20x24 Paper Negative Camera and Selecting Edmund Scientific Meniscus Lenses

[Mustafa Umut Sarac]

Hello there,

I want to take my mother and sisters portraits with 20x24 Fomabrom Grade 3 Matte Paper Negatives and contact on to the same paper.
There are 10 papers for 70 dollars at Freestyle and I can shoot only 5 frames.
I have no enlarger or timer and will use Edward Weston bulb lamp enlarging and rabbit hat shutter method.
I looked to the Edmund Scientific and there are meniscus lenses , same focal distance , different diameter.
What is the difference between large diameter lens and narrower second , third best.

AND Do I need to buy negative meniscus or positive meniscus lens ?

50mm Dia. x -505mm FL, Negative Meniscus Lens, Grade 2

36.5mm Dia. x 444.4mm FL, Positive Meniscus Lens, Grade 1

76.7mm Dia. x 324mm FL, Positive Meniscus Lens, Grade

58.5mm Dia x 350mm FL, Positive Meniscus Lens, Grade 1

http://www.edmundoptics.com/optics/optical-lenses/specialty-lenses/experimental-quality-positive-meniscus-lenses/3479

Umut

[Mustafa Umut Sarac]

88mm Dia. x 750mm FL, Positive Meniscus Lens, Grade 2

47mm Dia. x 700mm FL, Positive Meniscus Lens, Grade 1

I think these are the suitable ones for 24 inches , which is better grade 1 or 2 ?

And 40 or 80 mm diameter , what do you advise ?

Are Positive ones the suitable ones ?

Umut

[ic-racer]

Do you already have the 20x24 camera? If so, how much bellows draw is available?

[Mustafa Umut Sarac]

Do you already have the 20x24 camera? If so, how much bellows draw is available?

Hello ic-racer , I can build a box , glass and paper holder. All fixed , all focus would be done to move the box. No bellow , no movement.

Umut

[jp]

You want positive meniscus, One of the longer focal lengths. I'd suggest going for a larger diameter glass and putting a washer stop in front of it.
Chop up one sheet of paper for experimenting / testing exposure, focus, filtration, etc..

[Mustafa Umut Sarac]

Thank you very much jp.

I tried but shipping 35 euros for single element lens , rip off , I need other source.

Umut

[Randy]

Umut, try a lens from an unused set of eye glasses / reading glasses. I just did a crude test on my reading glasses on a light bulb that was about 3 meters from a wall and my glasses cast a sharp image at about 1 meter from the wall - so at about portrait distance, my glasses have a F/L of about 1000mm. My glasses are fairly week - shouldn't be to hard to find some stronger that should have a shorter F/L...I think.

[Tim Meisburger]

+1 has a FL of 1000mm. +2 500mm. +3 250mm.

Check with a local optician and see if they have round lens blanks in the fl you are looking for.

[Fr. Mark]

close-up lenses that screw on like filters are in diopters and I think they are also the focal lengths/markings mentioned in the previous post. I think they're pretty inexpensive, too. Thanks for the reminder about this, actually, I may try it for long lens with my camera(s).

[ic-racer]

Hello ic-racer , I can build a box , glass and paper holder. All fixed , all focus would be done to move the box. No bellow , no movement.

Umut

Ok, so you need to determine, either how far you want to be from your subject (your perspective for the picture) or how big you want the image on the paper negative.

Then you can use the 'thin lens equation' to determine your box size and lens strength.

As mentioned, you can convert your lens measured in 'diopters' to 'millimeter focal length' by knowing 'diopter' is the reciprocal of 'focal length' in meters.

2 diopter = 0.5m focal length etc.

For the sake of simplicity , lets say you want the head to be the same size as real life on your 20x24 paper negative. So in that case your box size will be twice the reciprocal of the diopter strength of your lens. The subject distance will also be the same.

So for full size head image on film with a "+1 Diopter" close-up lens your box needs to be 2000mm long and your subject will be 2000mm in front of the lens. etc.

If 2 meter subject distance produces unpleasing perspective to you, you can change that to, for example , 3 meters.

Then your box only needs to be 1500mm long, and the head will be 1/2 size on the paper negative, etc.

http://www.ebay.com/itm/46mm-Macro-Close-up-1-Lens-Filter-46mm-Close-Up-No-1-/320442406605?pt=LH_DefaultDomain_0&hash=item4a9bdb16cd

[salomons]

Hi, I had a similar project in mind and stumbled across this thread while doing research. Did you build the camera ? Can you share some images ? and some of the results ?. Many thanks

[Jim Jones]

Salomons -- Do some tests with any photo paper you hope to use for negatives to be contact printed. Many paper negatives impart a strong texture on the print. A simple positive meniscus lens similar to today's diopter close-up lens attachments was used in a few of the earliest cameras and more recently in simple box cameras. In this application they were often called landscape lenses. When used at small apertures, they were fairly satisfactory for contact prints. A book on photographic optics should have some information on how best to use them.

[Fr. Mark]

There's a book out there called primitive photography, I think, which has quite detailed instructions on making use of simpler lenses incl. meniscus lenses.

See reinvented equipment for a commercial source ready to use for LF cameras. Not v expensive for the coverage.

Once I re-find them (we moved recently) I hope to stick a close up lens on a Sinar lens board and play with some cardboard or plastic apertures to see what the images look like and if I like them well enough. It might be fun to have 1000mm (1 diopter) and 500mm (2 diopter) lenses for the 5x7 and 8x10 on the way to giant cameras.

[salomons]

Thnaks. A year and a half ago I built a box cam to try direct positive paper. Which led me down the slippery slope of buying a Palubel 8x10 on which i shoot Impossible
145265

But, I am still fascinated by life-size 1:1 portraiture. hence the questions. I was thinking to build another boxcam, and if it works, to build a 20x24 that is foldable / transportable. Am therefore interested in the build details of Mustafa's, or anyone other's box cam. Any insights would be appreciated

[Bernard_L]

Umut, this looks like your first attempt at building a camera. You should read some basic optics texbook (negative versus positive lens; basic lens equation 1/f=1/d1+1/d2, etc). Maybe you should start with a smaller format, like 4x5": mistakes are inevitable in the beginning, and with a smaller format they will cost less.

Completely fixed focus is an interesting idea, but... you close the door to making other pictures, landscapes and cityscapes. Such subjects probably have more patience than your family members for repeated tests.

Why do you buy Foma paper from Freestyle (USA?, does your price include shipping?) when it is available in Europe, e.g. from fotoimpex?

Do you have some drawings for your camera? Will you keep us informed of the progress of this project?

[ruilourosa]

Hello

You can use a close up! it´s the best route... you can even combine 2 in a symetrical way and cut off distortion. If you use two +1 you will have a 500mm. Separation between the two should be around one diameter. In between you can use a whaterhouse stop.

Beware the paper, the thicker the negative the grainier the positive... i would bet on a cheap glossy RC paper for negative, contrast could be tweaked by colour temperature or filtering the light. Use a diffuse lamp for contact proofing, it minimizes paper grain, a Talbot hint.

Rui lourosa

[pdh]

Hi, I had a similar project in mind and stumbled across this thread while doing research. Did you build the camera ? Can you share some images ? and some of the results ?. Many thanks

I believe that since the OP started the thread, his mother has passed away and he may never have got round to the project.

However, a few people have built inexpensive box or sliding box cameras (I'm one, and some details are here http://www.apug.org/forums/forum147/129594-lf-box.html). I took my cue from a chap called Graham Vasey (a rather good LF photographer) who had done something similar (tho' more sophisticated than mine). He publishes a blog and there are some details there - grahamvasey.wordpress.com I think.

I've also made an LF camera out of a cardboard box, using a lens made from a broken pair of spectacles and half a condenser lens.

A camera, after all, is no more than a black box with a hole to let in light at one end, and some sensitive material at the other.

Also have a look for online articles by a chap called Jon Grepstad.

[Ray Heath]

G'day all

I've been building sliding box simple lens cameras and film holders for about 10 years.

Just have a go.

145302
My cameras December 2015.

145303
A local scene about 12 months ago.

[Fr. Mark]

Wow! You combined two of my favorite things in one post: home built cameras and dairy cows!

I built a similar looking pinhole 8x10 to use some old 8x10 holders. I've never been totally happy with my own pinhole work.

Now you've got me thinking of modifying it to use a simple lens well stopped down, but still faster exposures than a 8x10 with 8" (200cm) focal length. This would not be a sliding box, it'd be a point and shoot fixed focal length.

I sometimes bring home junk lenses from the local camera shop and take them apart to have the elements to play with, I might have something suitable...