Friday, October 24, 2014

Macro Nikkor 12cm f6.3

So I got myself a new lens.  It is the Macro-Nikkor 12cm f6.3,  This is a pretty rare lens and is actually closer to an industrial lens than a camera lens.  It was designed for low magnifications on the Multiphot system that Nikon made and is one of four lenses for the system.  This is the longest of the four and has the greatest working distance and least magnification.



So lets see what the lens is and what it does.

It is a 120mm f6.3 lens constructed with 5 elements in 4 groups.  The lens is fairly old so has the older coatings.  This should not be much of an issue for macro work, but doesn't seem to flare in my work and has nice contrast.  The lens is small, with a 38mm front thread and a M39 rear thread.  There is no focal helicoid and will require bellows or other extension means to focus at various distances.  The iris is 6 blades and is operated similarly to the 105 mm f4 Bellows Nikkor.  That is, there are two rings. The first ring has 1 stop detents on it that will allow you to set a minimum closure and then a second ring that will allow continuous change of the diaphragm from fully open to the setting of the first ring.  In a departure from photographic lenses, the stops are marked from 1-7 where 1 is 6.3 and each number denotes a 1-stop reduction in iris side.

What does this lens give you that a standard micro lens does not?  First is image circle. This lens is designed to cover 4x5 inch film so will allow as much swing and tilt as your bellows will normally allow.  Don't expect any vignetting from movements like you can see with standard or even PC-E micro lenses.  Second is a flat field.  There is no appreciable field curvature which is critical in macro photography (greater than life size) where depth of focus is in fractions of a millimeter.

This lens requires substantial extension and I am often testing the limits of my PB-6 Bellows.  Bellows extension will allow for more magnification but the lens is optimized for about 1:2 to 4:1 so you will see some degradation in performance outside of these ranges on 35mm/FX images.  Working distance is much better than what I am used to with other lenses (e.g. a reversed 50mm) which makes lighting substantially easier.

To fit this lens to the bellows, a method to convert the Leica M39 screw thread to Nikon F bayonet is required.  This adapter (nikon's is BR-15) is pretty rare, but off brand adapters can be had on the internet if you are looking.

During my experimentation, the exposure difference between settings 1 and 2 on the lens barrel were actually 1.3 stops at the same extension.  This means that setting 2 is f10.  The remaining settings are close to 1 stop each, so 2 is f14 and 3 is f2.  I would not suggest going beyond setting 3 (f20) as diffraction starts to get the better of you, especially if you are using high-MP cameras.  Better to keep a wider aperture and use focus stacking techniques than trying to stop down the lens that much.  Also remember that the effective aperture as it relates to exposure also has to take into account the large extension you are using (usually over 100mm) so exposure times, and the noise inherent in those settings increase dramatically.

In the end this is a fine lens for bellows offering a small package to get into the macro range of photography with a lens specifically designed for this application.

For the best write-up on this lens (and the source for this entry) visit Enrico Savazzi's website here


Thursday, May 9, 2013

My First Lens Repair

It was a sunny day in May of 1993.  I was heavily into photography as the photo editor to the school yearbook and a staff photographer on the paper.  Not to mention my senior photography class and independent study photography project. I tended to always have a camera or two with me when I went to high school.

Back then we shot film.  I remember reading about the first digital cameras in magazines, but for mere mortals, we were still using the analog stuff.  My photo equipment at the time would be considered meager in the 21st century, but it was all that I had and I really didn't know any better.  I had a Nikon F with a broken meter head.  This was my flash camera which was typically mounted next to a Sunpak 544 "potato masher" flash.  My other camera was a Nikkormat FTN which was similar to the F but with a working meter.  For lenses, I had a 28mm f2.8 Vivitar lens, a 50mm f1.4 S Nikkor, a 43-86 f3.5 zoom, and a 135mm f3.5 Q lens.  All but the Vivitar were from the 1960's.  This kit had served me fairly well in those days, but I often wished that I had a slightly faster lens in the telephoto department.  I really didn't wish for anything longer most of the time, which is strange thinking to me these days.

That fateful day in May,  I was sitting in the passenger seat of the 1978 Buick LaSabre that served as the main mode of transportation for my brother and myself, and the Nikkormat with the 50mm f1.4 S was mounted on it was on the floorboard along with my book bag.  Well as fate would have it, I grabbed the book bag and it somehow caught the camera in one of the straps and it fell, lens first, onto the pavement.  The drop was perhaps six inches, but that was all it took.  Despite the Nikon legend of durability, this little drop did both camera and lens in.  The glass was okay, but the iris in the lens would no longer respond, and the focus ring did not move.  On the camera side, the shutter speed dial (located near the aperture ring on that model) would not turn and the camera shutter was not doing well either. 

It is now twenty-years later, and this lens has been sitting on my shelf for many years now;  mounted on it's original body, the Nikon F that my father has since given to me.  The F is in little better shape than the lens at this point, as the shutter has holes in the curtain.  Recently I was looking on YouTube and decided that there might be a video that could guide me into the lens repair.

Unfortunately for me, the videos on YouTube don't include this particular model of Nikkor, but a quick email to a Flickr friend gave me a clue on how to get started.  The focus ring is actually two rings threaded together.  The forward, beveled ring can be twisted off which reveals three screws that can then be removed so that the focus ring can be pulled off.  My focus issue was that the ring had landed on a rock and had dented the focus collar so that it was impinging on the underlying ring, causing the ring to not allow the helicoid to turn.

Digging deeper into the lens, I found that there is a copper retaining spring/ring deep in the lens that keeps an internal ring locked into the aperture ring screw.  This retaining spring had come loose so that the internal ring was not mating with the pin.  A bit of fiddling with a screw driver, and then careful re-assembly had the iris working correctly again. 

Fixing the focusing ring is not easy.  I do not have the correct tools, but I was able to bend the focus ring enough so that it will turn once more, but not as smoothly as any would like.

I would love to mount this on one of my digital cameras, but it is a Non-AI lens so can only be used on certain bodies, and even then only with stop down metering.  So I will probably never again use this lens in the field, but it was a nice feeling to be able to get this lens back into working condition.

Thursday, April 18, 2013

An Open Letter To The US Congress on Gun Violence

Dear Congress,

Please pass legislation to offer block grants to state and local governments to harden our schools against gun violence. I think that as a start, we need police presence at all schools as well as hardened doors and bulletproof glass on the 1st floor. I don't know why schools can't be at least as well protected as airports. While you're at it, provide money to increase law enforcement budgets so that all illegal weapons charges are properly investigated and prosecuted. This will get both guns and criminals off of the streets.

If you need more money, tax weapons and ammo like you do cigarettes. Please remember to have DHS et al to remit their taxes to this program for the 1.6 billion rounds they bought last year for whatever reason.
 
  Sincerely...
 

Monday, April 15, 2013

Tax Day: Form 1040EZ-LIB

IRS Form 1040EZ-LIB

(an easy Income Tax form for Progressives who want to pay their fair share)

1) Enter your W-2 Wage income:

2) Enter your 1099 Interest/Dividend income:

3) Enter your capital gains income:

4) Enter any other income (see note A):

5) Sum lines 1-4, this is your total income:

6) See Table A and enter multiplication factor:

7) Multiply Line 5 by line 6, this is your tax due:

8) Enter total taxes witheld by employer:

9) Enter total quarterly tax payments made:

10) Sum Lines 8 and 9, this is the tax you paid:

11) Subtract line 10 from line 7:

12) If Line 11 is negative, see note B; if positive, see note C; if zero, see note D

Table 1: Factor Single Married/Joint

0.1: $ 1-$8,700 $1-$17,400

0.15 $8,701-$35,350 $17,401-$70,700

0.25 $35,351-$85,650 $70,701-$142,700

0.28 $85,651-$178,650 $142,701-$217,450

0.33 $178,651-$388,350 $217,451-$388,350

0.35 over $388,350 over $388,350

Note A: Be honest! Hungry children are depending on you.

Note B: You have over paid your taxes and are a noble citizen! Thank your for your kind donation to your government. Rest assured that these funds will be put the best possible use.

Note C: You should be ashamed! Underpayment of your taxes most likely caused some poor child go go hungry last night. Write a check to the US Treasury immediately! To help cope with the guilt you should feel, add a bit extra to the check.

Note D: You nailed it, but we are watching you!

Saturday, March 23, 2013

Nikkor 7.5mm f5.6 Circular Fisheye Lens



The 7.5mm f5.6 is a hemispheric fisheye lens that provides a full 180 degrees of view in a circular image that is 23mm in diameter on the film. This lens will see everything in front and next to the lens. The effects are dramatic, but of limited utility.

This is not your typical Nikkor however. It is not a retro-focus design, and therefore the rear elements are very close to the film plane of the camera. In order for this lens to even be mounted on the camera, you need to lock the mirror up. The official Nikon line is that this camera is only to be mounted on the F and F2. I will add that if you have a Photomic finder on a Nikon F, you will have to remove it as it will get in the way. It will work with the Photomic finders of the F2 however. I can see no reason that the lens will not mount on the F3 or F4 which have full time, mechanical mirror lock up. Besides having limited compatibility, the camera design also precludes the use of TTL metering.

To use this lens, you need to use an external meter or the Sunny 16 rule. When I use this lens, I use a hand-held meter. The MLU also precludes the use of a view finder, so Nikon thoughtfully included one with the lens. The viewfinder is not exact however, giving a 120 degree angle of view. I find it nearly useless. If it will capture everything in front and on the side of you, you just need to align the camera and level it and try and avoid getting your fingers or feet in the frame. The finder fits over the rewind crank of the F and F2 but some have been modified to fit in the standard hot shoe.

This lens is also of a fixed focus design so all elements are fixed. Fortunately with such a short focal length, even wide open at f5.6, pretty much everything will be in focus. The front element of this lens, and the viewfinder for that matter, is very bulbous and sticks out. There is no ability to filter the lens and no lens shade in made. This makes the lens very susceptible to damage. You need to put the screw-on lens cap on as soon as you are done shooting to avoid damage. I do the same with the viewfinder lens cap. Since there is no ability to filter the front element of this lens, Nikon installed a filter turret inside of the lens that is selected via a wheel on the lens barrel. Sadly for us, this lens was made in the later 1960's so most of the filters are really use useful when using black and white films. The filters include a L1A for normal shooting, Yellow 48, Yellow 52, Orange 57, Red 60, and XO.

Construction of this lens is first rate, as was the norm with Nikkors of that era. The lens barrel is metal with a small rubber ring near the lens cap threads. There are six aperture blades that are not rounded and if you get a point light in the view, which is pretty easy when you see half of the world through it, you get a rather ugly flare. The lens coatings are older so the lens does lose some contrast if it flares. The aperture is selected by a lever on the side of the lens and it can be difficult to adjust when it's on the camera. The aperture range is from 5.6 to f22. I like to shoot it from f8 to f11.

  I am not a huge fan of writing about image quality. Still, I will write what I have found, but keep in mind that I don't do scientific tests, or even under controlled conditions. Also note that I have only used this lens on film cameras, so the high density pixel DSLRs might display more flaws than I see when I shoot film. The lens is sharp enough for my film use. While it isn't tack sharp, it will pass at proper viewing distances for film under most enlargements. Contrast is moderate, but it can suffer from flare which reduces contrast. There is some vignetting which appears as a ring around the edge of the image circle. This can be reduced slightly by stopping down, but since the angle of incidence of the light rays is so small, there will be some light loss no matter what. There is little CA that I can observe. There is major barrel distortion but that is normal for fisheyes.

While the lens works fairly well, it is more of a collectors piece than a working lens, especially these days. The going rate for these lenses is about $1,000, and it's very limited utility and shortcomings such as no TTL viewfinding or metering make 3rd party fisheye lenses that have retrofocus designs a more cost effective option. The newer optics are much easier to use, and will probably offer image quality as good, or better than this lens.

  I have also included a link to a YouTube video I made for operating the lens, and also some photos I shot of, and with, the lens itself.

7.5mm Nikkor mounting video

Monday, May 16, 2011

Iconic Photograph

The latest photograph to be dubbed "iconic" is here.

It will go down in history as the image that represents the death of Usama Bin Laden. While it is certainly historical, should it be titled "iconic?"

My trouble with the image is that it needs a good caption. Iconic images shouldn't need words or any historical context. If you didn't know the players in the room, what would the image tell you? Certainly there is tension in the air, and Sec. Clinton's hand over her mouth (later she claimed it was a cough due to allergies) adds to the dramatic impact of the image, but can any viewer see beyond that to make it iconic. If we replaced these people with sports fans watching a close championship game, would it be viewed any differently?

To me iconic is often, but not always, anonymous. The horror of the Vietnam war was captured in an image by Eddie Adams. Most people see the image and you don't need to know who the two main subjects are. It strikes a huge impact because of the human condition that was recorded.

How about this photo of Ali standing over Liston by Neil Leifer. Granted Ali is one of the best known fighters of all time, but this image is much more than just a portrait. It was a portrait of one boxer triumphing over another.

Finally, we have an image of the Afghan Girl by Steve McCurry. Most people don't know the circumstances of the photograph or the name of the model. Still, somehow the image speaks to us in the way that words do not. This is an iconic photograph.

Tuesday, April 19, 2011

Research Paradigms

I was a junior in high school in 1992. I was in a class entitled "Humanities" which had two quasi-indenedent sections. One part was a history class which dealt with the facts and themes of the era. A study of zeitgeist and chronology; while the English class was a study of the literature from that time in history.

As part of this class I was to given the assignment to write a nice little term paper comparing and contrasting the works of Dante and Chaucer. It was to be in the neighborhood of twenty-pages with at least 10 sources and done according to the writing style that we had been introduced to in the previous two years.

Of course twenty-pages, even generously double spaced, is quite a few words, and meeting the number of sources would prove to be challenging.

One night my brother and I went racing to the local library. Now the population of our little town in Connecticut at the time was only starting to exceed the total number of cows by this time, and the library was good enough to find a nice selection of mystery novels, but finding literary criticism of medieval literature proved to be futile. I am guessing that the women on the library book procurement committee were not concerned with expanding the town's ken in that particular area.

Not to be so easily deterred, my brother and I raced off to the library in the next town over. This library was a stately building of stone, built by the mill barons of yesteryear. Sadly while I had been able to find Caesar's Gallic Wars in this library some years earlier, I was unable to find any literary criticism about Dante and Chaucer.

After this epic failure, we returned home. We would have to venture on another evening to the University library to find our information.

After a good thirty-minute drive through the back woods of the state, we arrived in Storrs, CT. The University of Connecticut indeed had a plethora of information on the subject. Being lowly high school students, we had to find the books on the shelves, and then do our research in the library by a combination of notation by hand (laptop!? what was that?) and photocopies of relevant pages.

Once the information was gathered, a paper was written, and all was well in the world.

That was nearly twenty years ago. Today, as I type this on my laptop, I do a Google search of "Dante and Chaucer comparison," and I get 439,000 results in 0.3 seconds, sitting here on my couch. No running to various libraries, no fast reading to glean quotations and facts from musty, esoteric tomes, no scribbling by hand on note cards. It is all here, in HTML, easily cut and pasted into word processors to be carefully read at my leisure and digested so as to write a nice paper.

So what twenty-years has given us is instant access to more information than we could possibly use and in mind-boggling fast speeds. Sadly while this should make life quite easy for the researcher, it has given rise to a number of other issues.

First off is the tendency to be a bit lazy. I understand that there are now services dedicated to doing their own search to see if our intrepid, if ethically deficient, student has cut and pasted whole papers, or "Franken-papered" a report from various snippets of other writers. In my day we had to quote or paraphrase with a citation and then add our own thinking to the mix. Evidently this is being lost somehow.

Another issue is the reliability of the sources. In my day, if you got your quotation or source from some published book, it was held to be correct or at least to a standard that a teacher would accept. Obviously literary or other research was not published at great expense if it hadn't gone through at least some sort of peer review. Today with the advent of Wiki's and blogs and the like, the researcher had better be able to separate the wheat from the chaff. Just because I found 439,000 hits doesn't mean any of them are actually useful or even remotely accurate academic research that has been reviewed and accepted.

So today with information at our fingertips, we have to be ever mindful of what we are pulling out of cyberspace and use our own mind to see if that information, while easy to obtain, is worth the electrons that move it.