Restored a Polaroid conversion

This is a Polaroid 110B converted into a 4x5 format fixed lens camera, converted by someone else, not me. The one that famous handsome US actor Bard owned, and everyone loves 4x5 would definitily loves to have one too.

Client sent it to me, asking to replace the focus knob that seems cool but awkward to manipulate, and get rid of those decorations to "make it looks like a normal camera".

I didn't know what those decoration for at the first sight, till I took off those decoration plate. Oh, there is one hole at the RF housing, beneath the decoration plate, cracked.

That explain something.

And the viewing window, converted into a round shape, claimed that improves viewing, I compared this with original viewing window, can not tell any difference, so I figured that must be my own problem, I am dull in some area, especially this.

I thought maybe I can learn something on this, I turned up the housing, to see how the view window were converted, then I found out that it was made by very sophisticated skillful hand, obviously, which beyond my ability and guts and I don't dare to copy, no mention to sell it out.

The RF housing was cut off at the end, to match the cutting body, so obviously there will be a cutting phase to compensate, that need some putty. Many converted Polaroids I had seen, were all get exposy putty with enough amount, to ensure that fragile end will hold the job.

But not this one, I thought the builder must be following kind of "lighter the better" philosophy, no matter how easy the housing cracks at that part, that was not his problem.

Managed to bring this cracking housing back to normal, the result is somewhat OK to me. Oh, and I replaced the cold shoe, hope it could be as good as the original one, that sticks with sponge tape onto camera body, so bold mind and so creative that I never think of.

Replacing focus knob is an easy job, but I do admire that original converted knob, so pretty, so unique, and so hard to use.

And the infinity stop, I replaced that Velcro version conversion has, for I still can not solve the secrets that fix lens with Velcro and sponge tape. I took off the Velcro, bring back into the original one from Polaroid, and added a steel plate to ensure the fix position. When replacing this part, I made the i.stop calibration, found that must be my calibration procedure has something to improve, for my calibration result did not agree with it, hope my client can live with my error.

Well, these were some thoughts while I did the job, and I think best to keep myself in Byron area, only function counts, deco is not my dish...... 

Best dress for Byron camera

Bob made wonderful type 55 instant film, named New55, and he made some gorgeous test shots.
http://black-gallery.blogspot.com/

cam curve for Geronar 6.3/150

The red curve is for 6.3/150mm Geronar lens.

Compare this lens with Xenotar, Heliar, apo-symmar 150 lenses, the curve is interesting different with them, Geronar has its own character, no wonder it has shortest rail movement for infinity stop.

Consistency of RF mechanism

Had been measured and plotted 6 RF mechanisms last week, to verify their consistent performance, thus if they are, we can refer it as a constant, so the only variation of the cam curve is from lens focal performance.

To measure each one, mount the RF part, zeroing it by focus to infinity and make overlay images in window match well, then use this as zero point, focus at other distance, here I choose 8m, 7m, 6, 5, 4m, 3m, 2.4, 2.1m, 1.8m, 1.5, 1.2, 1.0m as target, and record the moving distance of the mirror arm, then plotting the curve representing the records.

Except curve No.4, all six curves has very similar character, indicates the RF mechanism is fairly consistent at their performance on focusing, but there DOES has mechanism like curve No.4, whose character is different, I would call it a "mine", for it is impossible to find out before you bought such a vintage camera produced sixty years ago, actually you could not expect too much. Luckily most people didn't convert 110B as an lens interchanging camera, so they never know.

Nevertheless, most of the RFs are good, but I prefer inspect one by one, before I made the dedicated cam grinding. 

Grinding Ground Glass

Never expect it so hard to buy grinding grit in Taiwan.


My previous version of gg panel was made of bakelite, and the ground glass is a piece of transparent acrylic sheet in 3mm thickness, frosted surface is from a thin layer of laminator sheet sandwiched between Fresnel lens and acrylic sheet.


Laminate sheet sleeve is for laminator to hot press the sandwiched photos or id card, to form a protect cover, very thin, fine evenly distributed frosted surface, but after hot press and rolled out from laminator, it becomes transparent. It is easy to get in any stationary store, and in 100sheet pack, you can choose any size you want, in my case, 4x6 inch sleeve is enough, I had to cut some edges.


I tried Scotch Magic tape before, but in my own opinion, laminator sheet is better. 

Last week I received new version aluminum gg panel, some minor modifications from previous version. Panel surface was sand blasted and dyed in matte black, looked much better quality than bakelite one. I put in Fresnel lens, laminator sheet, and then finally acrylic sheet on top, fixed with folding hood and six screws with washers. Left one is the new version, six big washer help fix the hood also the ground glass, and screw holes on hood edges are far more robust than old version, not easy to crack anymore, and looks more flat at side.

But then I compared my gg panel with the one on my Linhof Tech IV, first focus with Linhof gg panel, then replace it with my panel, my frosted surface obviously coarser, thought the focal point is dead on.


I thought that Byron is dedicated for snaps, and gg panel is for occasionally used as view camera, so the gg panel is not so critical. But as some requests from clients asking for better quality ground glass, and since the panel is upgraded from bakelite to aluminum, maybe I should consider a finer frosted surface.


I ordered some 3mm thick glass panels, and acrylic panels too.


There are articles about "how to make your own ground glass", easy to find them on web, but the grinding grit, aluminum oxide in 15 micron is not a common product to find in Taiwan's auction market, I made some calls, and most of store sells them in bulk package, 20 or 25kg, that is too much to me, I can use it for the rest of my life and to my son, and to my grandson!


Finally a shop is willing selling me in 2kg package, but in higher price, what can I say? I almost kneel down and kiss his feet.


Took a glass sheet in about A2 size as plate, I sprayed a tea spoonful of grit on it, with some drips of water, then acrylic panel face down, I began to made rotate grinding on it.

To made it easier to hold the panel while in grinding, I used a silicon sucker which has a big handle on it, so rotate the panel on glass is smooth and easy, no fingers directly touch the panel, avoiding any chance that wrong side of sheet got ground.

About 5 min for a panel, then I immersed the panel into water, wiped it with a towel, to check if there is any hot spot, there is, especially at the center, means that sucker makes center get less pressure, so I had to leave the panel away, with fingers evenly pressed on panel, make second rotation grinding.

That's about another 5minutes, then a panel with evenly frosted surface is done! With same way I make glass panel too, comparing two panels as ground glass, I can not tell the difference.

But since I made frosted glass myself, I should compare new panel (Fresnel lens+ frosted acrylic sheet) with older panel (Fresnel lens+ laminate sheet+ transparent acrylic sheet), to see if there any improvement.

I focused the same object, with two versions of gg panel.


This is from old version (Fresnel lens+ laminate sheet+ transparent acrylic sheet), there is some circular pattern on frosted surface, that is from Fresnel lens.

And this is from new version, Fresnel lens+ frosted acrylic sheet. Fresnel lens pattern is also distinguishable, but less than old one. 

It's not so obviously to tell in taken images, but it's easy to tell by naked eyes that frosted acrylic is finer than laminate sheet with transparent acrylic.

But there will be two options for clients to choose, acrylic sheet is lighter and not so easy to crack if falling; while glass sheet is heavier and prone to crack if falling on floor, but better scratch resistance.

Which one will you choose? Acrylic? Glass?

Some Ideas on Range-Coupled mechanism

Thinking of range-coupled mechanism these days, just came out of some ideas. No matter Linhof or Graphic, Horseman or other brands 4x5 cameras, if installed with rangefinders, all need a match cam for specific lens, otherwise no range-coupled functions available.
People are troubled when they tried to find lens and matched lens cam,  the pair are rare to find these days, and the price always sky high, handheld 4x5 photography restricted by this, so called range coupled 4x5 almost vanished.
What if

1. Range coupled function needs no match lens cam.
2. Any lens can be range coupled, no matter what camera used.
3. Lens calibration needs no professional expert. one lens can be calibrated in 10 minutes.

The idea came out these days, and I thought of this can be applied by any 4x5 camera, even 8x10! what will it be involved in LF photography history?
Too excited! can not sleep at night.

an interesting discussion here:
http://www.largeformatphotography.info/forum/showthread.php?t=79196

Rangefinder calibrations on 110B- part6

Now there goes to final part of RF calibration.

We match the lens with rangefinder with a tailored cam, so camera can be range coupled with ONE specific lens, but that is all it can do, if you want to use other lenses, these lenses are range UN-coupled, that is, rangefinder as a pure rangefinder only, reading out the rangefinder indicates, then we adjust the lens position to match the focus.

What if we could change this ONE-LENS-ONLY range coupled camera into a multi-lenses RF camera? I thought about this for years, and many clients asked the same question also, everyone wants multi range coupled function.

Here I list some issues on this conversion as follow:

Multi cam
More than one lens range coupled needs more than one more cam, how many cam possibly be installed on a camera?
As we measured, each cam needs at least 40° of rotation, so as 360° divided by 40°, maximum we can make 8 cams simultaneously be installed on one camera, but that is too much and too complicated, I would say 3 cams is enough.
Each cam separated and distributed at every 120°, that leaves enough space and tolerance to mechanism.

Stacked cam and rotating pole shape

Each cam curve is dedicated to match a specific lens, there may be differences between lenses, although they are in the same focal length, or even the same type. So it is impossible to order a batch of 3-in-1 cams that restrict  clients to use only 3 pre-defined lenses, and since lens has its own character, to amend the outer curve in such a 3-in-1 is tiresome.

Best way is to separated each cam, stack 3 in a row according to each client's specific request.

But for keeping these cam staying at their rotating angle (120°), we should change the rotating pole from circular shape into a triangular shape.

Mirror arm and cams

As mentioned above, best way for multi-cam is to stack them to match the clients' request, but the original shape of the cam is un-stack-able,  it is too thick.

You can see that original cam is thick to mirror arm, so this installation is unfeasible to 3-in-1 stack cam design, what we should do, is to reverse the mirror arm- cam relation, that is , to make mirror arm a thick arm, and make the cam a thin metal sheet. Such arrangement makes mirror arm easily be triggered by stacked cams, and metal sheet cam makes stacked thickness in bearable range. And the greatest advantage is to make cam much easier to file, to tailor its outer curve to match the lens character.

Field operations
If we solve all the problem mentioned above, the final problem arise as how to operate this mechanism in field. We need a knob to rotate the cam pole, to match the lens we change, that involves changing the outlook of the RF housing, but pity there is no space for it in my opinion, best way is to re-design and re-mold the RF housing, but consider the quantity and mold making cost, I stop at this place and never go any further.

Rangefinder calibrations on 110B- part5

Last step on paper work, then we can go on to practical procedure.

By measuring rangefinder character and lens focus moving range, now we are going to combine two focus system into one-- cam, this cam will be inter-interpreting two systems, to sync each other in one. But bear in mind, one cam is synchronized with one lens, not all lenses mounted on camera.

Let's see how to do it. if there is a 150mm lens we are going to use for range-coupled with rangefinder, then before a dedicated cam is made, we need to measure the rangefinder character (A) and lens focus moving range in advance (B).

Refer two relations between (A) and (B), we begin to draw dedicated cam's outer curve.

1. Define radius center and zero point.
   cam rotate pole radius is 2.8mm, and the zero point is 6.36mm
   The light blue dash line represents 127mm cam that Polaroid originally installed.
   
   
   
2. The mirror rotates or moves as cam outer curve changes, if the outer curve is aligned with orange dash line, which is a circle in fixed radius, then no matter how you rotate the cam, mirror will always stays at the same position.
   
   Mirror moves as cam outer curve keeps changing it's radius (black line), outer curve across orange curve at zero point, distance between two curves is 0 at it. Outer curve is more or less radius than orange curve at other rotating angles, and according to the lens/rangefinder relations, radius changes differently.
   Use orange line as reference, to point out all the radius changes.
3. As we measured before, cam rotates within 39° range as rail moves within 20.5mm range, effective outer curve will extended 10° more on both side, for easier installation in future.
   
   Draw lines across the orange curve, all lines radiate from pole center, distributed every 10°, these are the reference points. 
4. According to the lens/ rangefinder measuring data, we now locate each reference point. Let's say while we measure the rangefinder, and find out the data as follows
   infinity  0
   30m     0.04
   15m     0.07
   10m     0.1
   8m      0.12
   6m      0.16
   4.5m   0.22
   3.6m   0.28
   3m      0.35
   2.4m   0.44
   1.8m   0.52
   1.5m   0.6
   1.2m   0.73
   1.0m   0.88
   0.9m   1.01
   and the data was transfered into characteristic curve
   
   Another data comes from measuring lens focus moving range
   
   notice the y-axis in this chart, it transfer rail moving range(mm) into rotating degree, as rail moves within 20.5mm range and cam rotates within 39°, so even distributes two measurement, safely transfer two units.
   
   find the focus distance at 10°, 20°, 30°, 39°, in chart above we get 4.45m, 2.4m, 1.7m and 1.35m. Then we back to the rangefinder chart, to locate 4.45m, 2.4m, 1.7m and 1.35m. we find that radius should add 0.24mm, 0.43mm, 0.56mm, 0.68mm accordingly.
5. Drag reference points on orange curve according data we just read out from charts, move them to proper distance to reflect the variations.
   
   Then draw a smooth curve across all reference points,
   
6. Enclose the curve with cam outline, make it a dedicated Geronar 6.3/150mm lens cam for 110B.
   
   to compare new 150mm lens cam to original 127mm cam, you can tell the differences on outer curves. (orange curve: 127mm cam)
   

so this conclude cam design paper work, what left is to make this dedicated cam for your camera.

Rangefinder calibrations on 110B- part4

Rangefinder
First system to be measured is RF parts.
We need to draw a rangefinder characteristic curve, to represent it's focus range. so there is a chart, focus distance in x-axis, and y-axis is the mirror moving range.
As we all agree, that Polaroid mass produced 110B cameras, so rangefinder part should  represent same character in every camera body, but after measuring so many rangefinders, I found out that they all have their own characters. Maybe the camera was for 3x4 instant film, no image enlargement required, so it tolerates for range variety, but it is intolerable if we use this rangefinder on 5x4 camera.

Each rangefinder on Byron will be measure their characteristic curve individually, record and draw in chart, for further matching their prime lens.

To quick finish this tedious job, I managed to use a laser beam to do the focus, no need to peek all the time, thus won't hurt my eyes too much.

The measuring result will be something like this.

Lens
Lens measuring is simple and straightforward, you mount the lens on a 5x4 camera, set it focus at infinity, then define this location as zero point. As we already know that 110B rail has 20.5mm moving range, so we should find out the focus range this lens has in 20.5mm rail movement.

Stick a simple ruler at the side of the rail, and a pin as a pointer, now you can focus object at different distance and record the rail movement.

The result should be as early post I made "Lens Curves".

Rangefinder calibrations on 110B- part3

So actually there are two focus systems, one by focus through lens, and one by focus through RF mirror.
Lens mount on front standard, from infinity to someplace near, limited by the moving range of camera rail, 110B rail got maximum moving range 20.5mm, for 150mm lens, it's about to 1.5m; for 127mm lens, about 1.0m; for 90mm lens, about 0.6m.
Rangefinder rotates mirror to adjust focus, by measuring 127mm lens cam, I found out that RF mirror rotates only 1mm to accomplish focus range from infinity to 1m.

How to synchronize lens and RF? that's what cam stands for. different lens needs different cam, cam with different outer curve. Outer curve comes from lens focal length. for 90mm lens, it can be set focus range from infinity to 0.6m, much wider than 127mm lens (i~1.0m) or 150mm lens (i~1.5m), so 90mm lens cam outer curvature steeper, 150mm lens cam outer curvature flatter.
Later I will show you how to synchronize two systems.

Rangefinder calibrations on 110B- part2

Here are three main factors that you should know before you made a cam to fit to a lens.

1. Lens: You should know the range that lens can move on the rail, it is fixed range on 110B. But most important factor is within the moving range, how will the lens focus change?
Take 150mm lens as example, within the 110B rail moving range, it can focus between infinity to about 1.5m; in the same moving range, a 90mm lens can focus as near as 0.6m.

2. cam: cam curve controls the rotating range of the mirror, but cam rotates itself as rail moves, you should find out the cam rotation related to rail moving range.

3. RF mirror: All RF parts are fixed except mirror, it moves to change the RF focal point, I have shown you that for a 127mm lens, all the mirror moving range needed is within 1mm, but how about 150mm lens? how about 90mm lens?
Rail moving range is fixed, thus made 150mm lens to 1.5m, 127mm lens to 1.05m, 90mm lens to 0.6m. So we know that 1mm moving range for 127mm lens, and that will cover 150mm lens as well, but not enough for 90mm lens, we should extend beyond 1mm to reach the 0.6m focal point, it needs extended measures.

Rangefinder calibrations on 110B- part1

There is a mirror on rotation, according to the cam curves, thus each cam for different lens, will have different curve, reflecting the focal length.

this is cam for 127mm lens,

Vertical line on cam surface indicates when lens is focus on infinity. and as rotating in hole center, each degree of outer curve on top is keeping changing the radius distance, causing mirror rotate.

But how long the radius range a cam causes?

I used a usb micro scope to take photo of cam, and enlarged it, then make some distance measures.

After carefully measuring, converting digits into a curve, we found that outer curve of 127mm cam actually causes mirror rotate within 1mm range.

That means a lot, range finder that 110B equipped, focus from infinity to near 3.5feet, all controlled within 1mm range.

One set of Byron for sale!

I have one set of Byron on batch line, waiting for his master.
It is converted from 110B body, will be equipped with 4.7/127 and Angulon 6.8/90, all lenses in good condition.
the price is US$2,000
I will finish this batch and catch up the X'mas, so prize yourself a great present!

contact me if you are interested

salihonba@gmail.com

daniel

thank you for being interested in the kit, it is sold!

Byron for Xenotar 150/2.8 demo video

Finally, I made it!
Klaus, Jong, your big eye camera is on the way!

Welcome to Xenotar club

One goes to NY, one goes to Texas, one goes to Germany. 6 of Xenotar lenses this batch, next 3 will be on 2 weeks later.

This summer class is the most difficult one I ever met! Too hot to do the conversion, and all kind of challenges jumps out during the job, from places you never think of, take bellows as example, I made about 6 bellows prototype, and modified blue print 16 times, finally grabbed the key.

Then the front standard, factory went wrong on dimension FOUR times! can you imagine?! It is damn too hot!

Not yet mounting the RF housing, tonight's job.

Look carefully, the left one is a little bit small size on bellows, will replace it after shooting.

Bellows, bellows....

Bellows was re-sized for Xenotar 150, thinking that no matter the extension length or front opening size, is perfect fit to Big Eyes.

Mounting Xenotar 150 is an in-direct procedure, rear element needs to be taken off before front element/shutter mounted, then screw back the rear element.


I keep the bellows in no extension situation when screwing back the rear element, then the problem comes. Bellows is so perfect fit to the lens, the front opening size is just slightly bigger than rear element, so when I screwed the rear in no extension situation, some folds in front of the bellows were clipped, that is Ok since bellows has enough folds for rail movement, but it looks awful. Folds will not be clipped if you screwing the rear when bellows extended in half or full length, but that makes a deep hole and brings difficulty for screwing.

Solution? re-size the bellows, make front opening size even bigger, so no folds were clipped when bellows in no extension situation.

Byron got three version of bellows sizes now, Khaki color shows opening for #0 shutter lens, Blue opening shows the size for any other lenses other than Xenotar 150, and the Gray one shows the opening size exclusively for Xenotar 150, the Big Eyes.

All three sizes are bigger than 110B's original bellows.

And the RF parts was sent for fine tuning, for this lens, mechanist told me he needs to take part all RF parts, we will wait and see.

Before it came back, I made Byron as a simple view camera, and test the stability. Lens is heavy, but front standard works well. Without RF viewing windows, and my model keeps moving on chair, it is hard to capture him and the little tree he planted.

No folds are clipped if rear element is mounted when bellows extension in full length, but rather hard to do, and you can see one front side ridge of bellows were bumped..., reasons for re-sizing a bigger bellows is obviously clear.

Film expired? no matter developing time I changed, saturation is way less than what I saw.