## Disc film cameras that use replacable batteries?

NO batteries required.

Use, or Modify?, a 4×5 Large format film holder so you can attach or tape the film, removed from the cartridge, in the middle of it. Assuming it will not interfere with the dark-slide, you may have to remove the plastic center piece in the disc of film.

Now use the 4×5 LF film holder in Pinhole camera that accepts 4×5 LF film holders. It will expose all of the negatives simultaneously. Make an enlarger negative holder for the film and print it as one photo. Or send it to a lab and have each neg printed and then assemble in the same orientation. Think outside the film cartridge.

Or variations on that theme. Experimentation encouraged.

NOTE: Of course all work with film will MUST be done in a dark room, I.E. A room with absolutely no light.

No affiliation with the zero image camera i linked to other then i own one and love it. (Another option is to make your own)

## A Disc Camera likely to be usable in 2021

I have some Disc Film in the fridge that I would like to use, that I got from a film lot.

It seems unlikely that anything amazing will come out of it, but experimenting is part of my process and some recent results look really cool.

I found a lab that processes it, but I don’t own a Disc camera. They seem to cost a dime a dozen on second-hand marketplaces, however, I recall from using one in the past that the batteries are usually not removable by the user, to save space and make a thin camera (they are welded inside the body) – and therefore, batteries from this period might have ran out of juice or become damaged if I just bought any such model.

Given that over 30 different manufacturers made cameras that use disc film, I wonder if some of them were smart enough to design them to use regular, removable batteries.

These types of cameras are very under-documented across the internet.

## Complex polynomial mapping the closed unit disc to the closed unit disc.

The polynomial $$p(z)= z^n +a_{n-1}z^{n-1}+a_{n-2}z^{n-2}+…+a_0$$ maps the closed unit disc to the closed unit disc. Then prove that all coefficients of p(z) except the leading coefficient are zero.

I have no idea because Schwartz lemma can not be applied unless p(0)=0. Help please.

## hard drive – Cannot erase disc in disc utility before trade in

I am preparing my 2014 MacBook for a trade in. I followed the instructions that Apple sent but failed on the ‘turn FileVault off’ stage. I did this, but my prediction now is that at some point during the process my battery went flat as everything I’m reading implies that my disc is still encrypted.

I booted up into recovery mode to complete the Erase Hard drive and reinstall MacOS process.
Using Disc Utility I then erased the top disc it showed me – 251 GB Apple SSD SM0256F Media.

I then went to erase the 2nd disc it showed Mac OS X Base System (which shows 1.15GB used)
However I am unable to erase this in Disc Recovery. In the Erase tab the ‘erase free space’ / security options / erase buttons are all greyed out.

How can I erase this disc? Presumably this is what I need to reinstall MacOS as currently when I try to run reinstallation from disc recovery no disc shows in the installation dialog

Thanks so much

## complex analysis – Existence of conformal equivalence onto a disc

I am studying complex variables and trying to do the following question:

For what value(s) of $$cin(0,1)$$ does there exist a conformal equivalence from $$mathbb D-{zinmathbb C:|z-1/2|<1/4}$$ onto $$mathbb D-{zinmathbb C:|z|?

$$mathbb D$$ is the unit disk. I am not sure how to approach this question: the second set is a regular annulus, but the first set seems to be a disk with a portion missing that is off center. Thank you for any help or hint!

## connect wifi internet in external hard disc dur

I installed windows 10 on an external hard disc, this last is attached to my pc laptop via usb, while starting this pc I directly access the hard disc from boot (bios) so how can I connect on wifi internet from this hard disk, thank you in advance

## image processing – Open source Software to find and extract scanned negative frames from Kodak Disc and Minox negatives

I am looking for open source software that will find negatives on a sheet of scanned negatives and extract each one. Some of these negatives are Kodak disc, so the software needs to find rectangles of arbitrary rotation, rotate the images, and create new files. All of the rectangles are the same size.

This sounds like a capstone project in a computer science image processing course. It can’t be that hard to do, and it seems like a common request, but I haven’t found anything. If I can’t find the software, what are the building blocks that I would use to write it myself?

EDIT:

I found this blog post which provides a ksh script that uses trigonometry to compute the location of the disc images from three control points. This is super-cool, but you need to manually find the control points. And it doesn’t work with my other negatives, which are from a minox camera.

(For those who are interested, I am scanning the Minox images by laying them flat on my Epson flatbed scanner and covering them with a block of optical glass, and then using the scanner’s transparency mode.)

## windows 7 – Seagate serial ata disc drive – Data recovery

I have a Seagate Serial ATA Disc Drive (SATA) from my old Samsung laptop running Windows 7(internal drive). The computer had a faulty power Supply and would shut down randomly.
I would like to recover my data from this drive(very very important)
I tried using a Bridge but the drive was not detected, and I put it in my laptop and it wasn’t detected either.
Is there any way to recover the data from this drive
Thanks

## integration – Find the area of the part of the surface $z=ln (x^2+y^2+2)$ that lies above the disc $x^2+y^2 le 1$

Find the area of the part of the surface $$z=ln (x^2+y^2+2)$$ that lies above the disc $$x^2+y^2 le 1$$ by expressing the area in terms of a single integral

Let us suppose that the lateral surface area = $$S$$ between radius $$0$$ and $$1.$$

Equation of the surface, $$z = ln(x^2+y^2+2) = ln (r^2+2)$$

begin{align} S &= int_0^12pi r~ dl ,text { where dl is the arc length} \ & = int_0^12pi r sqrt{1+(frac{dz}{dr})^2}.dr \ & = int_0^12pi r sqrt{1+dfrac {4r^2}{(r^2+2)^2}}.dr \ & = int_0^1dfrac{2pi r}{r^2+2} sqrt{(r^2+4)^2-(2 sqrt 3)^2}.dr end{align}

Put, $$u = r^2+2 implies du=2r~dr$$ . Then:

begin{align} S & = int_2^3 dfrac{pi}{u}sqrt{(u+2)^2-(2 sqrt3)^2} .du \end{align}

Mathematica describes quite a complicated way of solving this integration. Could someone tell me an easier way of solving this.

## time machine – Terminal has Full Disc Access, yet I can’t change ownership of files on my external backup drive with sudo

After using Migration Assistant, the home directory ownerships in Time Machine backup got reversed, so now I can’t access my files but I can access the other user’s files. Not only that, I can’t modify the ownership with sudo even though Terminal has Full Disc Access.