Page 3 of 4 FirstFirst 1234 LastLast
Results 21 to 30 of 34

Thread: Converting Polaroid 250 camera to 4x5

  1. #21

    Join Date
    Nov 2017
    Location
    New Mexico
    Posts
    60

    Re: Converting Polaroid 250 camera to 4x5

    Part 7:
    Now that I have my ducks in a row for the tripping of the shutter, I have made the linkage to trip the shutter and allow the lens trip lever to return. As it turned out after hours of tring angles and dangles,I had to add a small return spring. Not a big deal as the force needed to always return the lens lever was slight. a Ball-Point pen spring would be more than enough.
    Click image for larger version. 

Name:	DSCF1882.jpg 
Views:	38 
Size:	58.7 KB 
ID:	175492
    Remember, you MUST always allow the lens trip lever to reset or you cannot re-cock the shutter.
    All speeds including "B" work as they should.
    All parts are at the same height as the cameras cast lens holder. The cover is fairly open and you do have some wiggle room it your parts are a little high. Your now are ready to finish the camera.
    For ecstatics I did use parts of the front cover. I used a mill to cut the casting but a good hack saw or coping saw can be used.
    All I wanted to cover was the tripping device and balance out the front of the camera. Nothing fancy,just for giggles.
    Click image for larger version. 

Name:	front cover.jpg 
Views:	33 
Size:	56.5 KB 
ID:	175493
    The cover pieces are held into place by the three long screws you saved. A dab of contact cement on the ridges will keep them from moving is bumped. Not really a big deal. As I said the cover is for looks.
    There are two "slits" in the covers for the original shutter and cocking levers. you can fill them in,or leave them alone.
    Click image for larger version. 

Name:	completed camera1.jpg 
Views:	49 
Size:	55.2 KB 
ID:	175494

  2. #22

    Join Date
    Nov 2017
    Location
    New Mexico
    Posts
    60

    Re: Converting Polaroid 250 camera to 4x5

    Part 8:
    The final part that needs to be made is the wooden Cut Film Holder spring back plate.
    All this does is to apply a force on the CFH to keep it in place and light tight. It must allow you to cam the CFH into/out of the CFH frame you made.
    I could have gone fancy with all brass fitting ha screws, but for this article I used what I had on hand. The city is a 50 mile round trip.
    The corners of the film back will have thumb screws and ligh springs. How light?.... 6 ounce compression force each. Just under two pounds of force total. That is all that is needed.
    All of the wooden parts are painted flat black. Walmart in it's hobby section sells little plastic four/six ounce Craft Paint for 50 cents a bottle. This paint will not flake off and seems to hold up very well.
    One bottle is more than enough for several coats of paint if needed.
    Click image for larger version. 

Name:	DSCF1891.jpg 
Views:	32 
Size:	62.8 KB 
ID:	175495
    What I did that is not mandatory,but cleans up the back of the camera, is to fill in the two gaps that used to hold the film pack. I just used scrap wood and glued it into place and covered what was left with 1/8" plywood.
    The camera is ready for use and it works well. I have only taken one exposure so far using X-Ray film and Microdol-X developer. I was trying an experiment that flopped but I got an interesting image.
    F:64- 5 second exposure. Microldol-x diluted 60:1. One hour stationary development.
    The silver halide grains clumped together giving the effect of almost Half-Tone images of a Newspaper. Hey, I tried.
    Click image for larger version. 

Name:	1stphotoB.jpg 
Views:	54 
Size:	101.8 KB 
ID:	175496
    The only disadvantage of this camera conversion is the close up minimum focusing distance. It is 43 inches. By your choice on lens you could do much better I'm sure.
    I hope you get the bug to do a conversion as I did. It was not hard and in total it only took me 14 hours to figure it out and get it right. It could be done to the extreme for unparalleled quality and beauty, but I just wanted a very light 4x5" camera that worked and did not cost as much as a used car.
    Oh yea, the camera is still under two pounds.
    Click image for larger version. 

Name:	DSCF1942.jpg 
Views:	32 
Size:	60.7 KB 
ID:	175499
    Click image for larger version. 

Name:	DSCF1943.JPG 
Views:	25 
Size:	90.3 KB 
ID:	175500
    With the tripod, meters,film holders, dark-cloth, cable release, bungee cord and bag to carry the equipment* I'm under 12 pounds! Man anyone could carry that a very long trek for that photo you must have.
    * tripod is very light. Carrying bag is hung from the tripod using the bungee cord and filled with stones or sand to keep it steady in a light wind.
    I hoping to use the camera for our very short lived waterfall this spring here in the desert. It's a long hike,all uphill,both-ways.
    Rob.

  3. #23
    Randy Moe's Avatar
    Join Date
    Dec 2011
    Posts
    9,997

    Re: Converting Polaroid 250 camera to 4x5

    We await your images.

    Good documentation.

    I want to make one!

  4. #24

    Join Date
    Mar 2013
    Posts
    5

    Re: Converting Polaroid 250 camera to 4x5

    Hi,

    I've been a long time reader of the forum, and inspired by Rob's original conversion I decided to try my own with a Land 340 and post (my first) a description. I've built a couple field cameras in the past, but none of those are handhold-able , and so I was really impressed by Rob's idea. I've also been looking for a cheap, light, handheld 4x5 camera for travelling, and considering those don't really exist - this conversion idea is perfect.

    Unlike Rob tho', I decided to keep the original lens and auto exposure, and use the camera as a sort of point-and-shoot 4x5 for the moment. I do have a Ysarex 127mm that I will probably end up attaching in future, but at the moment I'm enjoying the camera's simplicity of use. The conversion is very simple (and a little rough) but only took a couple days. Most of that time was spent waiting for parts to be delivered because it's impossible to source some of the bits need locally (very small town).

    Click image for larger version. 

Name:	DSC_0282.jpg 
Views:	36 
Size:	39.4 KB 
ID:	177226

    The back is made of a 2mm piece of mount board with 3 pieces of pine cut and glued to make the "U" shape. To attach it to the body of the polaroid, I filled the channels the original door closed in to with wood filler, which made it easy to glue the 4x5 back onto. I also attached a homemade wooden handle to make it easier to hold the new body shape. I originally had some light leaks where the pressure from the elastic wasn't quite strong enough to hold down the filter, but the green felt you see fixed that problem.

    Click image for larger version. 

Name:	DSC_0286.jpg 
Views:	47 
Size:	32.9 KB 
ID:	177227

    The reason I chose to use the elastic is that I have also made a 6x9 roll film adaptor (for a normal 6x9 Rada back that I already have), which wouldn't have fit under a back similar to Rob's. I'm hoping to think of a better solution in the future, but for now this works ok and the camera is usable.

    As I mentioned before the biggest difference with my conversion is that I kept the original lens and auto exposure. To add the 4x5 back the film plane was moved back a few cm which obviously meant the original 114mm wouldn't focus at infinity. To solve this, and after some trial and error, I attached a -1 dioptre (the power of which depends on exactly how far back you move the film plane) to the front of the lens using a 27-37mm step up ring and then gluing the dioptre to the front of that. It also has the advantage of allowing me to use normal filters on the front rather than the polaroid type made specifically for this camera, which are rare and expensive. To do this I also had to convert the camera to use 3 x AAA batteries, which are now housed outside the body in an adaptor that's stuck to the base of the body. This is necessary because the 4x5 back would cover the original battery housing making it impossible to change the batteries.

    Modifying the focal length like this has also meant that the lens will cover a 4x5 neg.

    Click image for larger version. 

Name:	DSC_0288.jpg 
Views:	35 
Size:	24.2 KB 
ID:	177228
    Click image for larger version. 

Name:	DSC_0287.jpg 
Views:	35 
Size:	31.5 KB 
ID:	177229

    I calibrated the rangefinder by turning a spare holder into a makeshift ground glass, which I can also use as a plate holder in future. It's a little harder calibrating the rangefinder than I had anticipated, but after a couple test shots it's getting there.

    I've also made a cable release that fits over the original shutter button which, along with the cap for the magic eye, gives me a bulb setting for focusing (with the gg) or timed exposure. At the moment I'm using standard film holders, but I'm hoping to get a grafmatic, which should make the camera even better for travelling. Unfortunately they seem to be very rare here in the UK, so it may be a while.

    I've managed to take a few shots with the camera, and it's as simple to use as I'd hoped. It's feather light, the rangefinder and auto exposure is accurate enough, and I've managed to make a couple lith prints from the resulting negatives already.

    So I'd finally like to thank Rob for the idea and inspiration

    Dafydd

  5. #25

    Join Date
    Nov 2017
    Location
    New Mexico
    Posts
    60

    Re: Converting Polaroid 250 camera to 4x5

    That is really cool! I plan to really use my camera if this darn wind ever stops.

  6. #26

    Join Date
    Mar 2013
    Posts
    5

    Re: Converting Polaroid 250 camera to 4x5

    thanks, and I'm having a similar problem at the moment.
    I have a couple sheets of slide film I'd like to use to give the auto exposure a real test, but spring is really late this year, so everything is still just grey and brown.

  7. #27

    Join Date
    Nov 2017
    Location
    New Mexico
    Posts
    60

    Re: Converting Polaroid 250 camera to 4x5

    The winds have died down. I loaded up some Fuji X-Ray film and did a shot of a cactus in my yard. I wanted to check for light leaks and the lens depth of field. The closest the lens will focus with the cameras bellows is 4 feet. I placed the camera 3 1/2 feet away and used F:11 to see what the image would look like. No dark cloth,nor ground glass,just the range finder was used.
    I'm still experimenting with development times and tray agitation. I had been using 9 minutes as a development time, this time I tried 15 minutes with no agitation after a five second wetting of the film. This proved to be too long but I did get an interesting film. I do not own a film scanner as yet that will take a 4x5 negative.
    Click image for larger version. 

Name:	Cactus2A.jpg 
Views:	35 
Size:	76.4 KB 
ID:	177848

  8. #28

    Join Date
    Nov 2017
    Location
    New Mexico
    Posts
    60

    Re: Converting Polaroid 250 camera to 4x5

    Now it time to play with my X-Ray film for correct exposure and development times.
    My old tractor, 2 seconds F:45, Microdol-X for 12 minutes agitation 5 seconds every 60 seconds.

    Click image for larger version. 

Name:	truck3.jpg 
Views:	16 
Size:	86.1 KB 
ID:	177902

    Click image for larger version. 

Name:	truck1.jpg 
Views:	18 
Size:	54.1 KB 
ID:	177903

    Click image for larger version. 

Name:	tractor1.jpg 
Views:	16 
Size:	90.4 KB 
ID:	177904
    Last edited by Rapidrob; 3-May-2018 at 17:14.

  9. #29

    Join Date
    Mar 2013
    Posts
    5

    Re: Converting Polaroid 250 camera to 4x5

    looks like your camera is working well, and your focusing seems accurate : )
    I'm currently travelling with mine in Lisbon and it's working great, well it seems to be, but I guess I won't know really until I get home.
    But I will have to redesign the back a bit, it's a bit awkward to load the roll film back when on the move quickly.

  10. #30
    ic-racer's Avatar
    Join Date
    Feb 2007
    Posts
    5,013

    Re: Converting Polaroid 250 camera to 4x5

    I have a 250 also, but I use it as an alternative to a pack-film back on my 4x5 camera.

Similar Threads

  1. Replies: 24
    Last Post: 28-May-2018, 18:47
  2. Converting Polaroid 800 to 4x5
    By Bob Farr in forum Cameras & Camera Accessories
    Replies: 2
    Last Post: 26-Sep-2012, 11:32
  3. Converting a B&J Enlarging/Reducing camera into an enlarger
    By mccolalx in forum Darkroom: Equipment
    Replies: 2
    Last Post: 9-Apr-2012, 23:19
  4. Converting Polaroid Scale for G-Claron
    By G Benaim in forum Lenses & Lens Accessories
    Replies: 6
    Last Post: 30-Jan-2008, 06:40
  5. Converting a 4x5 view camera to a......
    By omanoman in forum Cameras & Camera Accessories
    Replies: 61
    Last Post: 11-Apr-2007, 23:28

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •