation where I’m completely confident that I’ll never want to get a threaded connection apart, but, if you’re sure, go for it.

There’s an article in the March/April 2012 issue of photo technique entitled “Mastering the Camera Histogram for Better Exposure”. The article contains some important misstatements. I’m not sure how they got by the magazine’s vetting process, but, if they gain currency by inheriting the stature of the magazine in which they are published, they may serve to confuse photographers going forward.

In this post, I will deal with one of the misstatements. The author of the article, David Wells, is discussing the pixel count of the sensors in today’s digital cameras. He says:

Each pixel is usually made up of one red, one blue and two green sensors, a so-called “Bayer array…”

If engineers ruled the world, image capture pixels might actually be counted that way. However, for what I believe to be mainly marketing reasons, image capture pixels are actually counted quite differently. I dealt with this issue in passing in an essay back when The Last Word was a column in the CPA newsletter, Focus. It’s available here.

Here’s a simplified explanation of the way that image capture pixels are counted: each light-sensitive element that contributes to the final picture, no matter what filtration is in front of it, counts as a pixel. For a fuller discussion see the end of this post. For all the details, look here.

So Wells is off by a factor of four. In cameras using a Bayer pattern, each element of the four-sensor pattern (one red, one blue, and two green) counts as a pixel; the whole four-sensor pattern is, by the logic of the camera manufacturer and user community, four pixels.

But wait, I hear some of you thinking, I’ve got a 16 megapixel camera, and there are 16 million RGB triplets in the files I get out of my raw converter. That is indeed true. However, I have bad news for you. Two-thirds of that data (half the green, and three-quarters of the red and blue) is generated by the raw conversion program, by interpolation or some other method. If interpolation is not a term that makes you say “Aha!”, a lay equivalent might be guessing (to be sure, scientific guessing, but guessing nonetheless). If image processing mathematics doesn’t scare you, for a survey of methods for artful production of missing data in raw conversion, look here. If you’re not an engineer, take a look at Mike Collette’s great explanation of how digital capture works; it’s here. Look at slides 8 through 12.

Here’s the more complicated explanation.

The Japan Camera Industry Association (JCIA) has written a standard for counting pixels. All the camera manufacturers that I know of follow this standard. It’s called Guideline for Noting Digital Camera Specifications in Catalogs. Among other things, it says that the camera manufacturers shall give top billing to the number of effective pixels , and that the number of effective pixels is

…The number of pixels on the image sensor which receive input light through the optical lens, and which are effectively reflected in the final output data of the still image…

It’s a little circular to define effective pixels in terms of pixels, but that goes back to the intent of the specification, which was to keep manufacturers from claiming even higher pixel counts than the standard allows.

Note that all this only applies to specifying the number of pixels in a camera. When it comes to pixel counts of images converted from raw form, a pixel in a color image consists of at least three numbers: RGB, Lab, CMYK, etc. Confusing, isn’t it?

I took some pictures of the fog burning off yesterday morning, and continued in the early afternoon when there was some cloud cover. Here are the pictures in chronological order, which happens to be the order from most to least abstract. 135mm lens, about an hour and a half exposure.

Friday night, I told David Bayles that I was working on photography about four hours a day, and that seemed to be the right amount of time for me. We got into a discussion of the work ethic of some photographers. David said that Brett Weston immediately processed his film upon returning from a photographic trip, sometimes being in the darkroom at one in the morning.

I can see that. I’ve lived much of my life with that kind of intense focus, but that’s not what I want now. I am serious about photography. I am comfortable with that seriousness. But I won’t let photography run my life.

On Saturday, I started doing infrared slit scan photographs of some cirrus clouds. I worked for most of the morning. There weren’t very many clouds, and the structures were too small for the 47 mm lens I was using. Around one o’clock, some really spectacular clouds started to roll in. I looked down the valley, and saw many more similar clouds.

I had been planning on going to Brigitte Carnochan’s lecture at the Center for Photographic Art that day. “Ah, well,” I said, as I packed up my camera gear. “They’ll probably be some clouds when I get back.”

There weren’t. When I returned, the sky was bald.

I missed the best pictures of the day, but I heard a great lecture and got to see my friends at the Center.

If I had known that the clouds were going to go away, I would’ve done the same thing anyway. What kind of photographer does that make me?

Fog burning off yesterday around noon. 47mm lens, about 20 minute exposures.

Last night, I made some infrared slit scan photographs of a spectacular high cirrus formation, using a 47mm lens and my new lens hood (see previous post).  Time runs from right to left. Each exposure was about half an hour long.

When they’re using film, view camera photographers don’t need lens hoods. They only need to shade the lens at the instant of exposure, and the perfect implement to do that is right at hand: the dark slide they just pulled out of the film holder. When you’re making slit scan images, where the exposures can last hours, it’s just not practical to manually shade the lens, and the traditional implement is unavailable anyway.

At the same time, the effects of flare are much more damaging on slit scan images than on normal photographs. Usually, a little flare just causes a loss of contrast which may be more apparent in one part of the image that another. In the slit scan photograph, if the flare varies over time, you get bands of light and dark, contrasty and flat; they are really ugly.

I’ve been trying to use lens hoods to reduce the flare in my slit scan pictures, with only moderate success. Yesterday, I happened upon the solution. It occurred to me that I could heavily shade the area to the right and left of the slit. I only needed to open up the hood in a vertical direction.

A pair of scissors applied to a rubber lens hood, and I was ready for my first experiment. I picked my most problematic lens, the 47 mm. Here’s what it looks like with the hood on it:

This rather unaesthetic solution works perfectly.

The slit scan photography that I’m now doing requires that I use, at various times, three different filters: infrared pass, infrared block, and polarizing. The lenses I’m using for the series – 65 mm, 75 mm, 90 mm, 135 mm, and 210 mm – all take different filters. Some of the filters that I need are not available in the filter diameter of all the lenses. In addition, in trying to save some money, I wanted to use the same filter on more than one lens. For both those reasons, I purchased a set of filter step up (or step down, depending on your point of view – more on this later) rings. These allowed me to use the same filter on more than one lens.

A confusing factor is terminology. Some manufacturers say that a step up ring allows you to use a filter of larger diameter on a lens meant to accept a filter of a smaller diameter. Other manufacturers say exactly the opposite: a step down ring allows you to use a filter of larger diameter on the lens meant to accept the filter of a smaller diameter. Read the fine print before you buy.

A source of extreme frustration is an inability in some circumstances to remove the filter from the ring. It is maddening to watch the light fade as you try to remove an infrared pass filter so you can put on an infrared blocking filter to get a sunset. I’ve used silicone rubber to get enough gripping surface so that I could remove filters from lenses, but they do not work at all in providing grip on the ring. I have filters that are essentially permanently attached to their step up rings.

I have decided to abandon the idea of reducing my filter count by trying to use one filter on more than one lens. I am now looking for each of the three kinds of filters in the native diameter of all of my lenses. If I can’t find the right filter, I will purchase an adapter ring, and thereafter consider it part of the filter.

There’s got to be in a better way to attach filters to lenses. I have used cameras that use bayonet mount filters, and they seem to work perfectly. However, they’ve been around for years, and haven’t exactly taken over the marketplace; all but a tiny number of lenses use conventional screw in filters. Are therse filters the QWERTY keyboards of photography?

The Nikon D3 was a breakthrough camera, offering noise levels and ISO settings that hadn’t ever been simultaneously approached. Two years later, the D3s raised the bar somewhat, offering better ergonomics for the live view feature, and providing slightly better high ISO performance. The difference between the D4 and the D3s is larger than the difference between the D3s and its predecessor, but nowhere near the difference between the D2h and the D3.

The D4 offers D3s noise levels at slightly higher resolution. The economics on the D4 are improved. Pick almost any button on the camera, hold it down, and use the two wheels on the upper right of the camera body – the one on the front operated by your index finger, and the one on the back by your thumb – and you can quickly and accurately make changes without having to access the menu system. This allows the number of buttons and dials to be reduced, and makes the camera easy to learn, since there’s now one control paradigm that’s (mostly) consistently followed.

The D4 buffer is twice the size of the D3s, which had a buffer of twice the size of the D3. This means that, using lossless compression, you can shoot about 60 images at the fastest speed before the buffer fills up if you use a fast CompactFlash card. In the material that Nikon issued at the announcement of the D4, they talked about hundred images before the buffer filled using the XQD card. Since the XQD card that ships with the camera is, at 125 MB/s only slightly faster than a 100 MB/s CompactFlash card, I suspect that you have to use either a yet unannounced, faster XQD card or lossy compression, or both, to achieve the hundred image number.

The D4 still has the beautiful smooth image quality of the D3 series.

The D4 is lighter than its predecessor, but not by much. I understand the video is improved, but I’m not interested in that feature, and I’ve never used it.

My net. The D4 is a very nice camera, and is perfectly suited to my intended use. If you have a D3 or D3s that you’re happy with, I wouldn’t suggest rushing right out to upgrade.

I have owned a few pieces of photography equipment that, at least in retrospect, seem to be incredibly overcomplicated, have bizarre human interfaces, or demand extreme patience from the photographer. I’ve used some processes that meet the same criteria. In this post, I’ll take a trip down memory lane. Do any of you have similar recollections?

The focal plane shutter on the Speed Graphic. You could mount almost any lens on the Speed Graphic, even those without shutters. In that case, or if you wanted a faster shutter speed than could be obtained with a between the lens shutter, you used the built-in focal plane shutter. There were two controls, the spring tension and the shutter slit width. There was a table on the side of the camera that told you what shutter speed you’d get with the various combinations of tension and width. As the springs aged, you applied some windage to the numbers in the table.

Screw-in flash bulbs. In the fifties, if you wanted a lot of light, the conventional solution was flash bulbs. The electronic flashes of the day were relatively wimpy. The standard flash bulbs used a bayonet mount, but if you wanted a ton of light, you used flash bulbs that had a base like a standard incandescent light bulb. If you were in a hurry to get the second shot, you had to change them while they were hot, and it was easy to burn your fingers. The bayonet-mounted bulbs could be twisted and tossed in a single short motion, but the big bulbs needed to be unscrewed, and that’s where your fingers were in danger.

The original Braun Hobby batteries. The first-generation Braun Hobby electronic flashes had many virtues. The heads were light, because the batteries and electronics were all in a shoulder-slung black plastic box. The reflectors were flexible and nearly indestructible; if bashed, they would spring back to their original form. They put out a fair amount of light. However, they used lead-acid wet cells, which were a real pain. There were little plastic balls of various densities that floated or sank depending on the state of charge of the battery. They were hard to see in dim light, which is when you were most likely to be using the flash. The electrolyte dried out over time. Replacements were expensive.

The Kodak E2 process. In the fifties and sixties, you could process Ektachrome at home. Kodak made a kit available to amateur photographers for the purpose. In order to create a positive image, you had to solarize the film during development. You immersed the film in the first developer, then the hardening bath. After it had been in the hardener a while, you took the reel out of the tank and waved it back and forth in front of a photoflood light bulb as it dripped hardener. You can guess what happened if you splashed any of the drippings on the bulb.

The Kodak Rapid Color Processor Model 11. This was a big step forward from the tray processing that home photographers had previously used for color print processing. In 1963, Kodak introduced a new print process that was about as fast as B&W processing. It achieved the speed by taking place at 100 degrees Fahrenheit. The chemicals were one-shot, so using a small amount of them was important. The RCP11 was a horizontally rotating stainless steel drum that you filled with 100 degree water. It was textured on its outer surface so it would pick up chemicals from a tray underneath, and wet a print placed face-down on the top of the drum. To change chemicals, you’d tilt the tray and dump the old chemical in the sink, and then you’d pour in the new one. Washing was done by spraying water over the top of the whole thing. To keep the print on top of the drum, there was a mesh apron that contacted the back of the print and clipped into an assembly on the front of the processor. You’d have to put new water of the right temperature into the processor before each print unless you sprang for an aftermarket thermostatically controlled electric heater. The processor was extremely effective at heating and humidifying a small darkroom, to the point where the dry side wasn’t, and your enlarging lens fogged. Using it provided a steamroom-like experience for the photographer. I am not making this up.

Double-click, and cut the grass. In 1991, digital photo editing was making its break from the proprietary Scitex/Hell/Crossfield/Dainippon world, through the professional open systems from Silicon Graphics and others, to widely available Wintel and Apple personal computers. The state of the art machines were the Apple Quadra 900, and various Intel 486 computers; they weren’t really up to the task of dealing with print-quality images. Many operations took minutes. The mantra of the day was, “Double-click and go get coffee.” One person on the Compuserve photo forum said that, with the images he was working with, it should really be the title of this paragraph.

The Kodak Dye Transfer process. Beautiful, stable results, but, by all reports, unbelievably fiddly, involved, and error-prone. By great good fortune, I have no personal experience with this process.

Fifties tight-deadline photojournalism. Handheld 4×5 rangefinder cameras. Flimsy film from Kodak film packs. Developing film in 90 degree soup. Printing negatives wet. Drying prints by squeegeeing then against 220 degree ferrotype plates. Ugh.