Orientation of the meniscus lens in a simple box camera

james orme · Jul 7, 2020

So I broke up the Box Brownie but couldn't release the lens from inside the boards, guess after over 90 years it solidified a bit... (pic below). Still, it got a good clean and will put it back together.

The mock up cardboard box now has the lens in a pipe coupler (thanks Donald/ Nodda) and a 6mm aperture (from a hole punch) with a variable distance between them both. 1st attempt- classic mistake: put the meniscus lens the wrong way around (I know some people do this on purpose). 2nd try very happy with size of the image as it easily covers 8" x 10" need to work on the focus but not bad. Now going to try 42 mm between stop and lens before I build an actual wooden box. Been reading up about the Wollaston lens... all new to me, great stuff !

Thanks all.

Donald Qualls · Jul 7, 2020

I can't zoom in on that picture, but many of those cameras had the lens retained by a simple spring ring -- literally just a circle of wire with a gap to allow compressing it, sized to be tight inside the hole. If that's the case, a heavy pin or O-ring pick will usually let your pry the ring away from the wall of the hole and then you can get a hook or screwdriver tip under it and lift it out.

Once you're done cleaning the lens and hole, you can drop the lens back in (right way around, please), compress the ring a bit to start it in the hole, then push it down against the glass with a screwdriver tip.

james orme · Jul 28, 2020

So the box is built and I did a very rough test. The stop is approximately 40mm in front of the lens. I am going to make the stop distance shorter for the next test in the hope there will be less vignetting/ the projected circlular image will be slightly larger (?). The whole 10x8 'negative' isn't covered (the whole point was that I wanted to get a higher res photo to blow up- larger than the Box Brownie version).
The tracing paper on glass view/ focus test was tricky but it helped a bit.

Anyway I will post an image within the week. Surprised though that I got a reasonable image at all- and the focus ain't bad !

Cheers and thanks to all again. _J

Donald Qualls · Jul 28, 2020

If that's the lens out of the 2A Box Brownie, you may find it doesn't cover much if any more area than the original film. That's kind of the way they decided focal length for those box cameras: how big is the image circle?

It's likely the same stop size and separation as in the original camera will be very close to optimum for that lens in terms of image quality and image circle size.

james orme · Jul 28, 2020

Thanks Donald, I was trying to make a larger version of a Box Brownie. When I was told that these types of lenses were available (and cheap) I got the 40mm Dia. meniscus lens (238mm FL) - probably a mistake but that's what I've got to work with. However I have leaned on this forum it is still a Wollaston landscape set-up - so can't be bad...

Donald Qualls · Jul 29, 2020

Okay, I didn't reread the thread. A 238mm meniscus should just about cover 8x10 when you have the correct aperture setup. That's an f/6(ish), so stopping down to f/11 to f/16 (f/13 was common) should be about right. Your 6mm aperture is more like f/40, so probably a little small. If it's at the correct distance, it shouldn't vignette, but if the standoff is off a little, it will. You might be able to see the effect, if you can set up a ground glass and adjust the aperture standoff while viewing (in bright light) -- but first, it'd probably be better to expand your hole to about 16mm (f/15.5, which will also make the ground glass image a lot brighter), or at least 11-12 mm (f/22-ish, not as bright but more DOF, makes hyperfocal more useful).

james orme · Jul 29, 2020

Great, thanks for that. I used a paper hole punch on some beer can metal that's why the aperture came out that particular size- all a bit lo-fi... I thought the smaller aperture might help with the focus. I will use a larger aperture right now and might also bring the stop a bit closer to the lens. I used tracing paper on glass to do a focus test which kind of worked but it was a real hassle and the paper was too opaque. I have also nailed the thing up so it's trial and error now. Here's the cropped 5 hour exposure test from yesterday, you can see sun trails reflected on the cars.

Nodda Duma · Jul 29, 2020

Looking nice!

james orme · Jul 29, 2020

Thanks- I only have at hand a 9mm washer which looks substantially bigger than the previous stop. Will set up now and see what happens...

Donald Qualls · Jul 29, 2020

Let's see, 9mm should be about f/27, still on the small side, but likely to improve things some -- as well as shortening your exposure by about half (f/27 is one stop faster, roughly, than f/40).

james orme · Jul 29, 2020

It's out in the street now, in terms of conspicuousness it ain't exactly a rangefinder... Will get a larger washer tomorrow.

james orme · Jul 29, 2020

Here's today's 3 hour exposure with a 9mm washer. I think I might have gained a bit of coverage of the negative but lost some focus. This could also be because I reduced the distance from stop to lens. It was at the point of becoming over exposed and I am wondering if (for the purpose of this project) that I might have to revert to the 6mm hole punch... sacrificing coverage for clarity/ focus.

james orme · Jul 29, 2020

Here are a couple of the original project shots from a Box Brownie 2 and a Box Brownie 2A which obviously have smaller 'negatives' 2.5 : 4.25 inches and 2.25 X 3.25 respectively...

Thanks all

Bud Hamblen · Aug 4, 2020

You can tell by eye if you've got vignetting, Look through the lens from the back corners of the camera. If the aperture is cut off you'll get vignetting.

james orme · Aug 4, 2020

Thank you- that really makes sense. Will check in the morning. Last photo, which I haven't posted, wasn't great. A downside is that the thing is really quite heavy...

tezzasmall · Aug 5, 2020

NedL said:
It has become a fad to take advantage of this and "flip" the lens in a Kodak Brownie Hawkeye, which is a fixed focal length camera.

bvy said:
Blurred edges too...

I've never been one to follow fashion and fads, so fad or not, I have a Box Brownie that is going to get this treatment really soon, as I just love the blurred edges look!

Terry S

james orme · Aug 5, 2020

Cool. Here's a really bad photo (from the home made box- large meniscus lens) - the paper negative wasn't attached properly and there are a few light leaks that I need to gaffer tape up. The sun really burned through, have to change aperture or maybe use a ND filter.. will post a better (hopefully) photo next week with a few tweaks and sign off from this thread -with a lot of thanks !

.

james orme · Aug 5, 2020

Apols - you were talking about lens flipping, I did this by mistake in one of the earlier try outs...

Orientation of the meniscus lens in a simple box camera

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